scholarly journals Tufted Hairgrass Responses to Heat and Drought Stress

2007 ◽  
Vol 132 (3) ◽  
pp. 289-293 ◽  
Author(s):  
Eric Watkins ◽  
Bingru Huang ◽  
William A. Meyer
Keyword(s):  
Heat Stress ◽  
Drought Stress ◽  
Photochemical Efficiency ◽  
Single Leaf ◽  
Turf Quality ◽  
Resistant Lines ◽  
Relative Water ◽  
Summer Stress ◽  
Leaf Photosynthetic Rate ◽  
Field Plots

Tufted hairgrass [Deschampsia cespitosa (L.) Beauv.] is receiving increasing attention as a low-maintenance turfgrass for use in areas with reduced fertility or reduced sunlight. The objectives of this study were to examine physiological responses of tufted hairgrass to heat and drought stress and to distinguish whether better summer performance was related to better heat or drought tolerance. Four germplasm lines were chosen based on summer performance in field plots (two lines resistant to summer stress and two lines susceptible to summer stress) and were grown in growth chambers [14-hour photoperiod, 20/15 °C (day/night)]. Plants were exposed to either drought stress or heat stress (35/30 °C, day/night) for up to 49 days. Control plants maintained under normal conditions (20/15 °C, day/night, well watered) were included for both treatments. During the course of the study, single-leaf photosynthetic rate, photochemical efficiency, and relative water content were measured, and turf quality was visually rated. All parameters for all tufted hairgrass lines decreased under drought stress and heat stress, and the decline was more severe for summer stress-susceptible lines than for resistant lines. Lines that were previously considered resistant to summer stress exhibited superior photochemical efficiency under heat stress compared with the susceptible lines. When subjected to drought stress, the lines exhibited little or no differences in the measured parameters. These results suggest that observed variation in field summer performance among various tufted hairgrass germplasm lines may be mainly the result of their differences in heat tolerance. These results suggest that selecting for heat-tolerant germplasm could be important for further improvement in turf performance of tufted hairgrass during the summer.

scholarly journals Differential Physiological Responses and Genetic Variations in Fine Fescue Species for Heat and Drought Stress

2017 ◽  
Vol 142 (5) ◽  
pp. 367-375 ◽  
Author(s):  
Jinyu Wang ◽  
Patrick Burgess ◽  
Stacy A. Bonos ◽  
William A. Meyer ◽  
Bingru Huang
Keyword(s):  
Heat Stress ◽  
Drought Stress ◽  
Drought Tolerance ◽  
Heat Tolerance ◽  
Photochemical Efficiency ◽  
Physiological Parameters ◽  
Festuca Rubra ◽  
Relative Water ◽  
Prolonged Heat ◽  
Fine Fescue

Summer decline is typically characterized by heat and drought stress and is a major concern for fine fescue species (Festuca). The objectives of this study were to examine whether heat or drought stress is more detrimental, and to determine the genotypic variations in heat and drought tolerance for fine fescues. A total of 26 cultivars, including seven hard fescues (Festuca trachyphylla), eight chewings fescues (Festuca rubra ssp. commutate), seven strong creeping red fescues (Festuca rubra ssp. rubra), two sheep fescues (Festuca ovina ssp. hirtula), and two slender creeping red fescues (Festuca rubra ssp. littoralis) were subjected to prolonged heat or drought stress in growth chambers. Several physiological parameters, including turf quality (TQ), electrolyte leakage (EL), photochemical efficiency (Fv/Fm) chlorophyll content (Chl), and relative water content (RWC) were measured in plants exposed to heat or drought stress. The results indicated that heat stress was more detrimental than drought stress for fine fescue species. Based on TQ and major physiological parameters (EL and Fv/Fm) under heat stress, several cultivars with good heat tolerance were selected, including ‘Blue Ray’, ‘Spartan II’, ‘MN-HD1’, ‘Shoreline’, ‘Navigator II’, ‘Azure’, ‘Beacon’, ‘Aurora Gold’, ‘Reliant IV’, ‘Marco Polo’, ‘Garnet’, ‘Wendy Jean’, ‘Razor’, and ‘Cindy Lou’. Based on TQ and major physiological parameters (EL, RWC, and Fv/Fm) under drought stress, several cultivars with good drought tolerance were selected, including ‘Spartan II’, ‘MN-HD1’, ‘Reliant IV’, ‘Garnet’, ‘Azure’, and ‘Aurora Gold’. These cultivars could be used in hot, dry, or both environments and as breeding germplasm for developing heat tolerance, drought tolerance, or both.

