干旱高温胁迫对小麦生长及木聚糖含量的影响
Effects of water deficit and high temperature on growth and arabinoxylan concentrations in two different spring wheat varieties

选取两个水分处理（拔节期开始，95%和40%田间持水量）、两个温度水平（孕穗期开始，昼/夜温度分别为25℃/15℃和35℃/25℃）和两个春小麦品种（Superb和AC Crystal）在温室条件下进行试验，分析了小麦不同生育期生长及开花期叶片气体交换参数和成熟期产量及木聚糖含量的变化。结果表明：高温处理下Superb成熟时间比适温处理下提前20天，AC Crystal提前21天；孕穗期高温干旱两种胁迫均显著降低了小麦的株高，并且两种因子结合后产生的作用最强，其中，Superb的株高降低了16.7%，AC Crystal降低了30.6%; 两个小麦品种生育后期以AC Crystal的分蘖数较多，孕穗期温度水分适宜条件下AC Crystal分蘖数比Superb高18.7%，但其对温度敏感性较强。高温干旱显著降低了叶片气体交换参数的值，Superb在干旱高温条件下Pn比其在温度水分适宜条件下降低了68.9%。高温增加了小麦籽粒木聚糖的含量，特别是水溶性木聚糖(WEAX)，干旱环境下高温处理使得Superb的WEAX升高了49%；木聚糖含量与叶片各气体交换指标参数和产量之间呈显著的负相关关系。
In this study, effects of drought and heat stress to the two spring wheat growth and quality were investigated. The investigation was conducted in a controlled environment to evaluate the combined effects of water deficit (imposed at the stem elongation stage, 40% field capacity) and high temperature (imposed at the booting stage) on the wheat growth, leaf gas exchange, arabinoxylan concentrations and yields of two spring wheat varieties (‘Superb’ and ‘AC Crystal’) commonly grown in Canada. The temperature treatments were 25℃/15℃(day/night, T1) and 35℃/25℃(T2). Overall, time to maturity under high temperature was 20 days shorter for Superb and 21 days for AC Crystal, indicating that two varieties were more sensitive to high temperature stress. Plant height was sensitive to drought combined high temperature stress for both varieties at booting stage; the plant height of Superb was reduced by 16.7%, while AC Crystal was reduced by 30.6%. At the late growth stage the tillers of AC Crystal was more sensitive to high temperature which was 18.7% higher than that of Superb under appropriate water and temperature condition; Drought and high temperature decreased (P<0.05) leaf gas exchange parameters (Pn of Superb was decreased by 68.9% under drought and high temperature conditions) and the yields but increased the grain arabinoxylan concentrations, especially the water-extractable arabinoxylans (WEAX); High temperature treatment under drought conditions made the WEAX of Superb increased by 49%. The different arabinoxylan fractions were negatively correlated with the leaf gas exchange and yield.