Abstract: The study showed that different ecological environment and cultivation system in various ecological regions of Zhejiang Province resulted in some different physiological characteristics of nitrogen nutrition and stressresistance,especially in theaspect of NO₃^--N and NH₄⁺-N concentrations, between film-mulched and conventional flooded rice.Owing to the heat stress in Hangjiahu plain,the NO₃^--N concentration of film-mulched rice decreased to some extent,but NH₄⁺-N concentration increased markedly at tillering,jointing and booting stages,compared to conventional flooded rice.In Jinqu basin,the NO₃^--N concentration of film-mulched rice at booting stage was higher,while the NH₄⁺-N concentration in its roots was notably lower than those of conventional flooded rice,with NH₄⁺-N concentration in its basal stems and leaves somewhat increased.Generally,the glutamine synthetase(GS) and nitrate reductase (NR) activities in film-mulched rice leaves were enhanced at booting stage,while malondiadehyde (MDA),soluble sugar (SS) and proline(Pro) concentrations had little changes.In conclusion,film-mulched cultivation was beneficial to the rice growth and its high yielding.

Key words: Rice allelochemicals, Mechanisms of weed suppression, Quantitative trait, Marker assisted selection, Cloning