【摘要】 <正> 水稻地下部器官的生长和产量形成,与根系的功能,尤其与中、后期根系功能之间有密切关系。在水稻生育中、后期,根系发育日趋完善,整个根系可分为上层根(最上3个发根节位上的根)和下层根(自上而下第4发根节位以下所有节位的根)两大部分。这些不同层次根系发生的时间不同,着生部位不一,对产量形成的作用也不更多还原

【Abstract】 In 1980-81, the growth of the uppermost 3 nodal-roots（UR）and loweroodal-roots （LR） in rice plants and their relation to the yield formation were studied with population culture in nutrient solution. The total number of roots in each plant increased with the increase in the number of tillers, whereas the number of roots in each stem decreased toward the top of tiilering nodes, but the ratio of the UR to the total number of roots in each stem became greater with the elevation of tillering nodes.The emergence of the UR was accompanied by the young panicle differentiation while the growth of their rootlets was simultaneous with the grain filling （milk ripening）. The UR have a marked advantage over the LR in number, weight, and activity of roots and in their capacity of ³²p absorption from booting stage to fully ripening stage. The effect of the UR on the promotion of photosynthesis, on the accumulation of dry matter during the fertilization-maturing period, on the number of filled grains per panicle,on the weight of 1000 grains as well as on the panicle weight was greater than that of the LR. Thus, the UR would play a decisive role it the yield formation during the middle-late growth period. As the functional roots during the tillering stage the LR still have a certain effect on the yield formation during the generative growth period. Equal attention, therefore, should be paid to the functions of both the UR and the LR.The light condition in the community, especially the light intensity at the base of the culm, greatly affected the growth and functions of root system. And it was particularly true for the UR. Using the highyielding culture pattern of "thinner colony with more vigorous individuals" might improve the structure of population, accelerate the growth of root system and promote the functions of root system is the middle-late growth period.更多还原