拔节期与开花期测墒补灌对小麦旗叶荧光特性和水分利用效率的影响

Effects of supplemental irrigation by measuring the moisture content at jointing and anthesis on fluorescence characteristics and water use efficiency in flag leaves of wheat

为研究依据不同土层的土壤质量含水量进行测墒补灌对小麦(Triticum aestivum)拔节期与开花期旗叶荧光特性和水分利用效率的影响,2011–2012和2012–2013年度两个小麦生长季,设置0–20(D1)、0–40(D2)、0–60(D3)和0–140 cm(D4)4个土层进行处理,测定土壤质量含水量,以各土层平均土壤相对含水量在拔节期为65%和在开花期为70%为目标相对含水量进行补灌,全生育期不灌溉为对照(D0)。结果表明:(1)D2处理拔节至开花期40–100 cm土层和开花至成熟期40–140 cm土层的土壤贮水消耗量高于其他处理,开花至成熟期是小麦贮水消耗的最大时期。(2)开花后旗叶水分利用效率、PSII潜在活性(Fv/Fo)、PSII电子传输活性(Fm/Fo)、相对电子传递速率(ETR)和光化学猝灭系数(qP)D2处理最高,D3次之,D0最低。(3)两个小麦生长季,各处理的籽粒产量为D2>D3>D1>D4>D0,D2的水分利用效率分别为20.19 kg·hm–2·mm–1和21.92 kg·hm–2·mm–1,高于D0、D3和D4处理,与D1处理间无显著差异。综合分析,小麦拔节期和开花期依据0–40 cm土层的土壤质量含水量进行测墒补灌可兼顾高产和高水分利用效率。

Aims Our objective was to determine the effects of supplemental irrigation by measuring the moisture content at jointing and anthesis on fluorescence characteristics and water use efficiency in flag leaves of wheat（Triticum aestivum）. Methods Four irrigation treatments were imposed, i.e. the average relative soil water content in the soil layer of 0–20 cm（D1）, 0–40 cm（D2）, 0–60 cm（D3）, and 0–40 cm（D4） were raised to 65%（at jointing） and 70%（at anthesis）, respectively, by supplemental irrigation, with zero-irrigation as a control treatment（D0） in 2011–2012 and 2012–2013. Important findings The soil water consumption in the D2 treatment was significantly higher than in other treatments in the 40–100 cm soil layer from jointing to anthesis and in the 40–140 cm soil layer from anthesis to maturity; the latter stage showed the highest soil water consumption during wheat growing. The flag leaves of wheat plants in the D2 treatment showed the highest water use efficiency, potential photosynthesis activity of PSII（Fv/Fo）, electronic transpiration activity of PSII（Fm/Fo）, relative electron transport rate（ETR） and photochemistry quenching index（qP） after anthesis, followed by the D3 treatment, with those in the D0 treatment having the lowest values. In both growing seasons, the grain yield was ranked in the order of D2 〉 D3 〉 D1〉 D4 〉 D0 among the treatments; water use efficiency（WUE） in the D2 treatment was 20.19 kg·hm–2·mm–1 and 21.92 kg·hm–2·mm–1, respectively, higher than in the D0, D3, and D4 treatments. No significant difference was observed in any of the variables between the D1 and D2 treatments. Hence, the D2 treatment, with application of irrigation based on the soil moisture measurement in the 0–40 cm soil layer at jointing and anthesis, is the most optimal treatment for achieving high grain yield and high WUE.