Abstract
Light intensity strongly regulates plant biomass production through the utilization of light energy for photosynthesis. To examine the characteristics of biomass productivity acclimated to light intensity in napiergrass, which is well known as being the plant with the highest biomass productivity among herbaceous plants, the responses of total dry matter weight (TDW), and leaf area (LA) to changes in light intensity were compared between napiergrass and maize plants. TDW in both plants decreased under the conditions of low light intensity but recovered at the same level as those in the control plants under the condition of full sunlight exposure after that. Dramatical changes in TDW to light intensity were observed in napiergrass plant. Leaf areas (LA) in both plants remained high over the examination period, and leaf area ratio (LAR) in the napiergrass plant also remained higher during shade treatment. By shading, the distribution ratio of dry matter to the leaves dramatically increased while it was decreased in the roots of the napiergrass plant. Higher allocation of dry matter to the leaves was associated with maintenance of high LA in the napiergrass plant during shade treatment. In contrast, the distribution ratio of dry matter to the roots increased and the difference in the composition of dry matter distribution between the control and shaded plants was not clearly observed in napiergrass plant at 12 days after shading. Substantial change in the ratio of dry matter distribution and maintenance of high LA would be associated with high acclimation to light intensity in the napiergrass plant.
