Progress 10/01/11 to 09/30/12
Outputs
OUTPUTS: Semi-hardwood or hardwood stem cuttings of Ilex vomitoria Sol. ex Ait. Dare County [Dare County yaupon holly (syn. Virginia Dare yaupon holly] were treated with solutions of the potassium (K) salt (K-salt) of indolebutyric acid (K-IBA) at 0 to 8000 ppm. Nontreated semi-hardwood cuttings rooted at 78% whereas, regardless of auxin treatment, hardwood cuttings taken on two dates rooted at less than 15%. Treatment of cuttings with K-IBA was generally ineffective and resulted in a linear decrease in percent rooting of semi-hardwood cuttings. PARTICIPANTS: Nothing significant to report during this reporting period. TARGET AUDIENCES: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
Ilex vomitoria Sol. ex Ait. (Aquifoliaceae Bartl.) (yaupon, cassena, Christmas berry or evergreen holly) is a dioecious, evergreen species, native from southeast Virginia to central Florida and west to Oklahoma and Texas. Growth habit can vary from a small to a large upright shrub or a small tree. New growth in the spring has a purple cast that is soon lost becoming a lustrous dark green. One outstanding cultivar of I. vomitoria is a female selection, Dare County (syn. Virginia Dare). Dare County yaupon holly is a stiff and divergently large shrub or small tree. As a tree it can reach heights greater than 7 m with a spectacular fall and winter fruit display of reportedly orange drupes that persist into spring. Despite having considerable landscape merit, little if any information has been published regarding propagation of this cultivar other than it can be propagated by stem cuttings. Propagation studies indicated nontreated semi-hardwood cuttings rooted at 78% whereas, regardless of auxin treatment with the potassium (K) salt (K-salt) of indolebutyric acid (K-IBA) at 0 to 8000 ppm, hardwood cuttings taken on two dates rooted at less than 15%. Treatment of cuttings with K-IBA was generally ineffective and resulted in a linear decrease in percent rooting of semi-hardwood cuttings.
Publications
- Lambert, C.R., Blazich, F.A., and LeBude, A.V. 2012. Propagation of Ilex vomitoria Dare County by stem cuttings. J. Environ. Hort. 30:55-57.
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Progress 10/01/10 to 09/30/11
Outputs
OUTPUTS: Nontreated softwood cuttings of Variegatus osmanthus [Osmanthus heterophyllus (G. Don) P.S. Green Variegatus] collected in early June 2009 and late May 2010 rooted at greater than 70%. Treatment of cuttings with solutions of the potassium (K) salt (K-salt) of indolebutyric acid at 500 to 2000 ppm was generally ineffective and does not appear to be necessary for satisfactory rooting. PARTICIPANTS: Nothing significant to report during this reporting period. TARGET AUDIENCES: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Variegatus osmanthus [Osmanthus variegatus (G. Don) P.S. Green Variegatus (Oleaceae Hoffmanns. and Link)] is one of many cultivars of Osmanthus heterophyllus (holly tea olive, holly osmanthus, false holly). The cultivar is an extremely attractive, slow growing, evergreen shrub having leaves similar in morphology to the species. However, what makes Variegatus so attractive is the creamy white margins on the leaves. The striking foliage and the upright growth habit contribute to it being an outstanding landscape plant that can reach heights greater than 3 m. The various cultivars of O. heterophyllus are generally propagated by stem cuttings but propagation information regarding particular cultivars such as Variegatus is lacking. Propagation studies indicated the most consistent rooting (greater then 70%) of Variegatus osmanthus is achieved with nontreated softwood cuttings collected in late May to early June. Auxin treatment of softwood cuttings does not stimulate rooting and is unnecessary. Rooting of semi-hardwood cuttings is variable from year to year, and rooting of hardwood cuttings is negligible.
Publications
- Hibbert-Frey, H., Frampton, J., Blazich, F.A., Hundley, D. and Hinesley, L.E. 2011. Grafting Fraser fir (Abies fraseri): Effects of scion origin (crown position and branch order). HortScience 46:91-94.
- Lambert, C.R., Blazich, F.A. and LeBude, A.V. 2011. Propagation of Osmanthus heterophyllus Variegatus by stem cuttings. J. Environ. Hort. 29:204-206.
- Laing, J.M., Shear, T.H. and Blazich, F.A. 2011. How management strategies have affected Atlantic White-cedar recovery after massive wind damage in the Great Dismal Swamp. Forest Ecol. Mgt. 262:1337-1344.
- Rounsaville, T.J., Touchell, D.H., Ranney, T.G. and Blazich, F.A. 2011. Micropropagation of Mahonia Soft Caress. HortScience 46:1010-1014.
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Progress 10/01/09 to 09/30/10
Outputs
OUTPUTS: Seeds from five populations of Rhododendron vaseyi A. Gray (pinkshell azalea), representing the entire native distribution of the species, were germinated at 25C or an 8/16-hr thermoperiod of 30/20C with daily photoperiods at each temperature of 0 (total darkness),8,12, or 24 hr (continuous light). Germination was recorded every 3 days for 30 days. Responses to light and temperature of all populations were similar. Light was required for germination regardless of temperature. As photoperiod increased, germination increased for all populations with the alternating temperature partially compensating for the light requirement. The highest cumulative germination for all populations ranged from 51% to 67% and was achieved at 30/20C with a 24-hr photoperiod. These germination percentages, although at a moderate level, were due in part to rigorous cleaning and grading of seeds collected across a broad range of plants and growing conditions prior to initiation of the study, suggesting seed viability of R. vaseyi is inherently low. PARTICIPANTS: Nothing significant to report during this reporting period. TARGET AUDIENCES: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
Rhododendron vaseyi A. Gray (pinkshell azalea) is a rare, deciduous, ericaceous species endemic to six counties in western North Carolina at elevations above 914 m. It flowers from May to June producing clusters of fragrant pink to white flowers. The attractive spring flowers, excellent deep burgandy fall color, and exfoliating bark of the species make it an appealing landscape plant, especially popular among native-plant enthusiasts. Rhododendron vaseyi is often sold by local (western North Carolina) or mail-order nurseries that propagate the plants by either seeds or to a lesser extent by stem cuttings. Data were generated regarding the effects of light and temperature on germination of seeds of R. vaseyi from five populations in western North Carolina. Seeds from plants across the entire native distribution responded similarily to light and temperature treatments. Rigorous cleaning and grading techniques combined with a liberal application of seeds to a germination medium can compensate for low viability and help produce a uniform stand of seedlings. Small seed size plus the light requirement for germination dictates that seeds should simply be dusted on the surface of a germination medium, and be exposed to an 8/16 hr thermoperiod of 30/20C with a 24-hr photoperiod (continuous light). These conditions will maximize germination, which should begin 9 to 12 days after sowing and be nearly complete by 24 days.
Publications
- Hebert, C.J., Blazich, F.A., and LeBude, A.V. 2010. Seed germination of five populations of Rhododendron vaseyi. J. Environ. Hort. 28:166-172.
- Hibbert-Frey, H., Frampton, J., Blazich, F.A., and Hinesley, L.E. 2010. Grafting Fraser fir (Abies fraseri): Effect of grafting date, shade, and irrigation. HortScience 45:617-620.
