scholarly journals Heat Tolerance of Kentucky Bluegrass as Affected by Trinexapac-ethyl

HortScience ◽  
2001 ◽  
Vol 36 (2) ◽  
pp. 365-367 ◽  
Author(s):  
Neil L. Heckman ◽  
Garald L. Horst ◽  
Roch E. Gaussoin ◽  
Linda J. Young
Keyword(s):  
Heat Stress ◽  
Heat Tolerance ◽  
Vapor Pressure Deficit ◽  
Poa Pratensis ◽  
Acid Methyl Ester ◽  
Kentucky Bluegrass ◽  
Single Application ◽  
Heat Accumulation ◽  
Lethal Temperatures ◽  
Acid Methyl

Heat accumulation during storage of sod may reach lethal temperatures within 4 days, decreasing sod quality. Treatment with trinexapac-ethyl reduces heat accumulation during sod storage. However, heat tolerance of grasses treated with trinexapacethyl has not been documented. Our objectives were to: 1) determine the lethal temperatures for Kentucky bluegrass (Poa pratensis L.); and 2) identify the effect of a single application of trinexapac-ethyl on heat tolerance. Experimental design was a randomized complete block with three replications and a two (trinexapac-ethyl vs. control) × two (cultivars) factorial arrangement of treatments. Ten days after chemical treatment, Kentucky bluegrass sprigs were exposed to heat stress for 4 days in a temperature gradient block under low vapor pressure deficit. Treatment with trinexapac-ethyl at 0.23 kg·ha-1 reduced heat tolerance. Temperature needed to kill 50% of the population was 35.5 °C for treated vs. 36.1 °C for nontreated grass. Trinexapac-ethyl is in the same chemical family as the cyclohexanedione herbicides that interfere with lipid syntheses in grasses. This may be a reason for the slight decrease in heat tolerance. The practical value of trinexapac-ethyl treatment in reducing heat accumulation during storage of sod may be partially negated by a decrease in heat tolerance. Chemical name used: [(4-cyclopropyl-α-hydroxy-methylene)-3,5-dioxocyclohexanecarboxylic acid methyl ester] (trinexapac-ethyl).

scholarly journals Differential Responses to Heat Stress in Activities and Isozymes of Four Antioxidant Enzymes for Two Cultivars of Kentucky Bluegrass Contrasting in Heat Tolerance

2010 ◽  
Vol 135 (2) ◽  
pp. 116-124 ◽  
Author(s):  
Yali He ◽  
Bingru Huang
Keyword(s):  
Antioxidant Enzymes ◽  
Heat Stress ◽  
Heat Tolerance ◽  
Defense Mechanisms ◽  
Poa Pratensis ◽  
Kentucky Bluegrass ◽  
Guaiacol Peroxidase ◽  
Cool Season ◽  
Chl A ◽  
Antioxidant Mechanisms

Understanding antioxidant mechanisms for heat stress is important for improving heat tolerance in cool-season plant species. The objective of this study was to identify antioxidant enzymes associated with cultivar variations in heat tolerance in kentucky bluegrass (Poa pratensis) by comparing heat responses of activity and isoforms of antioxidant enzymes in two cultivars contrasting in heat tolerance. Plants of heat-tolerant ‘Eagleton’ and heat-sensitive ‘Brilliant’ were exposed to 20 °C (control) or 40 °C (heat stress) for 28 days in growth chambers. Chlorophyll (Chl) a content remained unchanged and Chl b content increased in ‘Eagleton’, while both of them decreased in ‘Brilliant’, and by 28 days, ‘Eagleton’ had significantly higher Chl a and b content than ‘Brilliant’. The activities of superoxide dismutase (SOD) were significantly higher in ‘Eagleton’ than in ‘Brilliant’ by 28 days of heat stress. An isozyme SOD2 was induced early during heat stress in ‘Eagleton’, while isozyme SOD3 degraded, to a lesser extent in ‘Eagleton’ than in ‘Brilliant’. Catalase (CAT) activity significantly increased in ‘Brilliant’ but remained constant in ‘Eagleton’, and ‘Brilliant’ had a significantly higher CAT activity and isozyme CAT1 than ‘Eagleton’ during heat stress. Significant increases in ascorbate peroxidase (APX) activities occurred under heat stress, to a greater extent in ‘Eagleton’, whereas isozymes did not exhibit difference between cultivars. Guaiacol-peroxidase (POD) activity declined during heat stress in both cultivars. The intensity of POD isozymes in ‘Brilliant’ remained constant, while ‘Eagleton’ showed a transient increases in POD1 at 7 days of heat stress. Our results indicated that antioxidant defense mechanisms for heat tolerance in kentucky bluegrass could be mainly associated with changes in activity and forms of isozymes of SOD for O2 scavenging and APX activity for H2O2 scavenging under heat stress.

