Effect of air temperatures on diurnal variation of water potential, conductance and CO2 assimilation of mango (Mangifera indica L.) leaves.
Pongsomboon W., Whiley A. W., Stephenson R. A., Subhadrabandhu S.
Author Affiliation: Maroochy Horticultural Research Station, PO Box 5083, SCMC, Nambour, Qld 4560, Australia.
: 472-481
Abstract : Potted mango cv. Nam Dok Mai trees on polyembryonic Kensington rootstock were maintained at an air temperatures of 15/10 or 30/20°C (day/night) and 80% RH. The soil temperature was maintained at 25°. The greatest decrease in leaf water potential, from -1.0 to -1.5 MPa, occurred between 06.00 and 08.00 h for both temperature regimes and recovery occurred between 12.00 and 16.00 h. With the 15/10° regime, stomatal conductance (gs) declined from 1.2 cm/s at 06.00 h to 0.6 cm/s between 12.00 and 16.00 h but recovered to the dawn rates by 18.00 h. At 30/20°, gs was lowest at 06.00 h (0.5 cm/s) rising to 2.4 cm/s at 14.00 h and then declining to 1.1 cm/s at 18.00 h. Assimilation of CO2 increased between 08.00 and 10.00 h for both temperature regimes and declined at 16.00 h, coinciding with a decrease in the photosynthetic photon flux density.