- Lowder, A.W., Kraus, H.T., Blazich, F.A., and Warren, S.L. 2010. Day/night temperatures influence growth and photosynthesis during containerized production of selected species of Helleborus (hellebores). J. Environ. Hort. 28:179-186.
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Progress 10/01/08 to 09/30/09
Outputs
OUTPUTS: Containerized seedlings of eastern redbud (Cercis canadensis L.) were grown in a greenhouse for 10 weeks with nitrogen application rates (NARs) ranging from 0 to 300 mg/liter. Seedlings fertilized with nitrogen (N) at 180 mg/liter had the greatest leaf area, leaf dry weight, and total plant dry weight. Plants allocated more resources to root growth at NARs less than 60 mg/liter. At NARs equal to or greater than 60 mg/liter, allocation of carbon to roots and tops was constant, with a root:top ratio of 0.25. Foliar concentrations of N, phosphorus, and sulfur increased linearly with increasing NAR while concentrations of potassium were not affected by NAR. Foliar concentrations of calcium and magnesium responded quadratically with minimum concentrations at 240 and 180 mg/liter, respectively. Boron also responded quadratically with maximum concentrations predicted at a NAR of 175 mg/liter. Concentrations of copper decreased linearly with NAR. Foliar iron, manganese (Mn),and sodium were not significantly affected by NAR. Foliar Mn concentrations were generally low and approached critical levels. Based on observed growth and the concentrations of various mineral nutrients, we conclude that during the first season of growth containerized eastern redbud should be fertilized with N at 180 mg/liter per daily irrigation. PARTICIPANTS: Nothing significant to report during this reporting period. TARGET AUDIENCES: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
Eastern redbud (Cercis canadensis L.) is grown commonly in the nursery industry, and optimun mineral nutrition is necessary to reduce grower costs and to minimize unwanted impacts to the environment. Results of this study demonstrated that during the first season of growth, containerized eastern redbud should be fertilized with N at 180 mg/liter per daily irrigation. Nitrogen rates above or below 180 mg/liter reduced growth. Plants grown with N rates less than 60 mg/liter, compared to plants grown at higher rates, allocated more resources to root growth. At N rates greater then 60 mg/liter, the root:top ratio was 0.25.
Publications
- Wooldridge, J.M., Blazich, F.A., and Warren, S.L. 2009. Propagation of eastern redbud (Cercis canadensis) by stem cuttings is influenced by clone and date of cutting collection. J. Environ. Hort. 27:109-114.
- Wooldridge, J.M., Blazich, F.A., and Warren, S.L. 2009. Propagation of selected clones of eastern redbud (Cercis canadensis) by stem cuttings. J. Environ. Hort. 27:12-16.
- Wooldridge, J.M., Warren, S.L., and Blazich, F.A. 2009. Nitrogen nutrition of eastern redbud (Cercis canadensis). J. Environ. Hort. 27:223-228.
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Progress 10/01/07 to 09/30/08
Outputs
OUTPUTS: Rooted stem cuttings of Snow White raphiolepis(Raphiolepis x delacourii Andre cv. Snow White) were grown in 3.8-liter black plasic containers containing a pine bark:sand (8:1, by vol.) substrate. Plants were fertilized at every irrigation, for 17 weeks, with a 4:1:2 nitrogen(N):phosphorus(P):potassium(K) nutrient solution containing N at 20, 60, 100, 140, 180, 220, or 240 mg/liter(ppm) supplied as ammonium nitrate. Maximum top and root dry weights were achieved with N at 145 mg/liter. Substrate solution electrical conductivity increased linearly with increasing nitrogen application rate(NAR) with maximum growth occurring at 1.28 dS/m, whereas substrate solution ph decreased linearly with increasing NAR with a pH of 5.3 at 145 mg/liter. Increasing the N rate beyond 145 mg/liter had minimal effect on top or root dry weight. Leaf area peaked at a NAR of 171 mg/liter with a plateau at 524 square centimeters. Leaf area increased 275% as the NAR increased from 20 to 171 mg/l. Specific leaf area increased linearly with increasing NARs. Carbon allocation between tops and roots was unaffected by NARs from 60 to 280 mg/liter. Root:top ratio decreased 56% between the pooled NARs(60 to 240 mg/liter and N at 20 mg/liter. Leaf area ratio increased linearly with increasing NARs. Foliar mineral nutrient concentrations of N, P, and sulfur increased linearly with increasing NAR, whereas concentrations of K, calcium, magnesium, and copper responded quadratically to increasing NARs. Top growth increased from inadequate at a NAR of 60 mg/liter to optimum at 145 mg/liter, whereas root growth was relatively similar over the same range. At 145 mg/liter mineral nutrient concentrations of the top are well within or exceed accepted levels reported, and growers can expect rapid growth of rooted cuttings. PARTICIPANTS: R. L. Lyons is no longer a cooperator regarding this project. TARGET AUDIENCES: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
Although Snow White raphiolepis has become a popular cultivar, specific nutritional guidelines for containerized culture of Snow White are unavailable. Results of this study will allow development of a more efficient means of production where growth can be optimized with lower nutrient applications. This would not only decrease fertilizer costs, but help reduce nutrient runoff issues. Increasing fertilizer concentrations of nitrogen(N) beyond 145 mg/liter(ppm) applied every other day neither improved top growth nor proved detrimental to root growth. Under these conditions, N at 145 mg/liter provided by a fertilizer having a 4N:1P:2K ratio with a corresponding electrical conductivity of 1.28 dS/m was considered optimal for growth of Snow White raphiolepis.
Publications
- Hinesley,L.E. and Blazich, F.A. 2008. Improving early field growth of Leyland cypress liners by grading and potting. J. Environ Hort. 26:35-38.
- LeBude, A.V., Blazich, F.A., Walker, L.C., and Robinson, S.M. 2008 Seed germination of two populations of Rhododendron vaseyi: Influence of light and temperature. J. Environ. Hort. 26:217-221.
- Tillman, A.L., Warren, S.L., and F.A. Blazich. 2008. Optimum nitrogen fertilization for production of containerized Raphiolepis x delacourii. J. Environ. Hort. 26:157-163.
- Wooldridge, J.M. 2008. Propagation by stem cuttings and nitrogen nutrition of eastern redbud(Cercis canadensis). MS Thesis, N.C. State Univ., Raleigh.
