Abstract
Injurious treatments before ear formation auch as shading, leafblade cutting of whole plant, too high soil temperature, all checked the growth of rice plant for a while in terms of tiller and root formation and dry matter production. In the treated plant, however, the number of tillers and roots increased more rapidly during early stage of ear development. At the same time, one more leaf was often formed resulting in delay of heading, and both the area of newly expanded leaf blades and the ratio of leaf-blade weight to total plant weight became larger in contrast to the control. At the end of development, the treated plant exceeded the control in plant weight due to the greater rate of growth at the later stages. The number of flowers per plant was increased in case of shading and leaf-blade cutting. It might be suggested that this process was induced as the result of a rejuvenation of plant activity which usually tends to go into senescence as the plant develops from younger vegetative to reproductive stage. Transitory starch usually stored abundantly in the leaf-sheath and culm of rice plant, was mobilized and utilized as the emergency resource of carbohydrates during recovery processes from the effect of injurious treatments.
