野生大豆(Glycine soja)YD63和栽培大豆(G.max)ZD19茎秆解剖结构比较

摘要

Anatomical differences of stem between a wild soybean and a soybean cultivar were observed using histochemical methods.Relationships among anatomical structure,function,and environmental adaptability were analyzed to understand soybean evolution and stress resistance.The main results are:1.Wild soybean had more stalk epidermal hairs and glandular trichomes,thicker cuticle and epidermis,and greater epidermal proportion than the cultivated one.Higher lignification and suberification degrees of wild soybean epidermis and exodermis were observed.2.Wild soybeans had greater proportionof cortex,phloem,xylem parenchyma and pith.With the greater proportion of parenchyma in stalks,wild soybeanshowed betterstress resistance.Due to the larger and thinner cell-wall of parenchyma cells,the strength of wild soybean stalks decreased and the plasticity increased.3.Compared with wild soybean,the cultivated soybean stems showed greater mechanical strength owing to its greater proportion of lignified tissues and thicker cell wall of epidermis,phloem fiber,xylem fiber and vessels.It is better at maintaining upright growth and morphology construction.4.The cultivated soybean had greater number of cell layer and thickness of vascular cambium than those of the wild one.Faster growing rate of xylem in cultivated soybeans and equal rate in wild ones resulted in more xylem in former stalks and almost equal proportion of xylem and phloem in later one.5.The phloem sclerenchyma of wild soybean almost continuously distributed,interrupted only in the pith ray,while that in cultivated ones showed flaky distribution.And its proportion was much larger than that of cultivated soybeans.6.With stronger wall strength (t/b) 2,greater proportion of small vessels and lower connectivity in xylem,wild soybean stems had higher safety and lower efficiency of water transportation.In summary,this research provided an anatomical basis for its application in further evolution and genetic improvement of resistance.%以野生大豆YD63和栽培大豆ZD19为研究对象,通过组织化学方法观察茎秆解剖结构的差异,分析和阐述这些解剖结构与功能和环境适应性间的关系,旨在为大豆抗逆性研究提供解剖学依据.结果表明:1.野生大豆表皮毛和腺毛多于栽培大豆,且角质层厚度、表皮厚度和表皮比例均大于栽培大豆,表皮和外皮层细胞的木质化和木栓化程度也高于栽培大豆;2.野生大豆皮层、韧皮部、木薄壁组织和髓的比例均大于栽培大豆,茎秆机械强度降低,可塑性升高,抗逆性增强;3.栽培大豆木质部、木纤维和总纤维比例均大于野生大豆,并且表皮细胞壁、韧皮纤维壁、木纤维壁和导管壁厚度均大于野生大豆.栽培大豆组织木质化的比例大于野生大豆,茎秆的机械强度升高,可以更好地维持直立生长和形态构建;4.栽培大豆微管形成层的细胞层数和厚度均大于野生大豆.栽培大豆木质部的比例大于韧皮部的比例,而野生大豆两者比例基本相同;5.野生大豆韧皮部厚壁组织几乎是连续分布,仅在髓射线处中断,而栽培大豆是不连续的,呈片状分布,野生大豆韧皮部厚壁组织的比例大于栽培大豆;6.野生大豆导管壁强度(t/b)2和小导管比例大于栽培大豆,水分运输的安全性较高,但野生大豆木质部的连通性和水分运输的效率低于栽培大豆.