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Progress 10/01/06 to 09/30/07
Outputs
OUTPUTS: Seeds of southern seaoats(Uniola paniculata L.) were removed from storage in July 2004, surface disinfested with 2.6% sodium hypochlorite(NaOCl) for 15 min, and sown in styrofoam tobacco(Nicotiana tabacum L.) float trays(flats) filled with a vermiculite-based hydroponic substrate. Trays were floated in plastic tubs(one tray per tub) containing a complete nutrient solution with nitrogen(N) at 10, 60, 120, 180, or 240 mg/liter from a 2N-3.5P-1K ratio(8N-32P205-5K20) liquid slow-release fertilizer. After 10 weeks the study was terminated and data recorded. Total plant, top, leaf, stem, and root dry weights increased quadratically with increasing nitrogen application rate(NAR) with maximum dry weights calculated to occur with N at 140 to 150 mg/liter, respectively. Other growth indexes of leaf area, root length, root area, plant height, crown growth index, tiller number, and leaf number also increased quadratically with increasing NAR similar to dry weight data. Leaf area, root
length, and root area were maximized with N at 157, 140, and 140 mg/liter, respectively. Root to top ratio and specific leaf area were both unaffected by NAR. Leaf mineral nutrient concentrations of N and phosphorus responded quadratically with increasing NAR whereas, foliar mineral nutrient concentrations of potassium, calcium, sulfur, sodium(Na), manganese, zinc, and copper responded linearly to increasing NARs. With the exception of Na and iron, foliar nutrient content for all analyzed nutrients increased quadratically with increasing NAR. Calculated leaf N concentration at maximum top dry weight was 31 mg/liter. Southern seaoats can be grown successfully using the float system with optimum N rates of 140 to 150 mg/liter provided by a fertilizer having a 2N-3.5P-1K ratio.
PARTICIPANTS: R. L. Lyons is no longer a cooperator on this project.
Impacts
Transplants of southern seaoats (Uniola paniculata), a major coastal dune stabilizing species of the southern Atlantic and Gulf Coasts of the United States, are curently in great demand. However, research on culture has been limited particularly with respect to mineral nutririon. Results of this research demonstrate that southern seaoats can be produced successfully using the float system and nitrogen in the nutrient solution at 140 to 150 mg/liter will maximize vegetative growth. Use of the float system for production of transplants could provide opportunities for former and current tobacco(Nicotiana tabacum) farmers to produce alternative crops using the float system. Production of the species may also provide an additional means to supplement farm incomes.
Publications
- Lasseigne, F.T., Warren, S.L., Blazich, F.A., and Ranney, T.G. 2007. Day/night temperature affects growth and photosynthesis of cultivated Salvia taxa. J. Amer. Soc. Hort. Sci. 132:492-500.
- Norden, D.S. 2007. Development of protocols for containerized production of seabeach amaranth(Amaranthus pumilus) and nitrogen nutrition of southern seaoats(Uniola paniculata) grown in the float system. M.S. Thesis, N.C. State University, Raleigh.
- Norden, D.S., Blazich, F.A., Warren. S.L., and Nash, D.L. 2007. Seed germination of seabeach amaranth(Amaranthus pumilus) in response to temperature, light, and gibberelin A3 treatments. J. Environ. Hort. 25:105-108.
- Wright, A.N., Warren, S.L., and Blazich, F.A. 2007. Effect of root-zone temperature on survival, growth, and root morphology of Kalmia latifolia and Ilex crenata 'Compacta'. J. Environ. Hort. 25:73-77.
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Progress 10/01/05 to 09/30/06
Outputs
Seeds of seabeach amaranth(Amaranthus pumilus Raf.), a species federally listed as threatened, stored at 4C for approximately 1 year(harvested September 2003) and freshly harvested seeds(October 2004) were soaked in November 2004 in solutions of the potassium(K) salt(K-salt) of gibberellin A3(K-GA3) at 0, 100, 500, or 1000 mg/liter for 24 hr in darkness. After treatment, seeds were germinated at 25C or an 8/16-hr thermoperiod of 30/20C with daily photoperiods at each temperature of 0(total darkness) or 16 hr. Germination was recorded every 3 days for 30 days. Stored and fresh seeds responded similarily. However, seeds that had been stored had greater viability and vigor and these data are presented. Regardless of germination temperature and photoperiod, nontreated seeds(0 mg/liter K-GA3) did not germinate. When germinated at 25C the response of seeds to K-GA3 treatment was linear for both photoperiods with significantly greater total(30-day) germination occurring in
the dark for seeds treated with 100, 500, or 1000 mg/liter. At 25C, the greatest total germination(84%) was observed for seeds treated with 1000 mg/liter K-GA3 and maintained in darkness, whereas for seeds exposed to a 16-hr photoperiod, maximum germination was 72%. At 30/20C the response to K-GA3 was quadratic with maximum germination at predicted rates of 882 and 875 mg/liter K-GA3(88% and 92%, respectively) for photoperiods of 0 and 16 hr, respectively. Treatment of seeds of seabeach amaranth with K-GA3 removed physiological(embryo) dormancy thus providing a means of eliminating the need for stratification(moist-prechilling). Treatment also reduced sensitivity of the seeds to light and appeared to broaden the range of temperatures for germination.
Impacts
Results of this investigation provide new information regarding removal of physiological(embryo) dormancy of seeds of seabeach amaranth thus providing a means of eliminating the need for lengthy stratification(moist-prechilling). This information will also aid in the production of seedling transplants for recovery efforts.
Publications
- Hinesley, L.E., Blazich, F.A., and Derby, S.A. 2006. Rooting softwood cuttings of Leyland cypress outdoors under shade. J. Environ. Hort. 24:124-128.
- LeBude, A.V.,Goldfarb, B., Blazich, F.A., Wright, J.A., Cazell, B., Wise, F.C., and Frampton, J. 2006. Container type and volume influenecs adventitious rooting and subsequent field growth of stem cuttings of loblolly pine. Southern J. Appl. For. 30:123-131
- Rosier, C.L., Frampton, J., Goldfarb, B., Blazich, F.A., and Wise, F.C. 2006. Improving the rooting capacity of stem cuttings of Virginia pine by severe stumping of parent trees. Southern J. Appl. For. 30:172-181.
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Progress 10/01/04 to 09/30/05
Outputs
Freshly harvested seeds of seabeach amaranth(Amaranthus pumilus Raf.), a species federally listed as threatened, were stratified(moist-prechilled) for 0, 30, 60, 90, or 120 days. Following stratification, seeds were germinated at 25C or an 8/16 hr thermoperiod of 30/20C with daily photoperiods at each temperature of 0(total darkness) or 16 hr. Germination was recorded every 3 days for 30 days. Regardless of photoperiod or duration of stratification, germination at 25C was negligible. After 120 days of stratification, total(30-day) germination at 25C with photoperiods of 0 or 16 hr was 4 and 3%, respectively, whereas considerable germination occurred at 30/20C. Germination increased linearly with increasing durations of stratification for both photoperiods when seeds were germinated at 30/20C. In addition, germination increased when seeds were exposed to light. After stratification of 30 days and germination in the dark at 30/20C, germination of 20% was observed by day
12 and increased to 27% by day 30, whereas for seeds exposed to a 16-hr photoperiod, 16% germination was noted by day 12 increasing to 38% by day 30. Following stratification of 120 days and germination in the dark at 30/20C, germination of 49% was observed by day 12 increasing to 50% by day 30, whereas for seeds exposed to light, 82% germination was realized by day 12 increasing to 85% by day 30.
Impacts
Results of this investigation provide new information regarding seed germination requirements of seabeach amaranth that should aid in the production of seedling transplants for recovery efforts.
Publications
- Blazich, F.A., Warren, S.L., Nash, D.L., and Reece, W.M. 2005. Seed germination of seabeach amaranth(Amaranthus pumilus) as influenced by stratification, temperature, and light. J. Environ. Hort. 23:33-36.
