铝胁迫对千年桐吸收和运输微量元素的影响

为探索千年桐体内微量元素对不同梯度铝胁迫的响应机制,分析铝胁迫下微量元素在根系和叶片间吸收和运输的规律,以土培和水培的1年生千年桐苗木为研究对象,在不同供铝水平下,测定千年桐苗木根系和叶片中微量元素(Fe、Mn、Cu、Zn)的含量。结果表明,铝处理显著促进盆栽苗根系微量元素的吸收,而对水培苗根系微量元素的吸收则表现为无显著作用或抑制作用,表明同一植物在不同生境下会形成不同的耐铝机制;微量元素在苗木不同器官的分配方式不同,千年桐盆栽苗吸收的微量元素除Mn外多集中在根系,而水培苗则除Fe外多集中在叶片;铝胁迫也会影响微量元素在苗木不同器官间的运输,如在铝浓度低于0.290 mmol·L^-1时,会促进水培苗Zn元素从根向叶的运输,而当铝浓度高于0.290 mmol·L^-1时,则会抑制Zn元素的向上运输。铝处理对千年桐盆栽苗和水培苗微量元素的影响有较大差异,与水培苗相比,盆栽苗在土壤原生环境下具有较好的抗性。因此,在今后的胁迫试验中,除了考虑植物自身的抗逆性,还要考虑原生环境的作用。

Effects of aluminum stress on the absorption and transportation of microelement in the roots and leaves of Aleurites montana

This study determined Fe,Mn,Cu and Zn contents in leaves and roots of 1-year-old Aleurites montana potted and hydroponic seedings under different concentrations of aluminum stress,to analyze the absorption and transportation of microelement contents between roots and leaves and to reveal the response mechanism of microelement contents to different concentrations of Al stress.The results showed that aluminum significantly promoted the absorption of Fe,Mn,Cu and Zn in roots for soil cultured seedlings,while exerted insignificant effect on or even inhibited the absorption of microelements in roots of hydroponic seedlings,indicating that the same plant developed different aluminum resistance under different cultured media.The distribution of microelements varied in different organs of A.montana.Most microelements,excluding Mn,were absorbed by roots of potted seedlings while those excluding Fe were concentrated in leaves of hydroponic seedings.Aluminum stress also affected the transport of microelements between different organs in seedlings.The transport of Zn from roots to leaves was promoted when Al concentration was lower than 0.290 mmol·L^-1,while the transport was inhibited when it was higher than 0.290 mmol·L^-1.The study indicated that there was a significant difference in the effect of aluminum stress on microelements of the A.montana potted and hydroponic seedlings.The potted seedlings had stronger resistance in primary environment compared with hydroponic seedlings.Therefore,in the future stress experiments,the role of primary environment should also be taken into account in addition to the stress resistance of plants.