为了解马尾松根系质膜H+-ATPase响应酸沉积的规律,生物量的变化,植物形态学,细胞内H+,暴露于模拟酸雨的马尾松幼苗中的酶活性和H-ATPase基因表达(SAR,研究了有和没有钒酸盐的pH5.6和4.6)。无论是否添加0.1mMNa3VO4,模拟酸雨暴露60天都会增加松树根中的细胞内H。用SAR处理的幼苗生长保持良好,甚至初级侧根长度,暴露于pH4.6的SAR的幼苗的根干重和根尖数量高于对照(pH6.6)。然而,钒酸盐的添加导致严重的生长抑制和形态参数的明显下降。同样,根系质膜H+-ATP酶的ATP水解活性和H+转运活性,两者都受到SAR的刺激,而它们都受到钒酸盐的抑制,在pH4.6的SAR条件下,在松树根中观察到最高的活性刺激。此外,SAR还诱导了所研究的H-ATPase亚基(atpB,atpe,atpF,atpH和atpI)。因此,根质膜H-ATPase通过增强其活性而将更多的质子泵入膜中,从而促进了适应酸雨的马尾松幼苗的生长,并且涉及在转录水平上上调根H-ATPase亚基的基因表达。
To understand the regulation of roots plasma membrane H+-ATPase in Masson pine responding to acid deposition, the changes in biomass, plant morphology, intracellular H+, enzyme activity and H+-ATPase genes expression in Masson pine seedlings exposed to simulated acid rain (SAR, pH 5.6 and 4.6) with and without vanadate were studied. Simulated acid rain exposure for 60 days increased the intracellular H+ in pine roots whether added with 0.1 mM Na3VO4 or not. The growth of seedlings treated with SAR was maintained well, even the primary lateral root length, root dry weight and number of root tips in seedlings exposed to SAR at pH 4.6 were higher than that of the control (pH 6.6). However, the addition of vanadate resulted in severe growth inhibition and obvious decline in morphological parameters. Similarly, ATP hydrolytic activity and H+ transport activity of roots plasma membrane H+-ATPase, both were stimulated by SAR whereas they were inhibited by vanadate, and the highest activity stimulation was observed in pine roots subjected to SAR at pH 4.6. In addition, SAR also induced the expression of the investigated H+-ATPase subunits (atpB, atpE, atpF, atpH and atpI). Therefore, the roots plasma membrane H+-ATPase is instrumental in the growth of Masson pine seedlings adapting to acid rain by a manner of pumping more protons across the membrane through enhancing its activity, and which involves the upregulated gene expression of roots H+-ATPase subunits at transcriptional level.