- Burgess, T.L., Blazich, F.A., Nash, D.L., and Randall-Schadel, B. 2005. Influence of selected surface disinfestants, fungicides, and temperature on seed germination and initial growth of southern sea oats(Uniola paniculata). J. Environ. Hort. 23:4-8.
- LeBude, A.V., Goldfarb, B., Blazich, F.A., Frampton, J. and Wise, F.C. 2005. Mist level influences vapor pressure deficit and gas exchange during rooting of juvenile stem cuttings of loblolly pine. HortScience 40:1448-1456.
- Rosier, C.L., Frampton, J., Goldfarb, B., Wise, F.C., and Blazich, F.A. 2005. Stumping height, crown position, and age of parent tree influence rooting of stem cuttings of Fraser fir. HortScience 40:771-777.
- Wright, A.N., Warren, S.L., Blazich, F.A., Harris, J.R., and Wright, R.D. 2005. Initial plant size and landscape exposure affect establishment of transplanted Kalmia latifolia 'Olympic Wedding'. J. Environ. Hort. 23:91-96.
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Progress 10/01/03 to 09/30/04
Outputs
The influence of cutting water potential on rooting of juvenile hardwood(dormant) and softwood(succulent) stem cuttings of loblolly pine(Pinus taeda L.) propagated under varying substrate water potentials and volumes of mist application were investigated. Mist treatment and substrate water potential contributed to cutting water potential of nonrooted stem cuttings. When substrate water potential was held constant across mist treatments, mist treatment contributed strongly to cutting water potential. Substrate water potential affected rooting percentage when mist treatment was sub-optimal or excessive, otherwise mist treatment had a stronger effect than substrate water potential on rooting percentage. Cuttings rooted best when subjected to moderate cutting water potentials(-0.5 to -1.2 MPa) during the initial 4 or 5 weeks of the rooting period. Cuttings experiencing either severe water deficit or no water deficit rooted poorly.
Impacts
This research demonstrates that the rooting environment should impose a moderate water stress on stem cuttings of loblolly to achieve optimum rooting. Results of this investigation may be applicable to stem cuttings of other woody species.
Publications
- LeBude,A.V., Goldfarb, B., Blazich, F.A., Wise, F.C., and J. Frampton. 2004. Mist, substrate water potential and cutting water potential influence rooting of stem cuttings of loblolly pine. Tree Physiol. 24:823-832.
- Rosier, C.L., Frampton, J., Goldfarb, B., Blazich, F.A., and Wise, F.C. 2004. Growth stage, auxin type, and concentration influence rooting of stem cuttings of Fraser fir. HortScience 39:1397-1402.
- Rosier, C.L., Frampton, J., Goldfarb, B., Wise, F.C., and Blazich, F.A. 2004. Growth stage, auxin type, and concentration influence rooting of Virginia pine stem cuttings. HortScience 39:1392-1396.
- Wright, A.N., Warren, S.L., Blazich, F.A., and Bloom, U. 2004. Root and shoot growth periodicity of Kalmia latifolia 'Sarah' and Ilex crenata'Compacta'. HortScience 39:243-247.
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Progress 10/01/02 to 09/30/03
Outputs
The length of time between transplanting and subsequent new root initiation, root growth rates, and root growth periodicity can influence the ability of woody ornamentals to survive transplanting into the landscape. Research was conducted to compare root growth of a difficult-to-transplant species, Kalmia latifolia L.{mountain laurel}, to that of an easy-to-transplant species, Ilex crenata Thunb.{Japanese holly}, over the course of 1 year. Micropropagated liners of 'Sarah' mountain laurel and rooted stem cuttings of 'Compacta' holly were potted in 3-liter containers. Plants were grown in a greenhouse from May to September at which time they were moved outside to a gravel pad where they remained until the following May. Destructive plant harvests were conducted every 2 to 4 weeks for 1 year. At each harvest leaf area, shoot dry weight{DW}{stems and leaves}, root length, root area, and root DW were determined. Throughout the experiment shoot DW and leaf area were
similar for the two cultivars. New root growth of 'Compacta' holly and 'Sarah' mountain laurel was measurable 15 to 30 days after potting, respectively. Root length and root area of 'Sarah' mountain laurel increased during May through December but decreased during January through April. Root length and root area of 'Compacta' holly increased linearly throughout the course of the study. Final root:shoot ratio was nine times larger for 'Compacta' holly than 'Sarah' mountain laurel.
Impacts
This research demonstrates that poor transplant performance of mountain laurel in the landscape may be related to its slow rate of root growth. Results suggest that cultural practices stimulating root growth may enhance transplant survival.
Publications
- Conden, P.J. and Blazich, F.A. 2003. Propagation of Castanopsis sclerophylla by stem cuttings. J. Environ. Hort. 21:61-63.
- Conden, P.J., Warren, S.L., and Blazich, F.A. 2003. Nitrogen nutrition of containerized Ternstroemia gymnanthera. J. Environ Hort. 21:73-77.
- Wright, A.N. 2002. The physiology of landscape establishment of Kalmia latifolia. Ph.D. Dissertation, N.C. State Univ., Raleigh.
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Progress 10/01/01 to 09/30/02
Outputs
Rooted stem cuttings of Japanese ternstroemia (Ternstroemia gymnanthera) were grown in 3.8-L plastic containers utilizing a substrate of 8 pine bark : 1 sand (by vol.) amended with micronutrients and dolomitic limestone. Plants were fertilized every other day with a solution consisting of P(K2 H2PO4) at a constant rate of 30 ppm, K(K2SO4) at a constant rate of 60 ppm, and a variable rate of N(NH4NO3) at 0,10,20,40,80,160, or 320 ppm. Leaf area and shoot (stems and leaves) dry weight increased with increasing N application rate (NAR) until a plateau was reached at 117 ppm. Root : shoot ratio was 0.8 with N at 0 ppm, increased to 0.9 with N at 10 ppm, then decreased to approximately 0.1 with N at 104 ppm. Root dry weight and root area increased in response to increasing NARs, reaching a plateau with N at 86 and 70 ppm, respectively. Leaf weight ratio (leaf dry weight/total plant dry weight) increased from 0.2 with N at 0 ppm to a plateau of approximately 0.6 with N at
109 ppm. Stem weight ratio (stem dry weight/total plant dry weight) was 0.4 with N at 0 ppm then decreased to a plateau of approximately 0.3 with N at 52 ppm. Root weight ratio (root dry weight/total plant dry weight) decreased steadily from 0.4 with N at 0 ppm to approximately 0.1 with N at 117 ppm. Shoot N,P,K, and S concentrations increased with increasing NARs, reaching plateaus at 117,23,124, and 183 ppm, respectively, while Mg was unaffected by NAR. Calcium concentrations increased to 0.75% with a NAR of 40 ppm, and decreased to a plateau of 0.6% with N at 107 ppm. Root mineral nutrient concentrations of N,P,K, and S increased with increasing NARs, reaching plateaus of 287,53,39, and 195 ppm, respectively, whereas Ca and Mg were not affected by NAR.
Impacts
Determination of an optimum rate of N fertilization for containerized culture of Japanese ternstroemia will increase availability of this popular landscape plant with reduced production costs. This research should also prevent or reduce excessive N application during containerized culture of this species which is often a source of ground water contamination, currently a topic of great concern to the nursery industry.
