• Journal of The Korean Society of Grassland and Forage Science
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• v.43 no.2
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• pp.67-74
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• 2023

To understand antioxidant enzyme response of two contrasting Arundinella hirta ecotypes to drought stress, drought-tolerant Youngduk and drought-sensitive Jinju-1, were comparatively analyzed changes in the enzymatic activities of peroxidase (POD), ascorbate peroxidase (APX), catalase (CAT), superoxide dismutase (SOD), and glutathione reductase (GR). Two ecotypes, drought-tolerant Youngduk and drought-sensitive Jinju-1 were subjected to drought stress by withholding water for 12 days. ROS accumulation level and electrolytic leakage were significantly increased in both A. hirta ecotypes by drought stress treatment but less in Youngduk than Jinju-1. The RWC significantly decreased in both the drought stress-treated ecotypes as compared to control, but less in Youngduk than Jinju-1. Soluble sugar and protein content were increased more in drought stress-treated Youngduk as compared to Jinju-1. The activities of antioxidant enzymes such as SOD, CAT, POD, APX, and GR increased significantly in both the drought stress-treated ecotypes Youngduk and Jinju-1 as compared to control. The increase in antioxidant enzyme activity level was more prominent in drought stress-treated Youngduk as compared to Jinju-1. Taken together, these results suggest that Youngduk was more tolerant to drought stress than Jinju-1, and seem to indicate that tolerance of A. hirta to drought stress is associated with increased activity of antioxidant enzymes.

• Horticultural Science & Technology
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• v.33 no.5
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• pp.625-632
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• 2015

Drought is a severe abiotic stress that affects global crop production. A drought model was created for 'Toyonoka' Fragaria ${\times}$ ananassa, and the effects of drought stress on contents of proline, sugars, and antioxidant enzyme activities were investigated. Strawberry transplants with identical growth were chosen for the experiments and the randomized design included four replications (10 plants per block). The experimental sets differed in the moisture level of the culture medium relative to the range of moisture content as follows: control, 70-85%; mild drought stress, 50-60%; moderate drought stress, 40-50%; and severe drought stress, 30-40%. Drought stress was imposed by limiting irrigation. Plants were sampled and physiological parameters w ere measured on 0, 2, 4, 6, 8, and 10 days after the commencement of droughts tress. The water potential of strawberry leaves decreased in the plants under mild, moderate, and severe stress during the course of the water stress treatment and exhibited a significant difference from the control. Strawberry leaves subjected to drought stress had higher accumulation of proline, sugars, and malondialdehyde, and higher activities of superoxide dismutase, peroxidase, and catalase than leaves of control plants. Malondialdehyde levels increased in parallel with the severity and duration of drought stress. By contrast, antioxidant enzyme activity displayed dynamic responses to drought stress, first increasing and subsequently decreasing as the severity and duration of drought stress increased. These results suggest that strawberry plants respond to drought stress by altering the activities of antioxidant enzymes and the levels of osmotically active metabolites. These biochemical response changes may confer adaptation to drought stress and improve the capacity of plants to withstand water-deficit conditions.

• Plant Biotechnology Reports
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• v.4 no.3
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• pp.213-222
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• 2010

Within their natural habitat, crops are often subjected to drought and heat stress, which suppress crop growth and decrease crop production. Causing overaccumulation of glycinebetaine (GB) has been used to enhance the crop yield under stress. Here, we investigated the response of wheat (Triticum aestivum L.) photosynthesis to drought, heat stress and their combination with a transgenic wheat line (T6) overaccumulating GB and its wild-type (WT) Shi4185. Drought stress (DS) was imposed by controlling irrigation until the relative water content (RWC) of the flag leaves decreased to between 78 and 82%. Heat stress (HS) was applied by exposing wheat plants to $40^{\circ}C$ for 4 h. A combination of drought and heat stress was applied by subjecting the drought-stressed plants to a heat stress as above. The results indicated that all stresses decreased photosynthesis, but the combination of drought and heat stress exacerbated the negative effects on photosynthesis more than exposure to drought or heat stress alone. Drought stress decreased the transpiration rate (Tr), stomatal conductance (Gs) and intercellular $CO_2$ concentration (Ci), while heat stress increased all of these; the deprivation of water was greater under drought stress than heat stress, but heat stress decreased the antioxidant enzyme activity to a greater extent. Overaccumulated GB could alleviate the decrease of photosynthesis caused by all stresses tested. These suggest that GB induces an increase of osmotic adjustments for drought tolerance, while its improvement of the antioxidative defense system including antioxidative enzymes and antioxidants may be more important for heat tolerance.

