Source: UNIV OF HAWAII submitted to
GENETIC DIVERSITY AND THE PROPAGATION OF NATIVE HAWAIIAN PLANTS FOR THE ORNAMENTALS INDUSTRY
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
TERMINATED
Funding Source
Reporting Frequency
Annual
Accession No.
0167486
Grant No.
(N/A)
Project No.
HAW00825-H
Proposal No.
(N/A)
Multistate No.
(N/A)
Program Code
(N/A)
Project Start Date
Oct 1, 2004
Project End Date
Sep 30, 2009
Grant Year
(N/A)
Project Director
Criley, R. A.
Recipient Organization
UNIV OF HAWAII
3190 MAILE WAY
HONOLULU,HI 96822
Performing Department
TROPICAL PLANT & SOIL SCIENCE
Non Technical Summary
A renewed interest in the use of native Hawaiian plants has prompted grower interest in their propagation. Since propagation protocols for most of the easy plants have been developed, it is the more difficult plant materials that growers are struggling to increase. This project seeks to identify superior germplasm and develop and disseminate propagation protocols for some selected difficult-to-propagate Hawaiian ornamental species. The project goal is to develop and disseminate propagation protocols for selected indigenous and endemic Hawaii plants that will be disseminated to the Hawaii nursery industry. Determination of genetic diversity will assist in plant improvement efforts as well as identify superior lines for introduction into the nursery industry.
Animal Health Component
(N/A)
Research Effort Categories
Basic
40%
Applied
30%
Developmental
30%
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
2022110108020%
2032110102010%
2032110105020%
2052110102020%
2052110105010%
2062110102010%
2062110105010%
Goals / Objectives
1) To develop and disseminate information supporting the efficient increase of native Hawaiian plants by utilizing conventional systems and technologies of seed and vegetative propagation, including micropropagation. 2) To determine, in conjunction with applied propagation approaches, the physiological basis for success in propagation of Hawaiian native plants by seed or vegetative means. 3) To identify, through molecular analysis, genetic resources of selected Malvaceous genera that can be utilized in clarifying species boundaries, population relationships, and genetic diversity for use in the ornamental horticulture trade and conservation efforts.
Project Methods
1) Seed collection and storage, environmental control - especially moisture, light, and temperature, - and seed production plots will be employed to deal with species for which this method appears to be the most viable and efficient means of increase. Success will be considered as acheived when a protocol can be written for seed production, storage, and seedling production of targeted species (Pritchardia spp.). Cutting propagation using softwood, intermediate wood, and hardwood cuttings, with modifications of the humidity and light environments, stock plant manipulations, and root-inducing hormones will be investigated for targeted species. Diverse micropropagation techniques including embryo culture, meristem culture, somatic embryogenesis will be employed for targeted species (Pittosporum spp., Pelea anisata). 2) Vegetative propagation physiology includes determination of inhibitors, carbohydrate reserves, storage compounds, and changes in anatomy and biochemistry of stems when stock plant manipulations are imposed. Diverse explant materials in micropropagation studies will allow improved strategies for successful regeneration of targeted species. 3) A variety of DNA analysis techniques will determine the diversity that exists among Hibiscus, Abutilon, and Hibiscadelphus species in Hawaii. This information will support bases for selection of parental lines for breeding work to develop new ornamentals as well as identify superior germplasm for introduction into the nursery industry.

