Comprehensive studies on school and root system development in cereal crops

用作者提出的新指标对水稻叶原基的形成、发育和叶片的出现进行了研究。这些研究阐明了新梢发育的规律，同时也揭示了根系发育的规律，表明对产量有贡献的根系的大小和分布格局是在成穗期以后形成的，并采用切叶法进行了试验，发现了新梢和根系发育的密切关系。这些结果表明，光合作用和水分关系对小麦生长发育可能有贡献，对小麦分蘖发育的研究表明，密度效应是存在的。地上部发育与根系发育同步进行。小麦根系由延伸至深层的种子根和分布于表层的节根组成。灌溉等管理措施对玉米种子根的分枝程度和节根的大小及分布有很大影响，并利用作者提出的新指标对玉米的生长发育进行了检验。结果发现，整个植物的组织是由营养阶段到生殖阶段的过渡所决定的。叶、茎和根的大小和形态反映了植物体的发育过程，包括阶段性转变。

Formation and development of leaf primordial and leaf emergence in rice were examined with the new index developed by the authors. Those studies clarified the regularity in the shoot development.At the same time, the regular development of root system.It was shown that dimension and distribution pattern of root system which have possible contribution to yield were formed after panicle formation stage.Also the leaf-cutting method was used for the experiments to find the intimate interrelation between shoot and roots development. Those results suggested the possible contribution of photosynthesis and water relation to growth and development.Studies on the development of tillers of wheat showed the existence the effect of the density. It was also confirmed that the shoot development proceeded with root system development synchronizedly. Root system of wheat was clarifed to be composed of seminal roots elongateing into deep soil layers and nodal roots distributed in surface soil layer. Management practices including irrigation and so on had great influences on both branching degree of seminal roots and the dimension and distribution of nodal roots.Development of maize was examined using the new index proposed by the authors. It was found that organization of the whole plant was determined with special references to transition from vegetative phase to reproductive phase. Size and form of leaf,stem and roots reflect the development of plant body including the phase transition.Branching of roots was also examined.