• Journal of The Korean Society of Grassland and Forage Science
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• v.42 no.2
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• pp.114-119
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• 2022

The objective of this study was to determine phosphorus effects on drought stress-induced oxidative stress in Kentucky bluegrass. Drought stress was induced by reducing of water to plants in pots. Two types of phosphorus were applied as potassium phosphate (P) or potassium phosphonate (PA). Application of phosphorus was efficient to ameliorate the adverse effects of drought. Osmotic potential, total chlorophyll and carotenoid content were significantly decreased by drought stress, but was relieved by P or PA application. Superoxide (O₂^•-) concentration was significantly increased more than 14-fold under drought-stressed plants, was accompanied with increase of hydrogen peroxide (H₂O₂) and lipid peroxidation (MDA). However, malondialdehyde (MDA) was much less in P or PA applied plants under drought stress condition. Activities of catalase (CAT), ascorbate peroxidase (APX) and guaiacol-peroxidase (GPX) were largely increased by drought stress and its increase rate was much higher in P or PA applied plants except APX. These results indicate that drought stress-induced oxidative stress is alleviated by P or PA application due to the increase of activities of antioxidant enzymes.

• The Plant Pathology Journal
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• v.29 no.2
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• pp.201-208
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• 2013

Drought stress is one of the major yield affecting factor for pepper plant. The effects of PGPRs were analyzed in relation with drought resistance. The PGPRs inoculated pepper plants tolerate the drought stress and survived as compared to non-inoculated pepper plants that died after 15 days of drought stress. Variations in protein and RNA accumulation patterns of inoculated and non-inoculated pepper plants subjected to drought conditions for 10 days were confirmed by two dimensional polyacrylamide gel electrophoresis (2D-PAGE) and differential display PCR (DD-PCR), respectively. A total of six differentially expressed stress proteins were identified in the treated pepper plants by 2D-PAGE. Among the stress proteins, specific genes of Cadhn, VA, sHSP and CaPR-10 showed more than a 1.5-fold expressed in amount in B. licheniformis K11-treated drought pepper compared to untreated drought pepper. The changes in proteins and gene expression patterns were attributed to the B. licheniformis K11. Accordingly, auxin and ACC deaminase producing PGPR B. licheniformis K11 could reduce drought stress in drought affected regions without the need for overusing agrochemicals and chemical fertilizer. These results will contribute to the development of a microbial agent for organic farming by PGPR.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.111-111
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• 2017

The development and productivity of maize (Zea mays L.) is frequently impacted by water scarcity, and consequently to increased drought tolerance in a priority target in maize breeding programs. To elucidate the molecular mechanisms of resistance to drought stress in maize, RNA-seq of the public database was used for transcriptome profiling of the seedling stage exposed to drought stress of three levels, such as moderate, severe drought stress and re-watering. In silico analysis of differentially expressed genes (DEGs), 176 up-regulated and 166 down-regulated DEGs was detected at moderated stress in tolerance type. These DEGs was increasing degradation of amino acid metabolism in biological pathways. Six modules based on a total of 4,771 DEGs responses to drought stress by the analysis of co-expression network between tolerance and susceptible type was constructed and showed to similar module types. These modules were discriminated yellow, greenyellow, turquoise, royalblue, brown4 and plum1 with 318, 2433, 375, 183, 1405 and 56 DEGs, respectively. This study was selected 30 DEGs to predicted drought stress response gene and was evaluated expression levels using drought stress treated sample and re-watering sample by quantitative Real-Time Polymerase Chain Reaction (qRT-PCR). 23 genes was shown increasing with drought stress and decreasing with re-watering. This study contribute to a better understanding of the molecular mechanisms of maize seedling stage responses to drought stress and could be useful for developing maize cultivar resistant to drought stress.

