硝态氮对不同基因型小白菜光合速率及品质的影响

试验研究表明，随营养液中硝态氮浓度的升高，7种基因型小白菜硝酸盐含量明显增加，可溶性糖含量降低，蛋白质、氨基酸、净光合速率(Pn)呈现出先增加后减少的趋势。而硝态氮含量过低或过高都可能不利于维生素C的累积。各基因型硝酸盐含量在高硝态氮环境中均无显著性差异，因此，在筛选硝酸盐累积较少的基因型时，应在硝态氮含量较低的养分条件下进行。长江青梗的氨基酸含量在4个不同处理中均低于其他6种基因型。

EFFECTS OF NITRATE SUPPLY ON PHOTOSYNTHETIC RATE AND QUALITY OF CHINESE PAKCHOI CABBAGE (BRASSICA PARICHINENSIS)

With increasing NO_3- -N in the nutrient solution, nitrate content increased markedly in the plants of Chinese pakchoi cabbage (Brassica parichinensis), soluble sugar content decreased and protein content, amino acid content and net photosynthetic rate (Pn) increased first, followed by a decline. Inadequate or excessive NO_3- -N supply was unfavorable for the accumulation of vitamin C. At higher N rate, no significant difference was observed among the 7 pakchoi cabbage varieties studied. Therefore, it is recommended that selection for low nitrate accumulation genotypes of pakchoi cabbage be conducted in low-nitrate nutrient solution. Amino acid content in the variety Changjiang Qinggeng was lower than that in the other 6 varieties in this experiment.