干旱、旱盐胁迫对刺槐生长及离子吸收分配的影响

Effects of Drought and Drought-NaCl Stresses on the Growth and Ionic Absorption and Distribution of Robinia pseudoacacia Clones

通过盆栽控盐(NaCl)、控水的方法,研究了2个刺槐无性系(W1和L78)生长及体内盐离子吸收和分配对干旱、旱盐胁迫的响应,探讨了无性系对两种胁迫响应机理的异同及抗旱与耐盐间的关系。结果表明:(1)两种胁迫均明显抑制了2个无性系的生长,其中旱盐胁迫对生长的抑制较干旱胁迫强;就2个无性系而言,干旱胁迫抑制W1生长的作用强,而旱盐胁迫抑制L78生长的作用强。(2)两种胁迫下,L78根中各离子的相对选择性比率(RSK,Na、RSCa,Na、RSMg,Na)小(与W1相比),而叶的RSK,Na、RSCa,Na、RSMg,Na大,造成根中K+、Ca2+、Mg2+的匮乏,是两种胁迫抑制L78生长的共同原因。L78根控制Na+吸收和向地上部运输的能力差,是旱盐胁迫进一步抑制L78生长(与干旱胁迫相比)的原因之一。(3)旱盐胁迫下,W1能维持相对稳定的矿质营养水平,尤其是K+、Ca2+,同时根对Na+的吸收和向地上部的运输有较强的控制能力,表现出较强的抗旱耐盐能力。(4)干旱胁迫下,W1根中离子总量降低幅度大于L78,表明无机离子在渗透调节中所占比重较L78小,说明有机渗调作用加强,加大了植物自身物质和能量的消耗,造成干旱抑制W1生长的作用较L78大。

The responses of growth and ionic distribution and selective absorption were investigated in two Robinia pseudoacacia clones （L78 and W1 ） to soil drought and drought-salt stresses. The responsive mechanisms of two clones to two stresses and the relation between drought tolerance and salt resistance by controlling NaCl and water by potted planting were analyzed. The results were as follows： （1）Both stresses obviously inhibited the growth of two clones; the inhibition of drought-salt stress on the growth of two clones was stronger than that of drought stress; the inhibition of drought stress on W1 ＇growth was stranger than that on L78 and the inhibition of drought-salt stress on L78 ＇ growth was stronger than that on W1. （2） The causes that two stresses inhibited the growth of L78 were small RSk.Na ,RSCa, Na, RSMg.Na （Relative Selectivity Ratio）of L78 root and big ones of its leaf which caused the lack of K^＋ ,Ca^2＋ ,Mg^2＋ in its root under two stresses. Meanwhile another causes were the bad ability of its root to control Na^＋ absorption and Na^＋ transportation to its shoot. （3） W1 showed the stronger drought-salt resistance because it could keep a relatively stable mineral nutrient level, especially K^＋ ,Ca^2＋ , and had the good ability of its root to control Na^＋ absorption and Na^＋ transportation to its shoot under drought-salt stress. （4） The total content of Na^＋ ,K^＋ , Ca^2＋ ,Mg^2＋ in W1 ＇s root had a bigger extent on the decline than that of L78 under drought stress. That is to say, the proportion of inorganic ions in osmotic adjustment reduced, and organic osmotic adjustment strengthened, which increased the consume of substances and ew ergy. So the inhibition of drought stress to W1＇ s growth was stranger than that to L78＇s.