花期前后不同干旱过程对玉米抗旱生理反应的影响

Effects of different drought process at pre and post-anthesis on the physiological reaction of drought-resistance of maize plants

本试验对盆栽玉米分别进行了正常供水;花前水分胁迫、花后正常供水;花前正常供水、花后水分胁迫共3种水分处理,在玉米生长的拔节期、喇叭口期、花期及成熟期进行了生理特性测定,研究了花前花后水分胁迫对根系伤流量、生长参数、活力及叶片生理特性的影响。结果表明,花期是玉米开始衰老的关键时期。正常供水条件下,玉米的根系伤流液量、根系活力、CAT活性、POD活性及膜透性呈现上升趋势,在开花期达到高峰后开始下降。花前水分胁迫条件下,根系活力减弱,保护酶活性较低,MDA含量显著增加。花后水分胁迫条件下,玉米保护酶活性有大幅的减弱,花前水分胁迫对玉米生长的影响是花后补充供水难以恢复的。

Three treatments with different water supply to maize plants before and after blooming was conducted in this experiment, namely, one was adequate water supply condition at the whole growth period; the second was water stress condition before blooming but normal water supply after blooming; the third was normal water supply before blooming but water stress after blooming. The bleeding intensity, some root growth parameters, root vigor, activity of protective enzymes and malondialdehyde （MDA） were determined at jointing stage, trumpet stage, flowering stage and mature stage. The results obtained were as follows： ① For the maize plants under adequate water supply condition, the bleeding intensity, root vigor, catalase （CAT） activity and peroxidase （POD） activity increased gradually from the trumpet stage to the following stage, they reached the maximum at atheists, and then fell. ② For the maize plants which were grown under water stress before blooming, the root growth was inhibited, bleeding intensity was decreased, and root vigor was lowered. ③ When maize plants grew under normal water supply condition before blooming but water stress condition after blooming, the anti-oxidizes defense system was seriously weakened because the activity of three protective enzymes dropped greatly. Furthermore, the MDA content had a sharp increase. As a consequence, the anthesis of maize is the key period for senescence starts of root and leaf. Even adequate water was supplied after blooming, the negative influence of water stress on maize growth before blooming is hard to be eliminated.