学术
细胞壁矿质元素含量在细胞生长中的动态变化
梁峰[1,2] 王忠[1] 郭建林[1] 沈丽珍[1] 杨清[1]
[1]南京农业大学生命科学学院,南京210095 [2]商丘师范学院生命科学系,商丘476000
摘 要:
在组织水平上已经描述了许多植物通气组织的形成过程，但对其发育过程的调控仍然知道得很少．利用CSEM-EDX微量分析技术，定点测量慈姑叶柄通气组织不同发育时期的细胞壁矿质元素的组成．这些元素除了C，O以外，还包括Mg，Ca，Cu，Zn，P等必需的矿质元素．结果发现，在叶柄发育的早期，通气组织细胞壁的K和Cl含量很高，分别高达36％和4.3％细胞壁干重．Mg的含量在第二阶段最高，达到细胞壁干重的0．86％．只有在第三和第四阶段监测到Cu和Zn元素，最高含量分别为2．5％和1.5％细胞干重．仅在第四和第五阶段才能检测到Ca，其最高含量为1．3％细胞壁干重．通气组织横膈膜细胞和圆柱体腔壁细胞的元素构成变化有相似的趋势，说明这种变化与组织的发育阶段关系密切．细胞壁的一些元素间呈现较高的相关性，其中K和Cl及Cu和Zn之间成较高的正相关．在不同发育阶段，细胞壁的元素含量呈现动态变化，说明细胞壁（质外体物质）的元素构成有很大的变动范围．早期的通气组织细胞壁大量积累K和Cl，暗示早期的气体空间充满液体（组织液）；Mg可能参与细胞伸展的调控：伸展中细胞的细胞壁积累高浓度的Cu和Zn，并不影响细胞的正常功能；而Ca的出现使细胞比硬度增加，将终止细胞伸展．Cu和Zn在细胞壁中的积累呈高度的直线关系，回归分析显示，二者呈现定量关系，推测它们可能有共同的或者类似的转运和吸收机制．[著者文摘]
文章出处:
《生物化学与生物物理进展》-2008年35卷2期 -170-179页
栏目信息:
Dynamic Changes of Mineral Element in The Cell Wall of Growth Cells Detected by CSEM-EDX
LIANG Feng, WANG Zhong, GUO Jian-Lin, SHEN Li-Zhen, YANG Qing（1.College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China; 2. Department of Life Sciences, Shangqiu Normal College, Shangqiu 476000, China ）
Abstract:
Aerenchyma formation has been described in depth in a number of species at a histological level. But large gaps remain in our understanding of its regulation as a developmental process. It is attempted to analyse essential mineral elements like K, Mg, Cu, Zn, Ca and P in the cell wall of aerenchyma cells in petioles of S. trifolia at five different developmental stages by CSEM-EDX technique. At early stage, K and CI concentrations in cell wall were high up to 36% and 4.3% of dry weight, respectively. It supported the hypotheses that aerenchyma spaces are filled with liquid at early developmental stages of aerenchyma in S. trifolia petiole. Mg concentration was high at stage 2, up to 0.86% of dry weight. Zinc and Cu were detected only at rapid expansion stages, during which the concentrations were up to 1.5% and 2.5%, respectively. Calcium was detected in the cell wall only at mature stages, the concentration was high up to 1.3% of dry weight at stages 4 and 5. These results confirmed that the element concentration of aerenchyma cell wall undergoes dynamic changes during different developmental stages, and a low Ca with high Zn and Cu concentration are needed for cell expansion. Copper and Zn deposition in the cell wall showed a significant positive linear correlation, suggesting that these two elements share same or similar uptake and transport mechanism in plants.[著者文摘]
Key words:
aerenchyma, cell expansion, essential mineral element, cryo-scanning electron microscope, energy dispersive X-ray microanalysis
基金资助:
中国科技部基金（JY03-A-11）和江苏省科技厅基金（BZ200304）资助项目. Acknowledgements We thank Dr. Joseph N. Woluhau （Department of Horticuture of Egerto University, KENYA） for his critical reading of this manuscript.
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