Studies on the Growth Phase and Effect of Fertilizer Application to Rice Plants in Malaya : I. Elongation and changes in dry weight of various organs of Indica rice plant and interrelation among them.

Abstract

This investigation was carried out at Bukit Merah Padi Experiment Station in malaya 1962 to 1963 under Colombo Plan. The results are summarized as follows. 1. The process of elongation of the organs showed a S-shaped curve (Fig. 1). The peak date of the principal elongation period was the mid-point of the mentioned S-shaped curve. The beginning or end date of the principal elongation period was subjected to the time when certain organs elongated and reached to 10 % or 90 % of final length. The peak date of the principal elongation period of related organs took place nearly about the same time as indicated below, (B0 : S1 : N2), (B1 : S2 : N8), (B2 : S3 : N4) and (B3 : S4 : N5) (See Tab. 1). The indicatin to each separate organs is explained in Fig. 2. All the numberings begin from the topmost part of plant descending to the base. Immediately after the peak date of the principal elongation period of leaf blades or sheaths, started the beginning date of the principal elongation period of the next upper organs and after the former reached the end date of its principal elongation period, started the peak date of the principal elongation period of the latter (Tab. 1, 3). 2. The changes in dry weight of organs also showed a S-shaped curve ( Fig. 3). The inter-relation among the different organs in respect of the changes in dry weight was more or less similar to that of the elongation process of organs (Tab. 1). 3. When the velocity of the elongation of a certain organ reached its maximum, the increase in dry weight was about to begin. When the increased dry weight reached its maximum, the elongation was about to terminate (Tab. 4-a, b). The elongation and increase in dry weight of organs continued to be systematic from the lower to the upper organs. 4. When the increase in the dry weight of panicle was great during the panicle pregnancy stage, there was naturally a reduction in the dry weight increase of the other organs. As soon as the formation of the panicle was about to be complete, N1 and N0 showed a marked increase in dry weight. After the fertilization there was a remarkable increase in dry weight of the panicle. As long as the increase in dry weight of the panicle was conspicuous, there was a decrease in the weight of sheaths and internodes. The decrease was slightly marked in Pe Bi Fun than Radin China 4. From then on, there was a slightly decline in the increasing tendency of dry weight of the panicle and also a halt in the decrease of the weight of sheaths and internodes. During about 5 days just after heading, the increasing weight of the panicle was small. This can reasonably be attributed to the effect probably caused by the enhanced consumption due to the respiration at the time of flowering and fertilization. 5. The peak date of the principal elongation period of each organs mentioned above were presumed. However, the full matured length or weight of certain organs varied with nutritional and environmental conditions. The above mentioned result on the regularity of elongation process and changes in dry matter was similar to that of Japonica rice plant. And it can be benificially used in the morphological and physiological diagnolosis of Indica rice plant.