Exogenous Salicylic Acid and Trehalose Ameliorate Short Term Drought Stress in Wheat Cultivars by Up-regulating Membrane Characteristics and Antioxidant Defense System

Abstract

In this study, the protective role of salicylic acid (SA) and trehalose (Tre) in relation to lipid peroxidation, membrane leakage, membrane stability index, antioxidant defense system as well as non-enzymatic antioxidants were investigated in drought stressed wheat Gemmieza-7 (drought sensitive cultivar) and Sahel-1 (drought tolerant cultivar) plants. Water stress reduced bio-membranes stability through inducing its lipid peroxidation resulting in an increment in membrane leakage with marked decrease in membrane stability index of flag leaf of both wheat cultivars during grain-filling. Moreover, it was obvious that drought significantly increased the activity of ascorbic acid oxidase (AAO), peroxidase (POD) and phenylalanine ammonia lyase (PAL) activities and induced non-significant reduction in polyphenol oxidase (PPO) activity in flag leaves of both wheat cultivars during grain-filling in comparing with well watered plants. Among cultivars, tolerant one showed higher enzymes activity than the sensitive one. Application of SA and/or Tre markedly increased AAO, POD and PAL activities and non-significant decrease in PPO activity in flag leaf of water stressed wheat plants. Generally, SA and Tre treatment appeared to be the most effective treatment in counteracting the negative effects of water stress and Sahel-1 appeared to induce better results than Gemmieza-7 and proved to be more tolerant.Drought stress caused significant increase in the amount of total phenols and flavonoids in flag leaf of both cultivars during grain-filling where the sensitive plants accumulated more total phenols and flavonoids contents than the tolerant one. Furthermore, water stress increased the non-photosynthetic pigment content of the two wheat cultivars particularly drought sensitive one during grain filling. These results suggest that the exogenous application of SA and/or Tre assisted the plants to become more tolerant to drought stress-induced oxidative damage by upregulating the membrane characteristics and enhancing their antioxidant defense system as well as non-enzymatic antioxidants.

Foliar Application of Salicylic Acid and Calcium Chloride Enhances Growth and Productivity of Lettuce (Lactuca sativa)

“…In addition, improving leaf water content by the application of salicylic acid led to accumulation of different osmolytes such as sugars, sugar alcohol and proline which are responsible for osmotic adjustment (Szepesi et al, 2005, Umebese et al, 2009and Bidabadi et al, 2012. Moreover, our results also coincide with those of Aldesuquy and Ghanem (2015) who found that salicylic acid increased leaf membrane stability index of drought stressed wheat plants.…”

Impact of osmotic stress on seedling growth observations, membrane characteristics and antioxidant defense system of different wheat genotypes

“…Therefore, the status of cellular membranes also indicates the degree of plant acclimation to stress. The impact of water stress on antioxidant defense system and membrane features in wheat and other plants was intensively studied [8,9].…”

Manipulation of plant methylglyoxal metabolic and signaling pathways for improving tolerance to drought stress

“…Besides metabolic adaptation, JA can enhance to drought stress by regulating signaling pathways to control stomatal closure . Similar to JA, SA improves plant responses to drought stress by activating antioxidant defence system and Gly system, RWC, chlorophyll content, and thereby performance (Aldesuquy and Ghanem 2015). Hence, manipulation of genes involved in hormone biosynthesis and signaling pathways particularly those related to ABA, JA, SA, and BR homeostasis can be regarded as efficient strategies for designing drought-tolerant crops.…”