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

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。

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

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.