Publications
- Burgess, T.L., Blazich, F.A. and Nash, D.L. 2002. Seed germination of southern seaoats (Uniola paniculata) as influenced by stratification, temperature, and light. J. Environ. Hort. 20:180-183.
- Condon, P.J. 2002. Propagation of Castanopsis sclerophylla and Lindera umbellata by Stem Cuttings and Nitrogen Nutrition of Containerized Ternstroemia gymnanthera. M.S. Thesis, N.C. State Univ., Raleigh.
- Rowe, D.B., Blazich, F.A., Goldfarb, B. and Wise, F.C. 2002. Nitrogen nutrition of hedged stock plants of loblolly pine. II. Influence of carbohydrate and nitrogen status on adventitious rooting of stem cuttings. New Forests 24:53-65.
- Rowe, D.B., Blazich, F.A. and Raper, C.D. 2002. Nitrogen nutrition of hedged stock plants of loblolly pine. I. Tissue nitrogen concentrations and carbohydrate status. New Forests 24:39-51.
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Progress 10/01/00 to 09/30/01
Outputs
Seeds of southern seaoats (Uniola paniculata) were removed from storage at 4C and stratified (moist-prechilled) for 0, 15 or 30 days at 4C. Following stratification, seeds were germinated at 25C or 30C or at 8/16 hr thermoperiods of 30/20C or 35/25C with daily photoperiods at each temperature of 0 (total darkness), 2, 4, 8, 12 or 24 hr. Germination was recorded every 3 days for 30 days. Light had no effect on germination. Regardless of photoperiod the influence of light was nonsignificant (P=0.45). On the other hand, temperature and stratification were significant (P=0.0001) and there was a significant interaction (P=0.001) between the two parameters. Averaged across all treatments, the highest total germination was realized at 35/25C (60%) followed by 30/20C (48%), 30C 37%, and 25C (31%). Stratification was not a requirement for germination, but stratification for 15 days increased the rate of germination, but not total germination. However, stratification for 30
days decreased germination due to seed decay caused by fungal growth despite seed treatment with 1.3% sodium hypochlorite prior to stratification. Seed decay during germination was observed and treatments to reduce decay should be investigated since viability tests with 2,3,5-triphenyltetrazolium chloride indicated that initial seed viability was >95%.
Impacts
This research should result in increased seed germination of southern seaoats allowing more efficient production of seedling transplants for beach restoration and dune stabilization.
Publications
- Starrett, M.C., F.A. Blazich, S.R. Shafer, and L.F. Grand. 2001. In vitro colonization of micropropagated Pieris floribunda by ericoid mycorrhizae. I. Establishment of mycorrhizae on microshoots. HortScience 36:353-356.
- Starrett, M.C., F.A. Blazich, S.R. Shafer, and L.F. Grand. 2001. In vitro colonization of micropropagated Pieris floribunda by ericoid mycorrhizae. II. Effects on acclimatization and growth. HortScience 36:357-359.
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Progress 01/01/00 to 12/31/00
Outputs
Stock plants of Anemone x hybrida Paxton 'Hororine Jobert' and 'Richard Ahrens' were grown in 3.8 L containers for 30 weeks beginning in April, and fertilized daily with a complete nutrient solution providing 10, 40, 80 or 150 mg/L nitrogen (N), in a constant ratio of 1 ammonium:2 nitrate. At the end of 30 weeks (November), 4-cm-long root cuttings were harvested from the stock plants and treated with the potassium salt of indolebutyric acid (K-IBA) at 0, 100, 500 or 1000 mg/L, then placed in cell packs containing a pine bark-based substrate, one cutting per cell. The containers were arranged under intermittent mist in a heated greenhouse. Overall, 91% of the cuttings regenerated a complete plant. There were cultivar differences in regeneration, and the highest K-IBA concentration was inhibitory to 'Hororine Jobert'. Nitrogen nutrition of the stock plants, K-IBA treatment of the root cuttings and fresh weight of the root cuttings, had no significant effect on percent
regeneration. Time to shoot emercence was reduced by higher rates of N applied to the stock plants, and increased at the highest concentration of K-IBA in 'Hororine Jobert', but not in 'Richard Ahrens'. Dry weights of the regenerated plants increased with increasing weight of the cutting from which they originated. They were related linearly to rate of N applied to the stock plants in 'Honorine Jobert', and quadratically in 'Richard Ahrens', with maximum plantlet weight predicated at 114 mg/L N. At the observed optimal rate of N applied to the stock plants, dry weights of the regenerated plants increased with increasing K-IBA concentration, in a quadratic manner. Maximum plantlet weight is predicted at 459 mg/L, K-IBA in 'Hororine Jobert', and at 425 mg/L in 'Richard Ahrens'.
Impacts
Improvement of existing propagation protocols for particular nursery crops or develoment of new procedures will increase availability with reduced cost and enrich the pallet of plants available to consumers. Nurserymen will also benefit by being able to propagate cost-effectively those plants which are in demand. In addition, the landscape will improve by becoming more diverse and by utilization of plants which are not adversely affected by various cultural, disease or insect problems.
Publications
- Dubois, J.-J.B., Blazich, F.A, Warren, S.L. and Goldfarb, B. 2000. Propagation of Anemone x hybrida by root cuttings. J. Environ Hort. 18(2):79-83.
- Dubois, J.-J.B., Warren, S.L. and Blazich, F.A. 2000. Nitrogen nutrition of containerized Anemone x hybrida. J. Environ. Hort. 18(3):145-148.
- Jull, L.G. and Blazich, F.A. 2000. Seed germination of selected provenances of Atlantic white-cedar as influenced by stratification, temperature, and light. HortScience 35(1):132-135.
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Progress 01/01/99 to 12/31/99
Outputs
Seedlings of Atlantic white-cedar [Chamaecyparis thyoides (L.) B.S.P.] were grown in controlled-environment chambers for 12 weeks under short- or long-day conditions with 9-hr days at 18,22,26 or 30C in factorial combination with 15-hr nights at 14,18,22 or 26C. Dry matter production was influenced by photoperiod and day/night temperature. For all day temperature x photoperiod interactions, except root:shoot ratio, growth was highest under long days. Day x night temperature interactions occurred for all growth measurements except root dry weight. Root dry weight was highest at 30/22C; top (shoot) dry weight at 26/22C. Nights of 14C resulted in the lowest top dry weight. Total plant dry weight was highest at nights of 22C for all day temperatures. At days of 30C, total plant dry weight was highest with nights < 22C; however, data for 30/22C and 26/22C were similar. The highest root:shoot ratio occurred at nights of 14C with days < 26C. Mean relative growth rate was
highest at nights of 22C with days of 26C or 30C. Maximum stem caliper occurred at days of 22C with nights > 18C. Height and crown width were highest at 26/22C. A day/night cycle of 30/22C with long days was optimal for seedling growth.
Impacts
(N/A)
Publications
- Arocha, L.O., Blazich, F.A., Warren, S.L., Thetford, M. and Berry, J.B. 1999. Seed germination of Rhododendron chapmanii : Influence of light and temperature. J. Environ. Hort. 17(4):193-196.
