土壤水分含量对小麦耗水特性和旗叶/根系衰老特性的影响

Effects of different soil water content on water consumption by wheat and analysis of senescence characteristics of root and flag leaf

为明确土壤含水量对小麦籽粒产量的影响及其形成的生理原因,于2019—2021年小麦生长季在山东省兖州区小孟镇史家王子村小麦试验站进行试验,选用冬小麦品种济麦22,设置4种土壤含水量处理:分别为全生育不灌水(W0),于小麦拔节期和开花期将0~40 cm土层土壤相对含水量均补灌至65%(W1)、75%(W2)、85%(W3),研究了土壤含水量对小麦耗水特性、旗叶与根系衰老特性和籽粒产量的影响。结果表明:W2处理的穗粒数和千粒重显著高于其他处理,获得了最高的籽粒产量和水分利用效率,相较于W0、W1、W3,籽粒产量分别高48.49%、20.80%、8.68%(2019—2020)和46.87%、17.36%、7.53%(2020—2021),水分利用效率分别高21.70%、14.25%、15.59%(2019—2020)和25.44%、11.90%、13.39%(2020—2021);W2处理开花后40~100 cm土层根长密度、40~60 cm土层根系超氧化物歧化酶活性和根系活力显著高于其他处理,丙二醛含量显著低于其他处理;W2处理开花后旗叶超氧化物歧化酶活性显著高于W0、W1处理,与W3处理无显著差异,丙二醛含量显著低于W0、W1处理,与W3处理无显著差异;W2处理显著提高了开花期至成熟期阶段耗水量、日耗水量、耗水模系数和40~120 cm土层土壤贮水消耗量。由此可见,适宜的土壤含水量能够促进根系下扎,延缓植株衰老,提高对深层土壤水分的吸收利用,保证了籽粒灌浆期水分供应,显著提高籽粒产量。在本试验条件下以小麦拔节期和开花期将0~40 cm土层土壤相对含水量均补灌至75%的W2处理效果最好。

The objective of this study is to clarify the effect of soil water content on wheat grain yield and the physiological reasons for its formation.During the winter wheat growing season from 2019 to 2021,four kinds of soil water content treatments were set under the field conditions of the wheat test station in Shijiawangzi village,Xiaomeng town,Yanzhou district,Shandong province:No-irrigation(W0),and the relative water content of the soil in the 0–40 cm soil layer was supplemented to 65%(W1),75%(W2),and 85%(W3)at jointing and anthesis stages,and the winter wheat variety was Jimai 22.The effects of soil water content on water consumption,leaf and root senescence,and grain yield of wheat were studied.The results showed that the number of kernel number and 1000-kernel weight of W2 treatment were significantly higher than those of other treatments,and the highest grain yield and water use efficiency were obtained.Compared with W0,W1,and W3,the grain yield was 48.49%,20.80%,8.68%(2019–2020)and 46.87%,17.36%,7.53%(2020–2021),respectively.The water use efficiency was 21.70%,14.25%,15.59%(2019–2020)and 25.44%,11.90%,13.39%(2020–2021),respectively.Compared with the other treatments,root length density in the 40–100 cm soil layer,superoxide dismutase activity and root activity in the 40–60 cm soil layer in W2 treatment were significantly higher than those in other treatments after anthesis,and the content of malondialdehyde was significantly lower than those in other treatments.After anthesis,the superoxide dismutase activity of flag leaves in W2 treatment was significantly higher than that in W0 and W1 treatments,but there was no significant difference in W3 treatment,and the content of malondialdehyde was significantly lower than that in W0 and W1 treatments,but there was no significant difference in W3 treatment.W2 treatment increased significantly water consumption,daily water consumption,water consumption model coefficient,and soil water storage consumption in the 40–120 cm soil layer from anthesis to maturity.In conclusion,the appropriate soil moisture content could promote root growth,delay plant aging,and then improve the absorption and utilization of deep soil moisture,ensure the supply of water during grain filling,and improve significantly grain yield in wheat.Under the conditions of this experiment,the effect of W2 treatment was the best when the relative water content of 0–40 cm soil layer was increased by 75% at the jointing and anthesis stages in wheat.