不同增温条件下松嫩草原狗尾草植硅体的形态特征研究

The morphological analysis of phytolith in Green Foxtail on Songnen grassland in different warming conditions

以中国吉林省长岭县为实验基地,运用开顶式气室法(OTC)对松嫩草原狗尾草进行增温种植实验,采用湿式灰化法提取其中的植硅体进行观察统计,以探讨松嫩草原狗尾草中植硅体的形态特征及其随模拟增温的变化规律,得到以下结果与结论:(1)松嫩草原狗尾草中的植硅体可分为哑铃形、尖形、帽形、棒形及毛发形5个大类和13个亚类,其中哑铃形植硅体的百分比率最高,其次是尖形,其他类型则百分比率较少.(2)帽形、棒形及毛发形植硅体的百分比率随着温度的升高而减少,哑铃形和尖形植硅体的百分比率随温度升高而增加.(3)从各亚类来看,随着温度的升高,狗尾草中植硅体形态趋于褶皱.(4)模拟增温促进了狗尾草中哑铃形植硅体的发育.

Open-Top Chamber（OTC）method was applied to simulate different warming conditions for raising green foxtail on Songnen grassland.Some well-grown green foxtail were transplanted into three OTCs with different extents of warming.In order to receive more accurate results,a comparative experiment in natural environment was set next to the OTCs.Phytoliths were extracted from green foxtail by wet cinefaction method.The paper analyses the morphology and percentages of different phytoliths to study their respective change rules in accordance with different temperatures.Four conclusions were come into shape：（1）Phytoliths in green foxtail are classified into five main classes,namely,the bilobate,point-shaped,hat-shaped,elongate,hair-shaped and tracheid,and thirteen subclasses.Of all phytolith types,the bilobate takes the highest percentage of 51.33%,followed by the point-shaped of 34%,while other types take rarely.（2）The percentage of hat-shaped,elongate and hair-shaped phytolith reduces along withgrowing temperature in the simulated greenhouse while that of the bilobate and point-shaped increase.Moreover,hatshaped and hair-shaped phytoliths respond significantly to warming.Hat-shaped phytolith takes less than 5%,but the percentage of change in the amplitude reaches 3%;the percentage of change in hair-shaped phytolith turns out2% while it is only 4.67% of the total.Other types have relatively small changes.（3）The morphology of phytolith in green foxtail tends to wrinkle under the warming treatment.When it comes to the bilobate,the split-degree of the end of the bilobate becomes larger because of the artificial simulated temperature gradient.The percentage in the hatshaped with echinate raised from 50% to 80.12% while hat-shaped with flat reduces from 50% to 19.88%.The morphological changes of elongate phytoliths also reflect the argument above.（4）The warming treatment promotes the growth of bilobate phytolith.The average length of bilobate increases 1.9um and average width increases 0.59 um under the warming conditions.