Fundamental study og germination of white potato : (2) Chemical variation of amylase during germiaton perlod

Abstract

l. The amount of amylase produced in seed potatoes at the germination period was studied. Two.varieties of white potato, Danshaku and Benimaru were used as experimental materials. 2. As to the variations in the amount of amylase at the period measured in each of the varieties : (1) The amount was smaller in the control plot compared with those in the peeled potatoes and ethylen-chlorhydrin treatment plots. In each of those plots, amylase increased from the 3rd day after planting, and it reached maximum on the 5th day, dccreasing after that date. The relation between the amount of amylase produced and the growth of buds was as follows : Until the 10th day from the date of planting, differences in the growth rates of buds among the plots were not distinct, but, since the 20th day, the difference became clearer and the growth of buds in the ethylen chlorhydrin plot predominated, where amyalse decreased distinctly. (2) Relations in amylase amount of the three plots of the variety Benimaru, was the same in tendency as that in the plots of Danshaku ; namely, until the 13th day, after planting the difference in growth rate of bud among 3 plots were not distinct. Since the 20th day, however, 'the growth rate was greatest in the peeled plot where the production of amylase became to decrease. 3. The difference between two varieties : The amounts of amylase produced in Danshaku and Benimaru respectively in each treatment plot began to increase gradually after the 3rd day from the date of planting, and reached their maxima on the 5th day being greater in Benimaru than in Danshaku, and in both the two varieties production of amylase was greater in the ethylen plots, Since the 5th day distinct decreasing tendency of the amount was remarked in each plot. Since the 20th day the rate of growth of buds was best in the peeled Beni-maru plot where the production of amylase was seen rapidly to decrease. It was considered in general that the amount of amylase increased from the beginning of bud germination of the seed potatoes and that, until the 10th day, the germination was affected by its presence. On the 10th day and afterwards the amount of amylase decreased rapidly while the buds showed high growth rates. It should be considered on the other hand that the bud growth in the latter part of the period might probably be affected by many factors other than amylase production.