Progress 10/01/04 to 09/30/09

Outputs
OUTPUTS: The objectives of this project were to develop propagation protocols for selected native Hawaiian ornamental plants. Nine experiments to root cuttings were conducted on Psydrax odorata, the most recent in 2009. This has proved an extremely difficult material to root. Seed propagation is limited by infestation of the seeds with seed-eating insect larvar. Greenwood terminals about 7 to 10 cm long represent the best choice of material, and IBA or a mixture of 2:1 IBA:NAA at concentrations ranging from 0.4 to 1.0% have yielded low percentages of callusing and occasional rooting. Bottom heat encouraged callus formation after 12 wk, but retreatment of the callus with rooting hormone did not stimulate root initiation. Pittosporum confertiflorum cuttings showed much variability in rooting success due to the parent plant. The most successful rooting was achieved with recently matured green terminal cuttings treated with 0.4% KIBA or 2:1 IBA:NAA; rooting required up to 21 weeks, and in post-transplanting about 20% of cuttings were lost. Pritchardia remota seed displays a morpho-physiological dormancy at fruit shed and a pattern intermediate between recalcitrant and orthodox species. The embryo must be allowed further development time before germination can occur. The seed tolerates a certain amount of desiccation with embryos removed from the seed able to withstand 25 to 75% humidity during drying and remain capable of germinating. . Removal of the operculum allowed rapid germination of intact seed as did treatment with gibberellic acid. Removal of a portion of the endosperm, simulating damage by rats in the native environment, still allowed germination (tested on P. hillebrandii and P. Kaalae). Germination was also hastened if the seed was held at 25 to 35 C. Difficulty in surface-sterilizing tissues of Melicope anisata, resulted in a M.S. thesis on the sterilization protocol without extension to further plantlet development. Microcuttings were most successfully sterilized following washing in soapy water, rinsing in sterile deionized water, 45 minutes exposure with agitation in 10% dilution of commercial bleach and additional rinsing, and placement in a half-strength Murashige and Skoog medium with 3% sucrose and additions of 100 mg/L carbenicillin and 100 mg/L streptomycin. Similar problems in disinfecting Pittosporum meristem explants led to treatment of stock plant shoot tips growing in a dry greenhouse environment with 70% EtOH. Subsequently, treatments in 10, 5, and 2% commercial bleach dilutions in sterile water solutions containing 0.15g/L citric acid and 0.10 g/L ascorbic acid led to greater success. PARTICIPANTS: The following graduate students have engaged in research under this project: Hector Perez (PhD, 2006) completed his studies on seed physiology of Pritchardia remota. Nellie Sugii is currently pursuing DNA studies on the biodiversity of native Hawaiian Abutilon species and should complete her dissertation in fall 2010. Elizabeth Huppman is currently pursuing DNA studies on Hawaiian species of Hibiscus and should complete her dissertation in fall 2010. Michelei Kikuchi completed an M.S. thesis on decontamination of Melicope explants in 2008. Kekaha Spencer (M.S. pending) completed her studies on decontamination of explants of Hawaiian Pittosporum species for micropropagation but has not submitted her thesis. TARGET AUDIENCES: The decontamination protocol developed for Melicope explant microcuttings should provide persons interested in conservation and preservation of Hawaiian native plants with a starting procedure for the micropropagation of this species. Additional work on a suitable medium and reculturing practices will be necessary to develop a complete protocol. PROJECT MODIFICATIONS: The project was terminated following a one-year extension to 30 September 2009.

Impacts
While nurserymen are still interested in vegetative propagation techniques for both Alahe'e and Ho'awa, the long period required for successful rooting has led the few who are producing these species to rely on seeds. Vegetative propagation would allow selection of desirable growth habits from diverse seedling populations. The results of these studies does not establish a solid propagation protocol, but it does provide guidelines for additional work. The studies with Mokihana were undertaken to support conservation of plants whose fruits are collected en masse in the wild by lei makers, but until successful micropropagation of plantlets can be achieved, we have only the initial surface sterilization steps to offer promise of achieving the goal. Propagation of Ho'awa by vegetative means is somewhat more promising via either tissue culture or conventional methods, but increased numbers of these attractive ornamentals await refinement of the protocols.

