Varietal variations in leaf anatomy as related to photosynthesis in soybean (Glycine max (L.) Merr.).

Abstract

The relationships of the leaf anatomies to the photosynthetic rates in soybean were examined using 14 cultivars. The net photosynthetic rate per unit leaf area was correlated significantly and negatively with the leaf area and C02 diffusion resistances in gaseous phase. The net photosynthetic rate per unit leaf area was correlated significantly and positively with the average mesophyll cell surface area, but not significantly with the mesophyll cell surface area per unit leaf area. Of the cultivars, Kizaya, Bonminori, A.K.(Harrow), Hill, Perry, Harosoy and Clark showed the photosyntheic rate per unit leaf area over 30mg C02dm-2h-1 (high photosynthetic cultivars) while Kimusume-Ibara 1, Shirobana-Sai 1. Hatogoroshi, Tachisuzunari. Akazaya and Norin 2 below 30mgC02 dm-2h-1 (low photosynthetic culti¥'ars). The high photosynthetic cultivars showed larger average mesophyll cell surface areas than those of the low photosynthetic culti.vars. The high photosynthetic cultivars were classified into two groups which differeci in three characters, mesophyll cell surface area per unit leaf area, chlorophyll and nitrogen contents and photosynthetic rate per unit mesophyll cell surface area. Of the high photosynthetic cultivars. Kizaya, Bonminori and A.H. (Harrow) showed lower ratios of chlorophyll and nitrogen contents to mesophyll cell surface area and lower photosynthetic rates per unit mesophyll cell surface area(Kizaya-Bonminori type) than the other high photosynthetic cultivars, Hill, Perry, Harosoy and Clark (Perry-Harosoy type). The Kizaya-Bonminori type cultivars showed mesophyll cell number per unit leaf area higher than the Perry-Harosoy type cultivars.