花粉粒萌芽期間氮的代謝作用

Nitrogen Metabolism Associated with Pollen Grain Germination

The germination of pollen g rains collected from a long period blooming flower (Lily, lilium longiflorum) and a short period blooming flower (Dish-Cloth Gourd, Luffa cylindrica) was studied. It was found that the germination pattern of the two plants was quite different. The protein content in germinating pollen of lily increased steadily and reach ed a maximum in 90 minutes and then decreased. In contrast, gourd pollen bad a larger amount of protein con tent before germination and decreased gradually during germination. It seems that for pollen germination, the lily required the synthesis of some new proteins but the gourd did not. The hypo thesis was further proved by the cycloheximide inhibition test for protein synthesis. When cycloheximide was added to the germinating pollen at the beginning, lily pollen tube elongation was entirely inhibited, whereas gourd tube elongation continued. From the pattern of protein metabolism during germination, the mechanism for the initiation of the tube elongation of these two kinds of pollen may be different. RNA metabolism and free amino acids con tent were determined. Both the lily and gourd pollen synthesized new RNA for tube elongation. During germination, free amino acids tended to increase. Based on the cycloheximide inhibition test, the germination patterns of eleven species of pollen grains could be separated into two groups, one was similar to the gourd type and the other belonged to the lily type.