灌水时期和灌水量对小麦耗水特性和旗叶光合作用及产量的影响

在2004—2005和2005—2006小麦生长季，以济麦20、泰山23和泰山22为试验材料，研究了不灌水(W0)、拔节水60 mm (W1)、拔节水60 mm+开花水60 mm (W2)和拔节水60 mm+开花水60 mm+灌浆水60 mm (W3) 4个灌水处理条件下小麦耗水特性、旗叶光合作用和产量变化。结果表明，2004—2005生长季，济麦20和泰山23均以W2处理籽粒产量最高，耗水量和灌水效率分别高于和低于W1处理；两品种的水分利用效率均以W1和W2处理高于其他处理，其中济麦20的W1和W2处理无显著差异，而泰山23的W1处理高于W2处理。2005—2006生长季，济麦20和泰山22分别以W1和W2处理获得最高籽粒产量，两处理的耗水量(451.3 mm和459.2 mm)无显著差异；两品种的水分利用效率均以W0处理最高，W3处理最低，其中济麦20的W1处理高于W2处理，而泰山22在两处理间无显著差异。随灌水量的增加，土壤供水量和降水量占总耗水量的百分率降低，灌水量占总耗水量的百分率增大。济麦20的W0处理的旗叶光合速率和磷酸蔗糖合成酶活性在灌浆初期与W1和W2和W3处理无显著差异，灌浆中后期显著降低，但W0处理有利于蔗糖向籽粒转移，灌浆后期旗叶中蔗糖滞留较少，这是W0处理的粒重显著高于其他处理的生理原因之一。综合考虑籽粒产量、水分利用效率和灌水效率，在未灌底墒水条件下，济麦20和泰山23以拔节水灌60 mm或拔节水和开花水各灌60 mm为节水高产的模式；在灌底墒水60 mm条件下，济麦20以拔节水灌60 mm、泰山22以拔节水灌60 mm或拔节水和开花水各灌60 mm为节水高产的模式。

Effects of Irrigation Stage and Amount on Water Consumption Characteristics, Flag Leaf Photosynthesis, and Grain Yield in Wheat

Shortage of water resource has become one of the major factors limiting wheat (Triticum aestivum L.) production in North China. Irrigation plays an important role to obtain high grain yield. Currently, studies on water consumption characteristics and the physiological basis of yield formation in wheat are seldom reported. In this study, three wide planted cultivars, Jimai 20, Taishan 23, and Taishan 22 were used in two independent experiments in 2004–2005 and 2005–2006 growing seasons. There were four irrigation treatments in both experiments, i.e., no irrigation (W0), soil water plus one irrigation at jointing stage (W1), soil water plus two irrigations at jointing and anthesis stage (W2), soil water plus three irrigations at jointing, anthesis, and grain-filling stage (W3). Each irrigation supplied water of 60 mm. In the 2004–2005 growing season, the highest grain yields of Jimai 20 and Taishan 23 were obtained in W2 treatment with water consumptions of 429.8 and 453.0 mm, respectively, which were higher than those of W1 treatment (402.9 and 416.6 mm). However, the irrigation efficiency of W2 treatment was lower than that of W1 treatment. The water use efficiencies (WUE) of W1 and W2 treatments were both higher than those of other treatments in the two cultivars. In Jimai 20, there was no significant difference between W1 and W2 treatments, whereas in Taishan 23, W1 had higher WUE than W2. In the 2005–2006 growing season, Jimai 20 yield the highest in W1 treatment, and Taishan 22 in W2 treatment, with water consumptions of 451.3 and 459.2 mm, respectively. The highest and the lowest WUE were in W0 and W3 treatments in both Jimai 20 and Taishan 22, respectively. In Jimai 20, the WUE was higher in W1 than in W2, whereas there was no significant difference between W1 and W2 in Taishan 22. With the increase of irrigation amount, the percentage of soil water supply amount and precipitation to total water consumption amount decreased and the percentage of irrigation amount to total water consumption amount increased. Compared with W1, W2, and W3 treatments, W0 treatment had lower flag leaf photosynthetic rate and sucrose phosphate synthase activity at medium and late grain-filling, but at early grain-filling, there was no significant difference between W0 and W1, W2, W3, and the transfer of sucrose from flag leaf to grain was more favorable in W0 than in W1, W2, and W3, thus, Jimai 20 obtained the highest grain weight in W0 treatment. In wheat production under conditions similar to this study, the optimal irrigation regimes are suggested as 60–120 mm for Jinmai 20 and Taishan 23 at jointing or at jointing and anthesis stages without irrigating base water, and 60 mm for Jinmai 20 at jointing or 60–120 mm for Taishan 22 at jointing or at jointing and anthesis stages with irrigating base water 60 mm .