小麦幼苗根系生理特性和解剖结构对根际pH的响应

Response of Root Physiological Characteristics and Anatomical Structure to Rhizosphere pH in Wheat Seedlings

为探讨根际pH对冬小麦根系生长的影响,以半冬性小麦品种‘矮抗58’(AK58)和‘百农4199’(BN4199)为材料,采用水培试验,设置3个pH水平(4.0、6.5、9.0,以6.5为对照),研究根际pH对冬小麦根系抗氧化酶系统的影响及根系解剖结构对pH的响应。结果表明:酸碱胁迫下,植株地上部及根系生物量、抗氧化酶活性较对照下降,且酸胁迫较碱胁迫下降幅度大。两品种根冠比表现为pH 4.0<pH 6.5<pH 9.0,丙二醛(MDA)含量表现为pH 6.5<pH 9.0<pH 4.0。与对照相比,两品种碱性条件下根系结构受损较小,而酸性条件下受损较大。相关分析表明地上部和根系干物质积累量与抗氧化酶活性呈显著正相关,与根系MDA含量呈极显著负相关。可见,酸碱胁迫下,保持较高的抗氧化酶活性有利于保持根系生长,从而提高小麦适应不良根际环境的能力。

To investigate the effect of rhizosphere pH on root growth of winter wheat,the semi-winter wheat varieties‘Aikang 58’(AK58)and‘Bainong 4199’(BN4199)were used as materials,the hydroponic experiments were conducted and 3 pH levels(4.0,6.5 and 9.0,6.5 as control)were set,the effect of rhizosphere pH on antioxidant enzyme system of winter wheat roots and the response of root anatomical structure to pH were studied.The results showed that the biomass of plant shoots and roots,and antioxidant enzyme activity decreased compared with the control under acid-base stress,and the acid stress decreased more than the alkali stress.The root/shoot ratio of the two cultivars showed pH 4.0<pH 6.5<pH 9.0,and malondialdehyde(MDA)content showed pH 6.5<pH 9.0<pH 4.0.Compared with the control,the root structure of two cultivars was less damaged under alkaline condition,but more damaged under acidic condition.The correlation analysis showed that the dry matter accumulation of shoots and roots had significantly positive correlation with antioxidant enzyme activity,and had significantly negative correlation with root MDA content.In conclusion,high antioxidant enzyme activity under acid-base stress is beneficial to maintaining root growth,and it can improve the ability of wheat to adapt for the poor rhizosphere environment.