一种锰超积累植物叶片金属分布的新模式。

Novel pattern of foliar metal distribution in a manganese hyperaccumulator.

作者信息

Fernando Denise R, Marshall Alan T, Gouget Barbara, Carrière Marie, Collins Richard N, Woodrow Ian E, Baker Alan J

机构信息

School of Botany, The University of Melbourne, Parkville, Vic. 3010, Australia.

Analytical Electron Microscopy Laboratory, Faculty of Science and Technology and Engineering, La Trobe University, Melbourne, Vic. 3086, Australia.

出版信息

Funct Plant Biol. 2008 May;35(3):193-200. doi: 10.1071/FP07272.

DOI:10.1071/FP07272

PMID:32688773

Abstract

The primary sequestration of foliar manganese (Mn) in Mn-hyperaccumulating plants can occur in either their photosynthetic or non-photosynthetic tissues, depending on the species. To date, only non-photosynthetic tissues have been found to be the major sinks in other hyperaccumulators. Here, electron (SEM) and proton (PIXE) microprobes were used to generate qualitative energy dispersive (EDS) X-ray maps of leaf cross sections. Two Mn hyperaccumulators, Garcinia amplexicaulis Vieill. (Clusiaceae) and Maytenus fournieri (Panch. and Sebert) Loesn. (Celastraceae), and the Mn accumulator Grevillea exul Lindley (Proteaceae) were studied. PIXE/EDS data obtained here for M. fournieri were in agreement with existing SEM/EDS data showing that the highest localised foliar Mn concentrations were in the epidermal tissues. However, this is the first in situ microprobe investigation of G. amplexicaulis and G. exul. The Mn X-ray maps of G. amplexicaulis revealed a previously undescribed third spatial distribution pattern among Mn-hyperaccumulating species. Manganese was relatively evenly distributed throughout the leaf photosynthetic and non-photosynthetic tissues, while in G. exul it was most highly concentrated in the epidermal cells.

摘要

根据植物种类的不同，锰超积累植物叶片中锰的主要隔离可能发生在光合组织或非光合组织中。迄今为止，在其他超积累植物中，仅发现非光合组织是主要的锰储存部位。在此，利用电子（扫描电子显微镜，SEM）和质子（粒子激发X射线发射，PIXE）微探针生成叶片横截面的定性能量色散（能谱仪，EDS）X射线图谱。对两种锰超积累植物，即抱茎藤黄（藤黄科）和小叶美登木（卫矛科），以及锰积累植物粉叶银桦（山龙眼科）进行了研究。此处获得的小叶美登木的PIXE/EDS数据与现有的SEM/EDS数据一致，表明叶片中锰的最高局部浓度存在于表皮组织中。然而，这是对抱茎藤黄和粉叶银桦首次进行的原位微探针研究。抱茎藤黄的锰X射线图谱揭示了锰超积累植物中一种此前未描述的第三种空间分布模式。锰在叶片的光合组织和非光合组织中分布相对均匀，而在粉叶银桦中，锰则高度集中在表皮细胞中。