scholarly journals Effects of SAG12-ipt and HSP18.2-ipt Expression on Cytokinin Production, Root Growth, and Leaf Senescence in Creeping Bentgrass Exposed to Drought Stress

2010 ◽  
Vol 135 (3) ◽  
pp. 230-239 ◽  
Author(s):  
Emily B. Merewitz ◽  
Thomas Gianfagna ◽  
Bingru Huang
Keyword(s):  
Drought Stress ◽  
Root Growth ◽  
Leaf Senescence ◽  
Photochemical Efficiency ◽  
Creeping Bentgrass ◽  
Growth Responses ◽  
Turf Quality ◽  
Relative Water ◽  
Transgenic Lines ◽  
Leaf Relative Water Content

Drought stress is a widespread abiotic stress that causes a decline in plant growth. Drought injury symptoms have been associated with an inhibition in cytokinin (CK) synthesis. The objectives of this study were to investigate whether expression of a gene (ipt) encoding the enzyme adenine isopentenyl phosphotransferase for CK synthesis ligated to a senescence-activated promoter (SAG12) or a heat shock promoter (HSP18.2) would improve drought tolerance in creeping bentgrass (Agrostis stolonifera) and to examine shoot and root growth responses to drought stress associated with changes in endogenous production of CK, and the proportional change in CK and abscisic acid (ABA) due to ipt transformation. Most SAG12-ipt and HSP18.2-ipt transgenic lines exhibited significantly higher turf quality, photochemical efficiency, chlorophyll content, leaf relative water content, and root:shoot ratio under drought stress than the null transformant or the wild-type ‘Penncross’ plants. Transgenic lines that had better growth and turf performance generally had higher CK content and a higher CK-to-ABA ratio, although the direct correlation of CK and ABA content with individual physiological parameters in individual lines was not clear. Our results demonstrated that expressing ipt resulted in the improvement of turf performance under drought stress in creeping bentgrass in some of the transgenic plants with SAG12-ipt or HSP18.2-ipt, which could be associated with the suppression of leaf senescence and promoting root growth relative to shoot growth due to the maintenance of higher CK level and a higher ratio of CK to ABA.

scholarly journals Evaluation of Heat and Drought as Components of Summer Stress on Tall Fescue Genotypes

HortScience ◽  
2013 ◽  
Vol 48 (12) ◽  
pp. 1562-1567 ◽  
Author(s):  
James W. Cross ◽  
Stacy A. Bonos ◽  
Bingru Huang ◽  
William A. Meyer
Keyword(s):  
New Jersey ◽  
Heat Tolerance ◽  
Tall Fescue ◽  
Photochemical Efficiency ◽  
Field Conditions ◽  
Superior Performance ◽  
Turf Quality ◽  
Relative Water ◽  
Summer Stress ◽  
Agricultural Experiment

Heat and drought are two major abiotic stresses causing a decline in quality in cool-season turfgrasses during the summer. The objectives of this study were 1) to determine whether genotypic variations in turf performance during summer stress in New Jersey is related primarily to heat tolerance or drought tolerance of tall fescue; and 2) to make selections of plants tolerant to summer stress for breeding efforts. Twenty-four tall fescue genotypes exhibiting differential performance during summer months in field conditions (12 summer stress-tolerant and 12 summer stress-sensitive) were selected from the germplasm pool present at the New Jersey Agricultural Experiment Station. Plants of these 24 genotypes were exposed to heat, drought, or heat + drought. There were generally no significant differences in turf quality, photochemical efficiency, relative water content, or electrolyte leakage between summer stress-tolerant and -sensitive genotypes, except in the heat treatment in which the summer stress-tolerant selections performed significantly better. The results indicate that the superior performance of the summer stress-tolerant plants under field conditions is mainly the result of superior heat tolerance.

scholarly journals Polyamine Application Effects on Gibberellic Acid Content in Creeping Bentgrass during Drought Stress

