几种禾本科植物淀粉粒形态比较及其考古学意义

对5种禾本科植物种子中的淀粉粒（包括粟、黍、青狗尾草、高粱及薏苡等）进行了形态学观察和描述，结合颗粒长度的测量和统计学分析，建立了区分这些作物淀粉粒的一般方法。结果显示，粟和黍的淀粉粒以多边形居多，比例分别为75％和96％；青狗尾草中的淀粉粒以圆形为主；高粱和薏苡的淀粉粒形态具有较高的多样性。表现在消光臂上，高粱淀粉粒的消光臂呈现弯曲特征，而其他4种作物淀粉粒的消光臂则较为平直。在颗粒的长度分布上，粟淀粉粒为2.77～18.40μm，黍淀粉粒为3.93～12.85μm，青狗尾草淀粉粒为 2.19～11.90μm，高粱淀粉粒为4.11～30.30μm，薏苡淀粉粒为 5.48～25.44μm。研究表明，粟、黍、青狗尾草、高粱及薏苡等5种禾本科植物的淀粉粒形态特征存在相似性，但是也有差异。综合运用二维形状、脐点位置、表面特征、消光臂特征及长度等多种指标，可以对这几种作物的淀粉粒进行一定程度的区分。这一研究结果可用于辅助对古代淀粉粒的种属鉴定。

MORPHOLOGICAL ANALYSES ON STARCH GRANULES OF FIVE GRASS SPECIES AND THEIR SIGNIFICANCE FOR ARCHAEOLOGY

Grass crops provide an important food source for humans,and their early use is also an important subject in archaeological research. Starch analysis has been developed to recover plant remains in archaeological sites. In this study we examined starches from seeds of five species of Poaceae: foxtail millet(Setaria italica),broomcorn millet(Panicum miliaceum), foxtail grass(Setaria viridis), Sorghum(Sorghum bicolor),and Job's tears(Coix lacryma-jobi). All the plant samples we studied were collected from different regions in China and were well identified,including three samples of foxtail millet,four of broomcorn millet,two of foxtail grass,three of sorghum,and two of Job's tears. In the study,morphological characteristics of starch granules were observed and described. A Zeiss Axioskop A1 microscope with attached Zeiss Axiocam MRc5 digital camera linked to a PC running AxioVision software was used to capture their images under DIC(Differential Interference Contrast),brightfield and polarised light. More than 100 granules were counted for each sample. The main variables recorded include two-dimensional shape,hilum positions,surface features,extinction cross shapes,and size(maximum length)distribution. In the geometrical shape of starch granule,the starch granules of foxtail millet and broomcorn millet are mainly polygonal,accounting for 75% and 96% ,respectively; those of foxtail grass mainly round or nearly round; and those of sorghum and Job's tears highly diverse shaped. Some regular polygonal starch granules,typical for sorghum but not for other species,can be used as a special indicator for identifying sorghum. In the extinction cross of starch granule,the starch granules of sorghum often show bent arms with zigzag patterns,while those of the other four species show quite straight arms. In the size(maximum length)distribution of starch granule,the starch granules of foxtail millet are 2.77～18.40μm; those of broomcorn millet 3.93～12.85μm; those of foxtail grass 2.19～11.90μm; and those of sorghum and Job's tears 4.11～30.30μm and 5.48～25.44μm,respectively. These characteristics mentioned above might provide a help for identifying different plants in archaeological sites to a certain extent.