Structural Studies Of American Flat-stem Soybean Compared With Other Types Soybeans

The anatomical structures of four different kinds of soybean's roots, stems, blades,petioles, flowers and pods were studied by using paraffin slice and light microscopy. Thepurpose of this experiment was to explore the relationship of hybrid parents and theiroffspring's structural evolution from the aspect of structural botany and to compare with highquality soybeans. The result showed that:Bicollateral bundle was first discovered in the stems and petioles of 7514-2 and 94-2-3-1and there was no report concerning about this kind bundle of soybean family. Bicollateralbundle was beneficial to the transport of nutrition. Large amounts of phellem fiber in theleaves strengthened the ability of resistance to lodging and bending, and proved the hereditaryrelationship of 94-2-3-1and its parent 7514-2.The cortex of American flat-stem soybean contained bacteria nests and it stimulated thecortex cells to quickly reproduce lots of new cells. Thus the cortex swelled and rose to formthe root nodule. The root nodule bacteria fixed the nitrogen. It turned the free nitrogen in theatmosphere into ammonia. This experiment firmly proved the formation of root nodule.The size of American flat-stem soybean's cross-section was smaller than the other threesoybeans. It proved that this structure feature was in proportion to the seed-bearing rate ofAmerican flat-stem soybean.Jiyu 67 had three layers palisade tissue. The spongy tissue, palisade tissue and the leafwere thicker than the other three soybeans. All these structure features were beneficial tophotosynthesis and could enhance the leaf's photosynthesis ability. They providedmorphological anatomy proofs for choosing high photosynthesis and high yield seed andstoring high quality seed resources. At the same time, it showed that two layers palisade tissueof American flat-stem, its thin leaf and sparse spongy tissue were the main factors thatresulted in the reduction of photosynthesis and high dropping rate of flowers and pods.The caliber of the secondary xylem of 94-2-3-1 was well developed and it helped totransport the substance and water within the plant and it was hereditary. The free state of thecortex and gaps between cells were good to storing the air and enhanced plant's dry-resistanceability. These made the high production of soybean possible. This structure of cortex cellsfunctioned as ventilating tissue and helped to provide oxygen for plants on condition ofhardened soil or dry environment.The suberinized exodermis of Jiyu 67 and 7514-2 were well developed. The brownstriped structure formed by the broken cells made the phellem water impervious and resist topressure, organic solvent and various chemical reagents, and protected the plant effectively.