滇杨与毛白杨插穗内源激素含量的比较研究

Comparative Study on the Endogenous Hormone Contents in Cuttings of Populus yunnanensis and P. tomentosa

【目的】对滇杨和毛白杨插穗基部皮层内源激素测定,探讨插穗生根过程中内源激素对不定根形成的影响。【方法】以易生根的滇杨和难生根的毛白杨为试材进行扦插繁殖,采用高效液相色谱法(HPLC)检测2种杨树插穗基部(土面以下)皮层内源生长素(IAA)、脱落酸(ABA)、赤霉素(GA3)和玉米素(ZT)含量的动态变化。【结果】滇杨插穗7 d时产生愈伤组织,21 d时不定根形成,毛白杨21 d出现愈伤组织,直至49 d都无不定根形成。滇杨插穗基部皮层内IAA和ZT含量均略高于毛白杨,但差异均不显著(P>0.05);毛白杨插穗基部皮层于整个观测期内有高浓度的ABA和GA3富集,且与滇杨插穗基部皮层的含量差异均达极显著水平(P<0.01)。【结论】IAA或ZT并不是影响毛白杨扦插难生根的主要因素,而高含量的ABA和GA3可能抑制了其插穗不定根的形成。

[Purpose]Endogenous hormones contents in cortices of the cutting base of Populus yunnanensis and P.tomentosa were tested to investigate the effect of endogenous hormones on adventitious root formation of cuttings.[Methods]The cuttings of easy-to-root P.yunnanensis and difficult-to-root P.tomentosa were cultured in soil.High performance liquid chromatography(HPLC)was used to examine the dynamic changes of IAA,ABA,GA3 and ZT in cortices of the cutting base.[Results]The cuttings of P.yunnanensis were 7 d for forming callus and 21 d for formatting adventitious roots,while P.tomentosa had callus in 21 d and failed rooting by 49 d.The contents of IAA and ZT in cortices of the cutting base of P.yunnanensis were higher than those in cortices of the cutting base of P.tomentosa,but the difference was not significant(P>0.05).However,the ABA and GA3 contents in cortices of the cutting base of P.tomentosa were significantly higher than those in cortices of the cutting base of P.yunnanensis throughout the rooting process(P<0.01).[Conclusion]IAA and ZT were not the main factors to affect the adventitious root formation,but the high contents of ABA and GA3 in cortices of the cutting base could be the main inducement of cuttings of P.tomentosa failed to take adventitious roots.