水分处理及覆膜历时对春玉米生理特性的影响

Effects of irrigation treatments and film mulching times on physiology of spring maize

【目的】探究不同水分处理模式及不同覆膜历时对春玉米光合特性与根系活力的影响,为春玉米节水高产栽培提供参考。【方法】在移动式遮雨棚下,以"隆玉58"为供试材料,采用子母桶栽土培法和一般桶栽相结合的方法,研究全生育期充分灌水和分生育期调亏灌水2种水分处理模式,以及覆膜到拔节期、覆膜到抽雄期和全生育期覆膜3种覆膜历时对春玉米苗期、拔节期和抽雄期净光合速率、蒸腾速率、水分利用效率以及根系活力的影响。【结果】调亏灌水期间的土壤水分亏缺降低了春玉米叶片的净光合速率和蒸腾速率,抽雄期恢复充分灌水后,两者均有一定程度的改善。相对于叶片的净光合速率,蒸腾速率对土壤水分亏缺更为敏感。与充分灌水相比,调亏灌水有利于叶片水分利用效率的提高。充分灌水下根系活力大于调亏灌水,抽雄期复水后,除覆膜到抽雄期处理外,其余2个处理均与充分灌水无显著性差异。【结论】叶片蒸腾速率对土壤水分状况较净光合速率更为敏感,水分亏缺可提高叶片的水分利用效率,覆膜到抽雄期可获得较高的净光合速率和叶片水分利用效率。

【Objective】This paper studied the effects of different irrigation treatments and mulching times on photosynthetic characteristics and root activity of spring maize,in order to provide basis for achieving high yield of water-saving for spring maize cultivation.【Method】The experiment cultivated spring maize(Longyu 58)in pots in combination with bared culturing under mobile rain-proof shelter.It contained two irrigation treatments,full irrigation all stages and regulated deficit irrigation in different stages,and three mulching periods,mulching till jointing stage,mulching till tasseling stage and mulching all stages.Then the effects on photosynthesis rate,transpiration rate,leaf water use efficiency and root activity of spring maize in seeding stage,jointing stage and tasseling stage were studied.【Result】Leaf photosynthesis rate and transpiration rate were reduced due to the low soil water content during the regulated deficit irrigation and restored after full irrigation was resumed during tasseling stage.Transpiration rate was more sensitive to soil water deficit than photosynthesis rate,resulting in the improvement of leaf water use efficiency when treated with regulated irrigation.The root activity was more active when treated with full irri-gation.After recovering water in tasseling stage,there was no significant difference between the full irrigation treatment and mulching treatments except mulching till tasseling.【Conclusion】Transpiration rate was more sensitive to soil water deficit than photosynthesis rate.Water deficits improved leaf water use efficiency.Mulching till tasseling stage was a reasonable choice for increasing net photosynthesis rate and water use efficiency.