低pH条件对紫花苜蓿结瘤的影响及机制初探

探讨了低pH条件下紫花苜蓿根毛变形和结瘤受到的影响及其机制。结果表明,在低pH条件下,初生根伸长和根瘤菌OD600值显著下降,根共生结瘤受到明显抑制。在接种根瘤菌、不加NF的条件下,pH5.0、pH4.7、pH4.5、pH4.2处理的根毛变形率分别比对照(pH6.5)减少了44.1%、56.4%、60.0%和69.0%;在加入NF、不接种根瘤菌的情况下,低pH(4.5)处理,根毛的变形也比对照(pH6.5)减少了45.9%。结果暗示,低pH条件下苜蓿结瘤初期的结瘤信号传导受阻,这可能是导致酸性条件下苜蓿结瘤减少的重要原因之一。

Preliminary study on the effect of low pH on the nodulation of Medicago sativa and corresponded mechanisms

Effects of low pH on root hair deformation(RHD)and nodulation in Medicago sativa were investigated and corresponded mechanisms was also discussed in present study.It was showed that primary root elongation,the OD600 of Rhizobium meliloti,and symbiotic nodulation of roots were obviously decreased at low pH.At pH5.0,pH4.7,pH4.5,pH4.2,the rate of RHD was less 44.1%,56.4%,60.0% and 69.0% respectively than that at pH6.5 in the presence of R.meliloti.Moreover,in the presence of NF RHD was also less 45.9% at pH4.5 than that at pH6.5.These results implied that the nodulation signal transduction of Medicago sativa at initial stages of symbiotic nodulation was inhibited at low pH,which might be an important cause resulted in the reduction of nodulation in Medicago sativa at acidity conditions.