scholarly journals Antioxidant Enzyme Activities and Gene Expression Patterns in Leaves of Kentucky Bluegrass in Response to Drought and Post-drought Recovery

2011 ◽  
Vol 136 (4) ◽  
pp. 247-255 ◽  
Author(s):  
Lixin Xu ◽  
Liebao Han ◽  
Bingru Huang
Keyword(s):  
Gene Expression ◽  
Drought Stress ◽  
Antioxidant Enzyme ◽  
Water Deficit ◽  
Poa Pratensis ◽  
Kentucky Bluegrass ◽  
Grass Species ◽  
Antioxidant Enzyme Activities ◽  
Guaiacol Peroxidase ◽  
Drought Recovery

The objectives of this study were to examine antioxidant enzyme responses to drought stress and rewatering at both enzymatic activity and transcript levels and to determine the major antioxidant processes associated with drought tolerance and post-drought recovery for a perennial grass species, kentucky bluegrass (Poa pratensis). Antioxidant enzyme responses to drought and rewatering in a drought-tolerant cultivar (Midnight) and a drought-sensitive cultivar (Brilliant) were compared in a growth chamber. Plants were exposed to 22 days of drought stress for ‘Midnight’ and 18 days for ‘Brilliant’ before rewatering to allow the leaf relative water content (RWC) of both cultivars to drop to the same level. ‘Midnight’ exhibited higher photochemical efficiency (Fv/Fm) and lower electrolyte leakage compared with ‘Brilliant’ when at the same water deficit status (26% to 28% RWC). After 6 days of rewatering, all physiological parameters returned to the control level for ‘Midnight’, but only Fv/Fm fully recovered for ‘Brilliant’. The transcript level of cytosolic copper/zinc superoxide dismutase (cyt Cu/Zn SOD) and ascorbate peroxidase (APX) was significantly higher in ‘Midnight’ than in ‘Brilliant’ when exposed to the same level of water deficit (26% to 28% RWC), suggesting that SOD and APX could be involved in scavenging oxidative stress-induced reactive oxygen species in kentucky bluegrass through changes in the level of gene expression. Significantly higher activities of APX, monodehydroascorbate reductase, glutathione reductase, and dehydroascorbate reductase as well as lower lipid peroxidation levels were observed in ‘Midnight’ versus ‘Brilliant’ when exposed to drought. However, the activities of SOD, catalase (CAT), and guaiacol peroxidase (POD) did not differ between the two cultivars. After 6 days of rewatering, ‘Midnight’ displayed significantly higher activity levels of CAT, POD, and APX compared with ‘Brilliant’. The enzyme activity results indicate that enzymes involved in the ascorbate–glutathine cycle may play important roles in antioxidant protection to drought damage, whereas CAT, POD, and APX could be associated with better post-drought recovery in kentucky bluegrass.

scholarly journals Wild Relatives of Wheat Respond Well to Water Deficit Stress: A Comparative Study of Antioxidant Enzyme Activities and Their Encoding Gene Expression

Agriculture ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 415
Author(s):  
Alireza Pour-Aboughadareh ◽  
Mansoor Omidi ◽  
Mohammad Reza Naghavi ◽  
Alireza Etminan ◽  
Ali Ashraf Mehrabi ◽  
...  
Keyword(s):  
Gene Expression ◽  
Antioxidant Enzymes ◽  
Antioxidant Enzyme ◽  
Water Deficit ◽  
Water Deficit Stress ◽  
Antioxidant Enzyme Activities ◽  
Guaiacol Peroxidase ◽  
Photosynthetic Parameters ◽  
Relative Expression ◽  
Encoding Genes

Previous studies have revealed that some wild wheat accessions respond well to water deficit treatments and have a good potential in terms of photosynthetic parameters, root system architecture, and several physiological properties. However, the biochemical responses and molecular mechanisms of antioxidant-encoding genes remain to be elucidated. Herein, we investigated the most tolerant accessions from A. crassa, Ae. tauschii, and Ae. cylindrica previously identified from a core collection in previous studies, along with a control variety of bread wheat (T. aestivum cv. Sirvan) through measuring the shoot fresh and dry biomasses; the activities of antioxidant enzymes (including ascorbate peroxidase (APX), catalase (CAT), guaiacol peroxidase (GPX), and peroxidase (POD)); and the relative expression of CAT, superoxide dismutase (MnSOD), and GPX and APX genes under control and water deficit conditions. Water deficit stress caused a significant decrease in the shoot biomasses but resulted in an increase in the activity of all antioxidant enzymes and relative expression of antioxidant enzyme-encoding genes. Principal component analysis showed a strong association between the shoot dry biomass and the activity of CAT, POD, and APX, as well as MnSOD gene expression. Thus, these traits can be used as biomarkers to screen the tolerant plant material in the early growth stage. Taken together, our findings exposed the fact that Ae. tauschii and Ae. crassa respond better to water deficit stress than Ae. cylindrica and a control variety. Furthermore, these accessions can be subjected to further molecular investigation.

