根系分区交替灌溉对玉米籽粒灌浆及相关生理特性的影响

Effect of Alternate Irrigation in Partitioned Roots on the Kernel-filling and Its Related Physiological Characteristics in Maize

本研究旨在探明根系分区交替灌溉对玉米强、弱势粒灌浆及其相关生理特性的影响。以高产玉米品种登海11为材料,自抽雄至成熟设置常规灌溉(CI)和根系分区交替灌溉(PAI)2种灌溉方式,观察植株穗位叶的光合特性、衰老特性、茎鞘非结构性碳水化合物(NSC)运转、强势粒和弱势粒中乙烯和多胺含量、籽粒灌浆特征及淀粉积累特性等变化。结果表明,与CI相比,PAI显著增加了籽粒产量,提高了灌浆后期穗位叶的光合性能,延缓了叶片衰老,促进了玉米茎鞘NSC的运转,增加了弱势粒中亚精胺(free-Spd)和精胺(free-Spm)含量,降低了弱势粒中腐胺(free-Put)含量和乙烯释放速率。PAI对强势粒多胺含量、乙烯释放速率以及灌浆速率和淀粉积累速率无显著影响。相关分析表明,籽粒灌浆速率和淀粉积累速率与内源free-Spd和free-Spm含量呈极显著正相关,与乙烯释放速率呈显著或极显著负相关。表明灌浆期较强的叶片光合能力、较高的茎鞘NSC运转率、弱势粒中较高的free-Spd和free-Spm水平以及较低的乙烯释放速率是PAI促进弱势粒灌浆和提高产量的重要原因。

This study investigated whether and how post-tasseling alternate irrigation in partitioned roots could enhance the filling of inferior caryopses in maize. A high-yielding maize cultivar, Denghai 11, was grown in a glasshouse, and two irrigation treatments, conventional irrigation （CI） and alternate irrigation in partitioned roots （PAl）, were applied from tasseling to maturity. Kernel filling rates and starch accumulation rates of superior and inferior caryopses and changes in ethylene evolution rate and polyamine contents in caryopses, photosynthetic and senescence characteristics of the ear leaf and non-structural carbohydrates （NSC） in stems were determined. The results showed that, compared with CI, PAI significantly increased kernel yield, strengthened photosynthetic characteristics of the ear leaf during late kernel-filling period, delayed leaf senescence, promoted NSC remobilization from stems plus sheath, and increased free-spermidine （free-Spd） and free-spermine （free-Spm） contents, whereas declined the free-putrescine （free-Put） content and ethylene evolution rate in inferior caryopses. No significant effect of PAI on the kernel filling of superior caryopses was detected. Correlation analysis showed that kernel-filling rates and starch accumulation rates were very significantly and positively correlated with free-Spd and free-Spm contents, and significantly and negatively correlated with ethylene evolution rate. The results indicate that PAI enhances the filling of inferior caryopses and increases kernel yield through increasing photosynthetic ability of the ear leaf, remobilization of NSC from stems, and free-Spd and free-Spm contents, and decreasing ethylene evolution rate in inferior caryopses during the grain-filling period.