Recipient Organization
MICHIGAN STATE UNIV
(N/A)
EAST LANSING,MI 48824
Performing Department
Plant, Soil and Microbial Science
Non Technical Summary
The U.S. turfgrass industry generated $124.6 billion in 2005 (Haydu et al., 2012) and continues to be a major source of revenue and jobs for communities. Turfgrasses, particularly those used on golf courses and athletic fields, are a major high value commodity, particularly in Michigan. A significant amount of monetary, labor, water, and chemical inputs are required to maintain turfgrasses to an acceptable level of quality for functionality as a playing surface. To a large degree, many of the inputs are needed due to the susceptibility of turfgrasses to abiotic and biotic stresses. Stresses that are highly damaging to turfgrasses and cause significant economic loss in northern areas include winter related stresses, biotic diseases, heat stress, drought stress, and other management stresses. Reducing costs of management, reducing environmental ipact, and required inputs is a major long term goal of this research. Practices that are developed based on knowledge of physiological responses of turfgrasses areurgently needed for sustainabiliity of the turfgrass industry.
Animal Health Component
50%
Research Effort Categories
Basic
50%
Applied
50%
Developmental
(N/A)
Goals / Objectives
The major goals of the project are to investigate 1) physiological responses associated with winterkill susceptibility or tolerance of cool season turfgrass species 2) physiological changes associated with turfgrass-pathogen interactions and abiotic stresses 3) hormone and metabolite physiology of turfgrass species associated with cultural practices or environmental stresses 4) management strategies to promote stress tolerance of turfgrasses.
Project Methods
Project I - Winterkill experimentsObjective 1 - These methods aim to determine acclimation timing and requirements for annual bluegrass associated with cultural practices, and effect on carbohydrates. Evaluate whether changing the cutting height at several timepoints prior to the start of a simulated acclimation has an effect on carbohydrate storage and plays a role in annual bluegrass survival of ice and low temperature conditions. Annual bluegrass plugs taken from an established annual bluegrass field will be subjected to different cutting treatments under greenhouse conditions. Plants will be trimmed to a standardized length and then will be subjected cutting treatmentsassociated with proximity to acclimation. PLants will be subjected to ice and temp treatments in growth chambers.? Ice and freeze tolerance measurements. This will include a determination of antifreeze protein content, total nonstructural carbohydrate content (TNC), fructans, and fatty acid profiles. Plants will be separated into leaf, crown, and root tissue for each analysis. Method for antifreeze proteins will be the same as in Yu et al 2001. TNC will be performed by the methods of Huang and Gao (2000). Fatty acid profiles will be evaluated as in Xu et al. (2011). Samples for freeze tolerance assays or freeze tests (-6 to -21°C) for LT50 determination will be conducted.Objective 2-Ethylene regulation project:Turf plots of CBG and ABG will be established at the Hancock Turfgrass Research Center at MSU. Turf plots will be treated with one of the following treatments throughout the late fall in order to allow for natural acclimation to cold temperatures. 1) negative control, no chemical treatment 2) ethephon (Proxy) as an ethylene application (label recommended) 3) ethylene precursor aminocyclopropane- 1-carboxylic acid (100 µmol L-1) as an ethylene application (Larkindale and Huang, 2004) 4) 25 µM aminoethoxyvinylglycine (AVG) to inhibit ethylene (Jespersen et al 2015) 5) ReTain (label recommended rate) to inhibit ethylene. Field plots will be split into1) no ice 2) ice cover treatments. A total of 80 field plots will be established (2 ice treatments x 2 species x 4 replications x 5 treatments). Field plots will be evaluated as described in objective 2. Plots will be irrigated to attempt to achieve ice at a 0.5" layer but of course ice establishment and persistence will be up to weather conditions.Plant growth regulator and plant priming projectsEstablished field plots will be treated with various PGR treatments following management chemicals throughout the summer and fall months. Four plugs from each plot will be taken and brought into the growth chamber in late fall. The plugs will be treated with ice as suggested in the methods above for objectives 1-3. These plugs will then be evaluated for differences in gas accumulation, fatty acid accumulation, MDA content, TTC reduction, regrowth, and overall turf quality following regrowth as described above.Prior to