2017 ◽  
Vol 142 (2) ◽  
pp. 135-142 ◽  
Author(s):  
Sanalkumar Krishnan ◽  
Emily B. Merewitz
Keyword(s):  
Drought Stress ◽  
Gibberellic Acid ◽  
Abiotic Stress Tolerance ◽  
Photochemical Efficiency ◽  
Canopy Temperature ◽  
Creeping Bentgrass ◽  
Relative Water ◽  
Consistent Basis ◽  
Chamber Studies ◽  
Growth Chamber Studies

Polyamines (PAs), spermine (Spm), and spermidine (Spd) may enhance the abiotic stress tolerance and growth of creeping bentgrass (Agrostis stolonifera). Growth chamber studies were conducted to investigate the effect of PA application on the physiological response and hormone content in creeping bentgrass ‘Penn-G2’ under drought. Spm (1 mm) and Spd (5 mm) were applied exogenously under drought or well-watered conditions. PA-treated plants maintained significantly higher turf quality (TQ), relative water content (RWC), photochemical efficiency, and membrane health while maintaining lower canopy temperature. Spm at the 1-mm rate had a 2.46-fold higher osmotic adjustment (OA) at 10 d compared with control plants. A greater content of gibberellic acid (GA) isoforms (GA1, GA4, and GA20) were observed compared with controls during both studies for PA-treated plants under drought. After 7 days of drought stress in Expt.1, GA1 levels were 3.26 higher for Spm 1-mm-treated plants compared with drought controls. GA4 contents were 69% and 65% higher compared with drought-stressed-untreated plants for Spd 5-mm application after 9 and 11 days. Higher levels of GA20 were observed at 10 days (Spd 5 mm, 108.9% higher) due to PA treatment compared with drought controls. In addition to differential regulation of GA isoforms, we observed enhanced abscisic acid (ABA) due to PA application; however, not on a consistent basis. This study showed that PA application may play a role in GA1, GA4, and ABA accumulation in creeping bentgrass ‘Penn G-2’ under drought stress.

scholarly journals Effects of Abscisic Acid on Drought Responses of Kentucky Bluegrass

2003 ◽  
Vol 128 (1) ◽  
pp. 36-41 ◽  
Author(s):  
Zhaolong Wang ◽  
Bingru Huang ◽  
Qingzhang Xu
Keyword(s):  
Abscisic Acid ◽  
Drought Stress ◽  
Osmotic Adjustment ◽  
Foliar Application ◽  
Poa Pratensis ◽  
Turgor Pressure ◽  
Photochemical Efficiency ◽  
Kentucky Bluegrass ◽  
Exogenous Aba ◽  
Turf Quality

Abscisic acid (ABA) is an important hormone regulating plant response to drought stress. The objective of this study was to investigate effects of exogenous ABA application on turf performance and physiological activities of kentucky bluegrass (Poa pratensis L.) in response to drought stress. Plants of two kentucky bluegrass cultivars, `Brilliant' (drought susceptible) and `Midnight' (drought tolerant), were treated with ABA (100 μm) or water by foliar application and then grown under drought stress (no irrigation) or well-watered (irrigation on alternate days) conditions in a growth chamber. The two cultivars responded similarly to ABA application under both watering regimes. Foliar application of ABA had no effects on turf quality or physiological parameters under well-watered conditions. ABA application, however, helped maintain higher turf quality and delayed the quality decline during drought stress, compared to the untreated control. ABA-treated plants exposed to drought stress had higher cell membrane stability, as indicated by less electrolyte leakage of leaves, and higher photochemical efficiency, expressed as Fv/Fm, compared to untreated plants. Leaf water potential was not significantly affected, whereas leaf turgor pressure increased with ABA application after 9 and 12 d of drought. Osmotic adjustment increased with ABA application, and was sustained for a longer period of drought in `Midnight' than in `Brilliant'. The results suggested that exogenous ABA application improved turf performance during drought in both drought-sensitive and tolerant cultivars of kentucky bluegrass. This positive effect of ABA could be related to increased osmotic adjustment, cell turgor maintenance, and reduced damage to cell membranes and the photosynthetic system.

scholarly journals 278 Gas Exchange and Water Relations of Diverse Tall Fescue Cultivars in Response to Drought Stress

