柚品种间的耐寒性差异及其机理

１９９５～１９９７年对８个柚品种的耐寒性及其机理进行了研究．结果表明：柚类忍受的临界低温为－３～－５℃，因品种而异．沙田柚、度尾蜜柚、泰国柚等在－３℃１２ｈ电渗率已达５０％以上，而王官溪蜜柚、霞河蜜柚在－５℃１２ｈ电渗率才达５２％，文旦柚、楚门文旦、坪山柚电渗率介于两类之间．但低温持续时间长，即使在－１℃（２４ｈ）王官溪蜜柚电渗率亦高达５１％．柚叶片组织细胞结构紧密度、可溶性蛋白质含量、游离脯氨酸含量、超氧物歧化酶活性、线粒体膜Ｎａ＋－Ｋ＋ＡＴＰ酶活性、束缚水／自由水比值等与柚品种的耐寒性呈正相关．

Differences of cold tolerance of pomelo cultivars and their mechanisms

Differences of cold tolerance of 8 pomelo (Citrus grandis Osbeck) cultivars and their mechanisms were detected from 1995 to 1997.　The results showed that the critical low temperature for pomelo was -3--5 ℃,　depending on different cultivars. The relative conductivities of Shatian, Duwei and Thai pomelo were over 50% at -3℃ for 12 hours,　while those of Guanxi and Xiahe were only 52% at - 5℃, and the conductivities of Wendan, Chumen and 　Pingshan were between them. When the low temperature was kept longer, the relative conductivity of Guanxi was still as high as 51% even at -1℃　for 24 hours.　The cell tense ratio, contents of soluble protein and free proline, superoxide dismutase and chondriosome membrane Na+ K+ATPase activities and the ratio of bound water to free water in the leaves were positively correlated with the cold tolerance.