Studies on Dry Matter Production of Soybean Plant : I. Ontogenic changes in photosynthetic-and respiratory capacity of soybean plant and its parts.

Net photosynthesis and evapotranspiration of field-grown soybean canopies

“…The effect of day may have been due to shaded, older leaves comprising a higher proportion of the canopy compared to younger leaves later in the period. Kumura and Naniwa (1965) have shown NCE to decrease with leaf age. On the other hand, Pendleton (1970a, 1970b) reported older leaves with NCE's as high as younger leaves, if the older leaves had not been subjected to shad ing.…”

“…Ontogenic Kumura and Naniwa (1965) have shown that the photosynthetic rate of a soybean leaf increases as the leaf develops, reaches a peak, and then declines with approaching senescence. The maximum photosynthetic rate of fully-expanded field-grown soybean leaves increases with the rise in po sition of the leaf on the main stem.…”

Net photosynthesis and evapotranspiration of field-grown soybean canopies

“…Maximum photosynthetic rate was at initial flowering, at a lower rate during pod formation and pod filling and then dropped rapidly. The projected light compensation point was 1,000 to 1,500 ft-c. Kumura (1965) showed light-saturation of a canopy of soybeans at about 40 klux for a LAI of 3.…”

“…However, Kumura and Naniwa (1965) reported substantial respiration by the pods, and it would seem likely that the seeds would contribute the major por tion. Therefore, since the pods show positive exchange, their actual rate of photosynthesis may be much larger than indicated by normal exchange measurements.…”

“…The photosynthetic and respiratory contribution of various parts of the soybean canopy were evaluated by Kumura and Naniwa (1965). The green pods made a positive contribution to the canopy exchange, although it was considerably less than that of the leaves.…”