东北地区不同湿度梯度条件下芦苇植硅体形态组合特征

Combined Characteristics of Phytoliths in Phragmites australis(Cav.) Trin.ex Steud.under the Control of Different Moisture Gradients in Northeast China

对东北3个地区5个地点不同生境的芦苇叶片中植硅体进行了分析,探讨了不同湿度梯度条件下芦苇植硅体的组合特征。共测芦苇植硅体4 372粒,5个地点芦苇样品中的植硅体类型相同,所鉴定出的植硅体类型共8种,不同生境下的芦苇植硅体的百分含量及形态大小明显不同。芦苇植硅体中的硅化气孔对极端环境的响应较为敏感,干旱环境中芦苇植硅体颗粒变大,硅化气孔的含量相应减少。较湿润的沙兰地区,植硅体的颗粒偏小,气孔的含量也较少;尖型的长度,对于湿度因子更为敏感,湿度不同的地区,尖型植硅体的长度发育不同;鞍型植硅体的形态组合在长春地区小湿度梯度的设置中,随着湿度的增大有增大的趋势,说明湿度的变化在一定程度上会影响芦苇植硅体形态大小,同时有利于芦苇植硅体的发育。

Leaves of Pragmites communis.were collected from five sampling sites in three zones or areas in NE China,each zone representing a different habitat.A total of 4 372 phytolith particles were counted from the leaves and classified into eight types.The main types from the five sampling sites are identical but the proportions and sizes of phytoliths in different habitats are different.Phytoliths are sensitive to environmental extremes,those from a saline-alkaline environment being much larger but correspondingly fewer;in relatively wet environments,phytoliths are smaller as well as fewer.The length of lanceolate phytoliths is more sensitive to humidity,and saddle-shaped phytoliths tend to increase along all the three dimensions with even a small increase in humidity.Higher humidity thus appears to favor the development of phytoliths in Pragmites communis.