Publications

  • No publications reported this period


Progress 10/01/07 to 09/30/08

Outputs
OUTPUTS: Studies were completed on approaches to surface sterilizing of Melicope anisata (Mokihana), the scented fruit of which is used in lei-making. While not listed as endangered, it is gathered extensively and reproduction in the wild is now rare. The objective of the study was to develop a protocol to achieve clean explants that could be grown in vitro to supply plants to lei makers and minimize the harvest of fruits in native areas. The successful protocol involved microcuttings that were scrubbed with a soft-bristled toothbrush in soapy water to remove some of the contaminants, as explant sources were available only from plants in the wild. Explants were subjected to agitation in soapy water, and then rinsed 3 times with sterile distilled water. These steps were followed with a 45 minute treatment in 10% bleach plus Tween 20 and agitation and 3 additional rinses sterile distilled water. An alternative to bleach was exposure to chlorine gas for 2 hours. Microcuttings were cultured on solid half-strength Murashige and Skoog medium supplemented with 30 g/L sucrose. The inclusion of 100 to 200 microgram streptomycin or 100 mg carbenicillin per liter was also helpful in suppressing bacterial contaminants. While contaminant-free explants were produced for Stage I (Establishment), longevity and shoot multiplication were not achieved. Abutilon menziesii is a native shrub with silvery heart-shaped leaves and pendent red blossoms. It is a federally listed endangered species, but it can be propagated for domestic use from cultivated plants. While it can be propagated from seed, progeny are variable, and selection of horticulturally-desirable forms requires vegetative propagation. Propagation by terminal cuttings has yielded mixed results as ease of rooting differs from plant to plant. Successful rooting was achieved using a 2500 ppm solution of 2:1 IBA:NAA under intermittent mist. Rooting was also achieved under high humidity conditions and with bottom heat, with root initiation evident 14 days after the cuttings were stuck in the medium and transplantable 3 weeks later. Shoot apical meristems were used as explants to develop an in vitro protocol for A. menziesii. Explants were washed in 10% bleach for 20 minutes, rinsed in sterile water, and plated onto full strength Murashige and Skoog medium supplemented with 0.1 mg/L bensyladenine. Ninety percent take was achieved. Rooting of in vitro shoots, however, is proving a challenge. Cuttings of Hibiscus kokio and H. brackenridgei were treated with aqueous solutions of 2 IBA: 1 NAA at final concentrations of 1666 to 2500 ppm. Rooting success was low, 30 and 60% for H. kokio and H. brackenridgei, respectively. PARTICIPANTS: Richard A. Criley is the principal investigator on this project. He is a member of the Tropical Plant and Soil Sciences Dept. of the University of Hawaii. Abutilon studies were reported from the research of graduate student Nelli Sugii. Hibiscus studies were reported from the research of graduate student Elizabeth Huppman. The studies by these two graduate students were conducted at the Harold Lyon Arboretum of the University of Hawaii. Disinfection of Melicope explants was the topic of the M.S. thesis by graduate student Michelei Kikuchi. Her work was partially supported by the National Tropical Botanical Garden at Lawai, Hawaii. TARGET AUDIENCES: Propagation of native ornamental plants is primarily targeted to Hawaii's commercial nursery operations. Their mission is to supply suitable native ornamentals to the landscape and retail garden center trade. Where propagation knowledge is insufficient our research support more efficient and successful ways to produce the needed quantities of plants. A secondary audience for this research is restoration-ecology operations that attempt to restore damaged ecosystems with native plants. Our peers in university research also benefit from published accounts of successful protocols, such as the disinfestation procedure for the Melicope. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
The potential to micropropagate the difficult-to-propagate Melicope species may be attained using a complex series of surface sterilization procedures. However, it has been difficult to prevent browning of the explants and keep them alive even after they have been established in sterile culture, and media and growth regulators for the multiplication phase have yet to be defined. The endangered Abutilon menziesii has been successfully propagated via cuttings which mean that superior clones can be selected and increased for release by the nursery industry. Poor rooting success for the hibiscus cuttings was attributed to wood selection as other research was successful in rooting these species. Commercial nurseries should manage stock plants to produce a more desirable type of cutting.

Publications

  • Kikuchi, M. 2008. A protocol for the decontamination of Melicope explants. M.S. Thesis. University of Hawaii, Honolulu, HI
  • Perez, H. E., R. A. Criley, and C. C. Baskin. 2008. Promoting germination in dormant seeds of Pritchardia remota (Kuntze) Beck., an endangered palm endemic to Hawaii. Natural Areas J. 28:251-260.
  • Perez, H.E. A.B. Shiels, H.M. Zaleski, and D.R. Drake. 2008. Germination after simulated rat damage in seeds of two endemic Hawaiian palm species J. Trop. Ecol. 24:555-558.


