ISHS Acta Horticulturae 740: I International Symposium on Papaya
LEAF PHOTOSYNTHETIC POTENTIAL OF FEMALE AND HERMAPHRODITE PAPAYA (CARICA PAPAYA CV. KHAEG NUAN) |
| Authors: | C. Chutteang, S. Yingjajaval, S. Wasee |
| Keywords: | light response, quantum yield, electron transport rate, CO2 compensation, carboxylation efficiency, chlorophyll content |
| Abstract:
Female papaya plant (F) shows putatively more vigorous growth than hermaphrodite (H). If physiological characteristics can substantiate such observation, they may be employed to identify plant sex at early stage. Leaf gas exchange and chlorophyll fluorescence were measured with LI6400 fluorometer at 28C, 70-75%RH and VPDair <1.5 kPa. Photosynthetic potential develops very fast during leaf age of 18-24 days, and remains steady for the next 10 days before it gradually declines. The carboxylation efficiency at 145 mmolCO2 m-2 s-1 of F leaf is significantly higher than the 106 of H. Together with higher electron transfer rate and stomatal conductance, the maximum net photosynthesis rate (Pm) of F leaf at 27.9 µmolCO2 m-2 s-1 is higher than 22.5 of H. Female plant also sustains the higher levels of photosynthesis process over a longer period of leaf age. Under condition of sufficient radiation and high stomatal conductance, leaf CO2 exchange rate of female is higher than hermaphrodite’s. | |
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