毛竹茎秆组织速生的时空发育特征

为探索毛竹从发笋到竹秆形成的组织发育规律,对不同发育时期和部位的毛竹茎秆进行组织解剖分析并进行数量化分析。结果表明:竹秆的快速发育主要表现在节间的纵轴方向,节间发育由细胞分裂和细胞伸长控制。发育初期,在薄壁细胞和纤维细胞上可以看到大量的细胞核出现,此时细胞分裂占主导地位;随着组织发育,细胞核逐渐减少并消失,薄壁细胞和纤维细胞的长度显著增加,细胞伸长在发育中后期占主导地位。竹秆的发育、成熟和老化从基部首先启动,中部和顶部要顺次晚一些。基部的纤维组织最先出现木质化,此时茎秆的高度大约为6 m。竹秆的细胞伸长呈阶段性的波动,薄壁组织的细胞长度在快速伸长期偏离正态分布,在缓慢伸长期呈正态分布。

Characteristics of Temporal and Spatial Tissue Development During the Rapidly Growing Stage of Moso Bamboo Culms

To explore the development regularity from shoot to stem, the culms in different developmental stages and portions of Moso bamboo (Phyllostachys heterocycla cv. pubescens) were studied by anatomy analysis. The results of histological observations indicated that the rapid development of culms mainly presented in longitudinal direction, which was dominated by cell division and cell elongation. In the initial stage of growth, numerous cell nuclei could be seen in parenchyma and fiber cells-an obvious sign of cell division-indicating the presence of meristematic tissue when cell division dominated the culms development. As the culm developed, the number of nuclei declined, until there were almost no detectable nuclei in the late stages of development. The development of culm was dominated by cell division in the initial stages and by cell elongation in the middle and late stages. The development, maturation and aging in different parts of the culm were studied systematically from the basal to the top internode. The lignification was appeared at fibrous tissue of basal internode in G7 stage when the length of culm was 6 m. The cell elongation of culms showed periodic fluctuations. The cell length of parenchyma, in the rapid elongating stage, deviated from normal distribution while it showed normal distribution in the slow elongating stage.