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PLANT ECOPHYSIOLOGY LAB
ABOUT THE LAB
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DESCRIPTION
The Plant Ecophysiology group studies plant responses to abiotic factors (e.g., flooding, drought, wind, irradiance and atmospheric CO2) and biotic factors (insects and diseases) with emphasis on subtropical and tropical horticultural crops. Plant responses studied include leaf gas exchange variables, plant water use, xylem sap flow, plant growth and yield. Plant responses to biotic factors are investigated in cooperation with entomologists and plant pathologists.
The limestone soil, high water table, and subtropical climate in south Florida provide an ideal environment for development of numerous plant stresses. We focus on understanding physiological bases for plant responses to these stresses in order to develop methods of avoiding or mitigating the negative impacts of these stresses on plants.
Another focus of the program is the development of best management practices to increase the compatibility of agriculture with the adjacent natural and urban ecosystems.
RESEARCH
Our research focuses on plant ecophysiology with the primary aim of assessing the effects of environmental stresses on whole-plant physiology of subtropical and tropical horticultural crops. We also collaborate with colleagues in other disciplines to determine the interactions of biotic and abiotic stresses on crop physiology.
Leaf gas exchange, chlorophyll fluorescence, and plant water relations are determined as physiological indicators of plant stress and to identify mechanism underlying the causes of these stresses.
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RESEARCH PROJECTS
Current Research Projects
Physiological, Biochemical, Growth, and Genomic Responses of Papaya (Carica papaya L.) to Soil Salinity
(Ana I. Vargas, Ph.D. Student)
In many tropical fruit production regions, including southern Florida, rising sea level associated with global climate change is increasing saltwater intrusion inland, leading to higher salinity in soil and/or irrigation water. Therefore, understanding the salinity thresholds that negatively affect tropical fruit crops, including papaya, is critical for developing strategies to mitigate crop salinity stress.
Ana is evaluating physiological (i.e., leaf gas exchange, leaf chlorophyll content, chlorophyll fluorescence), nutrient content, and growth of papaya (Carica papaya L.) in response to different salt concentrations in the irrigation water. She is also examining the use of brassinosteroids to mitigate salinity stress in commercial papaya cultivars. Additionally, in collaboration with Dr. Jugpreet Singh’s program, Ana is using a high-resolution physiological phenotyping platform to assess differences in salinity tolerance between domestic and wild type papaya accessions and assessing gene expression patterns related to salt stress in these accessions.
Sustaining Avocado Production in the Face of the Lethal Laurel Wilt Disease (Dr. Daniel Palberg- Postdoc)
Laurel wilt (LW), caused by the fungus Harringtonia lauricola, is a devastating vascular disease that can infect most members of the laurel family. So far in the United States, it has only infected avocado trees in Florida, where it has killed more than 290,000 avocado trees.
The effects of canopy removal and regrowth on within-tree movement of the H. lauricola as it relates to transpiration and xylem sap flow is being determined using a green fluorescent protein (GFP)-labeled strain of the fungus that was engineered in Dr. Jeff Rollins lab at the University of Florida. This should provide information on movement of the pathogen as it relates to hydraulics and anatomy of the vascular system. Also, there appears to be a difference in laurel wilt susceptibility among the three avocado races (West Indian, Mexican. and Guatemalan) due to differences and xylem anatomy and hydraulic conductivity. Using the GFP-labelled strain of the fungus, within-tree movement of the pathogen is being compared among clonally propagated plants of the three races and in related to differences in xylem anatomy and physiology.
Collection, Evaluation, and Domestication Potential of Underutilized Tropical Fruit Species with Promise for South Florida. (Dr. Federico Sanchez-Affiliate Research)
Federico's work focuses on the collection, evaluation, and domestication potential of underutilized tropical fruit species with promise for South Florida, with particular emphasis on ecological and physiological responses to abiotic stress. Current activities include research on plant stress tolerance, taxonomic studies within the genus Garcinia, and the preparation of extension publications in English and Spanish on tropical fruit crops suitable for commercial and specialty production in Florida.
PEOPLE
Many of our lab members are international, particularly from countries where subtropical and tropical horticultural crops are grown. Graduate students take classes on the main campus in Gainesville and conduct their research at the Tropical Research and Education Center (TREC). Most of them finish their coursework in 2-3 semesters and then move to TREC to concentrate on their research and stay in graduate student housing.
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CURRENT LAB MEMBERS
Current Lab Members
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Bruce Schaffer - Professor
- Postdoc Biology, University of Heidelberg, Germany, 1985
- Ph.D. Horticulture (Plant Physiology), Virginia Tech University, 1985
- M.S. Forest Biology, Colorado State University, 1981
- B.Sc. Entomology (Zoology, 2nd Major), Colorado State University, 1978
Ana I. Vargas - Biological Scientist III & Ph.D. Student- M.S. Engineering Management, Florida International University, Miami, FL, 2012
- B.Sc. Biology, Florida International University, Miami, FL, 2011
- B.Sc. Agronomy, University of Pinar del Rio, Cuba, 1998
Daniel Palberg– Postdoc- Ph.D. Environmental & Life Sciences, Trent University, Ontario, Canada, 2025
- Hons. B.Sc. Biochemistry & Molecular Biology, Trent University, Ontario, Canada, 2019
Federico W. Sanchez – Courtesy Assistant Professor- Ph.D. Horticultural Sciences, University of Florida, 2023
- M.S. Horticultural Sciences, University of Florida, 2021
- M.S. Applied Physiology and Kinesiology, University of Florida, 2024
- M.B.A. Harvard Business School, 1995
- B.Sc. Business Administration, UCAB, Venezuela, 1992
PUBLICATIONS
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Publication links
Google Scholar: Bruce Schaffer - Google Scholar
ResearchGate: https://www.researchgate.net/profile/Bruce_Schaffer