竹亚科植硅体形态学研究及其生态学意义

MORPHOLOGY OF PHYTOLITH IN BAMBUSOIDEAE (GRAMINEAE) AND ITS ECOLOGICAL SIGNIFICANCE

选择我国常见的竹亚科19属64种进行系统的植硅体形态学研究,对竹亚科特有的长鞍型植硅体的长度、宽度、高度(侧面宽)和硅质颗粒数目等参数进行了测量。研究发现,合轴散生竹长鞍型植硅体个体最大(长度20·6±0·2m,宽度12·8±0·5m,高度12·4±0·1m,颗粒数2·8±0·5),单轴散生竹次之(长度18·8±0·8m,宽度11·7±0·4m,高度11·8±0·3m,颗粒数1·9±0·1),复轴混生竹再次(长度18·3±1·5m,宽度11·2±1·5m,高度11·4±1·7m,颗粒数1·8±0·4),合轴丛生竹最小(长度18·0±1·8m,宽度9·7±0·5m,侧面宽10·1±1·4m,颗粒数2·6±0·3)。经判别分析显示以长鞍型植硅体三维形态参数和硅质颗粒数目为变量可以区分竹亚科植物各生态型,并初步明确了长鞍型植硅体形态与竹亚科生态型的对应关系,探讨了其与竹亚科植物生境条件之间的对应关系,以及在竹亚科植物演化序列中的意义,为利用竹亚科长鞍型植硅体形态进行古环境分析提供了基础性资料。

Phytolith analysis has been widely used in many scientific research fields such as Botany, Agriculture, and Environmental Archaeology. Different plants produce distinguishable phytoliths with different shapes and relative content percentages, and so do different genera or species within the same family and/or subfamily, particularly in Gramineae. Comprehensive morphological research on phytoliths has been carried out on leaf-blades from 64 species belonging to 19 genera in the subfamily Bambusoideae （Gramineae）. It reveals that there are several types of phytoliths in bamboos including fan-shape, long-saddle, tower-shape, sinuate elongate, smooth elongate, silica stoma, silica hair and hair tip, among which long-saddle phytolith is diagnostic for Bambusoideae. To find out the relationship between phytoliths and ecotypes of bamboos, long-saddle phytoliths from each bamboo species are measured to get morphological parameters such as length, width, and height as well as the amount of silica granules on the surface. Based on the classification of four ecotypes from different bamboos at genus level, these observations reveal that the average size of long-saddle phytoliths from sympodial scattering bamboos is the largest （ Length： 20. 6 ± 0.2μm, Width ： 12.8 ± 0.5 μm, Height： 12.4 ± 0.1 μm, Granule Amount： 2.8 ± 0.5 ）, with monopodial scattering bamboos closely followed （ L ： 18.8 ± 0.8μm, W ： 11.7 ± 0.4μm, H ： 11.8 ± 0.3 μm, GA ： 1.9 ± 0. 1 ） , then followed by the compound mixed bamboos （ L ： 18.3 ± 1.5μm, W ： 11.2 ± 1.5μm, H ： 11.4 ± 1.7μm, GA ： 1.8 ±0. 4）, and the average size of long-saddle phytoliths in sympodial caespitose bamboos is the smallest （L： 18.0± 1.8μm, W：9.7 ±0.5μm, H：10.1 ± 1.4μm, GA：2.6 ±0.3）. Further discriminant analysis on morphological varieties of long-saddle phytoliths also plot out these four ecotypes. In addition, the relationship between long-saddle phytoliths and the habitat of Bambusoideae is also discussed in the subfamily Bambusoideae.