Abstract: The results show that ADC activity,its metabolic product,putrescine content and ratio o f Spin/spd in nag leaves of hybrid rice exposed to nitrate stress were increased.The increment extent was different from nllcleocytoplasrnic systems an<l the interactions of them with environment concerned.Stable and positive effects of sterile-cytoplasms on ADC activities in the leaves were found.This implies that cytogenes may participate in the biosynthesis of ADC.Although the properties of negative or positive cytoplasmic effects on the enzyme activity in the leaves of test crosses were not altered by different conditions concerned.the extent of cytoplasmic effects in exposure of hybrid rice to nitrate stress was modified.Within Suitable physiological thresholds,positive cytoplasmic effects on ADC activities and grain yield of hybrid rice were pronounced by favorable environment in which putrescine accumulation within itS threshold proportionally promotes the growth of rice plant,while negatively cytoplasmic effects on them were observed under unfavorable conditions in which the rise in putrescine over its threshold relatively retards the growth of rice plant.This suggests that changes in polyamine biosynthesis and level may be an integral part of rice cytoplasmic responses in relations to environmental modulation.Additionally.the putrescine accumulation over its threshold with concomitant activation of IAA-oxidase and diamine-oxidase,and decreases of IAA concentrations was also observed.

Key words: Hybrid rice, Cytoplasmic effects, Polyamines, Argrinine decarboxyiase, Diamine-oxidase, Mann-Kendall test, spatial-temporal data mining, spatial-temporal dynamics, TRMM 3B42, rainstorm