模拟干旱对佛甲草生长和渗透调节物质积累的影响

 采用ＰＥＧ ６０００模拟干旱处理佛甲草，测定佛甲草鲜重、干重、含水量、根系脱氢酶活性、无机物含量、有机物含量、无机渗透调节物质和有机渗透调节物质含量，并用高效液相色谱法测定７种有机酸的含量。结果显示，与对照相比，在不同浓度ＰＥＧ ６０００模拟干旱胁迫下，佛甲草鲜重、干重、含水量、根系脱氢酶活性、无机物、Ｎａ^＋ 、Ｋ^＋ 、ＮＯ_３^－ 含量均呈下降趋势，而有机物、游离氨基酸、脯氨酸、可溶性糖含量均呈上升趋势；可溶性蛋白含量则呈先上 升后下降趋势；高效液相色谱法结果显示，７种有机酸含量变化幅度也各不相同。综合分析表明，模拟干旱处理对佛甲草生长有抑制作用，且随着干旱胁迫程度的增加，其受抑制程度也加重；在干旱胁迫下，佛甲草不是通过积累无机离子（Ｎａ^＋ 、Ｋ^＋ 、ＮＯ_３^－ ）而是通过积累有机渗透调节物质（游离氨基酸、脯氨酸、可溶性糖、可溶性蛋白、草酸、丙二酸等）进行调节。

Effect of drought stress using PEG-6000 on the growth and osmotica of Sedum lineare

Plants of Sedum lineare were treated with PEG-6000 at concentrations of 5%,10%,20%,or 30% to simulate drought stress,or without PEG-6000 treatment(control).The fresh and dry weights,water content,root dehydrogenase activity,and contents of inorganic matter,organic matter,inorganic osmotica,and organic osmotica of S.lineare were determined.Seven organic acids were determinated by high-performance liquid chromatography.Compared with the control,under PEG-6000 treatment,fresh and dry weights,water content,root dehydrogenase activity,contents of inorganic matter,Na+,K+,and NO3-decreased,but those of organic matter,free amino acid,proline,and soluble sugar increased,while soluble protein content initially increased and then decreased.HPLC showed that the change rates of seven organic acids differed from each other.Comprehensive analysis indicated that the simulated drought stress inhibited the growth of S.lineare,and the inhibitory effect became stronger with the increase in PEG-6000 concentration.Under the simulated drought stress,S.lineare did not accumulate inorganic osmotica(Na+,K+,NO3-),but used organic osmotica(such as free amino acids,proline,soluble sugar,soluble protein,oxalic acid and propane diacid) for osmotic adjustment.