- Glenn, C.T., Blazich, F.A. and Warren, S.L. 1999. Secondary seed dormancy of Rhododendron catawbiense and Rhododendron maximum. J. Environ. Hort. 17(1):1-4.
- Griffin, J.J., Blazich, F.A. and Ranney, T.G. 1999. Propagation of Magnolia virginiana 'Santa Rosa' by semi-hardwood cuttings. J. Environ. Hort. 17(1):47-48.
- Griffin, J.J., Blazich, F.A. and Ranney, T.G. 1999. Shading and IBA treatment do not improve rooting of stem cuttings of Quercus phillyraeoides 'Emerald Sentinel'. J. Environ. Hort. 17(3):123-125.
- Griffin, J.J., Warren, S.L., Blazich, F.A. and Ranney, T.G. 1999. Nitrogen nutrition of containerized Thuja x 'Green Giant'. J. Environ. Hort. 17(2):76-79.
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Progress 01/01/98 to 12/31/98
Outputs
Following harvest of capsules, drying, and seed extraction, seeds of Katmia latifolia L. (mountain laurel), Leucothoe fontanesiana (Steud.) Sleum (drooping leucothoe), Rhododendron carolinianum Rehd. (Carolina rhododendron), Rhododendron catawbiense Michx. (Catawba rhododendron), and Rhododendron maximum L. (rosebay rhododendron) were stored for 0, 1, 2, 3, 4 or 5 years at -18, 4 or 23C and then germinated at 25C or an 8/16 hr thermoperiod of 25/15C with daily photoperiods of 0, 1 or 24 hr. Storage at -18 or 4C were most effective for maintaining seed viability of all species. After 5 years storage at -18 or 4C, viability of L. fontanesiana, R. catawbiense, and R. maximum was relatively unchanged with total germination of 59%, 87%, and 88%, respectively. The same was noted for seeds of K. latifolia and R. carolinianum with total germination of 77% and 91%, respectively, after storage for 4 years at the same temperatures. Storage at 23C was the least effective for
maintaining viability. After storage for 1 year at 23C, germination decreased significantly for all species except R. carolinianum. By year 3, storage at 23C reduced seed viability of L. fontanesiana to essentially zero. The same occurred by year 4 for seeds of R. catawbiense and R. maximum stored at 23C. Viability of K. latifolia also decreased under storage at 23C with germination of 14% noted by year 4. Viability of R. carolinianum did not decrease as rapidly as the other species when stored at 23C with total germination of 77% occurring by year 4. Regardless of storage duration, the photoperiod and temperature requirements for maximum germination of all species did not change.
Impacts
(N/A)
Publications
- Glenn, C.T., Blazich, F.A. and Warren, S.L. 1998. Influence of storage temperatures on long-term seed viability of selected native ericaceous species. J. Environ. Hort. 16(3):166-172.
- Griffin, J.J., Blazich, F.A. and Ranney, T.G. 1998. Propagation of Thuja x 'Green Giant' by stem cuttings: Effects of growth stage, type of cutting, and IBA treatment. J. Environ. Hort. 16(4):190-192.
- Jull, L.G. 1998. Seed germination, seedling growth, and heat tolerance of Atlantic white-cedar [Chamaecyparis thyoides (L.) B.S.P.]. Ph.D. Thesis. N.C. State Univ., Raleigh. 121p.
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Progress 01/01/97 to 12/31/97
Outputs
Single-node explants were excised from shoots of actively growing, 2-year-old seedlings of Stewartia pseudocamellia Maxim. (Japanese stewartia) on three dates associated with specific stock plant growth stages. Following surface sterilization, explants were placed on agar-solidified Woody Plant Medium (WPM) containing either no growth regulators or N-(3-methyl-2-butenyl)-lH-purin-6-amine (2iP) at 5.0 or 10.0 ppm or 0.025 or 0.05 ppm N-phenyl-N-1,2,3-thiadiazol-5-ylurea (TDZ). The most frequent budbreak was noted for explants placed on media containing 2iP at either concentration. Explants cultured at the softwood stage had less contamination and greater budbreak than explants taken from more mature stem tissue. In another study, the three distal axillary nodes of each shoot were excised at 4-day intervals for 28 days beginning 52 days after stock plants were potted following cold storage at 7C (44F). Explants were surface sterilized and placed on WPM supplemented with
10 ppm 2iP either alone or in combination with 3 ppm gibberellic acid (GA3). Neither GA3 nor node position influenced budbreak frequency or shoot elongation. Days after potting (stock plant growth stage) influenced frequency of budbreak and shoot elongation with the optimal period for explant collection being 56 to 72 days after stock plants were potted. Elongated shoots (one microcutting per explant) were produced on both media. Microcuttings >10 mm were rooted using ex vitro procedures and acclimatized to greenhouse conditions.
Impacts
(N/A)
Publications
- MCGUIGAN, P.J., BLAZICH, F.A. and RANNEY, T.G. 1997. Micropropagation of Stewartia pseudocamellia. J. Environ. Hort. 15:65-68.
- STUBBS, H.L., BLAZICH, F.A., RANNEY, T.G. and WARREN, S.L. 1997. Propagation of 'Carolina Sapphire' smooth Arizona cypress by stem cuttings: Effects of growth stage, type of cutting, and IBA
- STUBBS, H.L., WARREN, S.L., BLAZICH, F.A. and RANNEY, T.G. Nitrogen nutrition of containerized Cupressus arizonica var. glabra 'Carolina Sapphire'. J. Environ. Hort. 15:80-83.
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Progress 01/01/96 to 12/30/96
Outputs
Stem cuttings of two clones (clones 1 and 2) of Quercus myrsinifolia, and one clone of Quercus canbyi, of seedling origin and in the adult growth phase, were taken for rooting at specific growth stages. Cuttings of clone 1 of Q. myrsinifolia were collected at the semi-hardwood, hardwood, or softwood stages in addition to a transitional stage between softwood and semi-hardwood. For clone 2, stem cuttings were taken only at the softwood and transitional softwood/semi-hardwood stages. Cuttings of Q. canbyi were collected at the semi-hardwood, hardwood, or softwood stages. Cuttings of both species were treated with 0, 1500, 3000, 6000, or 9000 mg/liter indolebutyric acid (IBA) in 50% isopropanol. Semi-hardwood or hardwood cuttings of Q. myrsinifolia or Q. canbyi did not root. Responses of stem cuttings of Q. myrsinifolia to IBA treatment varied by growth stage. For softwood cuttings response to IBA was quadratic with the greatest rooting noted for clones 1 (56%) and 2
(72%) when treated with 1500 and 3000 mg/liter IBA, respectively. Treatment with IBA had no effect on percent rooting of softwood/semi-hardwood cuttings of clone 1, with rooting ranging from 47% to 58%. However, a linear decrease in rooting in response to IBA was observed for clone 2 with the greatest rooting occurring for the nontreated cuttings (89%). Softwood cuttings of Q. canbyi responded quadratically to IBA treatment, with maximum rooting of 33% noted for cuttings treated with 1500 mg/liter IBA.
