Photosynthetic responses of tropical fruit plants to different temperatures and CO2 concentrations

Abstract

Climate change leads to a deterioration of environmental conditions that negatively affect yield, growth rates, photosynthesis, transpiration rates and moisture availability. Therefore, this study aims to assess the effect of climate change such as elevated temperature and CO2 concentration on the photosynthetic performance of tropical fruit plants. The leaves of five tropical fruit plants, namely Durian (Durio zibethinus), Mangsoteen (Garcinia mangostana), Kristal (Pometia pinnata), Dabai (Canarium odontophyllum), Engkalak (Litsea garciae) were sampled at Kuching, Kota Samarahan and Siburan, Sarawak. Leaves were collected from each mature trees and the effects of photosynthetic responses at different temperatures (25 and 30 °C), as well as CO2 concentrations (400 and 700 ppm) were measured using a portable photosynthesis system (LI-6400 XT). At 1800 μmol m−2 s−1, highest net photosynthetic assimilation rate (A) showed by D. zibethinus (46.12 μmol CO₂ m−2 s−1), G. mangostana (42.38 μmol CO₂ m−2 s−1) L. garciae (41.23 μmol CO₂ m−2 s−1), and P. pinnata (45.15 μmol CO₂ m−2 s−1). Meanwhile, for instantaneous gas-exchange performance, C. odontophyllum, G. mangostana and P. pinnata have a greater advantage to an increase in temperature and CO₂ concentration. In conclusion, these results suggest that G. mangostana and P. pinnata are more suitable for cultivation as they are more heat tolerant and adapt well to climate change. These results provide information which could be beneficial for farmers to prepare with the best management strategies, especially for tropical fruit plants, which are an important source for the agricultural sector in tropical region.