Greg McCollum, Ph.D.
Research Plant Physiologist

U. S. Horticultural Research Laboratory
2001 South Rock Road
Fort Pierce, FL 34945
Telephone: (772) 462-5836
Fax: (772) 462-5986
Email: GMccollum@ushrl.ars.usda.gov

Current Research Projects

Specific research objectives are to determine the physiological and biochemical changes induced in response to abiotic and biotic stresses. Recent accomplishments include determining: 1) mild heat treatments can enhance the tolerance of cucumbers, mangoes and tomatoes to chilling stress; 2) vapor heat treatments can enhance tolerance of grapefruit to irradiation treatment; 3) effects of ethylene, a stress related hormone, on gene expression in grapefruit; 4) biochemical characterization and cloning of several genes from citrus that are believed to be important components of the plant's natural defense mechanism against fungal and insect pests.

Selected Publications

McDonald, R.E., W.R. Miller, and T.G. McCollum. 2000 Canopy position and heat treatments influence gamma-irradiation-induced changes in phenylpropanoid metabolism in grapefruit. J. Amer. Soc. Hort. Sci. 125:364-369.

Mullins, E.D., T.G. McCollum, and R.E. McDonald. 2000. Consequences on ethylene metabolism of inactivation the ethylene receptor sites in diseased non-climacteric fruit. Postharvest Biol. Tech. 19:155-165.

Mullins, E.D., T.G. McCollum, and R.E. McDonald. 1999. Ethylene: A regulator of stress-induced ACC synthase in nonclimacteric fruit. Physiol. Plant. 107:1-7.

McDonald, R.E., T.G. McCollum, and E.A. Baldwin. 1999. Temperature of water heat treatments influences tomato fruit quality following low-temperature storage. Postharvest Biol. Tech. 16: 147-155.

McCollum, T.G., H. Doostdar, R. Neidz, R.T. Mayer, and R. E. McDonald. 1997. Biochemical, molecular genetic, and immunological characterization of a b-1,3-endoglucanase from 'Valencia' Orange Callus. J. Plant Physiol. 155 16-23.

Fajardo, J.E., T.G. McCollum, R.E. McDonald, and R.T. Mayer. 1998. Differential induction of proteins in orange flavedo by biologically based elicitors and challenged by Penicillium digitatum Sacc. Biol. Cont. 13:143-151.

McDonald, R.E., T.G. McCollum, and E.A. Baldwin. 1998. Heat treatment of mature-green tomatoes: differential effects of ethylene and partial ripening. J. Amer. Soc. Hort. Sci. 123:457-462.

Aquino, S.D., A. Piga, M. Agabbio, and T.G. McCollum. 1998. Film wrapping delays ageing of 'Minneola' tangelos under shelf-life conditions. Postharvest Biol. Tech. 14: 107-116.

Schirra, M., M. Agabbio, S.D. A'Quino, and T.G. McCollum. 1997. Postharvest heat conditioning effects on early ripening 'Gialla' cactus pear fruit. HortScience 32:702-704.

McDonald, R.E., P.D. Greany, P.E. Shaw, and T.G. McCollum. 1997. Preharvest application of gibberellic acid delay senesence of Florida grapefruit. J. Hort. Sci. 72:461-468.

Last modified: 8/7/2002.   Send comments or questions to rniedz@ushrl.ars.usda.gov