Do plants use nitrogen in photosynthesis
In what ways do plants use nitrogen? - Quora
In C3 crop plants about 60–80% of leaf nitrogen (N) is invested in the photosynthetic apparatus, and N nutrition plays a crucial role in determining photosynthetic capacity. The proportion of leaf N invested in photosynthetic components is fairly constant. By contrast, both N per unit leaf area and the allocation of N between the component photosynthetic processes depend on environmental factors such as N availability, irradiance and CO2 concentration. Light-harvesting and electron transport components often show a co-ordinated and equivalent response to N nutrition. In contrast, most studies have shown disproportionately large changes in ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) in response to N supply, demonstrating the importance of this protein in leaf N economy. At low light, for a given N availability, more protein is allocated towards light harvesting components in order to maximize light capture and, expressed per unit Chl, electron transport and carboxylation capacities are relatively small. High irradiance tends to alter the partitioning of N away from thylakoid protein to soluble proteins, particularly Rubisco. Growth at elevated CO2 often leads to decreases in the amounts of Rubisco and other photosynthetic components on a leaf area basis. This is explicable in terms of greater N sinks elsewhere in the plant as a result of increased carbohydrate availability and acclimatory changes. Models predict that in order to arrive at optimal N use efficiency (NUE) at likely future ambient CO2 concentrations, leaves will need to achieve a redistribution of N so that the ratio between the capacities for regeneration of ribulose-1,5-bisphosphate and carboxylation increases by 30–40%. Human intervention to improve the NUE of crops would have economic and environmental benefits, reducing pollution of water supply by nitrates. The NUE of photosynthesis could be increased either through manipulation of Rubisco amounts or properties, or by decreasing photorespiration. While decreasing Rubisco content could enhance NUE by only about 5%, eliminating photorespiration could produce a change of more than 50%.
18/09/2016 · In what ways do plants use nitrogen
The top leaves of crops absorb far more light than they can use, starving lower leaves of light. Scientists designed plants with light green leaves with hopes of allowing more light to penetrate the crop canopy and increase overall light use efficiency and yield. This strategy was tested in a recent modeling study that found leaves with reduced chlorophyll content do not actually improve canopy-level photosynthesis, but instead, conserve a significant amount of nitrogen that the plant might be able to reinvest to improve light use efficiency and increase yield.