Studies on nitrogen balance in duckweed-nitrogenous solution system and the subcellular distribution of absorbed nitrogen in duckweed (Spirodela oligorrhiza ) plants
浮萍放养体系中氮的平衡与浮萍体内氮的亚细胞分布研究

With the15N tracer technique,nitrogen balance in duckweed-nitrogenous solution system and the subcellular distribution of absorbed nitrogen in duckweed(Spirodela oligorrhiza) plants were investigated.The results indicated that N content and15N absorbed in duckweed plants at two treatments(where the concentrations of N were 28 and 56 mg/L) did not differe significantly,as N concentrations were high enough to meet the N need of duckweed plants.The uncovered15N in two treatments were also similar,which seemed to result from the denitrogenation through nitrification-denitrification processes that occurred in the system since the ammonium volatilization was limited under condition of solution pH 5.5.Approximately,98% of NH4+-15N absorbed by duckweed plants existed in the soluble fraction of the plant body(e.g.plasmic and vacuole saps),being associated with soluble proteins(including enzymes),peptides,and free amino acids,which is favorable to utilization of duckweed plants as one of feed resources.