Studies on Leaf Analysis : IX. Seasonal changes of mineral elements in successive leaves, internodes and ear on the main culm of rice plant, and their accumulation and translocation. (Subpart 1)

[摘要] With a view to obtaining fundamental data for accomplishing the knowledges on leaf analysis of rice plant, the experiments dealt with the seasonal changes of N, P & K contents in the main culm, and the pattern of their accumulation and translocation. There was considered the physiological roles of the successive leaves in the growth process of rice plant. The experiments were carried out under a normal fertilizer condition (N, P2 O5 & K2O were applied 3 Kan per Tan, respectively) on a paddy field, using var. Norin No. 37, through four crops, 1955∼58. As the results obtained from the four season crops, were similar to each other in tendency the 1958 year's results are reported here mainly as follows: 1) The N% (of dry matter) in L.B. (the leaf blade) was higher than that in L. S. (the leaf sheath) & I. N. (the internode). That % became lower in order from the lower leaves to the upper ones. But, the N% in the leaf at early dates in the field (e.g. 10th leaf) was higher than that in the leaf at a later period in the nursery (e.g. 8th leaf). In the field, the N% in lower leaves (80∼10th 1.) decreased rapidly, and they came to die, while the upper leaves (14∼16th 1.) at full expansion had lower % than the lower ones, and the N% in them decreased slowly from that time. The middle leaves (11∼13th 1.) had intermediate N%. Though L.S. had the same abovementioned trend as L.B., the N% in L.S. as well as in I.N. was lower than that in L.B. 2)N accumlation in the successive leaf blades reached their maximum 1∼2 weeks after expansion, and then the element was translocated rapidly. The higher was the position of each L.B., the more amount of the N was found in it. The amount reached a maximum in the 14th L.B., and decreased thereafter, the N amount in the terminal leaf (the 16th) being equal to that in the 11th. N amount in each successive L.S. was about 1/2∼1/3 times that in the corresponding L.B., and that behavior was similar to that in L.B.. 3) It was found that N in the upper leaves was translocated into the grain, and that in the middle leaves was assumed to play an important role in the stem and ear elongation. 4) P% in L.B. & L.S. decreased from the lower leaf to the upper one successively in the same way as N%, but was higher in L.S. & I.N., which were bothconductive tissues, than in L.B. Seasonal changes of P% was smaller in L.B. than in L.S. 5) Maximum P amounts were contained in the 13 or 14th leaf as in the case of N, but P amounts were much more in L.S. than in L.B. P amounts in L.S. decreased more greatly than that in L.B. as the grains ripened. 6) With actual values, P needed for grain formation in upper leaves was found to be approximately 3 times as much as that in middle leaves, so that P in upper ones did act a larger part in ripening. 7) The behavior of K was in the same way as that of P. But unlike the case of P, on later stage of ripening K% in L.S. increased slightly, and that in I.N. did very largely. 8) Seasonal changes of K amounts were in nearly the same manner as that of P, and its translocation in L. S. & I.N. stopped at a later stage of ripening. 9) The role of K in ripening was assumed to be smaller; it was true that the middle leaves contributed to the formation of stem and ear, and the upper ones did to the full ripe of ear, but as the K amount in the grain itself was small, much of the K amounts in upper parts might be regarded to have been utilized for maturation of vegetative tissues. 1O) With regard to the translocation quotients in successive leaves, those of N, P & K elements were low in the middle leaves, but high in the lower and upper ones. The facts were assumed to be due to some special characteristics of late maturing type of rice plant and also to different environmental conditions under which the middle leaves lived, as compared with early maturing type. [the rest omitted]

[学科分类] 农业科学（综合）