Growth and sugar accumulation in durum wheat plants under water stress

Abstract

SUMMARYThe effect of water stress on growth of Triticum durum L, was in\estigated in relation to sugar accumulation and water status ot wheat plants before, during and after a ptriud of water stress. The slight decrease in water potential in the first few days after withholding water had no detectable efTect on growth. Inhibition of growth was only apparent when the water content started to decline. Dry weight continued to increase during water stress, even under severe stress (after day 27) which was associated with a sharp rise in sugar content, accounting for 20 "o of the gain in dry matter between days 27 and 31, The increase in leaf length and leaf area of stressed plants following re-watering, from day 31, was owing to the leaves regaining turgidity after wilting. Growth inhibition coincided with a considerable increase in sugar content. The role of growth inhibition and other factors in sugar accumulation under water stress is discussed. Photosynthesis rather than reserve starch might be the major source of sugar accumulated under water stress in durum wheat.Key words: Water stress, sugars, growth, wheat. INTRODliCTIONSoluble sugars have been shown to increase in the leaves of wheat under water stress (Munns & Weir, 1981; Drossopoulos, Karamanos & Niavis, 1987;Kameli & Losel, 1993). They are also considered to play an importatit role in osmotic adjustment which is widely regarded as an adaptive response to water stress conditions (Turner & Jones, 1980; Morgati, 1984;Kameli & Losel. 1993, 1995. Factors which have been suggested to contribute to this increase under water stress include reduced translocation of sugars out of the leaves, slower utilization because of decreased growth and other changes, such as starch hydrolysis. These might contribute individually or together, under different conditions and in different plant species.The extent to which growth inhibition might be responsible for a rise in sugar concentration under water stress was investigated in this study by comparing the timing of the two responses in the same species. Changes in soluble and insoluble carbohydrates were examined, during and after water stress, in relation to growth. * Prtsent address: Depariement de Btologie, Ecoie Normale Superieure, Vieux-Kouba, Algiers, Algeria, t To whom correspondence shotild be addressed. M.^TERIALS AND METHODSSeeds of durum wheat {Triticum durum L.) \ariety MBB from Algeria were soaked for 24 h and gertninated m vermicuhte for 6 d. The seedlings were planted in pots of mixed compost and vermiculite (2:1 y/y), as described previously (Kameli & Losel, 1993). After 17 d of grow^th with normal water supply, stress was applied by withholding water from half of the pots, selected in a randomized manner. Stressed plants were again watered from day 31. Control plants received full water treatment throughout the period of the experiment. The plants were grown under fluorescent tubes (Osram white, 65/80 W) with irradiance 9()-100 //mol m"' s"', day and night temperatures 22 + 2 and 18 + 2 °C respectively, an...

Water stress causes differential effects on germination indices, total soluble sugar and proline content in wheat (Triticum aestivum L.) genotypes

“…These results are in accordance with the findings of Mohammadkhani and Heidari (2008), Tatar and Gevrek (2008) and Kameli and Losel (1996) who reported that wheat sugar and proline content increased under drought stress conditions. Higher proline content in wheat plants after water stress has also been reported by Vendruscolo et al (2007) and Patel and Vora (1985).…”

UV-C treatment on physiological response of potato (Solanum tuberosum L.) during low temperature storage

“…Sugar accumulation is a response phenomenon under different stresses, such as cold stress (Malone et al 2006), osmotic and salinity stress (Watanabe et al 2012), and water stress (Kameli and Lösel 1996). This may related to the fact that the sugars are effective in the regulation of osmotic pressure in plant cells.…”

Plant Water-Stress Response Mechanisms

“…The increase of sugar in various plant tissues response to water stress are supported the idea of contribution of solutes while the plants exposed to different stress levels. The studies have shown that soluble sugars accumulate in leaves during water stress [60,71,79,[87][88][89][90], and have suggested that these sugars might contribute to osmoregulation [65], at least under moderate stress. Quick et al, (1992) [60] compared the effect of water stress on the rate of photosynthesis and the partitioning of photosynthate in four different species, including two annuals (Lupinus albus L. and Helianthus annuus L.), and two woody perennials (Vitis vinifera cv.…”