Plasticity in photosynthesis of bat laurel (Prunus polystachya) in tropical rainforest of Singapore

Abstract

Rainforests are one of the most important habitats that contain an extraordinary amount of our global biodiversity. However, due to human disturbance we have lost a great portion of primary forests. Thankfully due to the rising awareness of the importance of rainforests, secondary rainforests are regenerating, providing a new environmental condition for different species as it is a much higher light environment than primary forests. Plants are then forced to adjust their traits in order to adapt to the new lighting conditions. This study investigates the plasticity in photosynthesis characteristics of Prunus polystachya, we predicted that understory leaves will have a higher chlorophyll content, higher overall carbon fixed during photosynthesis and higher photosynthetic induction. These predictions were made since understory leaves receive very little light, they rely heavily on sun flecks for photosynthesis, therefore they should have photosynthetic traits that will maximise all the sunlight they receive. We found that understory leaves do indeed have a higher chlorophyll density and carbon fix amount, but the hypothesis of understory leaves have a higher photosynthetic induction was not supported. The findings of this study could assist in determining how different species excel under different conditions, leading to the prediction of floristic composition of primary and secondary forests. In the field of conservation of forests, it will assist in predicting the species turnover rate between primary and secondary rainforests by having knowledge of which species will need protection and which we should focus on the regeneration of secondary forests.