Impacts
(N/A)
Publications
- CURTIS, D.L., RANNEY, T. G., BLAZICH, F.A. and WHITMANN II, E.P. 1996. Rooting and subsequent overwinter survival of stem cuttings of Stewartia ovata. J. Environ. Hort. 14:163-166.
- MCGUIGAN, P. J., BLAZICH, F.A. and RANNEY, T.G. 1996.Propag.
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Progress 01/01/95 to 12/30/95
Outputs
Uniconazole was applied as a foliar spray at 0, 90, 130, 170, or 210 mg/liter torooted stem cuttings of Forsythia x intermedia `Spectabilis' potted in calcined clay. Plants were harvested 0, 40, 80, 120, and 369 days after treatment (DAT). Treatment with uniconazole at 90 to 210 mg/liter suppressed leaf area and dry weight an average of 16% and 18%, respectively, compared to the nontreated controls when averaged over all harvest periods. Stem and root dry weight suppression was greatest at 80 DAT, 47% and 37%, respectively. Uniconazole suppressed root length from 15% to 36% and root area from 15% to 33%, depending on harvest date. Internode length and stem diameter of uniconazole-treated plants were suppressed at all harvest dates except 369 DAT. Uniconazole resulted in increased and decreased root : shoot ratios 40 and 80 DAT, respectively; while root : shoot ratios were not affected for the remainder of the study. Relative growth rates of leaves, stems, and roots
decreased with increasing uniconazole concentration; however, no relative growth rates were suppressed beyond 80 DAT. Generally, mineral nutrient concentrations increased as a result of uniconazole application. The proportion of mineral nutrients allocated to leaves and roots was not affected while the proportion of nutrients allocated to stems decreased with uniconazole application compared to the controls.
Impacts
(N/A)
Publications
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Progress 01/01/94 to 12/30/94
Outputs
Catawba rhododendron (Rhododendron catawbiense) seedlings of two provenances, Johnston County, N.C. (elevation = 67 m), and Yancey County, N.C. (elevation = 1954 m), were grown in controlled environment chambers for 18 weeks with days at 18, 22, 26, or 30C in factorial combination with nights at 14, 18, 22, or 26C. Shoot and root dry weights and total leaf areas of seedlings of the Yancey County provenance (high elevation) exceeded those of the Johnston County (low elevation) provenance at all temperature combinations. Leaf area was maximal at 22/22C, 18/26C, and 22/26C and minimal at 30/14C (day/night). Shoot dry weight responded similarly. Root dry weight decreased linearly with increasing day temperature, but showed a quadratic response to night temperature. Leaf weight ratio (leaf dry weight:total plant dry weight) increased, while root weight ratio (root dry weight:total plant dry weight) decreased with increasing day temperature. Leaf weight ratio was
consistently higher than either stem or root weight ratios. Day/night cycles of 22 to 26/22C appear optimal for seedling growth.
Impacts
(N/A)
Publications
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Progress 01/01/93 to 12/30/93
Outputs
Cotyledons and hypocotyls of Fraser fir (Abies fraseri) were excised from seeds treated with hydrogen peroxide for 9 days and placed on bud induction medium containing 10 mg BA/liter and 0.01 mg NAA/liter or medium without growth regulators. Although adventitious buds did not develop, cotyledons exposed to growth regulators responded differently than cotyledons placed on medium lacking growth regulators. Cotyledons and hypocotyls responded similarly to growth regulators during the initial phase in culture, but cell divisions ceased in cotyledons, thus preventing meristemoid and subsequent bud development. After 3 days on medium containing growth regulators, cell divisions were localized in epidermal and subjacent layers of hypocotyls, whereas similar cell divisions were not observed in hypocotyls placed on medium without growth regulators. Cell clusters consisting of two to five cells (promeristemoids) were present after 7 days on hypocotyls placed on bud induction
medium. In hypocotyls placed on medium without growth regulators, stomata continued to develop and cells within the cortex became vacuolated during the first 2 weeks in culture. All explants were transferred to secondary medium after 3 weeks. Cell clusters continued to enlarge into meristemoids on hypocotyls initially placed on bud induction medium. Gradually, meristemoids developed into buds and cataphylls were observed covering bud meristems.
Impacts
(N/A)
Publications
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Progress 01/01/92 to 12/30/92
Outputs
Containerized seedlings of eastern redcedar (Juniperus virginiana) were fertilized weekly for 175 days with a solution containing 50 ppm P, 150 ppm K, and either 0, 5, 10, 20, 40, 80, 160, 320, or 640 ppm N. Plant height, stem diameter, and shoot and root dry weights increased asymptotically with applied N; 640 ppm N diminished response. Growth after 175 (height, stem diameter) and 180 (shoot and root dry weights) days was optimal (90% of maximum) at N concentrations of 115, 155, 230, and 105 ppm, respectively; 1.5% foliar N optimized height growth. Foliar concentrations of N, P and K increased in treated plants over the duration of the experiment, while Ca, Mg, and Mn decreased or remained constant. Starch concentration of fertilized plants decreased sharply after initiation of the experiment, but controls (0 ppm N) showed little change during the first 120 days. For all treatments, sucrose concentration remained constant over the summer but increased sharply in late
fall. At 180 days, concentrations of starch, sucrose, hexose, N, P, K, and B increased asymptotically with applied N; concentrations of Ca, Mg, and Mn decreased.
Impacts
(N/A)
Publications
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Progress 01/01/91 to 12/30/91
Outputs
Seedlings of flame azalea (Rhododendron calendulaceum) were grown for 12 weeks under long day conditions at 9-hour day temperatures of 18, 22, 26, and 30 C in factorial combination with 15 hour night temperatures of 14, 18, 22, and 26 C. Total plant dry weight, top dry weight, leaf area and dry weights of leaves, stems and roots were influenced by both day and night temperatures as well as their interactions. Dry matter production was lowest at a night temperature of 14 C. Root, leaf, top and total dry weights were maximized at a day temperature of 26 C in combination with night temperatures of 18 to 26 C. Stem dry weight was maximized at day temperatures of 26 to 30 C with a night temperature of 22 C. Leaf area was greatest under day temperatures of 18 and 26 C in combination with night temperatures of 18 or 26 C. Within the optimal day/night temperature range of 26/18-26 C for total plant dry weight, there was no evidence that alternating temperatures enhanced
growth. Shoot/root ratios were highest at day temperatures of 18 and 30 C. Leaf area ratio and specific leaf area were greatest at day and night temperatures of 18 C and decreased as temperature increased. Regardless of day/night temperature, leaf weight ratio was higher than both stem weight ratio and root weight ratio. Net leaf photosynthetic rate increased with day temperatures up to 30 C.
Impacts
(N/A)
Publications
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Progress 01/01/90 to 12/30/90
Outputs
Cotyledons, hypocotyls, and cotyledon-hypocotyl explants were excised from seedsof Fraser fir (Abies fraseri) subjected to H2O2 treatment for 3, 6, 9 or 12 days and cultured on media containing 0 to 30 mg/l benzyladenine (BA). Adventitious buds developed on hypocotyls and hypocotyls of cotyledon-hypocotyl explants, but rarely on cotyledons. Excised hypocotyls produced more buds than hypocotyls of cotyledon hypocotyl explants (1.6 vs. 1.1). Hypocotyls excised from seeds treated with H2O2 for 6 or 9 days and placed on medium containing 10 mg/l BA yielded the greatest number of buds with a mean of 3 buds per hypocotyl. Elongated adventitious shoots were placed on media containing 0 to 40 mg/l indolebutyric acid (IBA) to induce rooting. Forty-eight percent of shoots treated with 40 mg/l IBA rooted and the greatest number of roots per rooted shoot (3.0) was also noted at this concentration. Plantlets were transferred to growing medium but acclimation was unsuccessful.
