不同水分处理下冬小麦冠层温度、叶片水势和水分利用效率的变化及相关关系

小区栽培冬小麦,设计5种程度的干旱胁迫,利用防雨棚分别控制土壤重量含水量为田间持水量的45％、55％、65％、70％、80％,观测不同水分处理下冬小麦冠层温度、叶片水势和水分利用效率的变化及相关关系.结果显示,随着含水量的增加,各处理的平均和最高冠层温度整体呈下降趋势,叶水势和蒸腾速率呈上升趋势,在小麦抽穗期干旱胁迫最严重处理表现出最大水分利用效率,开花期的水分利用效率较抽穗期整体下降了50.70％;相关分析表明,抽穗期小麦的冠层温度与空气饱和差极显著正相关(P＜0.01),开花期的冠层温度和叶水势呈显著负相关(P＜0.05),冠层温度和空气饱和差存在着极显著正相关,空气饱和差和蒸腾速率极显著负相关,冠层温度和水分利用效率有着显著的正相关性.综上所述,冠层温度在小麦抽穗和开花期完全可以作为作物水分状况的有效监测指标之一.

Variation and interrelationship of winter wheat canopy temperature, leaf water potential and water use efficiency under different water treatments

To reveal the variation and interrelationship of winter wheat canopy temperature,leaf water potential and transpiration rate and water use efficiency,we designed five different degrees of drought stress through plot culture in rainproof installations,in which the water content was 45%,55%,65%,70% and 80% of field capacity respectively.The results showed that with the increase in the amount of irrigation for each treatment,the average and maximum canopy temperature showed a downward trend as leaf water potential and transpiration rate showed a rising trend overall,when the wheat suffered the most severe drought stress in the heading stage,it showed the greatest water use efficiency,and it decreased by 50.70% overall at flowering stage compared with that at heading stage;Correlation analysis showed that canopy temperature and air saturation deficit was in very significant positive correlation at heading stage(P<0.01),and at flowering stage,canopy temperature and leaf water potential was in significant negative correlation(P<0.05),canopy temperature and air saturation deficit was in very significant positive correlation,air saturation deficit and transpiration rate was in significant negative correlation,canopy temperature and water use efficiency was in significant positive correlation.To sum up,at heading and flowering stages of wheat,canopy temperature can be used as one of the effective indexes to monitor water status of crops.