Polyploidy and cellular mechanisms changing leaf size: comparison of diploid and autotetraploid populations in two species of Lolium.
Polyploidy and cellular mechanisms changing leaf size: comparison of diploid and autotetraploid populations in two species of Lolium.
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DOI：
10.1093/aob/mci245
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发表时间：
2005-10
期刊：
影响因子：
4.2
通讯作者：
S. Sugiyama
中科院分区：
文献类型：
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作者：
S. Sugiyama
背景和目的包括叶片在内的植物器官的生长和发育依赖于细胞的分裂和扩张。更大的细胞倍性会增加叶片的大小，但这种效应的机制尚不清楚。因此，本研究通过对多年生黑麦草和多花黑麦草的二倍体和同源四倍体品种叶片发育过程中叶肉层细胞参数的比较，研究了细胞分裂和扩张在多倍体引起的叶片大小增加中的作用。方法在盆栽条件下，对两种不同倍性水平的3个品种进行盆栽试验，测定每个品种6个植株的叶片伸长速率和叶基细胞长度分布。用运动学方法计算了与细胞分裂和伸长活动相关的细胞参数。关键结果四倍体品种的叶片伸长速率比二倍体品种快，导致叶片更长，这主要是因为它们的成熟细胞更长。表皮细胞和叶肉细胞的长度相差20倍，但在两个物种的四倍体品种中都更大。四倍体品种细胞长度的增加是由较快的细胞伸长速率引起的，而不是由较长的细胞伸长时间引起的。二倍体和四倍体品种的细胞分裂参数如细胞产量和细胞周期时间没有显著差异。结论多倍体主要通过增加细胞的伸长率来增加叶片的大小，而不是延长伸长期的时间，从而增加最终的细胞大小。
BACKGROUND AND AIMS Growth and development of plant organs, including leaves, depend on cell division and expansion. Leaf size is increased by greater cell ploidy, but the mechanism of this effect is poorly understood. Therefore, in this study, the role of cell division and expansion in the increase of leaf size caused by polyploidy was examined by comparing various cell parameters of the mesophyll layer of developing leaves of diploid and autotetraploid cultivars of two grass species, Lolium perenne and L. multiflorum. METHODS Three cultivars of each ploidy level of both species were grown under pot conditions in a controlled growth chamber, and leaf elongation rate and the cell length profile at the leaf base were measured on six plants in each cultivar. Cell parameters related to division and elongation activities were calculated by a kinematic method. KEY RESULTS Tetraploid cultivars had faster leaf elongation rates than did diploid cultivars in both species, resulting in longer leaves, mainly due to their longer mature cells. Epidermal and mesophyll cells differed 20-fold in length, but were both greater in the tetraploid cultivars of both species. The increase in cell length of the tetraploid cultivars was caused by a faster cell elongation rate, not by a longer period of cell elongation. There were no significant differences between cell division parameters, such as cell production rate and cell cycle time, in the diploid and tetraploid cultivars. CONCLUSION The results demonstrated clearly that polyploidy increases leaf size mainly by increasing the cell elongation rate, but not the duration of the period of elongation, and thus increases final cell size.