夏玉米产量及根系生长对旱涝急转的响应特征

Response Characteristics of Summer Maize Yield and Root Growth to Drought-Flood Abrupt Alternation

为了探明旱涝急转胁迫下夏玉米产量及根系生长的动态变化规律,采用测桶试验,设置不同程度的旱涝急转组以及对照组,分别于旱期开始、旱期结束、涝期结束、复水前期(15 d)、复水后期(21 d)测量根、冠干重以及根系形态指标,收获期测量产量及其构成。结果表明:①旱涝急转组产量均低于正常组,平均减产率为63.04%;粒重减小是旱涝急转组减产的主要原因,平均减幅为70.41%;重涝组与对照组差异显著。②根干物质、根冠比在旱涝急转涝期减少(降低)最为严重,平均降幅分别为41.41%、37.12%;根长密度、根表面积、平均直径、根体积的削减主要集中在复水期;比根长、比表面积虽然在复水期低于对照组,但在旱涝急转受旱阶段略高于对照组,旱期平均增大3.19%、1.74%。旱涝急转对根系生长的抑制直接导致了粒重的减小,从而降低了产量。

In order to ascertain the dynamic change law of summer maize yield and root growth under the drought-flood abrupt alternation,using the barrel measurement method,the experiment set up different degrees and durations of drought-flood abrupt alternation groups and the check group.Dry matter weight of root and crown,and root morphological indicators were measured at the beginning of the drought period,the end of the drought period,the end of the flood period,15 days before rewatering and 21 days after rewatering.The yield and its composition were measured at harvest period.The results show that a)the yield of drought-flood abrupt alternation groups is lower than that of the check groups and the average yield reduction rate is 63.04%;the average reduction rate of grain weight is 70.41%;the heavy flood groups are significantly different from the check group.b)The damage of root dry weight and root-shoot ratio is the most serious during the flood period,with an average reduction rate of 41.41%and 37.12%respectively;the damage to root length density,root surface area,average diameter and root volume is more serious during the rewatering period;the damage to specific root length and specific surface area is lower than that of the check group during the rewatering period,but is higher than that of the check group during the drought period,with an average increase of 3.19%and 1.74%.The inhibition of drought-flood abrupt alternation on root growth directly leads to the reduction of grain weight,thereby reducing the yield.