It is true that chlorophyll synthesis in plants decrease with increasing levels of stresses including salt stress, acid rain, air and soil pollution and drought stress. How do one explain the increases in Chl. a/b ratio under these conditions?
Hello Stephen,
Chlorophyll a is in the energy transduction 'core' of the light harvesting system. Chl b is associated with proteins in the `outer' antenna complexes which also capture light energy. The energy of Chl b is transferred to the core. When there is abundant nutrients and water these stimulate synthesis of the proteins and Chl b in the `outer' antenna complexes, relative to the `core' so increasing the b/a ratio. This is seen in the case of N fertilizer applications: lots of N increase Chl a+b and the b/a ratio which is seen often as a dark blue-green colour of leaves. Hope this helps. Look at Lawlor DW Photosynthesis Longman.
In general, Chlorophyll b is more sensitive to abiotic stress compared to chl a. By increasing the proportion of chlorophyll a relative to chlorophyll b, plants may prioritize the utilization of available light energy for photosynthesis, thus mitigating the impact of stress on photosynthetic activity.
- Badges
- Science topic
- Similar topics
- Agricultural Science
- Agronomy
- Crop Science