Studies on the sterility in barley : II. On the relation between sterility and residual autumn habit, with special reference to the translocation efficiency.

[摘要] Previous works published by Sudo (1941) and by the present writer (1949) on sterility in barley indicate that the leading cause is non-pollination depending on the abnormal dehiscence of anthers, which resulted from their functional weakness at the flowering time. The present work dealing with the residual antumn habit has been designed to obtain an information on the mechanism of this functional weakness in flowering from the physiological point of view. When winter barley variety is sown in spring, provided completely with the necessary conditions for cancellation of autumn habit by chilling for more than 30 days at 1°C before sowing, the flowering takes place normally, , resulting in fewer occurrences of sterility. However, if the necessary conditions are not given sufficiently, that is, duration of chilling is in the range of 20 to 30 days, the flowering delays for about 2 weeks compared with that of the completely verbalized, and sterility occurs in considerably high percentage as shown in Fig. 1. [graph] Moreover, when the chilling period is shortened to less than 20 days, the plants sown in spring fail to reach ear formation in that season and the formation of leaves and tillers is extremely promoted without setting any flowers, the plants remaining the "rosette" stage. As seen from this "rosette" phenomenon, it will be obvious that vegetative growth and reproductive growth belong respectively to the essentially different phases in plant growth : The former includes the leaf growth and tillering, while the letter includes elongation of culm after the ear formation and the growth of spike. In the early stages, as the reproductive organs involving culm and eat have little, if any, ability to produce carbohydrates and other materials necessary for their growth in quantity by themselves, the materials employed for their growth are drawn from the vegetative organs consisting of leaves and roots. Then the amount of dry weight of the reproductive organs is plotted against days curves represented by Fig. 2 are obtained. The circles represent the 40 days treatment, the crosses, 20 days treatment. These curves show S figures on the whole, but nearly straight lines before and after flowering time. So the increment in dry weight per day, dWc/dt, is easily obtained by calculating the regression coefficient. In the 40 days and 20 days treatment, these values are 92.4 and 51.8 in mg. respectively. The photosynthesis is, in general, proportional to leaf area, consequently to leaf dry weight. Therefore, the quotient, dWc/Wl, where dWc and Wl denote the increment in dry weight of the reproductive organ per day and the leaf dry weight present at the measuring time of dWc respectively, comes to indicate the "transloca- [graph] tion efficiency". Indicating this quotient as percentage, 9.5 % and 4.0 % are obtained in the 40 days and the 20 days treatments respectively at the flowering time as shown in Table 1. The culm weight divided by the leaf, C/L or C. L ratio, is considered to be the mean values of translocation efficiencies which are seen in every stage of growth period between the time of estimation of this ratio. [table] C. L ratio is, for the most part, of the same meaning as the formula of BAKHUZEN'S "structural efficiency", and is of equal value to the translocation efficiency as a criterion of efficiency indicating the intensity of material migration from the vegetative organs to the reproductive ones. It is likewise a more convenient method from the point of view of experimental procedures. 1.1395 and 0.7542 are, as C. L ratios, obtained in the 40 days and 20 days treatment respectively, and they correspond fairly well with the translocation efficiencies and are as parallel with the tendencies of sterilizing percentage as the translocation efficiencies. In the present experiments, it should be noted that this C. [the rest omitted]

[学科分类] 农业科学（综合）