© 2004 Heron Publishing—Victoria, Canada
Flooding, root temperature, physiology and growth of two Annona species
Maritza Ojeda (1, 2, 3), Bruce Schaffer (2, 4) and Frederick S. Davies (1)
1. Horticultural Sciences Department, University of Florida, IFAS, P.O. Box 110690, Gainesville, FL 32611, USA / 2. Tropical Research and Education Center, IFAS, University of Florida, 18905 SW 280th Street, Homestead, FL 33031, USA / 3. Universidad Centroccidental Lisandro Alvarado, Apartado 400, Barquisimeto, Lara, Venezuela / 4. Corresponding author (bas@ifas.ufl.edu) / Received October 1, 2003; accepted February 8, 2004; published online July 1, 2004
Summary
The effects of root zone temperature (RZT) and flooding on physiology and growth of Annona glabra L. (pond apple) and A. muricata L. (soursop) were investigated. Trees planted in containers were exposed to RZTs of 5, 10, 20, 25 or 35 °C in controlled
root temperature chambers. Trees at each RZT were either non-flooded (control) or continuously flooded. There were four replications
over time for each treatment combination. Pond apple was more flood-tolerant than soursop. A combination of flooding and RZTs
of 5 and 10 °C resulted in tree mortality of both species by Week 4. Only trees that appeared to develop morphological adaptations
survived continuous flooding. In both species, net CO2 assimilation (A) decreased to nearly zero within 1 week following exposure to RZTs of 5 or 10 °C and became consistently negative over the
remaining experimental period. Flooding reduced leaf chlorohyll index (measured with a SPAD meter), A and plant growth, and increased root electrolyte leakage from soursop. Optimum growth occurred at RZTs of 25 to 35 °C for
non-flooded pond apple trees and at 20 to 25 °C for flooded trees. Soursop exhibited maximum growth at RZTs of 35 °C under
non-flooded conditions and at 25 °C under flooded conditions.
Keywords:
Annona muricata, Annona glabra, chlorophyll, net CO2 assimilation, pond apple, root electrolyte leakage, soil redox potential, soursop.
