Photosynthesis and Water in the Rubber Tree

Photosynthesis in rubber is highly temperature-dependent. It decreases sharply below 20 °C and above 36 °C. The response of photosynthesis to temperature is a key area concerning both global climate change and adaptation of crops to new planting areas. Temperature may directly affect the 

As rubber plantations are currently expanding to new areas under drier climatic conditions than traditional ones (north-eastern Thailand, Mato-Grosso in Brazil, north-western India), the performance of rubber trees under water stress has become a major issue. Two main traits are to be considered performance (the ability to transfer water and grow under water stress) and resistance (the ability to avoid damage and survive under water stress). Performance mainly relies on the conductivity of the hydraulic system from root to leaf, whereas resistance mainly relies on susceptibility to cavitation, leading to embolism, within xylem vessels. Stomatal closure occurs to avoid severe cavitation. Hence, differences in susceptibility to cavitation among rubber clones are likely to induce differences in resistance to severe water stress. 

---