淹水条件下玉米耐淹阈值研究

以沿淮低洼地砂姜黑土为研究对象，研究玉米对淹水胁迫的反应及水淹程度的定量表达和耐淹阈值。试验在砂姜黑土原装土柱中进行，共设置6个处理，每个处理埋设相应的根袋，分别在六叶期和大喇叭口期进行淹水。淹水期间每天取2个根袋测定玉米植株养分含量和生物量；淹水结束后再统一取样进行相应的测定。结果显示，淹水对玉米生长影响很大，2个时期的生物量均随淹水时间的延长大幅度下降，营养元素（N、P、K）的吸收受到严重抑制，六叶期比大喇叭口期更敏感。六叶期处理间生物量与淹水时间呈极显著的（0.996*）抛物线关系。根据方程计算，减至对照50%生物量的淹水阈值约为3 d，这一结果和生物量与氮素含量或累积量的相关分析结果完全一致。淹水严重影响玉米生长、降低生物量、抑制养分的吸收。不同时期淹水只是影响程度不同。六叶期淹水其耐淹阈值约为3 d。

Submergence tolerance threshold of maize under flooded conditions

We studied the maize response to flooding stress, and quantitatively determined the expression and submergence tolerance threshold of the maize under flooded conditions in the low-lying areas along Huai River. Test was conducted in the lime concretion black soil of the Original soil column, 6 treatments were treated with burying the corresponding root bag, and flooding in six leaf stage and Huge bellbottom period, respectively. Nutrient content and biomass of two root bags of maize stalk were measured each day during the flood, and overall measurement was performed by uniform sampling after the flood. Significant impact of water-logging on maize growth was found. For the two studied periods, biomass dropped substantially with the extension of submergence time, and absorption of the nutrition elements (N, P, K) was severely inhibited. They were more sensitive in Six leaf stage than in Huge bellbottom period. At Six leaf stage, a parabola relationship (R² = 0.986) could be fitted between biomass and the flooded time. According to the equation, the time for biomass reduction to half of CK, i.e. submergence tolerance threshold, is three days. The result is consistent with the analysis between biomass and nitrogen content or its cumulant. In conclusion, water-logging would influence the growth of maize seriously, with lower biomass and restraint of nutrients absorption. Varied degrees of influence was observed for different periods of submergence. The submergence tolerance threshold for Six leaf stage is approximately three days.