半根和全根干旱对嘎拉苹果组培苗渗透调节物质积累的影响

以1年生苹果组培苗为试验材料，用改良的Hoagland营养液加20％聚乙二醇6000进行半根渗透胁迫（HRS）处理，与全根渗透胁迫（WRS）和只加营养液的对照（CK）进行比较，研究了根系不均匀供水条件下植株的叶片水势、脯氨酸、游离氨基酸、町溶性糖、淀粉等几种有机溶质，以及Na^-、K^-、Mg^2＋、Ca^2＋、Cl^-、SO4^2-、NO3^-等无机离子的含量变化特点。结果表明，HRS与CK之问叶片的日出前水势不存在显著差异，但显著高于WRS。叶片的日出前水势与叶片中脯氨酸和可溶性糖含量之间呈负相关关系，与淀粉含量之问呈正相关关系，与Na^-、K^-、Mg^2＋、Ca^2＋、Cl^-、SO4^2-、NO3^-之间没有相关关系。表明干旱胁迫后苹果幼苗叶片中脯氨酸等有机溶质参与渗透调节作用，无机离子的作用较小。HRS叶片中有机溶质没有大量积累，表明HRS植株整体的水分供应状况良好。

Effects of Half -and Whole -rhizoshpere Droughts on Osmosis - regulating Substances in In Vitro Seedlings of Gala Apple (Malus pumila Mill.)

One-year-old in vitro apple seedlings were laid under the treatment of half-rhizospere drought resulting from the addition of polyethylene glycol (PEG-6000,20% w/v) to its modified Hoagland's nutrient solution and then compared with those under the treatments of whole-rhizoshpere osmotic stress (WRS) and the control treatment to study the varying patterns of the leaves of the seedlings with water unevenly supplied to their rhizosphere in water potential,proline,free amino acid,soluble sugar,starch,Na+,K+,Ca 2+,Cl-,SO 2-_4 and NO-_3 contents.The results indicated that the leaves of the seedling suffering from half-rhizosphere drought did not differed in water potential from those under the control treatment before sunrise but significantly surpassed those of the seedlings suffering from whole-rhizosphere drought (WRS).Before sunrise,the water potentials of the leaves appeared to negatively correlate with their proline and soluble sugar contents, positively correlate with their starch contents,and presented no correlations with Na+,K+,Ca 2+,Cl-,SO 2-_4 and NO-_3;and these reveal that such organic solutes as proline of the apple seedlings suffering from drought participated in osmotic regulation but the inorganic ions exerted small influences.The leaves of the seedlings suffering from half-rhizosphere drought did not accumulate the organic solutes in great quantities and this indicated that the seedlings suffering from half-rhizosphere drought has a good supply of water.