干旱胁迫对苗期木薯内源激素含量的影响

Impacts of drought stress on content of endogenous phytohormones at seedling stage of cassava

以SC124、KU50、C4和SC8四个木薯品种为试验材料,运用酶联免疫吸附测定法,研究了盆栽条件下干旱胁迫对苗期木薯根系与叶片中内源激素脱落酸(ABA)、吲哚乙酸(IAA)、赤霉素(GA)和玉米素核苷(ZR)的含量以及四种激素间平衡关系的影响。结果表明:随着干旱程度的加强,四种激素的含量在不同木薯品种内呈现不同的变化趋势。干旱至第10天时,ABA含量在苗期木薯叶片内增加,在根系内含量也增加(KU50除外);IAA在叶片中含量下降,根系内含量因品种不同,变化趋势相差明显,其中SC124和KU50中IAA含量显著下降,而在SC8和C4中含量上升;GA含量在四种品种的根系中均下降,叶片GA含量在C4和KU50中略有下降而在SC124和SC8中上升;ZR含量在四种品种的根系中均下降,叶片中ZR含量在C4中上升,SC8中下降,而在KU50和SC124中无明显变化。IAA/ABA,ZR/ABA在根系中比值下降,SC124降幅最大,SC8降幅最小,KU50、C4降幅居中,说明IAA/ABA,ZR/ABA与木薯的抗旱能力具有一定相关性。该研究结果解释了苗期木薯根系和叶片内源激素对干旱胁迫的适应性反应,为筛选不同木薯抗旱品种提供了理论依据。

Using four kinds of cassava varieties （SC124 ,KU50 ,C4 and SC8 ） as test materials ,the enzyme-linked immunosorbent assay was conducted to determine the content changes and the balance of endogenous phytohormones ,in-cluding abscisic acid （ABA ） ,indole-acetic acid （IAA ） ,gibberellin （GA ） and aeatin riboside （ZR） ,in roots and leaves of cassava at seedling stage under drought stress .The results showed that ,with the strengthening of drought stress ,the content of various hormones showed different trends in different cassava varieties .At the tenth day of drought stress ,the content of ABA increased in leaves ,so did in roots （except for KU50 ）;the content of IAA decreased in leaves of all va-rieties ,while significantly decreased in roots of SC124 and KU50 but increased in roots of SC8 and C4;the content of GA decreased in roots of all varieties ,while increased in leaves of SC124 and SC8 but decreased slightly in leaves of C4 and KU50;the content of ZR decreased in roots of all varieties ,while increased in leaves of C4 ,decreased in leaves of SC8 ,but no significant change in leaves of KU 50 and SC124 .The ratio of IAA/ABA and ZR/ABA decreased in roots , in which ,the reduction rate of SC124 was the largest ,that of SC8 was the smallest ,and that of KU50 and C4 was in the middle .This indicated that the ratio of IAA/ABA and ZR/ABA has a certain relevance to drought resistance of cassava . The research explained the adaptive responses of endogenous hormones in roots and leaves of cassava at seedling stage to drought stress ,and provided a theoretical basis for screening drought-resistant varieties of cassava .