Volaire Florence
Institut National de Recherche Agronomique, Laboratoire d'Ecophysiologie des Plantes sous Stress Environnementaux, 2 place Viala, 34060 Montpellier cedex 1, France.
New Phytol. 2003 Dec;160(3):501-510. doi: 10.1046/j.1469-8137.2003.00906.x. Epub 2003 Oct 24.
• In semiarid areas, populations of cereal crop plants can be reduced by severe drought occurring during the vegetative stage, leading to subsequent serious yield reduction. This study aimed to analyse and compare survival and dehydration tolerance in two contrasting barley (Hordeum vulgare) cultivars (cvs) and in a drought resistant perennial grass, cocksfoot (Dactylis glomerata). • In pot experiments, seedlings were subjected to intensifying droughts for analysis of adaptive responses and survival following a range of final soil water potentials (SWP). • Survival rates were 100% in cocksfoot and 32% in the drought resistant barley cv. Tadmor at a SWP of -2.5 MPa. In cocksfoot, lamina water potentials decreased earlier and water content in enclosed leaf bases stabilized at low SWP. This strategy of dehydration tolerance was associated with high survival. • At moderate water deficit, barley cv. Tadmor exhibited a 5-fold greater osmotic adjustment in lamina, lower senescence and higher accumulation of dehydrins in enclosed leaf bases than the drought sensitive cv. Plaisant. However, under severe drought, water content in enclosed leaf bases declined constantly and was associated with similar mortality in both cvs. Dehydration tolerance was low in barley and not correlated with dehydrin accumulation or resistance to moderate drought.
• 在半干旱地区,谷类作物在营养生长阶段遭遇严重干旱会导致种群数量减少,进而造成后续严重减产。本研究旨在分析和比较两种对比鲜明的大麦(Hordeum vulgare)品种以及一种抗旱多年生禾本科植物鸭茅(Dactylis glomerata)的存活能力和耐旱性。
• 在盆栽试验中,让幼苗经受逐渐加剧的干旱,以分析一系列最终土壤水势(SWP)下的适应性反应和存活情况。
• 在土壤水势为-2.5兆帕时,鸭茅的存活率为100%,抗旱大麦品种塔德莫尔(Tadmor)的存活率为32%。在鸭茅中,叶片水势下降更早,封闭叶基部的含水量在低土壤水势下趋于稳定。这种耐旱策略与高存活率相关。
• 在中度水分亏缺时,大麦品种塔德莫尔叶片的渗透调节能力比干旱敏感品种普莱桑特(Plaisant)高5倍,衰老程度更低,封闭叶基部脱水素的积累量更高。然而,在严重干旱下,封闭叶基部的含水量持续下降,两个品种的死亡率相近。大麦的耐旱性较低,且与脱水素积累或对中度干旱的抗性无关。