灌水模式对冬小麦光合特性、水分利用效率和产量的影响

试验于2013-2014和2014-2015年连续2个生长季在自动控制干旱棚内的隔离池中进行,拔节期设3个灌水梯度,灌水量分别为0(J₀)、37.5(J₁)、75 mm(J₂),扬花期设3个灌水梯度,灌水量分别为0(F₀)、37.5(F₁)、75 mm(F₂),灌浆期所有处理均按75 mm灌溉,共9个处理,研究不同灌溉模式对小麦中后期不同生育阶段植株生长、耗水量、水分利用效率、光合特性和产量构成因素的影响.结果表明: 拔节期干旱(0和37.5 mm)显著降低了小麦扬花期的净光合速率和拔节后的叶面积,扬花期的灌水量直接影响扬花期后的旗叶净光合速率;拔节期干旱扬花期补水和扬花期干旱灌浆期补水都可以有效提高植株的干物质量;拔节期灌水量越多,全生育期耗水量越大;除J₁F₂外,全生育期灌水量越大,耗水量越大,产量也越高;J₁F₂处理产量和水分利用效率最高.扬花期充足的灌水量使J₁F₂处理具有较高的花后旗叶净光合速率,此期补偿性灌溉加快了干物质积累,也保证了较高的穗粒数,使其最终产量高于J₂F₂处理或与之持平,同时J₁F₂拔节期较低的灌水量降低了小麦生育中后期的耗水量,其水分利用效率也显著高于其他处理.综上,J₁F₂是小麦生育中期理想的水分处理组合.

Effects of irrigation regimes on photosynthesis,water use efficiency and grain yield in winter wheat

The effects of different irrigation regimes on photosynthesis, plant growth, water use efficiency (WUE), and grain yield in winter wheat were examined in a common garden with rainout shelter during 2013-2014 and 2014-2015 growing seasons. The experiment consisted of two irrigation timings, jointing stage (J) and anthesis (F), and three irrigation levels, 0, 37.5 and 75 mm, which generated nine irrigation combinations, i.e. J₀F₀, J₀F₁, J₀F₂, J₁F₀, J₁F₁, J₁F₂, J₂F₀, J₂F₁ and J₂F₂. All plots received 75 mm irrigation at grain filling stage. The results showed that water stress at jointing stage significantly reduced leaf area after jointing stage and the net photosynthetic rate (P_n) at anthesis. Post-anthesis flag leaf P_n was significantly affected by irrigation at anthesis. Water stress at jointing stage followed irrigation at anthesis or that at anthesis followed irrigation at grain filling stage increased dry matter accumulation of wheat plants. Higher amount of irrigation at jointing stage led to higher water consumption in the entire growing period. High amount of irrigation during the entire growing period resulted in high water consumption and grain yield with an exception of J₁F₂ treatment. Among all the treatments, the J₁F₂ treatment had superior grain yield and WUE. Sufficient water supply at anthesis resulted in high flag leaf P_n after flowering in J₁F₂. Irrigation at anthesis for J₁F₂ enhanced wheat dry matter accumulation and kernel numbers per spike, and consequently high yield. Small amount of irrigation at jointing stage reduced wheat water consumption at middle and late growth stages. The wheat WUE in treatments with small amount of irrigation at jointing stage (J₁F₂) was higher than in other treatments. In this study, J₁F₂ was the best irrigation regime for winter wheat.