控释氮肥对杂交水稻生育后期根系形态生理特征和衰老的影响

采用微区和小区试验的方法,研究了控释氮肥对杂交水稻生育后期根系形态生理特征及对根系衰老过程中膜脂过氧化产物和活性氧清除酶活性的影响。研究表明,施用控释氮肥,明显地增加杂交水稻生育后期的根干重、根长和根长密度,而根半径减小;提高根系活力和吸收面积,使杂交水稻生育后期根系中MDA含量降低和SOD、POD和CAT的活性提高。控释氮肥中,氮的逐渐释放,可减少具有强烈伤害的活性氧产物速率及其累积数量,提高活性氧清除酶的活性,在很大程度上延缓了杂交水稻生育后期根系的衰老和吸氮能力的衰退。

Effect of controlled release nitrogen fertilizer on the morphological and physiological characteristics and senescence of root system during late growth stages of hybrid rice

Controlled release nitrogen fertilizers(CRNF) are physically prepared from the granules of the soluble nitrogen fertilizers by coating them with film-forming materials to reduce their dissolution rate.These fertilizers are made to release nitrogen nutrient gradually to synchronize with the nitrogen requirement of crop plants during different growth stages.This study quantified the effect of CRNF on root morphological and physiological characteristics during late growth stages of hybrid rice,and lipid peroxidative products,active oxygen scavenging enzymes in root system during the root senescence process of hybrid rice.The results showed that the CRNF could increase the root dry weight,root length,and root length density,while the root radius became smaller during later growth stages of hybrid rice.At the meantime,the CRNF(decreased) the MDA contents but increased active oxygen scavenging enzyme activities.The CRNF could also increase the activity of SOD,POD and CAT during root senescence process,and the gradually release of nitrogen nutrient from the CRNF could decrease the production and accumulation of active oxygen in the root system,thus enhance the activities of active oxygen scavenging enzymes.Therefore,the CRNF could significantly retard the senescence and decline of nitrogen absorbing capacity of the root systems through regulating nitrogen release rate from CRNF during late growth stages of(hybrid) rice.