丛枝菌根促进枳砧纽荷尔脐橙镁吸收与转运的机制

The arbuscular mycorrhizal fungus having been identified to have a promoting role in Mg uptake and translocation in Newhall navel orange grafted on trifoliate orange from the preliminary study, will be used in this program, the differences in secretion components and concentrations in roots, Mg forms and their dynamics in rhizosphere of mycorrhizal and non-mycorrhizal trifoliate orange and Newhall navel orange grafted on trifoliate orange will be investigated under Mg adequacy and Mg deficiency stress, combination with the differences in anotomical features and related physiological indices, with an attempt to clarify the physiological mechanism underlying Mg activation and uptake in rhizosphere of mycorrhizal Newhall navel orange grafted on trifoliate orange under Mg deficiency stress. The results could not only provide foundation on exploring promotion mechanism of arbuscular mycorrhizas on Mg uptake and translocation in Newhall navel orange grafted on trifoliate orange at proteomic level further, but also offer a new theoretical and practical basis in solving Mg deficiency problems in Newhall navel orange in production.

本项目利用前期研究筛选的能促进枳砧纽荷尔脐橙镁吸收与转运的丛枝菌根真菌，研究镁适量及缺镁胁迫下菌根化与非菌根化枳及枳砧纽荷尔脐橙根系分泌物组分与含量、根际镁形态及其动态的差异，结合其解剖结构及相关生理指标差异，以探明缺镁胁迫下菌根化枳砧纽荷尔脐橙根际镁的活化与吸收的生理机制。研究结果能为下一步在蛋白质组水平上探讨丛枝菌根促进枳砧纽荷尔脐橙镁吸收与转运的机制奠定基础，还为解决生产上纽荷尔脐橙缺镁问题提供新的理论和实践依据。

我国柑橘产区主栽脐橙品种纽荷尔极易表现出明显的缺镁黄化症状。本项目采用盆栽法研究了镁缺乏与镁充足条件下丛枝菌根(AM)真菌Glomus versiforme对枳砧纽荷尔与椪柑植株的生长、镁含量与分布及光合作用的影响。结果表明：低镁抑制纽荷尔植株的生长较椪柑明显，低镁条件下纽荷尔植株春梢叶的镁含量和CO2同化率下降比椪柑明显，其根部可溶性糖含量也更低。AM真菌接种处理促进了纽荷尔与椪柑植株的生长，提高了二者不同部位镁含量及春梢叶的光合作用，尤其是缺镁条件下的纽荷尔植株。可见，温室条件下低镁土壤中G. versiforme接种处理可促进纽荷尔植株生长及镁的吸收与分布。另外，本研究还发现AM真菌Glomus intraradices接种处理的枳砧纽荷尔与椪柑对低锌胁迫表现出不同的反应，纽荷尔的菌根依赖性较高。低锌土壤中G. intraradices接种处理可促进枳砧纽荷尔植株的生长及锌的吸收与分布。因此，在生产上AM真菌接种处理可作为减轻或消除纽荷尔脐橙缺镁或缺锌黄化的一种新途径。