Effect of cold acclimation on growth and water uptake of ‘hamlin’ orange
Severe freezes occurred in central Florida during 1980s, killing many sweet orange (Citrus sinensis L.) trees. Citrus trees, particularly young trees, are greatly affected by seasonal variation of climatic factors especially low temperature. Experiments were conducted at the University of Florida, Southwest Florida Research and Education Center, to evaluate the growth, evapotranspiration rate and water use of ‘Hamlin’ orange trees in response to differential cold acclimation using growth chambers. Results showed that the overall growth of the cold acclimated plants were 65% lower than that of the warmer controls. With acclimation to low temperatures, evapotranspiration rate was also found to decrease by 68.5%. It can be concluded from these studies that cold temperatures signifi cantly affect the physiology of ‘Hamlin’ orange trees reducing water use and thus reducing the devastating effects of dehydration associated with freezing temperatures. Based on plant water use during cold temperatures, need-based citrus irrigation schedules can be effectively modeled. Optimal irrigation scheduling will optimize water use and minimize leaching of essential nutrients.