scholarly journals Differential Responses of Nutrients to Heat Stress in Warm-season and Cool-season Turfgrasses

HortScience ◽  
2009 ◽  
Vol 44 (7) ◽  
pp. 2009-2014 ◽  
Author(s):  
Hua Shen ◽  
Hongmei Du ◽  
Zhaolong Wang ◽  
Bingru Huang
Keyword(s):  
Heat Stress ◽  
Heat Tolerance ◽  
Poa Pratensis ◽  
Warm Season ◽  
Kentucky Bluegrass ◽  
Grass Species ◽  
Cool Season ◽  
Temperature Conditions ◽  
Differential Responses ◽  
K Concentration

The objective of this study was to compare differential nutrient responses to heat stress in relation to heat tolerance for warm-season (C4) common bermudagrass [Cynodon dactylon (L.) Pers.] and cool-season (C3) kentucky bluegrass (Poa pratensis L.). Both species were exposed to two temperature regimes in growth chambers: optimal day/night temperature conditions (24/20 °C for kentucky bluegrass and 34/30 °C for bermudagrass) or heat stress (10 °C above the respective optimal temperature for each species). Heat injury in leaves was evaluated and the concentrations of several major macronutrients [nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), and magnesium (Mg)] in both grass species were measured at 0, 7, 14, 21, and 28 days of treatment. Heat stress reduced leaf photochemical efficiency and cellular membrane stability in both species, but bermudagrass leaves exhibited less damage in these parameters than kentucky bluegrass. Heat stress caused a significant decline in N, P, and K concentration, beginning at 7 days in kentucky bluegrass, but had no significant effects on N, P, and K concentration in bermudagrass during the 28-day treatment period. The concentration of Ca and Mg increased under heat stress in both kentucky bluegrass and bermudagrass, but there were no significant differences between the species under optimal or high-temperature conditions, suggesting they were not involved in heat responses in either species. The differential responses of N, P, and K to heat stress could at least partially account for the differences in heat tolerance between the two species and demonstrate the importance of sufficient N, P, and K in turfgrass adaptation to heat stress.

scholarly journals Multiple Trinexapac-ethyl Applications Reduce Kentucky Bluegrass Sod Storage Temperatures

2001 ◽  
Vol 11 (4) ◽  
pp. 595-598 ◽  
Author(s):  
Neil L. Heckman ◽  
Roch E. Gaussoin ◽  
Garald L. Horst
Keyword(s):  
Methyl Ester ◽  
Experimental Design ◽  
Poa Pratensis ◽  
Acid Methyl Ester ◽  
Kentucky Bluegrass ◽  
Acid Methyl ◽  
Rate Of Heating ◽  
Market Areas ◽  
Storage Times ◽  
Storage Temperatures

Sod heating during storage can limit the distance sod may be shipped. Two experiments were conducted to determine the effect of multiple preharvest applications of trinexapac-ethyl [4-cyclopropyl-α-hydroxy-methylene)-3,5-dioxocyclohexanecarboxylic acid methyl ester] at 0.23 kg·ha-1 (0.21 lb/acre) on kentucky bluegrass (Poa pratensis) sod temperatures during the first 24 h of storage. Experimental design was completely randomized with three replications and a 2 (trinexapac-ethyl verses control) × 3 (8-h storage intervals) factorial arrangement of treatments. Trinexapac-ethyl treatments were applied 6 and 2 weeks before harvest in the first experiment and 10, 6, and 2 weeks before harvest in the second experiment. Two and three applications of trinexapac-ethyl reduced sod storage temperatures. The reduction in rate of heating in treated sod became significantly different than untreated sod within 4 h after harvest. Mean sod temperatures in both experiments were 3 °C (6 °F) cooler in treated sod after 12 h of storage than untreated sod. These results suggest that trinexapac-ethyl could be used by sod growers to extend storage times and increase shipping and market areas. A multiple application program can enable sod growers to maximize the enhancement effects of trinexapacethyl on sod storage life.

scholarly journals Differential Responses of Hybrid Bluegrass and Kentucky Bluegrass to Drought and Heat Stress

