Cell Membrane Stability as a Measure of Drought and Heat Tolerance in Wheat¹

Abstract

Drought and heat tolerance tests that were developed for sorghum (Sorghum bicolor L. Moench) were adapted to and evaluated in field grown wheat (Triticum aestivum L. and T. durum Desf.) during 1977/1978 and 1978/1979.The drought tolerance test is based on the measurement of the electroconductivity of aqueous media containing leaf discs that were previously water stressed in vitro by exposure to a solution of polyethylene glycol‐6,000 (PEG). The heat tolerance test is similarly based on exposure of leaf discs to heating, in vitro, to 44 C.Drought tolerance of wheat leaves decreased with plant age. For a given plant growth stage, some variation was revealed in drought tolerance, according to leaf position. Maximal separation of wheat cultivars in drought tolerance was obtained with 40% (w/v) solution of PEG, when plants were grown under conditions of favorable moisture regime and sampled during the late jointing growth stage.Wheat was more drought tolerant than maize, sorghum or millet, based on published data.When plants were sampled during a period of water stress, they were more drought tolerant than well‐watered plants, indicating adjustment of cell membrane stability to drought stress. Wheat cultivars varied in their ability to adjust, in this respect.Unlike in sorghum, drought and heat tolerance were not correlated in wheat.The inclusion of a limited number of barley (Hordeum vulgare) and triticale (X Triticosecale Wittmark) genotypes in this study indicated that the methods discussed work equally well with these crop plants.

Drought Adaptation Mechanisms Should Guide Experimental Design

“…PSII quantum efficiency and estimated electron transport rate are similarly affected by many processes, and in particular vary greatly with light intensity [58,59]. Chlorophyll bleaching and loss of membrane integrity are other examples of damage [60]. Low stem and leaf hydraulic conductance can limit recovery of leaves after re-watering [61].…”

Improving Drought-Avoidance Root Traits in Chickpea (Cicer arietinumL.) -Current Status of Research at ICRISAT

“…Membrane injury occurs when dehydration reaches a critical point. Though electrolyte leakage from the cell is a measure of cell injury (Nayyar et al, 2005), the relationship between electrolyte leakage and crop performance under waterlimited conditions has not been demonstrated (Blum and Ebercorn, 1981;Blum, 1988).…”

Plant water relations and proline accumulation on two cowpea (Vigna unguiculata (L.) Walp.) cultivars as a response to water stress

“…Water stress may be determined by measuring physiological parameters such as leaf water potential, leaf osmotic potential, osmotic adjustment, leaf diffusive resistance (LDR), leaf relative water content (RWC), leaf temperature, leaf thickness, leaf rolling (Turner, 1981), proline content (Bates, Waldren & Teare, 1973) and cell membrane stability (Sullivan & Ross, 1979;Blum & Ebercon, 1981).…”

“…The polyethylene glycol (PEG) test used to measure cell membrane stability (CMS) has been shown as an efficient method to determine drought resistance in many crops such as sorghum (Sullivan & Ross, 1979;Premanchandra et aI., 1992) and wheat (Blum & Ebercon, 1981). Premachandra & Shimada (1988) indicated that CMS, measured by the PEG test, was significantly and positively correlated with leaf water potential, osmotic potential of leaf tissues, excised-leaf water retention, degree of leaf rolling, total plant weight and total root length under different soil moisture levels.…”