柑桔抗溃疡病品种叶细胞膜脂组分的研究

Membrane Lipid Composition of Citrus Leaves from Plants Resistance or Susceptible to Citrus Bacterial Canker Disease

柑桔溃疡病（ｃｉｔｒｕｓｂａｃｔｅｒｉａｌｃａｎｋｅｒｄｉｓｅａｓｅ，ＣＢＣＤ）是由ＸａｎｔｈｏｍｏｎａｓｃａｍｐｅｓｔｒｉｓＰｖ．ｃｉｔｒｉ（ＸＣＣ）引发的。本研究检测了抗ＣＢＣＤ柑桔品种和对Ｘｃｃ敏感品种叶细胞膜脂组分及含量。抗病品种及敏感品种之叶细胞膜脂种类相似，主要为磷脂酰胆碱（ＰＣ）、磷脂酰乙醇胺（ＰＥ）、磷脂酰甘油（ＰＧ）和磷脂酰肌醇（ＰＩ），其中ＰＣ和ＰＥ占总量的７５％以上，尤以ＰＣ居首。抗病品种ＰＣ、ＰＥ、ＰＧ、ＰＩ总含量（１．２４～１．６５ｍｇ／ｇＦＷ）明显小于敏感品种（２．３２～５．０８ｍｇ／ｇＦＷ）；抗病品种磷脂分子中的不饱和脂肪酸（油酸、亚油酸和亚麻酸）与饱和脂肪酸（软脂酸和硬脂酸）的比率也小于敏感品种。抗ＣＢＣＤ品种和对ＸＣＣ敏感品种的叶细胞膜都含有显量的游离甾醇（０．５９～１．０１ｍｇ／ｇＦＷ）和痕量的甾醇酯。检出的游离甾醇主要有β－谷甾醇、菜油甾醇和羊毛甾醇，其中以β－谷甾醇含量最高，占总甾醇量的６０％以上。抗病品种的游离β－谷甾醇比敏感品种高３０％左右。各抗病品种叶细胞膜脂中的游离甾醇与总磷脂的比率（０．５２～０．７４）均显著高于敏感品种（０．１２～０．２８）。

The contents and composition of lipids in citrus leaves in relation to their general resistance to infection by strains of Xanthomonas campestris pv. citri (Xcc) were determined. The composition and contents of sterols and phospholipids and the degree of fatty acid unsaturation were significantly different between resistant and susceptible species.Leaves from resistant plants had less phospholipid, but more free sterols than those from susceptible plants. The predominant fatty acids in the phospholipids were palmitic (16: 0),linoleic (18: 2) and α-linolenic acid (18: 3). The degree of fatty acids unsaturation was higher in susceptible plants than in resistant plants. Major phospholipids in citrus leaves were phosphotidylchloline (PC), Phosphatidylethanolamine (PE), phosphatidylglycerol (PG) and phosphatidylinositol (PI). β-sitosterol, campesterol and lanosterol were major sterol in the leaves of citrus plants with resistant species having a higher ratio of free sterols to total phospholipids than susceptible species. Differences in lipid metabolism may contribute to differences in Xcc-resistance of citrus leaves.