Research Areas
Sugar uptake, transport and accumulation by heterotrophic plant cells
Studies are conducted primarily at the cellular and organellar level using either protoplasts, tissue discs, cytoplasts and/or isolated membrane vesicles. Research focuses on the mechanisms of sucrose and hexose uptake into the cell, their means of intracellular transport, their accumulation into the vacuole and their metabolic utilization (vacuolar export). We are presently defining the coordinated action of the recently described fluid-phase endocytic system with membrane-bound carriers during sugar uptake at different apoplastic concentrations. We depend heavily on the use of fluorescent markers, inhibitors of endocytosis and membrane-bound carriers, cellular fractionation, fluorescent and high definition confocal microscopy, and immunohistochemistry.
Citrate synthesis and accumulation in Citrus fruits
Citric acid is amongst the most important components of Citrus juices. Despite its reduced concentration compared to sugars, small variations translate into large palatable differences. Our present studies focus on the investigation of all parameters involved in citrate synthesis, accumulation into the vacuole and utilization between varieties showing a wide range of citric acid concentration during development and at maturity. We look at enzymatic involvement, tonoplast permeability, citrate transporters and electrochemical characteristics of the tonoplast/vacuole.
Effect of water deficit on Citrus fruit quality
Already established as a means to improve fruit quality and water usage, application of a "mild water stress" is being investigated as a means to improve the quality of Florida Citrus. Several years of field work have established the consistent increase in Brix on mildly stressed fruits with no apparent reduction in yield. With one more year still pending, we intend to follow with post-harvest work aimed at determining the effect of mild water stress on the postharvest shelf life of Citrus fruits.
Alternative methods of fruit labeling
Prompted by Government regulations, fruits and vegetables will be required labels containing pertinent information. The existing methods of fruit labeling have the disadvantages of not being permanent, can be modified in addition to the numerous technical problems at the packinghouse level. Based on a new laser imprinting technology, we are conducting studies on the anatomy of the laser imprint characters on the epidermis of a variety of fruits and vegetables including citrus, potato, tomato, avocado and others.
