Zn盐和干旱胁迫对纹党种子萌发和幼苗生理特性的影响

Effects of Zn salt and drought stress on seed germination and seedling physiological characteristics of Codonopsis pilosula in Gansu province

以甘肃道地中药材纹党(Codonopsis pilosula)为对象,通过室内砂培方法,研究了不同浓度(10-6mol·L-1,10-5mol·L-1,10-4mol·L-1,10-3mol·L-1)Zn2+和不同浓度(5%、10%、15%、20%、30%)PEG模拟干旱胁迫下对纹党种子萌发、幼苗生长、渗透调节物质积累和活性氧代谢的影响。结果表明:低浓度Zn2+和PEG能显著促进纹党种子萌发和幼苗生长,随着干旱胁迫和Zn2+浓度的加剧,种子萌发率显著降低,幼苗生长受阻,纹党种子萌发和幼苗生长能耐受的渗透势临界阈值为-0.94 MPa;叶片O2·产生速率和H2O2含量明显增加,SOD、POD、CAT和APX活性先升后降,高浓度Zn2+和PEG处理下GSH和As A含量明显降低,幼苗叶片中Pro、可溶性糖和MDA含量随Zn2+和PEG浓度升高而升高。10-6和10-5mol·L-1Zn盐可提高纹党对适度干旱胁迫的适应能力,而10-3mol·L-1的Zn盐与干旱胁迫下伤害度达到最大。

A sand cultivation experiment was conducted to study the effects of Zn2 ＋ with different concentrations （10 - 6 mol·L - 1 ,10 - 5 mol·L - 1 ,10 - 4 mol·L - 1 ,and 10 - 3 mol·L - 1 ） and PEG -6000 （5% 、10% 、15% 、20% 、30% ） on seed germination ,seedling growth ,osmotica accumulation ,and active oxygen metabolism of Codonopsis pilosula ,an authentic Chinese herbal medicine in Gansu province .The results showed that the low concentrations of Zn2 ＋ and PEG could significantly enhance seed germination and seedling growth .With the increase of Zn2 ＋ and PEG concentrations , the germination rate became decreased significantly ,and seedling growth was inhibited .The lowest permeability threshold was - 0 .94 MPa .O2 · production rate and H2O2 contents in leaf were increased dramatically .In addition ,activities of superoxide dismutase ,peroxidase ,catalase ,and ascorbate peroxidase went down after an initial increase .Contents of glutathione and ascorbic acid in leaf were decreased markedly .Levels of proline ,soluble sugar and malonaldehyde con-tents in young seedling leaf went up significantly with the increase of Zn2 ＋ and PEG concentrations .It was found that 10 - 6 and 10 - 5 mol·L - 1 zinc salt could improve the drought tolerance capability of Codonopsis pilosula to moderate stress .10 - 3 mol·L - 1 zinc salt and drought stress caused the maximal damages .