HortScience ◽  
2008 ◽  
Vol 43 (7) ◽  
pp. 2191-2195 ◽  
Author(s):  
Eleni M. Abraham ◽  
William A. Meyer ◽  
Stacy A. Bonos ◽  
Bingru Huang
Keyword(s):  
Heat Stress ◽  
Heat Tolerance ◽  
Transpiration Rate ◽  
Soil Depth ◽  
Poa Pratensis ◽  
Kentucky Bluegrass ◽  
Optimal Temperature ◽  
Turf Quality ◽  
Differential Responses ◽  
Drought And Heat Stress

This study was designed to investigate differential responses of hybrids from Texas bluegrass (Poa arachnifera Torr.) × Kentucky bluegrass (Poa pratensis L.) (KBG) and KBG genotypes to drought and heat stress. Plants of two hybrids, ‘845’ and ‘BDF’, and two KBG genotypes (‘Midnight’ and ‘C-74’) were grown under optimal temperature (22/18 °C) and well-watered (control) or unwatered (drought) or superoptimal temperatures (35/30 °C; heat stress) conditions for 35 days in growth chambers. Under optimal conditions, the two hybrids and two KBG genotypes were not significantly different in turf quality, leaf photochemical efficiency expressed as chlorophyll fluorescence ratio (Fv/Fm), leaf net photosynthetic rate (Pn), transpiration rate, water use efficiency (WUE), root dry matter, or root viability. The results suggest that the interspecific hybridization resulted in similar growth and physiological traits in the hybrid bluegrass as in a turf-type species under optimal temperature and irrigation regimes. Under drought stress, all these parameters were comparable to those for KBG ‘Midnight’, but significantly higher than the corresponding parameters for KBG ‘C-74’. Under heat stress, both hybrids had significantly higher turf quality, Fv/Fm, Pn, transpiration rate, WUE, root dry weight in deeper soil depth (40 to 60 cm), and root viability in the upper 40-cm layer compared with both KBG genotypes. These results suggested that hybrid bluegrass exhibited improvement in drought and heat tolerance, particularly in comparison with KBG ‘C-74’, but to a great extent for heat tolerance. The maintenance of higher transpiration and photosynthesis, WUE, and root viability was associated with the improvement in heat tolerance in hybrid bluegrass.

scholarly journals Antioxidant and Hormone Responses to Heat Stress in Two Kentucky Bluegrass Cultivars Contrasting in Heat Tolerance

2014 ◽  
Vol 139 (5) ◽  
pp. 587-596 ◽  
Author(s):  
Feifei Li ◽  
Da Zhan ◽  
Lixin Xu ◽  
Liebao Han ◽  
Xunzhong Zhang
Keyword(s):  
Heat Stress ◽  
Antioxidant Enzyme ◽  
Heat Tolerance ◽  
Poa Pratensis ◽  
Perennial Grass ◽  
Kentucky Bluegrass ◽  
Grass Species ◽  
Limiting Factor ◽  
Antioxidant Enzyme Activities ◽  
Aba Content

Heat stress is a major limiting factor for growth of cool-season perennial grass species, and mechanisms of heat tolerance have not been well understood. This study was designed to investigate antioxidant enzyme and hormone metabolism responses to heat stress in two kentucky bluegrass (Poa pratensis L.) cultivars contrasting in heat tolerance. The plants were subjected to 20/20 °C [day/night (control)] or 38/30 °C [day/night (heat stress)] for 28 days in growth chambers. Heat stress increased leaf electrolyte leakage (EL) and malondialdehyde (MDA) with heat-tolerant cultivar EverGlade exhibiting lower levels of EL and MDA relative to heat-sensitive cultivar Kenblue under heat stress. Superoxide dismutase (SOD) and catalase (CAT) activity increased and then declined during 28 days of heat stress. Peroxidase (POD) and ascorbate peroxidase (APX) activity declined and then increased during heat stress. ‘EverGlade’ had greater activities of SOD, CAT, POD, and APX relative to ‘Kenblue’ under heat stress. In addition, ‘EverGlade’ had two additional SOD isozymes and three additional POD isozymes relative to ‘Kenblue’ under heat stress. Leaf abscisic acid (ABA) increased in response to heat stress. Leaf indole-3-acetic acid (IAA) increased and then declined during heat stress. ‘OverGlade’ had higher ABA and IAA content relative to ‘Kenblue’. At the end of heat stress, leaf IAA and ABA content were 27.8% and 73% higher in ‘EverGlade’ relative to ‘Kenblue’, respectively. The results indicated that antioxidant enzymes and the hormones (ABA and IAA) were associated with kentucky bluegrass heat tolerance. Selection and use of cultivars with higher IAA and ABA content and greater antioxidant enzyme activities may improve kentucky bluegrass growth and quality under heat stress.

