Georgia Journal of Science


The ability by land plants to partially close their stomata in response to high vapor pressure deficit, called the limited transpiration trait, is a rare phenomenon in crop plants. The characteristic has been demonstrated in several crop species including Sorghum bicolor. The molecular and physiological basis for the limited transpiration trait is however, not clear. This study was conducted to determine the physiological attributes associated with the limited transpiration trait in three sorghum genotypes SC1345, SC35 and Macia. Plants of these three sorghum genotypes were established in a greenhouse and subjected to water deficit stress. Chlorophyll fluorescence and relative water content were assessed after exposing plants to water deficit. The two genotypes with an ability to express the limited transpiration trait (SC35 and Macia) were able to maintain a higher water status while genotype SC1345, which does not have a transpiration breakpoint, had a significantly lower water status compared to controls. In addition, an interesting pattern for chlorophyll fluorescence was observed in the genotypes expressing the limited transpiration trait. The results confirm that the limited transpiration trait helps to maintain plant water status, and also suggest that chlorophyll fluorescence could be used to screen for the trait.


We would like to acknowledge the following funding source: Georgia Southern University Undergraduate Research Funding. We thank Dr Sarah Gremillion for reviewing the manuscript.