Studies on the photosynthetic characteristics of Oenanthe stolonifera DC.
1988
Kim, S.Y. | Lee, B.Y. (Seoul National Univ., Suwon (Korea R.). Coll. of Agriculture)
This study carried out to elucidae the effect of environmental factors such as light intensity, temperature, soil water content, and nutrients on photosynthesis of Oenanthe stolonifera. Plants grown at full sunlight showed light compensation point of 2.3 klux and light saturation point of 60 klux. These parameters showed a tendency to decrease with decrease in light intensity during plant growth. Dark respiration rate increased with temperature increase, and maximum photosynthetic rate appeared at 25 deg C under high light intensity above 30 klux. Decrease in net photosynthetic rate at high temperatures was associated with a rapid increase in respiration. Maximum photosynthetic rate was observed at high temperatures with high light intensities, and at low temperatures with low light intensities. Optimum temperature for net photosynthesis tended to decrease with decrease in light intensity during plant growth. As the soil water content decreased, the net photosynthetic rate decreased. Especially, the rapid decrease of photosynthetic rate appeared at the initial wilting period. N, K, and Mg were very important factors. The maximum photosynthetic rate was observed at full strength under 20 deg C and 50 klux, whereas it also was obseved at 1/2 or 1/4 of full strength under 10 deg C 9 klux. Chlorophyll contents were increased with decrease in light intensity and the leaves grown at 25% of full sunlight had chlorophyll twice as much as those at full sunlight. No difference in chlorophyll a/b ratio was found among the control and shading treatments with the values being around 3.0. Electron microscope observation of chloroplast sections indicated that the number of thylakoids per granum increased rapidly with decrease in light intensity during plant growth
显示更多 [+] 显示较少 [-]