Ecological Studies on Vegetative Growth in Rice Plants : 2. On the growth of leaves in connection with leaf emergence.

Abstract

This investigation was carried to observed the growing processes from differentiation to withering of leaves on the main stem at definite positions and was to know the leaf emerging sequence in connection with these observation. The materials were grown in Wagner pot with soil by direct sowing method. The results obtained can be summarized as follows: 1) When a leaf attained its full size, the shoot always had four immature leaves. 2) Both of the elongation period and life duration (the period from its full emergence to the time when the area of its blade had 50 % greened) of lower leaves were shorter than those of upper. In other words, the longer the elongation period required for the leaf, the longer the life duration became. And the leaf emmerged at the early stages of shorter day intervals required shorter life duration, and vice versa. 3) The elongation speed per day of lower leaves was faster than that of upper. 4) The leaf-blade length and the leaf-sheath length became longer from lower to upper one and longest at the 3 rd (blade) or 4 th (sheath) leaf below the boot leaf, and thereafter the leaves emergenced were shorter than those of their predecessors. But, these facts could not be applied to a plant which has only a few number of leaves on the main stem. These observations suggest that the day intervals of leaf emergence have no relation with the length of immediately lower leaf sheath.