As a trial to maintain freshness of vegetable, a storage test was tried, using Brassica chinensis L. on the 25th day after germination. Washed plants were soaked in the solution contained 140 p.p.m. of ammonia-, nitrate- or urea-nitrogen for 1 to 2 minutes, then, the treated plants were stored at 4 to 5℃ or at room temperature. 1) Change of chlorophyll and reducing sugar content: The velocity of decrease in the both compounds was fairly slowed down by urea-treatment, while, accelerated by ammonium-treatment. 2) Ammonia content: Urea seemed to have an inclination to check the formation of ammonia by autolysis. 3) Change of urease and nitrate reductase activities: No apparent difference was found in the treated plants. 4) Ammonia dehydrogenase: A little activity of the enzyme was kept on the second day of storage in urea- or ammonium- treated plant and no activity was found in the control or nitratetreated plant. 5) Urea dehydrogenase: The activity was enhanced by urea-treatment and comparatively large activity was recorded on the second day of storage, on the contrary, no or little activity was estimated in the other treatments. 6) By the colorimetry modified in our laboratory, 50 to 60 γ of urea-nitrgen were estimated in 100 g of urea-treated plant. The ability of taking urea in plant fell rapidly into decay, as time went on, and no ability was found in the plant on the third day of storage.
Mendeley出力
