Modern phytolith research is the premise to accurately reconstruct the regional paleovegetation and paleoclimate. It is thus particularly important to study the spatial distribution characteristics of the phytolith assemblages and the response of the phytolith to environmental factors. In this study, we collected 54 topsoil samples along the isohyet of 600 mm in Northeast China to examine the distribution patterns of phytolith along the gradient of single environmental factor. With this special sampling method, we targeted to reveal the responses of phytolith assemblages in the topsoil to the variation of temperature. The results showed that there were a large number of phytoliths with various morphotypes in the 54 topsoil samples in Northeast China. The phytolith morphotypes were the same, including elongate, lanceolate, blocky, cuneiform, tabular, saddle, rondel, bilobate, trapeziform polylobate, prism, silicified stomata, conduit, papillae, sclereid and carinate. In gene-ral, the contributions of elongate and lanceolate were high; the contributions of short cell phytoliths, blocky, tabular and cuneiform were small relatively; the contributions of the other types of phytoliths were less than 1.0% and appeared sporadically in the topsoil samples. Besides, the phytolith assemblages of the topsoil samples were different among Xiaoxing'an Mountains, Songliao Plain and Liaoxi hills. Combined with the discriminant analysis, the samples from the three regions could be effectively separated based on the phytoliths assemblages, with a total accuracy of 94.4%. Specifi-cally, the average percentage of elongate, lanceolate, prism was the largest in Xiaoxing'an Mountains, and was the smallest in Liaoxi hills; the percentage of saddle, bilobate, papillae was the largest in Liaoxi hills and the smallest in Xiaoxing'an Mountains; the percentage of blocky, tabular, cuneiform was the largest in Songliao Plain. Meanwhile, the percentages of the elongate, lanceolate, prism, saddle, bilobate, papillae, blocky, tabular, cuneiform were significant diffe-rences among the three regions. There were significant negative correlations between the percentages of elongate, lanceolate, prism and the annual average temperature, and positive relationships between the percentages of the blocky, tabular, cuneiform, bilobate, papillae and the annual average temperature. However, the percentage of saddle, rondel and trapeziform polylobate did not change with increasing annual average temperature.
植硅体的现代过程研究是利用植硅体这一指标精准恢复区域古植被、古气候的前提和关键环节,探讨表土植硅体组合的空间分布特征及其对环境因子的响应尤为重要。本研究在东北地区沿着年降水量为600 mm等降水线采集54块表土样品,研究单一温度控制下表土植硅体的空间分布规律,以期寻找对温度比较敏感的植硅体类型。结果表明: 54块表土样品中植硅体类型相同,共鉴定出15类,分别是棒型、尖型、块状、扇型、扁平状、帽型、鞍型、哑铃型、齿型、三棱柱型、硅化气孔、导管型、硅质突起、弓型、椎骨状,且主要以棒型、尖型为主,短细胞、块状、扁平状次之,其他类型植硅体的平均百分含量不足1.0%。小兴安岭、松辽平原和辽西低山丘陵3个区域的表土植硅体组合特征存在差异,判别分析结果能够将3个区域样点有效区分开,总的判别正确率为94.4%,其中棒型、尖型、三棱柱型的平均含量在小兴安岭最大,在辽西低山丘陵最小;而鞍型、哑铃型、硅质突起与之相反;块状、扁平状、扇型则主要是在松辽平原最大,且棒型、尖型、三棱柱型、鞍型、哑铃型、硅质突起、块状、扁平状和扇型的百分含量在3个区域之间存在显著差异。棒型、尖型、三棱柱型的百分含量与年均温之间存在显著负相关,块状、扁平状、扇型、哑铃型、硅质突起的百分含量与年均温呈显著正相关,而鞍型、帽型、齿型的百分含量与年均温没有显著相关性。.
Keywords: environmental sense; isohyet; phytolith.