Histological examination of hypocotyls of Fraser fir placed on bud induction medium showed similarities between the stages leading to in vitro adventitious bud formation on hypocotyls of Fraser fir and those occurring on cotyledons of other conifers. It was also observed that meristemoid formation was greater than actual bud formation on hypocotyls of Fraser fir.
Impacts
(N/A)
Publications
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Progress 01/01/89 to 12/30/89
Outputs
Seeds of mountain laurel (Kalmia latifolia) were germinated twice daily, 1, 2, 4, 8, 12, and 24 hr. Seeds exhibited an obligate light requirement. At 25C, increasing photoperiods increased germination with maximum germination (90%) occurring by day 18 under continuous illumination. The alternating temperature of 25/15C enhanced germination when light was limiting. At this temperature maximum germination of 86 to 87% was reached by day 24 for photoperiods > 8 hr. Studies are in progress to determine photoperiods and temperatures which optimize growth following germination. Rooted cuttings of Chapman's rhododendron (Rhodendron chapmanii), a rare and endangered species, in soilless medium were challenged with inoculum of the soilborne fungus Phytophthora cinnamomi. A portion of plants received a soil drench of metalaxyl at 0.16 ml/liter at 2 month intervals. Chapman's rhododendron was highly susceptible to P. cinnamomi, but five of six plants treated with metalaxyl did
not develop symptoms of Phytophothora root rot. In one plant which developed root rot symptoms, P. Cinnamomi was recovered in culture. Propagation of two cultivars of Osmanthus heterophyllus by stem cuttings was investigated. Nontreated semihardwood and hardwood cuttings of 'Ilicifolius' rooted in high percentages (> 80%) while comparable results for 'Rotundifolius' were only noted for hardwood cuttings. Response of both cultivars to indolebutyric acid (IBA) treatment (0.25 to 1.
Impacts
(N/A)
Publications
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Progress 01/01/88 to 12/30/88
Outputs
Seeds of flame azalea (Rhododendron calendulaceum) were germinated at 25 degreesC and 25/15 degrees C with daily photoperiods at each temperature of 0, 0.5, 0.5 twice daily, 1, 2, 4, 8, 12, and 24 hr. Seeds exhibited an obligate light requirement. At 25 degrees C, increasing photoperiods increased germination with maximum germination (85%) occurring by day 12 under the 24 hr photoperiod. The alternating temperature of 25/15 degrees C enhanced germination when light was limiting. At this temperature, maximum germination was reached by day 24 for all photoperiods -0.5 hr although at photoperiods of 4 to 24 hr maximum germination was noted at day 18. Studies are in progress to determine photoperiods and temperatures which optimize growth following germination. Experiments investigated the relationship of light and temperature in Fraser fir (Abies fraseri) germination. Illumination during the warm portion of a 9/15 hr thermoperiod of 20/10 degrees C or 30/20 degrees C
stimulated 42-day germination and the degree of stimulation depended upon the timing of the light treatment. A 1 hr light treatment was least effective during the initial portion of the warm cycle and varying the time of illumination had the greatest effect at 20/10 degrees C. The role of phytochrome in the photomorphogenic response was ascertained by demonstration of red/far-red reversibility.
Impacts
(N/A)
Publications
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Progress 01/01/87 to 12/30/87
Outputs
Approaches for tissue culture propagation of Fraser fir (Abies fraseri) utilizing embryonic tissues as explants were investigated. Cotyledons, hypocotyls and intact embryos of germinating seeds harvested at several stages of development were cultured on media containing benzylaminopurine at concentrations ranging from 0 to 25 mg/l. Adventitious shoot formation occurred primarily on excised hypocotyls and hypocotyls of intact embryos, but rarely on cotyledons. More than 45% of the excised hypocotyls and 30% of the hypocotyls of intact embryos formed adventitious shoots. The range of shoots formed per responsive explant was 1 to 13. Experiments are in progress for optimization of adventitious shoot initiation, subsequent shoot growth and rooting of the shoots. Procedures were developed for propagation of Fortune's Osmanthus (Osmanthus x fortunei) by rooting softwood cuttings and for micropropagation of flame azalea (Rhododendron calendulaceum).
Impacts
(N/A)
Publications
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Progress 01/01/86 to 12/30/86
Outputs
Timing of severance, auxin treatment, and staking were evaluated for their effects on reducing abaxial-concave bending of softwood Fraser fir (Abies fraseri) stem cuttings. Cuttings collected July 21, were much less plagiotropic after a 135-day rooting period than those collected 3 weeks earlier. This upright habit was related to stronger internal support from increased amounts of xylem and lignified pith at severance. Staking also reduced abaxial-concave bending, but postseverance auxin treatment had no effect. Stakes apparently provided external support until stems became lignified. Nonstaked cuttings collected June 30 continued to exhibit greatest bending at the end of the 2nd growing season. Basal defoliation and wounding in preparation for rooting increased plagiotropic growth and reduced survival during rooting, but did not affect the percentage of rooting. Evaluation of xylem distribution indicated that abaxial- concave bending in the 2nd season was caused by
greater production of compression wood and total xylem on adaxial than on abaxial sides of the original cutting segments. Research continued in attempts to induce adventitious bud formation on Fraser fir cotyledons in vitro. Procedures were developed to hasten growth of umbrella pine (Sciadopitys verticillata) seedlings.
Impacts
(N/A)
Publications
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Progress 01/01/85 to 12/30/85
Outputs
Research was conducted to refine propagation procedures for horticulturally important species, particularly nursery crops. Fraser fir (Abies fraseri) stock plants grown as transplants (4 years old) or sheared Christmas trees (14 years old) were subjected to independent combinations of hedging and chemical treatments to induce orthotropic shoot production. Decapitation treatments that removed the most top growth produced the greatest number of orthotropic shoots in each age class after one growing season. Spray application of dikegulac at 1000 and 3000 ppm did not stimulate orthotropic shoot formation. Orthotropic shoots induced on maturing Christmas trees rooted in lower percentage than plagiotropic cuttings from similar nondecapitated trees. Since rooting and survival of the severed shoots were largely or totally unaffected by hedging treatments, decapitation treatments that produced the most shoots the lst year continued to exhibit the most rooted cuttings at the end
of the following season. Procedures were developed for in vitro culture of intact embryos excised from Fraser fir seeds and for cotyledons taken from seeds germinated under aseptic conditions. In addition to developing techniques for rooting stem cuttings, micropropagation procedures, one utilizing axillary shoot multiplication and the other adventitious shoot multiplication, were developed for Chapman's rhododendron (Rhododendron chapmanii), a "rare and endangered species.
Impacts
(N/A)
Publications
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