Abstract: The effect of Cerium(Ⅲ) on metabolism enzyme activity of nitrogen and absorption of nitrogen and phosphor in soybean seedlings exposed to two levels of simulated ultraviolet-B radiation stress(UV-B,280-320 nm) was studied in hydroponics under greenhouse conditions.The results showed that the nitrate reductase activity,nitrate nitrogen and phosphor content in soybean seedlings' leaves in UV-B treatment significantly decreased compared to the check.Therefore,it was indicated that nitrate reductase activity was seriously inhibited by UV-B stress which led to a decrease of the nitrate nitrogen and phosphor content.The inhibitory action was stronger,as the UV-B stress was with high intensity and lasted longer time.The suitable concentration by 20mg·L-1 of CeCl3 could promote absorption nitrate nitrogen and phosphor content in soybean seedlings to alleviate the decrease of nitrate nitrogen and phosphor content.

Key words: Cerium(Ⅲ), Cerium(Ⅲ), UV-B radiation, Soybean seedlings, Nitrate reductase(NR), Nitrate nitrogen, Phosphor