麻类作物植硅体形态研究

大麻在中国被称为“五谷”之一，可纤用、油用、药用以及用于宗教活动等，在社会生活中发挥着重要的作用。由于早期大麻果实易腐烂灰化、不易保存，因此建立大麻的植硅体鉴定标准，对揭示其起源、驯化和传播过程具有重要意义。本研究对大麻(Cannabis sativa L.)、红麻(大麻槿)(Hibiscus cannabinus L.)、黄麻(Corchorus capsularis L.)、青麻(苘麻)(Abutilon theophrasti Medicus)、亚麻(Linum usitatissimum L.)、苎麻(Boehmeria nivea (L.)Gaudich.)等6种麻类作物的果实或种子进行了系统的植硅体形态研究，探寻具有鉴定意义的特征植硅体类型，为研究其起源、驯化和传播提供新的方法。将每份样品解剖出不同的部位，采用湿式灰化法对每个部位分别进行植硅体提取，并在光学显微镜和扫描电镜下分别进行观察分析。结果表明，发育植硅体的部位有：大麻的苞片和果皮、苎麻的果被和果皮、黄麻种皮以及青麻种皮，未见植硅体的部位有：红麻和亚麻的种子。仅有大麻果皮中存在典型形态特征的植硅体，如不规则多边疣粒板型(单体或聚合形态)、不规则多边平滑板型(单体或聚合形态)、双层嵌套板型。分析表明，大麻的不规则多边板型(包括不规则多边疣粒板型及不规则多边平滑板型)植硅体形态大小稳定，种内差异较小，且与木本植物、草本植物中形态类似的植硅体区别明显。综上，不规则多边板型植硅体为大麻特有的植硅体类型，可用于鉴定大麻的种属。其中，不规则多边疣粒板型植硅体形态特征更明显且产量更丰富，平均1g大麻果实的不规则多边疣粒板型植硅体产量可达10.2±0.4×10⁶粒，可作为鉴定大麻种属的主要特征植硅体，其主要特征为：1)单体为边缘棱角分明、正面具若干小型疣状突起、背面具0~3个大小相近的乳突的多裂片式不规则多边形板状结构，长度为15.4±2.3μm，宽度为10.8±1.7μm，厚度为6.2±1.0μm；2)由若干形态相同、大小相近的单体通过边缘裂片间隙拼合为片状平面拼图结构；3)与不规则多边平滑板型植硅体(长度为27.9±4.5μm，宽度为18.6±3.1μm，厚度为10.0±1.4μm)形成双层嵌套结构。进一步分析表明，大麻不同品种间不规则多边疣粒板型植硅体在形态大小上细微的差异与品种间果实形态大小差异以及气候条件无直接关系，推测其形态的种内差异可能是受局地土壤环境影响所致。

Study on phytolith morphology of bast fiber crops

Hemp is known as one of the "five cereals" in China and plays an important role in social life as it can be used in fiber, oil, medicine and religious activities. Early hemp seeds are easy to rot and ash, which is difficult to preserve. Therefore, the establishment of phytolith identification standards of hemp is of great significance to reveal the origin, domestication and spread of hemp. In this study, phytolith morphology of fruits or seeds of hemp(Cannabis sativa L.), kenaf(Hibiscus cannabinus L.), jute(Corchorus capsularis L.), piemarker(Abutilon theophrasti Medicus), flax(Linum usitatissimum L.)and ramie(Boehmeria nivea(L.)Gaudich.)were systematically studied to explore the characteristic phytolith types with identification significance, and to provide a new method for studying their origin, domestication and spread. The research materials included hemp fruits from 18 different origins(numbered D1~D18), kenaf seeds from 6 different origins(numbered HO1~HO6), jute seeds from 8 different origins(numbered HU1~HU8), piemarker seeds from 9 different origins(numbered Q1~Q9), flax seeds from 10 different origins(numbered Y1 to Y10)and ramie fruit from 1 origin(numbered Z). Each sample was dissected into different parts, and phytoliths were extracted from each part by wet ashing method, and observed and analyzed under light microscope and scanning electron microscope respectively. The results showed that phytoliths were developed in the bract and pericarp of hemp and ramie, and in the seed coat of jute and piemarker, while no phytoliths were seen in the seeds of kenaf and flax. The phytolith with typical morphological characteristics, such as Tabular Sinuate Verrucate(monomeric or polymeric form)(Figs. 5-6~10, Figs. 6-5~7), Tabular Sinuate Psilate(monomeric or polymeric form)(Figs. 11-15~10, Figs. 6-7~9)and Tabular Sinuate Nested(Figs. 5-16~19, Figs. 6-10~13), was only found in hemp pericarp. The monomer of Tabular Sinuate Verrucate phytolith is ploylobed irregular polygonal plate structure with angular edges. Adaxial surface with several small verrucous processes covering the surface; abaxial surface with 0~3 papillae of similar size; the side is irregular rectangle, the surface is decorated with concave and convex texture. The morphology of polymerization is that a number of monomers are pieced together through the gap between the edge lobes to form a lamellar plane jigsaw structure, and the distribution is chain from the side view. Tabular Sinuate Psilate phytolith is similar to Tabular Sinuate Verrucate phytolith in shape, but its size is larger(27.9±4.5μm in length, 18.6±3.1μm in width and 10.0±1.4μm in thickness)and its surface is smooth. Tabular Sinuate Nested phytolith is a double-layer nested structure with fixed direction formed by nesting of Tabular Sinuate Verrucate back mastoid process and Tabular Sinuate Psilate front groove. The analysis showed that Tabular Sinuate Verrucate and Tabular Sinuate Psilate phytoliths of hemp were stable in shape and size, with little intraspecific difference, and clearly differentiated from the similar phytoliths of woody plants and herbaceous plants. Therefore, we conclude that Tabular Sinuate Verrucate and Tabular Sinuate Psilate are unique phytolith types of hemp and can be used to identify the species genus of hemp. The Tabular Sinuate Verrucate phytoliths are more distinctive and abundant. The average number of Tabular Sinuate Verrucate phytoliths in 1 gram of hemp fruit was 10.2±0.4×106, which can be used as the main characteristic phytolith for the identification of hemp species. The monomer is characterized as follows: a)the monomer is a ploylobed irregular polygonal plate structure with angular edges, many small verrucous processes on the front and 0~3 papillae on the back, 15.4±2.3μm in length, 10.8±1.7μm in width and 6.2±1.0μm in thickness; b)many monomers with the same shape and similar size are pieced together into a lamellar plane jigsaw structure through the gap between edge lobes; c)form a nested double layers structure with Tabular Sinuate Psilate phytolith. Further analysis showed that there was no significant difference in the shape and size of Tabular Sinuate Verrucate phytolith among different varieties within the error range, and the slight difference of hemp phytoliths was not directly related to the fruit shape and size of different varieties and climate conditions, which might be caused by local soil environment.