扁茎大豆与栽培大豆营养器官解剖结构比较

Anatomical structure comparison of nutritive organ between fasciated stem soybean and cultivated soybean

利用光学显微摄影技术,比较了两个大豆属植物根、茎、叶和叶柄的解剖结构特征.结果表明:扁茎大豆根内皮层维管形成层带明显,次生木质部导管发达、口径大,且皮层内有菌窝出现;茎的横切面表面积较大,茎中维管束的管孔链数和维管束数目较多,中间髓细胞呈狭长柱形,四周髓细胞发达,体积大、排列紧密.导致扁茎大豆不抗倒伏、光合能力下降以及结实率低的因素可能是:茎的表皮细胞呈方形紧密排列,凯氏带中没有淀粉鞘;叶片只有两层栅栏组织和叶片较薄、海绵组织稀疏;叶柄横切面面积较小.中国普通大豆吉育67叶片有三层栅栏组织,并且海绵组织、栅栏组织和叶片的厚度均明显大于扁茎大豆,有利于植物光合作用;吉育67根的栓质化外皮层发达,对植物体起到了有效的保护作用.

The anatomical structures of roots, stems, leaves and petioles of various plant type soybeans were compared by paraffin slice and light microscopy. The results showed that： compared with other types, fasciated stem soybean has some merits contributed to storage and transportation of nutriments and water： including obvious vascular cambium in root endodermis, developed vascular in secondary xylem, big diameter and bacteria nest in cortex; larger stem transection, more siphonopore chain number of vascular bundle and vascular bundle number, long and narrow column type of intermediate myelocyte cells,developed ambient myelocyte ceils, big volume,closely spaced. But the factors that make fasciated soybean prone to lodging,low photosynthetic capacity and low seed setting rate factor may be：stem square epidermal ceils closely arranged,casparian strip without starch sheath ; only two layer palisade tissue in leaf, thinner leaf, sparse sponge tissue- small petiole transection. In addition, new line 94-2-3-1 ,namely offspring of fasciated stem soybean, has parental genetic characteristics, big and developed vascular diameter of secondary xylem, and free cortical cell, with cell gap, be helpful for gas storage and enhancing drought resistance, satisfying oxygen supply. Jiyu 67 had three layers palisade tissue. The spongy tissue, palisade tissue and the leaf were thicker than the fasciated stem soybean. All these structure features were beneficial to photosynthesis. The suberinized exodermis of Jiyu 67 was well developed,and protected the plant effectively.