Abstract: Optical microscopic and scanning electron microscopic studied on the comparative anatomy offour type stem woods of soybean (Glycine L. ) show that all of them are the diffuse-poruswoods. There are a lot of solitary pores and seldom multiple pores in the secondary xylem ofwild soybean (G. soja ). Semi-wild soybean has multiple pores and seldom multi-celled porechains. There are many multiple proes and pore-chains in the secondary xylem of semi-culturedsoybean. Cultured soybean (G. max) has more multiple pores and pore-chains than otherspecies of soybean. G. soja'swood rays consist of unseriate ray and seldom multiseriate ray.They are more multiseriate rays in scmi-wild and scmi-cultured soybcans. The largest numberof multiseriate rays is in G. max. The distribution of tyloses in the vessels of secondary xylemis different among the four species of soybean. The structural evolutionary approach is G. soja→semi-wild soybean→semi-cultured soybean→G. max, indicating that G. soja is primitiveand G.,max. is most evolutionary.

Key words: Glycine L, Secondary xylem, Vessel, Structural study, winter wheat, light-response curves, tillage practices, grain yield, diurnal variation of photosynthesis