scholarly journals Transcriptome Sequencing of Two Kentucky Bluegrass (Poa pratensis L.) Genotypes in Response to Heat Stress

2018 ◽  
Vol 47 (2) ◽  
pp. 328-338
Author(s):  
Qiong LI ◽  
Yali HE ◽  
Mingyue TU ◽  
Junhui YAN ◽  
Liangliang YU ◽  
...  
Keyword(s):  
Heat Stress ◽  
Heat Shock ◽  
De Novo ◽  
Average Length ◽  
Poa Pratensis ◽  
Brachypodium Distachyon ◽  
Enrichment Analysis ◽  
Basic Mechanism ◽  
Kentucky Bluegrass ◽  
Summer Stress

Kentucky bluegrass (Poa pratensis L.) (KBG) is a major cool-season turfgrass. However, as its complex genetic background and production modes, limited genomic and transcriptomic information of KBG was known so far. In this study, a transcriptome study between wild type material Ninglan (summer stress sensitive) and cultivar material KBG03 (summer stress tolerant) was conducted, under optimal (25 °C) and high (40 °C) temperatures. A total of 81.42 Gb clean reads were generated and de novo assembled into 110,784 unigenes with an average length of 1,105 bp. About 50% KBG unigenes were similar to the non-redundant (NR) database. Among the NR BLASTx top hits, 27.47% unigenes were matched to Brachypodium distachyon. After heat stress, a massive amount of unigenes showed significantly differential expression in both genotypes. After 2h heat stress, more specially up-regulated differentially expressed unigenes (DEGs) and less down-regulated DEGs were detected in Ninglan than in KBG03. At 24h, the expression of 1710 and 730 unigenes were increased and decreased uniquely in Ninglan, and 1361 up-regulated DEGs and 757 down-regulated DEGs were just found in KBG03. More heat shock proteins (HSPs) and heat shock transcription factors (HSFs) DEGs were also identified at 2h than 24h in both genotypes. In addition, by Gene Ontology (GO) enrichment analysis, three core terms (“protein folding”, “response to heat”, and “response to hydrogen peroxide”) of biological process (BP) ontology were found in both genotypes under different heat stress time. The DEGs shared in both genotypes might be related to the basic mechanism of thermal response in KBG.

scholarly journals Development of SCAR markers related to heat tolerance in Kentucky bluegrass

2020 ◽  
Vol 48 (2) ◽  
pp. 509-522
Author(s):  
Mingyue TU ◽  
Yali HE ◽  
Xiaoli LI ◽  
Ying ZOU ◽  
Xiaojun YUAN
Keyword(s):  
High Temperature ◽  
Heat Tolerance ◽  
Poa Pratensis ◽  
Kentucky Bluegrass ◽  
Temperature Tolerance ◽  
Scar Markers ◽  
Sequence Characterized Amplified Region ◽  
High Temperature Tolerance ◽  
Significant Difference ◽  
Cool Season Grass

As a high-quality cool-season grass, Kentucky bluegrass (Poa pratensis) is facing increasing threat of high temperature, so improving its heat tolerance (HT) has become an important breeding target. In this study, the HT of 84 materials was identified in the artificial climate chamber, and 15 most heat-tolerant and 15 most heat-sensitive materials were selected respectively to construct two DNA pools. There was a significant difference in high-temperature tolerance time between the plants in the two pools, which was more than 22 days. A total of 304 sequence-related amplified polymorphism (SRAP) and 88 simple sequence repeat (SSR) markers were used to screen the polymorphic bands between the two pools. Then, these bands were transformed into sequence characterized amplified region (SCAR) markers, and finally 12 SCAR dominant markers related to HT were obtained, which could detect the heat-sensitive materials efficiently. Among them, S-me8×em2 and S-me52×em5 had the best identification effect, and the consistency between the absence of these two markers and the heat-sensitive phenotype was 87%. According to the comparison with NCBI database, the sequences of 12 SCAR markers had no homology with known HT related genes. Next, we would further verify the HT identification efficiency of these SCAR markers in single plants within materials, and try to use them in molecular marker-assisted breeding.  

