高粱苗(Sorghum vulgare)水分亏缺时所累积的游离脯氨酸的来源

在完全营养液中,用Glu或Ala替代Ca(NO_3)_2为氮源时,在水分胁迫条件下可得到同样程度的Pro累积量。但是用Ser为氮源时,在正常水分条件下Glu和Ala的相对含量较少,Ser和Gln相对含量较高,在水分胁迫条件下,Pro的累积受到抑制。在缺钾营养液中培养时,植株游离氨基酸中Glu和Ala相对量较少,Ser和Gln相对量较高,在水分胁迫条件下,Pro累积也受到抑制。在缺钾营养液中,用Glu或Ala替代Ca(NO_3)_2为氮源时,在水分胁迫条件下Pro的累积可达到甚至超过完全营养液中Pro的相对量。

THE ORIGIN OF ACCUMULATED PROLINE ASSOCIATED WITH WATER STRESS IN SORGHUM SEEDLINGS

In the present study carried out in phytotron, the accumulation of Pro associated with water stress occurred to the same extent in sorghum seedlings grown in culture solutions with different nitrogen source, i. e., Ca(NO_3)_2, Gin or Ala, but was inhibited when Ser was used as nitrogen source. The relative contents of Glu and Ala were lower and that of Ser and Gln was higher in seedlings grown in culture solution with Ser as nitrogen source, compared with seedlings grown in culture solution with Ca(NO_3)_2, Glu or Ala, without water stress.The relative contents of Glu and Ala in total free amino acids were lower and that of Ser and Gln was higher in seedlings grown in potassium-free culture solution, the accumulation of Pro was inhibited also under water stress condition. When Glu or Ala was used instead of Ca(NO_3)_2, as nitrogen source in potassium-free culture solution, the accumulation of Pro as a result of water stress was equal to or higher than that in seedlings grown in potassium-containing culture solution. The importance of Glu and Ala in the accumulation of Pro and the reason of the inhibition of Pro accumulation as a result of potassium deficiency under water stress was discussed.