Water availability effect on gas exchanges and on phenology of 'Cabula' orange
2017
Oliveira, C. R. M de | Mello-Farias, P. C. | Oliveira, D. S. C de | Chaves, A. L. S. | Herter, F. G.
As a continental country, Brazil has very diverse climate and growing conditions, which can be adverse to citrus growing in certain regions hindering regular fruit production. To know more about the effects of water stress on gas exchanges and phenological characteristics of orange tree cultivar 'Cabula', an experiment was conducted in a greenhouse where these parameters were analyzed by managing applied water. Three treatments were applied, and irrigation was based on suppling water to maintain 100, 50 and 25% of the soil water storage capacity. All technical features were assessed within 210 days, and a completely randomized design was used. The results were analyzed by means of variance analysis and compared by Tukey test at 5% probability. Starting at 100 days of drought, it was found that many of the gas exchange parameters were affected, observing reductions in photosynthesis (A) and transpiration (E), which followed the decrease in stomatal conductance (gs). Reductions were also observed in tree height and stem diameter of plants under stress. The production of flowers and fruits was also significantly (P<0.05) affected by the reduction in water availability. In general, it was observed that photosynthetic rate, growth parameters and producing flowers and fruits were higher in treatment “without stress”, suggesting that these require irrigation under farming field conditions above 50% of field capacity to keep production at satisfactory levels.
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