NaCl胁迫下苹果幼树叶片膜透性、脯氨酸及矿质营养水平的变化

Changes of leaf membrane penetration,proline and mineral nutrient contents of young apple tree under NaCl stress

以2年生盆栽富士苹果树(砧木为平邑甜茶)为试材,研究了NaCl胁迫对其叶片膜透性、脯氨酸及矿质营养含量的影响,结果表明:0.3%盐胁迫处理的电导率在中前期高于对照,1%盐处理中期高于对照;盐胁迫后半期0.3%NaCl处理的脯氨酸含量高于对照。NaCl胁迫下,苹果体内各器官Na+含量大小的顺序是:根>新梢>主干韧皮部>叶>主干木质部,在0.1%NaCl胁迫下,新梢和叶片中的Na+没有明显变化,根、主干韧皮部和主干木质部含量明显提高,在0.3%NaCl胁迫下各器官中Na+含量明显提高,地上部叶片、主干韧皮部和新梢中Na+含量提高幅度最大。NaCl胁迫对各器官的N、P、K+含量没有明显影响,但胁迫下N/Na+、P/Na+和K+/Na+比值不同程度的降低,从而使树体内的元素平衡受到破坏,导致树体受害。N、K+含量在叶片中含量最高,P在新梢中含量最高,N、P、K+在主干木质部中含量均最低。

The effects of NaCl stress on leaf membrane penetration, proline and mineral nutrient contents of two-year-old potted Fuji apple tree with rootstock of Malus hupehensis Reld. were studied. Results showed that the relative conductance ratio of the leaves with 0.3% NaCl stress treatment was increased comparing with that of no NaCl stress treatment at middle and later stages, but for the 0.1% NaCl stress treatment it was increased at the middle stage. The proline content of 0.3% NaCl stress was higher than that of the control at the later stage. The order of Na+ contents in different organs of apple tree under NaCl stress was: root > vegetative shoot > phloem of trunk > leaf > xylem. Under 0.1% NaCl stress, the Na+ contents of vegetative shoots and leaves had no significant change and that of roots, phloem of trunk, xylem of trunk increased significantly; under 0.3% NaCl stress, the Na+ contents in different organs was increased significantly and the increased extent of Na+ contents of leaves, phloem of trunk and vegetative shoot were larger than that of others. NaCl stress had no effect on N, P and K+ contents of apple tree, but the rate of N/Na+,P/Na+ and K+/Na+ were decreased and this would impact the balance of mineral nutrients of apple tree and made the tree suffering injury. The contents of N, K+ was the highest in leaves, P was the highest in vegetative shoot, and contents N, P and K+ were the lowest in xylem of trunk.