干旱胁迫与施氮对麻疯树幼苗渗透调节物质积累的影响

Effects of drought stress and nitrogen fertilization rate on the accumulation of osmolytes in Jatropha curcas seedlings

采用盆栽控水的方法,研究干旱胁迫(80%FC、60%FC、40%FC和20%FC)及施氮(N00 g.pot-1、Nl1.2 g.pot-1、Nm3.6 g.pot-1和Nh6.0 g.pot-1)对麻疯树幼苗叶、茎和根部主要渗透调节物质积累的影响.结果表明:干旱胁迫条件下,麻疯树幼苗茎和根部的游离脯氨酸、可溶性蛋白和茎部可溶性糖大量积累,叶片中脯氨酸含量也随干旱胁迫程度的增加大幅度上升;Na+、Ca2+和Mg2+在麻疯树幼苗叶、茎和根中大量积累,而K+仅在茎中大量积累,叶片和根部K+含量略微上升.施氮对植株渗透调节物质的影响与干旱胁迫强度和施氮水平有关.在80%FC和60%FC水分条件下,增加N肥施用量能明显促进麻疯树幼苗各组分渗透调节物质的积累;在40%FC水分条件下,Nh处理对渗透调节物质积累的促进作用减弱;而在20%FC条件下,Nl处理植株的渗透调节能力较高,Nm和Nh处理对植株渗透调节的促进作用不明显甚至转为抑制.

A pot experiment with controlled water supply was conducted to study the effects of different drought stress degree（80% FC,60% FC,40% FC,and 20% FC） and nitrogen fertilization rate（0 g·pot-1,1.2 g·pot-1,3.6 g·pot-1,and 6.0 g·pot-1） on the accumulation of osmolytes in different organs of Jatropha curcas seedlings.Under drought stress,the soluble protein and free proline in seedling shoots and roots and the soluble sugar in seedling shoots had a great accumulation,and the free proline content in seedling leaves had a great increase with increasing drought stress degree.Also under drought stress,the Na＋,Ca2＋,and Mg2＋ all highly accumulated in seedling various organs,while K＋ only accumulated greatly in shoots but slightly in leaves and roots.The effects of nitrogen fertilization on the accumulation of osmolytes in seedlings depended on drought stress degree and nitrogen fertilization rate.At 80% FC and 60% FC,increasing nitrogen fertilization rate could markedly promote the accumulation of osmolytes in the organs of J.curcas seedlings;at 40% FC,applying 6.0 g·pot-1 weakened the promotion effect on the osmolytes accumulation;whereas at 20%,applying 1.2 g·pot-1 made the plants have a higher capability in osmoregulation,but applying 3.6 g·pot-1 and 6.0 g·pot-1 had less promotion effect,and even,inhibited osmolytes accumulation.