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为了探究不同生长阶段土壤水分含量持续下降过程对玉米生长发育和产量形成的影响,通过设置遮雨棚人工控水试验,分析不同生长阶段持续干旱条件下玉米株高、叶面积指数(LAI)、光合性能、地上生物量和产量等生理生态指标的动态变化.试验因素为控水时段和控水持续时间,从拔节普遍期开始分别控水20(T_1)和27d(T_2),从抽雄普遍期开始控水20(T_3)和27d(T_4),加上不控水对照(CK),共5个处理.结果表明:持续干旱导致植株叶片卷曲、打绺,下部叶片衰老加快,对LAI影响较大,从而降低生物量的累积与籽粒产量.T_1~T_4处理结束时LAI分别为CK的74.9%、68.2%、60.5%和48.3%.玉米植株在经历持续控水后,叶片最大净光合速率(P_(n max))逐渐下降,T_1(T_3)和T_2(T_4)处理结束时P_(n max)分别降至CK的23%及不足10%,复水2周后,P_(n max)能恢复到CK的90%左右.T_1和T_2处理产量较CK分别下降18.5%和24.0%,T_3和T_4处理分别减产41.6%和45.8%.抽雄期持续干旱对玉米地上生物量及产量构成的影响大于拔节期干旱.干旱程度(D)能够定量表示土壤干旱状况,与玉米减产率存在线性定量关系,可通过计算D来预测玉米的减产情况.
In order to investigate the effect of soil moisture content in different growth stages on the growth and yield formation of maize, artificial shelter was set up to control the plant height, leaf area index (LAI) Photosynthetic characteristics, aboveground biomass and yield, etc. The experimental factors were the period of water control and the duration of water control. From the beginning of the jointing stage, water (T 1) and 27 days (T 2) (T_3), 27d (T_4) and uncontrolled water control (CK), a total of five treatments were carried out.The results showed that the effect of continuous drought on leaf curling, (P <0.05), and the biomass and the grain yield were reduced, and the LAI at the end of T_1 ~ T_4 treatments were 74.9%, 68.2%, 60.5% and 48.3% of that of CK respectively.When the corn plants under continuous water control, the maximum net photosynthetic rate (N max) decreased gradually, P nmax decreased to 23% and less than 10% of CK respectively after T_1 (T_3) and T_2 (T_4) And returned to about 90% of CK.The production of T_1 and T_2 decreased by 18.5% and 24.0% respectively compared with CK, and the production of T_3 and T_4 The yield of corn was 41.6% and 45.8%, respectively.Drought degree (D) could quantitatively indicate the soil drought status and there was a linear and quantitative relationship between the yield and the yield of maize By calculating D to predict the reduction of corn production.