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杉木根系细胞壁活化铁磷能力及其影响因子分析 被引量:7

Mobilization of Insoluble Iron Bound Phosphate and Effective Factors by Root Cell Walls of Chinese Fir
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摘要 [目的]以南方红壤中储量较大的难溶性铁磷为对象,研究杉木根系细胞壁活化难溶性铁磷的能力,分析林龄、根径级、以及木质部和韧皮部等不同组织部位对杉木根系细胞壁活化铁磷能力的影响情况,以期为南方林区红壤潜在可利用磷素含量的研究提供理论依据。[方法]在福建三明莘口教学林场的10年生杉木幼龄林、22年生杉木中龄林和34年生杉木老龄林中各选择3株平均木作为研究对象,按根直径〈2 mm,2~5 mm,5~10 mm,10~20 mm,20~30 mm,〉30 mm等6个径级进行分组,分别从不同径级根系的木质部和韧皮部中提取细胞壁,采用钼锑抗比色法测定细胞壁对难溶性铁磷活化的有效磷含量,分析比较杉木根系细胞壁活化难溶性铁磷的能力,以及根径级、组织部位及林龄等因子对杉木根系细胞壁活化铁磷的影响。[结果]杉木根系细胞壁对铁磷的活化量为17.67~497.50 mg·kg-1。根径级小于10 mm的根系,其木质部和韧皮部中细胞壁对铁磷的活化能力均高于径级大于10 mm的根系。与同一根径级木质部相比,各林龄杉木根系韧皮部的细胞壁对铁磷活化能力均较高。不同林龄杉木同一根径级的木质部和韧皮部,其提取出的细胞壁对铁磷活化能力均表现为:老龄林〉中龄林〉幼龄林。[结论]杉木根径级、组织部位及林龄等因子对其根系细胞壁活化铁磷的影响均较显著。总体上表现为从径级较小根系提取的细胞壁活化铁磷能力高于径级较大根系;随着林龄的增加,根系对铁磷的活化能力呈逐渐增强的趋势,且韧皮部细胞壁的活化能力明显高于木质部。这可能与细胞壁磷溶解内含物的累积及空间结构特征发育规律有关。由于根直径较小的细根生长发育较快,有利于细胞壁活性物质的形成与积累;而与木质部相比,韧皮部作为植物贮藏组织之一,其化学成分含量明显较高;林龄对根系的生长,特别是对细胞壁内果胶等主要内含物的积累具重要作用。因此,今后应对参与细胞壁合成和重组的基因和蛋白进行系统研究,以期找出逆境胁迫下细胞壁通过释放特异性活性物质等途径的作用机制。 [Objective]Aims: The insoluble iron bound phosphate in red soil of southern China was used to study the capacity of cell wall of Chinese fir roots in mobilizing insoluble iron bound phosphate and the impact factors,including forest age,root diameter and tissue structure of Chinese fir root cell wall. This study aims at providing a theoretical basis for fully using potentially available phosphorus content in the forest red soil of southern China.[Method]Methods: In Xinkou Forest Station of Sanming in Fujian,we chose 3 average trees from different aged forests,the 10-year-old as the young forest,22-year-old as middle-aged forest and 34-year-old as old forest of Chinese fir plantations,and classified the roots into 6 classes according to the root diameter,less than 2 mm,2-5 mm,5-10 mm,10-20 mm,20-30 mm,and more than 30 mm. The cell wall was extracted from xylem and phloem of different root classes,respectively. The phosphorus content mobilized by cell-wall from insoluble iron bound phosphate was determined by using the molybdenum antimony colorimetric method,to analyze and compare the ability of cell wall of Chinese fir root in mobilization of insoluble iron bound phosphate,and the influence factors,such as root diameter,tissue structures and forest age.[Result]The mobilizing phosphorus content by Chinese fir root cell wall from insoluble iron bound phosphate was from 17 . 67 mg kg-1 to 497 . 50 mg kg-1 . The xylem and phloem cell wall of less than 10 mm diameter roots had greater ability of activating insoluble iron bound phosphate than that of the more than 10 mm diameter roots. Compared with xylem in each forest age, the phloem cell wall of the same diameter root activated more insoluble iron bound phosphate. There was difference in activating ability of insoluble iron bound phosphate among the different forest ages with the same root diameter,and the ability of cell wall in activating insoluble iron bound phosphate was as follows: old forest 〉 middle-aged forest 〉 young forest.[Conclusion]The factors such as root diameter,tissue structures and forest age of Chinese fir had a significantly impact on the capacity for root cell wall to activate insoluble iron bound phosphate. The smaller diameter roots had greater ability activating insoluble iron bound phosphate than the bigger roots; the older forest had greater ability in activating insoluble iron bound phosphate than the younger,and the cell wall extracted from phloem had significantly greater activation ability than that from the xylem. This would be related to the inclusions accumulation of phosphorus dissolved of the cell wall and development pattern of spatial structure. The rapid growth of fine root would conducive to the formation and accumulation of active substances of cell wall. Phloem is a storage tissue of plants,and it has a higher chemical contents compared with the xylem. The forest age especially plays an important role in accumulation of the main contents like pectin in the cell wall. Thus, it is proposed that the genes and proteins involved in cell wall synthesis and restructuring should be studied and emphasized in the future,to understand the mechanism of cell wall in mobilizing insoluble iron bound phosphate through releasing specific active substances under stress condition.
出处 《林业科学》 EI CAS CSCD 北大核心 2015年第9期59-64,共6页 Scientia Silvae Sinicae
基金 国家自然科学基金项目(31370531 31100472) 福建省自然科学基金杰青项目(2014J06009) 福建省科技重大专项(2012NZ0001)
关键词 杉木 根细胞壁 难溶性磷 木质部 韧皮部 Cunninghamia lanceolata root cell wall insoluble phosphate xylem phloem
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