HortScience ◽  
1999 ◽  
Vol 34 (3) ◽  
pp. 490C-490
Author(s):  
Bingru Huang ◽  
Hongwen Gao
Keyword(s):  
Drought Stress ◽  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Tall Fescue ◽  
Festuca Arundinacea ◽  
Stomatal Closure ◽  
Photochemical Efficiency ◽  
Physiological Factors ◽  
Relative Water

To investigate shoot physiological responses to drought stress of six tall fescue (Festuca arundinacea) cultivars representing several generations of turfgrass improvement, forage-type `Kentucky-31', turf-type `Phoenix', `Phoenix', and `Houndog V', and dwarf-type `Rebel Jr` and `Bonsai' were grown in well-watered or drying soil for 35 days in a greenhouse. Net photosynthetic rate (Pn), stomatal conductance (gs), transpiration rate (Tr), relative water content (RWC), and photochemical efficiency (Fv/Fm) declined during drought progression in all cultivars, but the time and the severity of reductions varied with cultivars and physiological factors. Pn, RWC, gs, and Tr decreased significantly for `Rebel Jr', `Bonsai', and `Phoenix' when soil water content declined to 20% after 9 days of treatment (DOT) and for `Falcon II', `Houndog V', and `Kentucky-31' when soil water content dropped to 10% at 15 DOT. A significant decrease in Fv/Fm was not observed in drought-stressed plants until 21 DOT for `Rebel Jr', `Bonsai', and `Phoenix' and 28 DOT for `Houndog V', `Kentucky-31', and `Falcon II'. The decline in Pn was due mostly to internal water deficit and stomatal closure under short-term or mild drought-stress conditions. After a prolonged period of drought (35 DOT), higher Pn in `Falcon II', `Houndog V', and `Kentucky-31' could be attributed to their higher Fv/Fm.

scholarly journals Alleviation of drought stress by silicon supplementation in pistachio (Pistacia vera L.) plants

2013 ◽  
Vol 25 (1) ◽  
pp. 21-29 ◽  
Author(s):  
Ghader Habibi ◽  
Roghieh Hajiboland
Keyword(s):  
Drought Stress ◽  
Photochemical Efficiency ◽  
Dry Weight ◽  
Pistacia Vera ◽  
Antioxidant Defence ◽  
Photosynthetic Gas Exchange ◽  
Relative Water ◽  
Effects Of Drought ◽  
Net Assimilation ◽  
Quantum Yield Of Psii

ABSTRACT The effect of silicon (Si) supplementation (0.35 g Na2SiO3 kg-1 soil, 2.73 mmol Si kg-1 soil) was studied in drought-stressed pistachio (Pistacia vera L. ‘Ahmadaghaii’) plants under field conditions. Silicon treatment significantly increased plant dry weight and relative water content under drought stress. The application of Si for drought-stressed plants improved the maximum quantum yield of PSII. A reduction in the net assimilation rate due to drought stress was alleviated by Si application, accompanied by an increase in stomatal conductance. Silicon treatment resulted in higher catalase and superoxide dismutase activities and lower lipid peroxidation in the leaves of drought-stressed plants. The results suggest that supplementation of water-deficient pistachio plants with Si alleviates the adverse effects of drought due to its enhancement of photochemical efficiency and photosynthetic gas exchange, as well as an activation of the antioxidant defence capacity in this species.

scholarly journals Creeping Bentgrass Responses to Drought Stress and Polyamine Application

2015 ◽  
Vol 140 (1) ◽  
pp. 94-101 ◽  
Author(s):  
Vijaya Shukla ◽  
Yingmei Ma ◽  
Emily Merewitz
Keyword(s):  
Drought Stress ◽  
Photochemical Efficiency ◽  
Creeping Bentgrass ◽  
Optimal Growth ◽  
Growth Conditions ◽  
Major Effect ◽  
Abiotic Stress Response ◽  
Low Concentrations ◽  
Malondialdehyde Content ◽  
Relative Water