freezing of the soil in the field, plugs of ABG turf (4") will be taken and placed in a freezer in late fall/early winter. For ice treatment, ABG plants will be misted under low temperature in order to develop an ice layer of 1" depth. Plants will be exposed to two ice treatments 1) no ice 2) ice cover both at -4°C in freezers. Plants will be sampled at 0, 20, 40 and 80 days of ice cover. Thus, a total of 256 turf plugs will be taken (1 species x 4 replications x 8 chemical treatments x 2 ice treatments x 4 sampling dates). On a given sampling day, turfgrass plugs will then be cut in half. Half of the plugs will go towards a regrowth assay in a greenhouse (plants will be de-acclimated for one week in a refrigerator prior to transferring to the greenhouse) and percent regrowth will be documented weekly or on an as needed basis. Field plots of CBG and ABG will also be evaluated throughout the summer/fall treatments and in the spring for spring green-up. Turf quality ratings will also be taken on a scale of 1 to 9 with 9 being healthy green turf and 1 being necrotic turf (Beard, 2001). Normalized difference vegetative index (NDVI) will be measured to get a quantitative measure of plot health and density. Field plots will be evaluated in the spring for recovery and survival based on percent survival, turf quality ratings, light box measurements, and NDVI measurements. Treatments with the most potential for use in the turfgrass industry will be investigated in depth for how they may alter plant acclimation strategies and ice tolerance. These methods will be developed as appropriate following initial results.Objective 3.Annual bluegrass (P. annua var reptans) ecotypes will be collected from approximately 20 golf courses and wheat fields throughout Michigan through MSU's strong connections with the Michigan Turfgrass Foundation (MTF) and wheat growers. We will also acquire an ecotype sensitive to freezing temperatures in the perennial form from Quebec (Hoffman et al., 2014). These collected plants will be screened for tendency to revert between annual and perennial forms and will be evaluated for physiological traits and life cycle habits. In total, 160 plants will be screened (20 ecotypes x 2 cultural treatments x 4 replications). To document and quantitatively distinguish plants of P. annua var annua and P. annua var reptans, collected plants will be clonally propagated by tillers and then maintained either with regular mowing/clipping or left uncut for approximately 2 months or until a shift in growth habit is observed as described in La Mantia and Huff (2011). Plant height, spread, number of flowers, average leaf width, and specific leaf area will be documented as described in La Mantia and Huff (2011). Hormone profiles of select annual bluegrass ecotypes in an annual or perennial state will also be measured as in Krishnan and Merewitz, 2015. The genome size of each ecotype will be determined. The genome size will be considered when all data is interpreted and if any comparisons are made between ecotypes as in Arumuganathan and Earle (1991) with a few modifications. This is an inexpensive method and can be used for many ecotypes. All physiological parameters and screening data will be analyzed according to the appropriate experimental design and statistical model.Objective 4.10 of the ecotypes identified in objective 1 will be to assess tolerance to low temperatures (10 ecotypes x 2 temperatures x 2 cultural treatments x 4 replications = 160 plants). The experiment will be repeated in time. All annual bluegrass ecotypes in both the annual or perennial form will be screened for low temperature tolerance using LT50 measurements as described in (Hoffman et al., 2014). Following LT50 assessments, carbohydrate and fatty acid analysis (Huang and Gao 2000 and Xu et al. 2011) will be evaluated in a separate set of samples exposed to optimal and low temperature conditions.Project II - Impacts of plant growth regulators on abiotic and biotic stress toleranceEvaluating biochemical changes associated with plant growth regulator application will be done using hydroponic studies and heat stress. Plant transpiration will be measured to determine if any differences in stomatal conductance are present. Plant hormones, heat shock proteins and metabolite analysis will be performed on plants treated with GA inhibiting PGRs compared to plants not treated with PGRs under both optimal and high temperature conditions. An understanding of turfgrass responses to PGR and heat stress will allow for a better ability to interpret the more complex interactions of PGR-plant-disease systems. Once heat and PGR experiments are performed, diseases such as dollar spot, brown patch, and bacterial disease will be introduced into the methods.