氮素对不同抗旱性春小麦叶片温度、气体交换和WUE关系的影响

The Relationship of Leaf Temperature to Photosynthetic Parameters and Water Use Efficiency and the Responses to Nitrogen of Different Drought-tolerance Spring Wheat Cultivars

重点探讨了不同抗旱性春小麦幼苗叶片温度和叶片气体交换、作物水分利用效率(WUE)之间的关系及其氮素响应机制。通过对不同氮素水平和抗旱性春小麦苗期叶片光合气体交换参数的测定,研究了叶片温度(Tl)与水分-光合参数间的关系。结果表明,旱地品种Tl显著高于水浇地品种,并随氮素水平的提高其变化幅度显著低于水地品种;氮素供应后Tl显著升高,但在N15和N30处理之间叶片温度变化幅度降低;单叶WUE与Tl之间存在显著的负二次相关,在Tl<30℃时,WUE随Tl升高持续增加,其机理在于在此温度区间光合速率(Pn)与Tl存在显著正相关,气孔导度(Gs)下降和蒸腾速率(Tr)升高均对WUE无明显影响;当Tl>30℃时,主要受气孔行为的限制,WUE下降。氮素通过提高小麦叶片温度,增强光合机构活性来提高Pn和单叶WUE,从而提高小麦适应环境胁迫的能力和实现抗旱性和光合同化与水分高效利用的协调统一。

The water use efficiency of crop is affected by many physiol ecolcgical factors, the relationship of leaf temperature with gas exchange and WUE in wheat leaves of different drought-resistance cultivars and its response to nitrogen level have been discussed in this papers. The gas exchange in spring wheat leaves during its seedling stages under different nitrogen supply and drought-tolerance cultivars have been determined in this stimulant experiment, and the relationships of leaf temperature with photosynthetic rate （Pn） , transpiration rate（Tr） , stomatal conductance （Gs） , intercellular CO2 concentration （Ci） and water use efficiency （WUE） have been studied. The results showed that T1 of dryland cultivar higher than the contrast significantly, and the varied extent lower. Nitrogen supplying has increased T1 significantly, but there was not varied extent between N15 and N30. The WUE presented a negative quadratic relation with T1, the WUE increased continuously as T1〈30℃ and decreased as T1〉30℃, the mechanisms is that Pn increased continuously with T1 increased as T1 less than 30℃, the decreased Gs and increased Tr had not significant effect on WUE, but as T1 more than 30℃ the stoma had going to limited the increasing of WUE. Nitrogen could increase Pn and WUE by increase T1 and promote the photosynthetic instruments activity, and then increase adaptive capability to surrounding stress and harmonize the photosynthesis and water use efficiently.