Studies on the empty husks (shiina) in rice plant. : II. The influence of hormone-treatment on the occurrence of empty husks in rice plant.

[摘要] Young rice plants (45 days seedings) were soaked 8 or 24 hours in α-naphtharene acetic acid solution as shown in table 1, then they were transplanted in pots, and cultivated as usual in grass house under normal condition. In 1948 half number of pots of each plot were kept for 10 days under a roof at the heading time to test the effects under restricted sunshine. (The auther formerly reported on the effects of restricted sunshine upon the occurrence of empty husks.) Length ot plants, number of culms per plant, number of leaves of main stem, and heading date were investigated according as plant growth, and after they were harvested, empty husks (sterile grains and blasted grains) were searched on the panicles and the sterilizing percentage ((No. of sterile grains)/(No. of flowers)×100) and the blasting percentage ((No. of blasted grains)/(No. of flowers)×100) were calculated on each plot, and compared respectively. The chief results may be summerized as follws : -- (1) In 1946, the environmental condition was very favourable for fertilization and maturation of rice plant and the strilizing percentage and the blasting percentage were researched on the main stems which would be more vigorous than other stems, therefor the sterilizing percentage and the blasting percentage were very low. With regard to the sterilizing percentage, there was no evident difference among the plots, but the blasting percentage was remarkably less in treated plots than in untreated plot. (2) In 1948, the sterilizing percentage and the blasting percentage were estimated on all panicles of every plots. In this experiment the sterilizing percentage as well as the blasting percentage was remarkably less in treated plots especially in D (0.002%-24 hours), E (0.001%-24 hours) and G plot (0.005%-8 hours) than in untreated plot, and these facts were more conspicuous under restricted sunshine. (3) It may be possible to infer from those results that the physiological function of treated plant may be more active than that of untreated plant. This difference of physiological avtivity has little effect upon the occurrence of sterile grains, so far as the occurrence of sterile grains is rare under favourable condition, nevertheless when the environmental condition is not so favourable it has an effect upon the occurrence of sterile grains as well as upon the occurrence of blasted grains. Generally, empty husks occur numerously under unfavourable environmental condition, therefore it may be possible to control the occurrence of empty husks by hormone-treatment.

[学科分类] 农业科学（综合）