小麦

The purpose of this study is to investigate the effects of stage of growth and environmental conditions upon the amylase activity in wheat varieties. The results are summarized as follows : (1) The changes of amylase activity occurring in wheat plants of varieties differing in cold-hardiness, during from the seedling to ripening stages, were measured. Amylase activities in seedlings were closely related to the cold resistance of the variety. And then five types of change with the development of stage were recognized. (2) It was found that there was the daily change of amylase activity in wheat seedlings, and this daily change curve showed the two peaks and the unique curve according to the variety. (3) Amylase activity in seedlings grown under three different temperature conditions in the phytotron with day and night temperatures controlled at 25～ 20, 20-15 and 15 -43℃ respectively, was measured using two wheat varieties belonging to cold-hardy and non-hardy varieties. Amylase activity was higher in all seedlings grown at the higher temperature ranges, the hardy variety always had higher activity than the nonhardy variety. There was an increase in the amylase activity of seedlings stored in a refrigerator at -5℃ and the rate of increase in hardy variety was higher than that in the non-hardy variety. (4) Amylase activity in the seedlings receiving a supply of nitrogen was higher than that in the seedlings grown without any nitrogen addition. (5) From the above-mentioned fact, it is clear that the amylase activity in the wheat seedlings is closely related to the cold resistance under the uniform stage of growth and environmental condition.