Polyamines (PAs) such as spermidine (Spd), spermine (Spm), and putrescine are involved in various biological functions including abiotic stress response. Whether PAs play an important role in cool-season turfgrass tolerance of drought stress is not well investigated. We have conducted a series of growth chamber (GC) studies including one hydroponic and two soil-based GC studies with creeping bentgrass (Agrostis stolonifera) ‘Penncross’ and ‘Penn-G2’ to determine whether exogenous application of PAs may affect plant growth and stress tolerance. Application of relatively low concentrations of Spd (500 or 750 μM) or Spm (500 μM) promoted tillering rates under optimal growth conditions in hydroponics. The same levels of PA treatments moderated the damages associated with drought stress in the soil-based GC studies. The most notable differences in drought response associated with PA treatment were increased membrane health. This was observed as greater photochemical efficiency, higher quantum yield, less electrolyte leakage, and less lipid peroxidation (malondialdehyde content) in PA-treated plants compared with control plants. The relatively low level of exogenous PAs used in this study did not have a major effect on plant water relations under drought stress. Canopy temperatures and soil moisture content were unaffected by any PA treatment; however, on some days during early drought stress, relative water content was significantly higher in PA-treated plants compared with controls. PA could play a major role in protecting photosynthetic and cellular membranes during drought stress of creeping bentgrass.

scholarly journals Effects of Epichloë festucae Fungal Endophyte Infection on Drought and Heat Stress Responses of Strong Creeping Red Fescue

2015 ◽  
Vol 140 (3) ◽  
pp. 257-264 ◽  
Author(s):  
Zipeng Tian ◽  
Bingru Huang ◽  
Faith C. Belanger
Keyword(s):  
Heat Stress ◽  
Stress Tolerance ◽  
Stress Responses ◽  
Photochemical Efficiency ◽  
Fungal Endophyte ◽  
Plant Tolerance ◽  
Red Fescue ◽  
Epichloë Festucae ◽  
Endophyte Infection ◽  
Relative Water

Strong creeping red fescue (Festuca rubra ssp. rubra) is an important cool season turfgrass species. Cultivars are often infected with the fungal endophyte Epichloë festucae. Endophyte infection is known to confer insect and disease resistance to the plants. The effect of endophyte infection on drought or heat stress tolerance of strong creeping red fescue is not yet established. The objectives of this controlled-environment study were to determine if endophyte infection had any effect on physiological parameters associated with plant tolerance to drought or heat stress or the combination of the two stresses. In this study, endophyte status had no effect on turf quality (TQ), relative water content (RWC), photochemical efficiency, chlorophyll content, electrolyte leakage (EL), or malondialdehyde (MDA) content of the plants under any of the stress treatments. Our results suggested that E. festucae infection had no physiological effects on improving drought, heat or the combined stress tolerance in strong creeping red fescue.

scholarly journals Evaluation of Drought Tolerance and Avoidance Traits for Six Creeping Bentgrass Cultivars

HortScience ◽  
2008 ◽  
Vol 43 (2) ◽  
pp. 519-524 ◽  
Author(s):  
Stephen E. McCann ◽  
Bingru Huang
Keyword(s):  
Drought Stress ◽  
Drought Tolerance ◽  
Water Use ◽  
Photochemical Efficiency ◽  
Creeping Bentgrass ◽  
Root Production ◽  
Drought Avoidance ◽  
Relative Water ◽  
Leaf Relative Water Content ◽  
Use Efficiency

The objectives of this study were: 1) to compare drought responses between the more recently developed creeping bentgrass cultivars to standard cultivars and 2) to determine differential drought tolerance and avoidance characteristics associated with cultivar variation in drought resistance. Six cultivars of creeping bentgrass (Agrostis stoloniferia) (‘Penn A-4’, ‘Independence’, ‘Declaration’, ‘L-93’, ‘Penncross’, and ‘Putter’) were maintained in growth chambers at 20 °C day/15 °C night either well-watered or exposed to drought stress by withholding water for 17 days. Cultivars varied in turf performance and physiological responses (leaf relative water content and photochemical efficiency) to drought stress, which was reflected in their differences in drought tolerance (osmotic adjustment) and drought avoidance traits (water use rate and efficiency, root viability, root length, and number). ‘Penn A-4,’ ‘Independence,’ and ‘L-93’ generally performed better than other three cultivars under drought conditions, mainly through maintaining higher water use efficiency, root viability, root elongation, or root production. The majority of physiological parameters evaluated suggested that of the six creeping bentgrass cultivars examined in this study, the three cultivars with better ability to survive drought stress used mainly avoidance traits related to water use and water uptake.

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