Progress 10/01/06 to 09/30/07

Outputs
OUTPUTS: Obj.#1 Seed of Psydrax odorata has a germination percentage of <10% because of insect damage. Vegetative propagation could permit selection of desirable horticultural types with upright growth suitable for tree forms or dense branching for shrubs. Attempts to propagate summer greenwood using various auxins, auxin cofactors, or hot water treatment were unsuccessful, with small amounts of callus produced after 4 months. Another native plant, Osteomeles anthyllidifolia, with landscape potential as a groundcover or low foundation planting, was propagated in low percentages (20 - 40%) using a 2:1 IBA-NAA combination at the rates of 5000 and 6000 ppm applied to the recently matured bases of terminal cuttings of a prostrate form of this plant. After 6 weeks in the propagation medium, rooting was light, and a longer period for root development was needed. Tissue culture approaches have been employed on 2 other difficult-to-root species, Pittosporum confertiflorum and Pelea anisata. The principal challenge has been to establish sterile cultures. The most successful results to date for P. confertiflorium have come from axillary bud meristems surfaced-sterilized with bleach plus anti-oxidants using sonication. These meristems were placed on half-strength liquid MS medium with vitamins, 3% sucrose, and anti-oxidants. Although survival to 6 weeks was good, necrosis was evident on many explants after this time. Explants for Pelea were field-collected as cultivated plants do not exist; as a result much contamination was encountered. Small nodal pieces of Pelea surface-sterilized with bleach followed by one hour soaks in a streptomycium/mefenoxam solution were successfully decontaminated of bacterial but not fungal microorganisms. Stage I establishment continues to be plagued by contamination. Obj.#2 No progress to report. Obj.#3 Collections of 13 Hawaii's native species and subspecies of Hibiscus were made. Both seed and vegetative propagation by cuttings were utilized to accumulate plants that are held at the Harold Lyon Arboretum of the University of Hawaii. DNA extractions are being made to compare genetic diversity and relationships among collections from different islands. PARTICIPANTS: Richard Criley, principal investigator. Professor of horticulture. Advisor to graduate students (below) whose work is being reported. Teaches in the TPSS Department course on plant propagation. Elizabeth Huppman. PhD candidate. Investigations into Hawaiian hibiscus. Employed by the Harold Lyon Arboretum, which gave her a 6-months sabbatical to pursue this work. Target completion, fall 2008 or spring 2009. Michelei Kikuchi. M.S. candidate. Investigations into tissue culture propagation of mokihana (Pelea anisata). Collects explants on the island of Kauai where this species is native. Employed by the National Tropical Botanical Garden on the island of Kauai. Target completion, May 2008. Kekaha Spencer, M.S. candidate. Investigations into tissue culture propagation of Ho'awa (Pittosporum confertiflorum). Part time student whose target completion date is May 2008. TARGET AUDIENCES: Hawaii nurserymen: a target audience for vegetative propagation of Alahe'e (Psydrax odorata) and 'ulei (Osteomeles anthyllidifolia), both of which are desirable species for landscape use in Hawaii. Both species are difficult to propagate vegetatively and have problems related to seed germination. Successful protocols for propagation of these materials would increase their availability for use in landscaping. They would also be targets for results from the tissue culture research when successful protocols for multiplication are achieved. The work on Pelea anisata would also be of value to environmental interests as wild collection of the fruits for use in lei has reduced the regenerating population of this very-difficult to propagate plant. Botanical gardens, nurseries, and plant breeders would be the targets for improved cultivars of Hawaiian hibiscus. Concern over transport of the germplasm between Islands requires knowledge of the extent of genetic diversity to support claims for conserving specific germplasm. On the other hand, improved color assortments of native Hawaiian hibiscus will appeal to Hawaii's nursery industry. Plant breeders need to know genetic relationships in order to make successful crosses. PROJECT MODIFICATIONS: The final year of this project will be 2007-2008. No modifications are proposed.

Impacts
Successful protocols for vegetative propagation of Psydrax and Osteromeles cannot yet be formulated. Progress is being made in decontamination of explants of Pittosporum and Pelea, but this is only a first step in attempts to develop protocols for successful increase via aseptic culture. Accumulation of diverse Hibiscus germplasm and its characterization by RAPD and SSR analyses will provide a basis for breeding and selection of desirable horticultural forms of Hawaii's most showy native plants.

Publications

  • No publications reported this period


Progress 10/01/05 to 09/30/06

Outputs
Studies on Pritchardia seed desiccation tolerance for the purpose of successful storage of endangered Hawaii palm species germplasm were concluded. Embryos of Pritchardia remota tolerate relatively high levels of drying and remain viable, but are not viable when moisture is reduced to < 10%, and thus would not maintain long term viability in conventional genebank conditions. While P. remota seed are dormant at shedding as a result of restriction by the operculum and endocarp and limiting moisture content, germination can be hastened following hydration at > 25 C. Removal of the operculum and treatment with gibberellic acid at 10 to 1000 ppm hastened germination while mechanical scarification did not. Lipoxygenases increased following dormancy-breaking treatments, suggesting a role of these enzymes in dormancy alleviation. The propagation of uluhe fern, Dicranopteris linearis, from spores sown on Steeves medium was achieved, with germination occurring in 2 weeks at 23 C and 12 hr broad spectrum light. The development of sporophytes was slow, and transfer from aseptic conditions to a more natural medium was not very successful. Mokihana (Melicope spp.), a small tree or shrub native to the island of Kauai, is difficult to propagate. Collection of its fragrant fruits for lei has reduced populations along most of the readily traversed trails, and seedlings are rarely seen in the wild. All plant parts, including roots, immature leaves, nodes, apical meristems, and embryos have been used as explants for aseptic culture on a variety of media including Murashige & Skoog and Woody Plant Medium, and different concentrations of auxins and cytokinins. Citric acid to prevent oxidative browning was essential. Contamination rates were high as all explants had to be gathered from wild material. The tissues yielding the best responses were apical meristems, leaf primordia, and immature leaves. Auxins and cytokinins at 3 to 6 mg per liter induced a hard, white friable callus. This callus is being used as a source of tissue from which somatic embryogenesis may be stimulated.