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 Growth and Physiological Traits Associated with Drought Survival and Post-drought Recovery in Perennial Turfgrass Species

2010 ◽  
Vol 135 (2) ◽  
pp. 125-133 ◽  
Author(s):  
Qi Chai ◽  
Fang Jin ◽  
Emily Merewitz ◽  
Bingru Huang
Keyword(s):  
Cell Wall ◽  
Drought Stress ◽  
Osmotic Adjustment ◽  
Perennial Grass ◽  
Kentucky Bluegrass ◽  
Physiological Traits ◽  
Grass Species ◽  
Cell Wall Elasticity ◽  
Drought Recovery ◽  
Drought Survival

The objective of this study was to determine physiological traits for drought survival and post-drought recovery upon re-watering in two C3 perennial grass species, kentucky bluegrass [KBG (Poa pratensis)] and perennial ryegrass [PRG (Lolium perenne)]. Plants were maintained well watered or exposed to drought stress by withholding irrigation and were then re-watered in a growth chamber. KBG had significantly higher grass quality and leaf photochemical efficiency, and lower electrolyte leakage than PRG during 20 days of drought. After 7 days of re-watering, drought-damaged leaves were rehydrated to the control level in KBG, but could not fully recover in PRG. KBG produced a greater number of new roots, while PRG had more rapid elongation of new roots after 16 days of re-watering. Superior drought tolerance in KBG was associated with osmotic adjustment, higher cell wall elasticity, and lower relative water content at zero turgor. Osmotic adjustment, cell wall elasticity, and cell membrane stability could play important roles in leaf desiccation tolerance and drought survival in perennial grass species. In addition, post-drought recovery of leaf hydration level and physiological activity could be associated with the accumulation of carbohydrates in leaves and rhizomes during drought stress and new root production after re-watering.

scholarly journals Physiological and Antioxidant Parameters in Two Lycoris Species as Influenced by Water Deficit Stress

HortScience ◽  
2015 ◽  
Vol 50 (11) ◽  
pp. 1702-1708 ◽  
Author(s):  
Sheng Xu ◽  
Mingmin Jiang ◽  
Jiangyan Fu ◽  
Lijian Liang ◽  
Bing Xia ◽  
...  
Keyword(s):  
Antioxidant Enzyme ◽  
Water Deficit ◽  
Enzyme Activities ◽  
Water Status ◽  
Sugar Content ◽  
Soluble Sugar ◽  
Net Photosynthesis ◽  
Water Deficit Stress ◽  
Antioxidant Enzyme Activities ◽  
Guaiacol Peroxidase

From a field experiment, the changes in morphophysiological characters and antioxidant enzyme activities were studied in two Lycoris species (Lycoris radiata and Lycoris aurea) subjected to 16 days of water deficit stress. With the increase of water deficit stress processing time, leaf relative water content (RWC), membrane stability index (MSI), net photosynthesis (Pn), stomatal conductance (gS), transpiration rate (E), and chlorophyll (Chl) content decreased in both studied species. The water use efficiency (WUE) showed an opposite tendency between the two species under water deficit stress, where WUE of L. aurea decreased moderately and WUE of L. aurea increased somehow. Intercellular CO2 concentration (Ci) in L. aurea and L. radiata decreased in respond to water deficit stress at early stages of stress treatment, then increased throughout the rest of the stress period, and reached levels higher than those in well-watered plants at the end of the treatment. In addition, there was a significant increment in soluble sugar content and proline accumulation under water deficit stress in both species, and L. radiata showed a much more accumulation. The activity of superoxide dismutase (SOD), guaiacol peroxidase (POD), and ascorbate peroxidase (APX) increased in both plants subjected to water deficit stress while declined as the stress time increased. In L. aurea, catalase (CAT) showed a sustained increment, but it responded later and after a transient increase declined again in L. radiata under water deficit stress. In conclusion, L. radiata was more tolerant to water deficit stress than L. aurea as evidenced by its relatively higher water status, higher levels of proline, soluble sugar and pigments, and stronger photoprotection. Moreover, relatively higher antioxidant enzyme activities and lower levels of thiobarbituric acid reactive substances (TBARS) in L. radiata were also associated with its better protection against water deficit stress-induced oxidative damage.

scholarly journals Changes in Carbohydrate Metabolism in Two Kentucky Bluegrass Cultivars during Drought Stress and Recovery

2013 ◽  
Vol 138 (1) ◽  
pp. 24-30 ◽  
Author(s):  
Zhimin Yang ◽  
Lixin Xu ◽  
Jingjin Yu ◽  
Michelle DaCosta ◽  
Bingru Huang
Keyword(s):  
Drought Stress ◽  
Drought Tolerance ◽  
Carbohydrate Metabolism ◽  
Poa Pratensis ◽  
Soluble Sugars ◽  
Sucrose Phosphate Synthase ◽  
Kentucky Bluegrass ◽  
Water Soluble ◽  
Drought Recovery ◽  
Physiological Analysis

Carbohydrate metabolism is important for plant adaptation to drought stress. The objective of this study was to examine major forms of carbohydrates associated with superior drought tolerance and post-drought recovery in kentucky bluegrass (Poa pratensis) by comparing responses of different forms of carbohydrates with drought stress and re-watering in two cultivars contrasting in drought tolerance. Plants of drought-tolerant ‘Midnight’ and drought-sensitive ‘Brilliant’ were maintained well watered or subjected to drought stress for 10 days by withholding irrigation, and drought-stressed plants were re-watered for 3 days. Physiological analysis (turf quality, relative water content, and electrolyte leakage) confirmed the genetic variability of the two cultivars in drought tolerance. The two cultivars exhibited differential responses to drought stress and re-watering for the content of water-soluble sugars (sucrose, fructose, and glucose) and storage carbohydrates (starch and fructan), and ‘Midnight’ maintained higher sucrose content at 10 days of drought stress and more fructan at 3 days of re-watering. The greater accumulation of sucrose in ‘Midnight’ under drought stress corresponded with higher activities of two sucrose-synthesizing enzymes (sucrose phosphate synthase and sucrose synthase) but was not related to the sucrose-degrading enzyme activity (acid invertase). These results suggested that increased sucrose accumulation resulting from the maintenance of active sucrose synthesis could be associated with superior turf performance during drought stress, whereas increased fructan accumulation could contribute to rapid re-growth and post-drought recovery on re-watering in kentucky bluegrass.

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