花期根剪对苹果幼树叶营养及光合特性的影响

EFFECTS OF ROOT-PRUNING ON APPLE LEAF NUTRITIONCONTENTS AND PHOTOSYNTHETIC CHARACTERS

对田间３年生富士／海棠进行花期根剪处理．根剪后叶全Ｎ含量降低，但经４～６周得以恢复，同时造成叶片可溶性精含量降低，而对叶Ｐ、Ｋ含量无显著影响。处理后叶Ｐｎ显著低于未处理植株，４周后渐渐恢复，但仍低于对照，说明根剪对Ｐｎ造成不可逆影响。光合日变化趋势无明显差异变化．

Three-years old, grown in field. Fuji/M, micromalus, were root pruned atblooming stage. After root-pruning,for each week,the contents of leaf mineral elementN. P. K.and the soluble surgar and shoot leaf photosynthetic characters were analysised. The results indicated that the N content of root-pruned trees was lower than thecontroled ones(CK) (no root-pruning),and they would became the similar after 28 to42 days;but root-pruning had no effects on the content of leaf P. or K. Root-pruningalso leaded to lower leaf soluble-sugar contents. Pn of treated-trees became muchlower compared with the no root-pruning ones,but the diurnal variation of Pn weresimilar between treated ones and controled ones.