Impacts
The results of the palm seed desiccation tolerance studies suggest that nurserymen should sow fresh seed using hydration and warm medium temperatures for rapid germination. Seed can be stored, but not for long periods of time. Nonetheless, this information can be useful in conservation of endangered germplasm such as Pritchardia remota. The native fern, Dicranopteris linearis offers potential as a ground cover and antagonist to invasive species if it can be produced in quantity. With sporophytes difficult to transplant from the wild, aseptic culture appears to be the best way to obtain large numbers of plants for restoration and watershed management. Successful propagation of mokihana can allow its production in cultivated plots and minimize loss of germplasm in natural environments. Overcoming contamination problems for in vitro culture is the first step in the process of tissue culturing this endemic species.

Publications

  • Criley, R. A. 2006. Notes on propagation of various tropical woody ornamentals. Comb. Proc. Intern. Plant Prop. Soc. 55:507-511.
  • Perez, H. E. 2006. Implications of embryo desiccation tolerance, seed dormancy, and seed damage for conservation of Pritchardia palms endemic to Hawaii. Ph.D. dissertation, University of Hawaii, Honolulu, HI 180 p.
  • Romanchak, E. A., R. A. Criley and N. Sugii. 2006. The propagation of uluhe fern (Dicranopteris linearis): vegetative versus spores. Comb. Proc. Intern. Plant Prop. Soc. 55:517-519.


Progress 10/01/04 to 09/30/05

Outputs
A propagation experiment using soft terminal cuttings of Osteomeles anthyllifolia treated with a series of auxin concentrations from 0 to 7000 ppm yielded poor results while somewhat more woody cuttings showed a greater tendency to produce roots. Seed of Dianella sandwicensis was collected in Oct. 2004 and stored at 8 C until sown at intervals up to 6 months later. Germination for seed sown within 3 months of harvest was about 80% and began to decline at about 4 months. Days to sprouting ranged from 41 to 67 and averaged 58. Only 4% germination was observed for seed sown 8 months after collection. Asexual propagation of Dicranopteris linearis fern by division and layering was not successful and offers little promise for use in restoration or landscaping. Spore propagation has yielded gametophytes in aseptic culture, but sporophyte production has proven difficult. Plantlet production from spores offers the best option for large numbers of liners for planting out. Pritchardia seed germination was improved if the operculum was removed, if seed was treated for 24 hr with gibberellic acid at 10 to 1000 ppm, or if germination was conducted at 35 C. These results will improve the capacity of nursery managers to produce these palms for landscape use as well as for recovery of endangered species. In a study to evaluate genetic diversity of native Hawaiian Hibiscus for use in ornamental horticulture and improved cultivar development, DNA has been purified for 14 species/subspecies. This will be subjected to RAPD analysis.

Impacts
An effective protocol for ulei (Osteomeles anthyllidifolia) is not yet defined, but the data suggest that vegetative propagation is possible if cuttings with matured wood are used. Seed requires a long time to germinate and vegetative propagation by cuttings will enable more use of this attractive ornamental in landscapes. Our germination results suggest that Dianella sandwicensis seed has a short viability period, even with cold storage, and should be sown within 6 months of collection. Uluhe fern (Dicranopteris linearis) must be propagated by spores in order to obtain the large number of plants needed for restoration and/or landscape use. Conditions that improve germination of Pritchardia seed have been developed that will enable nurseries to germinate efficiently seeds of these palms for landscape use as well as for recovery of endangered palm species. The impact of DNA extraction of Hawaiian hibiscus is difficult to quantify as the studies of genetic diversity to which it will be put have yet to be completed.

Publications

  • Perez, H.E. 2005. Rapid excision of Pritchardia embryos. Palms. 49(1):36-39.


Progress 10/01/03 to 09/30/04

Outputs
Objective 1: Experiments on propagation of Hoawa (Pittosporum confertiflorum) by cuttings indicated that terminal cuttings yielded greater success than did cuttings from the second or third flushes below the terminal. With 4000 ppm KIBA as a control, results coupling 0.003M quercetin or 0.003M chlororesorcinol with 4000 ppm KIBA showed no improvement in rooting percentage over the controls. All rooting percentages were low. Objective 2: Desiccation tolerance of developing embryos of Pritchardia remota improved 128 days after anthesis (DAA) through fruit shedding. Embryos extracted from the seed 290 DAA tolerated drying in a range of 75 to 25% relative humidity as evidenced by their capacity to germinate. Similarly, the critical water content for 50% germination decreased to 350 mg/g DW at 290 DAA compared to 1600 mg/gm DW at 128 DAA. These results suggest that this palm does not possess a typical recalcitrant seed storage physiology. Embryos possess a higher moisture content than endosperm and endocarp, but 168 hr of imbibition is required for sufficient moisture uptake to overcome physiological and morphological dormancy. The endosperm, endocarp, and operculum appear to slow imbibition. Removal of the operculum to permit imbibition allowed 62% germination within 2 days and 100% germination after 7 days versus only 25% germination for intact seed at 7 days. Objective 3: No progress to report.