scholarly journals Membrane Lipid Composition and Heat Tolerance in Cool-season Turfgrasses, including a Hybrid Bluegrass

2009 ◽  
Vol 134 (5) ◽  
pp. 511-520 ◽  
Author(s):  
Kemin Su ◽  
Dale J. Bremer ◽  
Richard Jeannotte ◽  
Ruth Welti ◽  
Celeste Yang
Keyword(s):  
Heat Tolerance ◽  
Molecular Species ◽  
Festuca Arundinacea ◽  
Membrane Lipids ◽  
Poa Pratensis ◽  
Kentucky Bluegrass ◽  
Membrane Lipid ◽  
Cool Season ◽  
Lipid Molecular Species ◽  
Heat Tolerant

Cool-season turfgrasses may experience heat stress during summer. Hybrid bluegrasses (HBGs), crosses between kentucky bluegrass [KBG (Poa pratensis L.)] and native texas bluegrass (Poa arachnifera Torr.), have improved heat tolerance but the mechanisms of heat tolerance are poorly understood. Our objectives were to quantitatively profile membrane lipid molecular species in three cool-season turfgrasses exposed to optimal (22/15 °C, 14/10 h light/dark) and supra-optimal temperatures (35/25 °C and 40/30 °C, 14/10 h light/dark). Grasses included a low heat-tolerant tall fescue [TF (Festuca arundinacea Schreb. ‘Dynasty’)], a mid-heat–tolerant KBG (‘Apollo’), and a heat-tolerant HBG (‘Thermal Blue’). At high temperature, glycolipid digalactosyldiacylglycerol (DGDG) in HBG was 12% and 16% greater than in KBG and TF, respectively, and the ratio DGDG to monogalactosyldiacylglycerol was 19% and 44% greater in HBG than in KBG and TF, respectively. Greater heat tolerance in HBG and KBG was associated with higher contents of phosphatidylethanolamine and phosphatidylglycerol, and with reduced overall unsaturation compared with TF. Overall, 20 lipid molecular species were present in greater amounts and another 20 species in lesser amounts in HBG and KBG than in TF. Results suggest 40 membrane lipid molecules are potential biomarkers for heat tolerance and that compositional changes in membrane lipids in response to heat contribute to differences in heat tolerance among cool-season grasses.

scholarly journals Differential Effectiveness of Doubling Ambient Atmospheric CO2 Concentration Mitigating Adverse Effects of Drought, Heat, and Combined Stress in Kentucky Bluegrass

2014 ◽  
Vol 139 (4) ◽  
pp. 364-373
Author(s):  
Yali Song ◽  
Bingru Huang
Keyword(s):  
Heat Stress ◽  
Poa Pratensis ◽  
Relative Effectiveness ◽  
Kentucky Bluegrass ◽  
Grass Species ◽  
Combined Stress ◽  
Cool Season ◽  
Positive Effects ◽  
Effects Of Drought ◽  
Drought And Heat Stress

Drought and heat stress can limit the growth of cool-season grass species, whereas doubling ambient CO2 has been shown to promote plant growth. The objectives of this study were to examine differential responses of shoot and root growth as well as photosynthesis and respiration to doubling ambient CO2 during drought or heat stress alone or the two stresses combined and to determine the relative effectiveness of doubling ambient CO2 in mitigating negative effects of drought or heat stress alone and in combination in a cool-season perennial grass species. Kentucky bluegrass (Poa pratensis cv. Baron) plants were exposed to ambient CO2 (400 μL·L−1) or doubling ambient CO2 (800 μL·L−1) concentrations while subjected to the following stress treatments in growth chambers: drought stress by withholding irrigation, heat stress (35 °C), or the combined two stresses for 28 days. Doubling ambient CO2 increased root and shoot growth as well as root/shoot ratio under all treatments. Doubling ambient CO2 enhanced leaf net photosynthetic rate (Pn) to a greater extent under drought or heat alone, whereas it reduced respiration rate (R), to a larger degree under heat and the combined stress, leading to a greater ratio of Pn/R. Doubling ambient CO2 mitigated adverse physiological effects of drought or heat stress alone, whereas fewer effects were observed under the combined drought and heat stress. The positive effects of doubling ambient CO2 were associated with the development of roots biomass and the maintenance of a positive carbon balance under either stress alone or the combined drought and heat stress.

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