• Journal of The Korean Society of Grassland and Forage Science
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• v.42 no.2
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• pp.120-126
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• 2022

The objective of this study was to determine effects of phosphorus on lignification and carbohydrate metabolism in Kentucky bluegrass under drought stress. Drought stress was induced by reducing of water to plants in pots. Two types of phosphorus were applied as potassium phosphate (PO₄^3-; P) or potassium phosphonate (PO₃^3-; PA) in drought-stressed plants. Drought had significant negative effects on plant growth, as revealed by reduced biomass of shoot. Drought-induced increase of lignin content was concomitant with the increase of phenylalanine ammonia-lyase (PAL). Soluble sugar content was highly increased but fructan content was largely decreased by drought stress. However, the application of phosphorus was efficient to ameliorate the adverse effects of drought. PA application improved reduced shoot growth and relative water content, and inhibited lignification synthesis with a reduction of PAL activity. P or PA application maintained soluble sugar and fructan content at similar levels to controls under drought stress. These results indicate that phosphorus application may mitigate the drought stress by inhibiting the lignification and promoting the fructan assimilation.

• Journal of The Korean Society of Grassland and Forage Science
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• v.42 no.3
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• pp.208-214
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• 2022

Drought stress is a condition that occurs frequently in the field, it reduces of the agricultural yield of field crops. The aim of the study was to screen drought-adapted genotype of Italian rye grass. The experiments were conducted between the two Italian ryegrass (Lolium multiflorum L.) cultivars viz. Hwasan (H) and Kowinearly (KE). The plants were exposed to drought for 14 days. The results suggest that the morphological traits and biomass yield of KE significantly affected by drought stress-induced oxidative stress as the hydrogen peroxide (H₂O₂) level was induced, while these parameters were unchanged or less affected in H. Furthermore, the cultivar H showed better adaptation by maintaining several physiological parameter including photosystem-II (Fv/Fm), water use efficiency (WUE) and relative water content (RWC%) level in response to drought stress. These results indicate that the cultivar H shows improved drought tolerance by generic variation, improving photosynthetic efficiency and reducing oxidative stress damages under drought stress. These findings can be useful to the breeder and farmer for improving drought tolerance in Italian rye grass through breeding programs.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.1
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• pp.73-80
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• 2006

Sesame (Sesamum indicum L.) seeds contain abundant oil and antioxidative lignans related to the seed quality. To evaluate the potential effects of drought stress on the chemical composition of sesame seeds, eighteen cultivars were imposed water-deficit condition by withholding irrigation during 15 days at podding and maturing stage, compared with well-watered plants as control in seed yield and chemical composition. Drought treatments showed great decrease of seed yield with not affecting seed weight. The contents of sesamin and sesamolin decreased while lignan glycosides inversely increased in response to drought stress. Oil content was not significantly changed by drought treatment in spite of its slight decrease. In case of fatty acid composition, there were significant differences in increase of oleic acid while inverse decrease of linoleic acid under drought stress condition. These results demonstrate that the chemical composition of sesame seed may be modified with drought stress. In particular, the increase of sesaminol glucosides with strong antioxidative activity was observed.

• Journal of Biosystems Engineering
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• v.40 no.4
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• pp.335-344
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• 2015

Purpose: Soybean growth is adversely affected by environmental stresses such as drought, extreme temperatures, and nutrient deficiency. The objective of this study was to develop a method for rapid measurement of drought stress in soybean plants using a hyperspectral fluorescence imaging technique. Methods: Hyperspectral fluorescence images were obtained using UV-A light with 365 nm excitation. Two soybean cultivars under drought stress were analyzed. A partial least square regression (PLSR) model was used to predict drought stress in soybeans. Results: Partial least square (PLS) images were obtained for the two soybean cultivars using the results of the developed model during the period of drought stress treatment. Analysis of the PLS images showed that the accuracy of drought stress discrimination in the two cultivars was 0.973 for an 8-day treatment group and 0.969 for a 6-day treatment group. Conclusions: These results validate the use of hyperspectral fluorescence images for assessing drought stress in soybeans.