Impacts
An effective protocol for Hoawa is not yet defined, but the data suggest that vegetative propagation is possible. Hoawa seed are very difficult to germinate, and vegetative propagation by cuttings will enable more use of these attractive ornamentals in the landscape. The studies with P. remota will have a dual impact as the nursery industry will have a better idea of when to harvest fruits and what the optimum moisture conditions are for good germination. Conservation and restoration interests will also be able to store seed longer knowing how much desiccation can be tolerated and this will permit better management of a limited germplasm base for their purposes. Although species differences can be expected, it is useful to know that these native Hawaiian palms can be stored and still exhibit the capacity to germinate given the proper storage conditions.

Publications

  • No publications reported this period


Progress 10/01/02 to 09/30/03

Outputs
The continuing trials to produce an effective propagation protocol for Alahe'e (Psydrax odorata) this year involved banding of the cuttings while on the stock plants to blanche the cutting bases and use of quercetin (a flavonoid) and chlororesorcinol (an auxin synergist), both at 10-3 M coupled with 4000 ppm equivalent from potassium salt of IBA. There did not appear to be a marked effect of banding, and rooting was only slightly improved with the use of choloresorcinol + auxin over the auxin alone. Rooting percentages were < 20% in all treatments. Germination and dormancy studies in seed of Pritchardia species revealed that seed germinated well in either light or dark and somewhat faster when buried than when left on the medium surface. Seed storage for at least one year appears possible without significant loss of viability at temperatures ranging from 15 to 20 C. Simulating predation by removal of 22.5 and 45% of the endosperm enhanced germination rates over intact controls or removal of 67.5% of the endosperm. Analyses of sugars and lipids in the seeds suggest that the mono/oligosaccharide ratio would not explain desiccation tolerance, but that ratios of the saturated and unsaturated fatty acids may play a role in desiccation tolerance.

Impacts
At this point, there is no effective and reliable protocol for vegetative propagation of Psydrax odorata. The dormancy and desiccation tolerance studies on Pritchardia species may lead to storage protocols that enable nurserymen and conservationists to use seed collected in good years of seed production for plant production in years when seed production was low. Restoration of endangered Pritchardia palms will benefit from knowledge of the mechanisms of germination and dormancy and how they can lead to seed banks with diverse germplasm content.

Publications

  • Herring, E.C. and Criley, R.A. 2003. The Hawaiian native plant propagation web site: Developing a web-based information resource. HortTechnology. 13(3):545-548.


Progress 10/01/01 to 09/30/02

Outputs
Recently-matured, terminal cuttings of Pittosporum confertiflorum, P. floculosum and an unidentified species were treated with IBA concentrations of 3000, 4500, 6000, and 7500 mg/L in 30% ethanol. The length of time for adequate rooting to transplantable root mass from sticking the cuttings was about 21 weeks. Source of propagule and its maturity were critical to success as no cuttings rooted from two sources of P. confertiflorum or the P. floculosum plant, but 70% rooting was achieved for a P. confertiflorum from the Lyon Arboretum and 20% for cuttings from an unidentified species. In general, concentrations of 3000 to 4500 mg IBA/L seem to be sufficient to stimulate rooting of P. confertiflorum, but the choice of cutting materials is critical. Terminal leafy greenwood cuttings of Psydrax odorata were treated with a commercial preparation of 2 parts IBA : 1 part NAA at a concentration of 3750 mg (total auxin)/L plus additional treatments of 110 F hot water (10 minutes) or three phenolic materials. In the comparison of no hot water versus hot water, stems of many cuttings were killed where immersed in the hot water. Few cuttings had rooted overall 10 weeks after treatment, but 10-3 M chlororesorcinol + the auxin provided the most rooted cuttings followed by 10-3 M cholorgenic acid and 10-3 M caffeic acid. An isozyme fingerprinting technique was used to distinguish between different sources of native Hawaiian Gardenia species and some cultivated H. augustum cultivars. A Jaccard tree showed that G. augusta was clearly distinguishable from G. brighamii, G. mannii, and G. taitensis, while G. remyi was distinct from all of them. Clones of G. brighamii could be identified although there were small differences between sources, and G. brighamii was separable from G. mannii and G. taitensis.

