【摘要】 杨梅、沙棘和赤杨三种放线菌结瘤植物根瘤、根部有机氮化物的组分中,都含有占总有机氮化物50％以上的尿囊酸,说明在它们的根瘤中合成了大量的酰脲;同时,三种植物结瘤植株的茎木质部提取物中也含有大量的尿囊酸,表明根瘤将其合成的酰脲向植物地上部位运送。三种植物的根瘤还将其合成的特定的氨基酸及酰胺向地上部位转运,其中杨梅根瘤将固定的氮素以Asn和Gln的形式输出,而根部则以Arg的形式向上转运;沙棘根瘤以Ash,Gln及Ser,赤杨根瘤以Cit的形式合成并转运固定的氮素;后两种植物的无根瘤植株,以NH₄⁺为氮源时,在转运的氨基酸组分中Arg的比例明显提高。更多还原

【Abstract】 Using high-pressure liquid chromatography （HPLC） and automatic amino acid analyzer, we have analysed the composition and content of organic N compounds in the extracts of root, nodules and xylem of three actinorhizal plant species: Myrica rubra, Alnus tinctoria and Hippophae rhamnoides. A large quantity of allantoic acid was found in the extracts of nodules and nodulated xylem of all tested plants. It is suggested that ureide can be synthesized in the nodules and transported to the shoot of the plant. The quantity of ureide transported to the shoot is 20%～30% greater in nodulated plant than that in nonnodulated plant.A small quantity of amino acids and amides was found in the transported organic N compounds. Gln and Asn were synthesized chiefly in the nodules of M. rubra, and Arg, a major amino acid, was formed in the root and largely transported to the shoot. Cit was mainly synthesized in the nodules of A. tinctoria and transported to the shoot. In non-nodulated plants, however, both Gln and Arg occupied a dominant position in transported amino acids when plants were grown with NH₄⁺. Gln, Asn and Ser were major transported amino acids in nodulated plants of H. rhamnoides. But in non-nodulated plants of this species, when NH₄⁺ was the nitrogen source, the percentage of Arg in the transported amino acids increased.更多还原