Return to the faculty index...
BIOL
1201
Plant Physiology 3060
High salinity reduces growth in plants and species differ in their abilities to adapt to this stress. Many agricultural crops are particularly sensitive to high salinity and as a result there is a negative effect on food production. I have long been interested in understanding the mechanisms that permit certain plants to adapt to high salinity stress with the hope this information could be used to improve the tolerance of sensitive plants to saline conditions. Presently we are studying adaptations of plant cells to significant, step increases in salinity. This work involves heterotrophic and photomixotrophic cell-suspension cultures derived from Alternanthera philoxeroides (alligator weed). In nature this species grows at relatively low salinity but unlike many co-occurring species, alligator weed can tolerate substantial increases in salinity such as occurs after hurricane over-wash. In past studies of step increases in salinity, we have examined the physiology of osmotic adjustment in heterotrophic cultures and the development of photosynthesis in photomixotrophic cultures. Present studies are examining salinity tolerance at the molecular level.
A second area of interest in my laboratory is plant survival in flooded soils. Plants adapted to flooded conditions produce large gas spaces known as aerenchyma. These gas spaces permit diffusion of oxygen from stems to roots, which must carry out metabolism in an oxygen poor environment. Our studies have focused on the growth and development of gas spaces in roots of different wetland plants. Our long-term goal in this area is to determine how gas space development is regulated in wetland plants.
Mudalige RG, Longstreth DJ. (2006) Effects of salinity on photosynthetic characteristics in photomixotrophic cell-suspension cultures from Alternanthera philoxeroides (Mart.) Griseb. Plant Cell, Tissue and Organ Culture 84: 301-308
Longstreth DJ, Burow GB and Yu G (2004) Solutes involved in osmotic adjustment to increasing salinity in suspension cells of Alternanthera philoxeroides (Mart.) Griseb. Plant Cell, Tissue and Organ Culture 78: 225-230
Longstreth DJ, Borkhsenious ON. 2000. Root cell ultrastructure in developing aerenchyma tissue of three wetland species. Annals of Botany 86:641-646
Schussler, EE, Longstreth DJ. 2000. Changes in cell structure during the formation of root aerenchyma in Sagittaria lancifolia (Alismataceae). American Journal of Botany 87:12-19
Schussler, EE, Longstreth DJ. 1996. Aerenchyma develops by cell lysis in roots and cell separation in leaf petioles in Sagittaria lancifolia (Alismataceae). American Journal of Botany 83: 1266-73