Impacts
Since seed germination of the Hawaiian species of Pittosporum is limited by seed availability and inconsistency of germination time, vegetative propagation is preferred both for reliability of supply and for reproduction of horticulturally desirable clones. Two trials (one reported in this year) indicate that recently-matured terminal greenwood cuttings treated with 3000 to 4500 mg/L indole-3-butyric acid offers good potential for increasing these plants. The Hawaiian Pittosporums are attractive landscape plants with both compact shrubs and tree forms that have varied leaf shapes and sizes, textures and colors. When the time to germinate seed is included, cuttings are faster in attaining marketable size. Psydrax odorata produces many fruits, but the seed is infested with larvae that render only about 10% germinable. Vegetative propagation would enable more uniform progeny as well as the opportunity to select desirable plant growth habits. P. odorata could potentially substitute for the unbiquitous Murraya paniculata in Hawaii landscapes. Reliable vegetative propagation by cuttings still awaits defined protocols, including root stimulating substances. The use of an isozyme "fingerprinting" technique is less expensive than DNA-based protocols, and satisfactorily distinguished among different species and clones of both native and common gardenias using only a few enzyme systems. This may be useful in tracing original populations of the native Hawaiian gardenias as well as opening a window to look at the relationships among other native gardenias in the Pacific and Asia.

Publications

  • No publications reported this period


Progress 10/01/00 to 09/30/01

Outputs
A data-based web site on the propagation of native Hawaiian plants with ornamental potential was user-tested and completed: (http://pdcs.ctahr.hawaii.edu:591/hawnprop) This site provides information about seed or vegetative means of propagating nearly 100 plant materials endemic or indigenous to Hawaii. An attempt to root softwood and greenwood cuttings of the Hawaiian ho'awa, Pittosporum confertiflorum, from five source plants was initiated in July 2001. After 10 weeks (the ending period for this report), only a few of the softwood cuttings had begun to root in response to treatment with 4000 ppm KIBA, but many of the remaining cuttings were healthy and showing some callusing. The source material was important as cuttings from one source were not performing well. Final data will be collected during the next reporting year.

Impacts
The web site on the propagation of native Hawaiian ornamental plants is linked to several other propagation web sites, to the Botanical Gardens URL at the Hamilton Library of the University of Hawaii, and carries a PDCS identification code that enables web searchers to find it. During the site construction and testing period, improvements were made and users declared it a valuable contribution as it includes information from in-print sources that are not easily found using computer search engines as well as information gathered from botanical garden and nursery sources unavailable to most persons. The author, Ms. Eileen Herring, plans to add to and update this web site for another 1 year. It may be possible to develop a CD that provides a picture in time for the information. This question and other issues related to intellectual property rights are being investigated. There are a number of attractive ho'awa species in Hawaii for which a good seed source is not generally available. The lack of plant material has meant it is not generally specified for landscapes although ho'awa make good small ornamental trees. The results of this research are expected to point the way for commercial nurseries to propagate desirable clones for use in landscapes.

Publications

  • Herring, E. 2001. The Hawaiian native plant web site. http:// pdcs.ctahr.hawaii.edu:591/hawnprop/ (a web site developed as a graduate student for the M.S. in Horticulture)


Progress 10/01/99 to 09/30/00

Outputs
A database on the propagation of native Hawaiian plants was developed by M.S. student Eileen Herring, and a test version was placed on-line for evaluation by potential users. The website is not yet in its final version as additional plants and references remain to be added, but response to Ms. Herring from users has been favorable. The website address is http://www.ctahr.hawaii.edu.591/hawnprop/. Charpenteira tomentosa var maakauaensis (papala) was successfully propagated by terminal cuttings using 2500 ppm Dip N Grow rooting compound. This plant material appears to be easy to propagate vegetatively. It has a potential use as an interior plant. A small-leaved Metrosideros polymorpha ('ohia) with potential as a potted plant was treated with paclobutrazol to learn whether the growth retardant would stimulate flower bud formation. While growth retardation was evident, there was no flower initiation associated with the treatment. The selection is easy to propagate, however, with a standard 2500 ppm Dip N Grow rooting hormone applied to recently matured terminal cuttings. Obj. 2: No progress to report.

Impacts
The Propagation of Native Hawiian Plants website will permit persons interested in conservation, garden culture, or commercial nursery operation to locate information compiled in one easy-to-search database. This is a valuable service because the information is located in a diverse body of literature, some of which is obscure and not easy to find. The ease of propagation of the papala and the 'ohia selection mean that they may be readily increased for possible use as potted plants.

