Photosynthetic characteristics of red and green leaves in growing seedlings of Jatropha curcas

The use of Jatropha (Jatropha curcas L.) as a source of biofuel is documented. The physiological characteristics and growth studies of Jatropha have received less attention. In the present study, we measured leaf gas exchange with an infrared gas analyzer for red (immature) and green (mature) leaves of Jatropha curcas in response to various environmental conditions including photosynthetic photon flux density (PPFD), vapor pressure difference, and temperature. The seedlings were grown in pots for 45 days in a natural environment. Jatropha is a C3 plant based on its leaf–gas exchange characteristics. The optimal light-saturated photosynthetic CO2 assimilation, leaf conductance, and transpiration occurred in the range of 500–1000 μmol m^–2 s^–1 PPFD, depending upon the leaf positions and leaf types during growth. The net rates of photosynthesis, stomatal conductance, transpiration, and water-use efficiency were significantly affected by the leaf position and epigenetic variables, i.e. temperature, vapor pressure difference, and irradiance.