Publications

  • No publications reported this period


Progress 10/01/98 to 09/30/99

Outputs
Obj. 1: Attempts to improve vegetative propagation of Psydrax odorata cuttings by hot water treatment plus auxin and dithiothreitol (1.0, 0.5, 0.1 and 0.05 M) were not successful. Seed of 3 Pittosporum sp. collected at Waimea Arboretum yielded only a few seedlings of P. flocculosum 60 days after germination, while 2 other species failed to germinate. Cuttings from juvenile plants of Colubrina oppositaefolia were successfully propagated under mist following treatment with 4000 ppm auxin. Seedlings of a cross between Hibiscus clayii and H. koko saintjohnianus have begun to flower and show intermediate characteristics between the two parents. Selection for larger petalled types is underway and desirable hybrids will be propagated vegetatively. Obj. 2: No progress to report.

Impacts
Two papers reviewing successful propagation of ornamental Hawaiian plants were published.

Publications

  • Criley, R.A. 1999. Propagation of indigenous and endemic ornamental Hawaiian plants. Proc. Intern. Plant Prop. Soc. 48:669-674.
  • Criley, R.A. 1999. Aloha Hawaii. Amer. Nurseryman. 190(3):50-61. (propagation and use of Hawaiian native plants)


Progress 10/01/97 to 09/30/98

Outputs
Obj. 1. The native plant, alahe'e (Psydrax odorata; syn. Canthium odoratum),has attractive foliage and tolerance to varied environmental conditions that could make it a substitute for the widely planted mockorange (Murraya paniculata). Seed, however,is commonly infested with insect larvae, and is less than 10% germinable. Vegetative propagation can be used to increase desirable forms with compact growth, but the rooting of cuttings has proved difficult. Alahe'e cuttings from 5 source plants (2 at the Lyon Arboretum, 2 at the Hoolulu Botanical Gardens, and 1 from the University of Hawaii Manoa campus) were subjected to treatments previously showing promise in stimulating root production (CSRS Report 96-97). Green terminal cuttings of 7.5 to 10 cm length with at least 3 nodes were inserted in 1 vermiculite : 1 perlite medium for 12 weeks in a high humidity enviornment. Rooting percentages were low, and rooted cuttings developed only from the UHM stock plant, which is regularly pruned. Root and callus production were highest for treatments combining 5000 ppm IBA and 0.1 M dithioerythritol, 5000 ppm IBA and 0.1 M quercitin, or 10,000 ppm phenyl-indole-3-thiolobutyrate (PITB). Additional trials will be necessary to develop a reliable propagation protocol. Terminal cuttings of pohinahina (Beach vitex, Vitex rotundifolia) from vigorously-growing potted plants rooted 100% in 4 weeks following treatment with talc preparations containing 3000 and 8000 ppm IBA. Rooting was also good on control cuttings but these took 2 to 3 weeks longer to root. Hand pollination of greenhouse-grown Hibiscus clayii resulted in good seed set. Germination occurred in 3 to 4 weeks, and seedlings grew rapidly, producing their first flowers 5 to 6 months later. Obj. 2: Seed of Styphelia tameiameiae (pukiawe) were removed from the hard matrix of the fruit, dehydrated in a alcohol series and embedded in paraffin wax. Sections were cut on a microtome at 10 microns thickness. Microscopic examination revealed a well-developed embryo, thus ruling out a poorly-developed or immature embryo as a cause of delayed and poor germination.

Impacts
(N/A)

Publications

  • No publications reported this period


Progress 10/01/96 to 09/30/97

Outputs
One of the attractive native Hawaiian plants that may be substituted for mockorange in Hawaii's landscapes is alahe`e (Canthium odoratum - Psydrax odorata). Nine hundred cuttings of Canthium odoratum were collected from the Mokuleia Forest Reserve in Dec. 1996 and treated with different auxin, phenolic, thiol, and flavonoid compounds to stimulate rooting. Cuttings were rooted under high humidity as previous attemtps to root this species under intermittent mist were largely unsuccessful. Rooting success was poor, but the trials have suggested which compounds and conbinations offer a better chance for success. When comparing results between mature brown wood and recently matured greenwood, more greenwood cuttings had rooted with a higher rooting index than cuttings from older wood. Successfully-rooted plants from this experiment are being grown under shade to serve as stock plants for future experiments. Eragrostis variabilis seedlings developed 20 to 30 cm long root systems within 5 weeks of germination. This deep-rooted characteristic is probably responsible for the drought tolerance of this species, which has been offered as a possible plant material for vegetation restoration on the island of Kaho`olawe. From a seedling population of Osteomeles anthyllidifolia, two plants have been selected with fine leaves and a more compact growing habit than is usually seen in the wild. Such selections may have unique uses for Hawaiian landscapes.

Impacts
(N/A)

Publications

  • No publications reported this period


Progress 10/01/94 to 09/30/95

Outputs
No progress to report. This project was initiated on October 1, 1995.

Impacts
(N/A)

Publications

  • NO PUBLICATIONS REPORTED THIS PERIOD.