ARS | Publication request: Effects of ambient and elevated carbon dioxide on the responses of leaf gas exchange, multispectral imaging and primary metabolism of water-stress resistant transgenic maize to drought

Submitted to: BARC Poster Day
Publication Type: Abstract Only
Publication Acceptance Date: April 19, 2012
Publication Date: April 19, 2012
Citation: Barnaby, J.Y., Kim, M.S., Cho, B., Reddy, V., Sicher Jr, R.C. 2012. Effects of ambient and elevated carbon dioxide on the responses of leaf gas exchange, multispectral imaging and primary metabolism of water-stress resistant transgenic maize to drought. BARC Poster Day.

Technical Abstract: ¬ Both traditional breeding methods and recombinant DNA techniques have been employed to develop commercial maize germplasm (Zea mays L.) with improved yields under moisture stressed conditions. In the current study, we compared responses to water stress of two experimental, transgenic maize lines [Pioneer P0791HR (R1), P1151HR (R2)] to that of the parental germplasm [33P84 (S)]. Photosynthetic rates, stomatal conductance and leaf water potential were greater in the resistant (R1 and R2) compared to the sensitive (S) line after 17 d of water stress treatment. These findings were confirmed by multispectral wavelength imaging in the red and green regions of the spectrum. Stress avoidance of the transgenes compared to the parental line was even greater when plants were grown at elevated compared to ambient carbon dioxide. Key metabolites, such as hexoses, asparagine, proline and malate, are important indicators of water stress in maize leaves [Sicher and Barnaby, Physiol. Plant. 144:238 (2012)]. Responses of these key metabolites to 17 d of water stress were diminished in leaf samples of R1 and R2 when compared to the S germplasm. Our findings indicated that maize germplasm selections based on improved yield under moisture stress also benefitted the drought responses of maize during vegetative growth. Moreover, we will show that one of the two transgenic maize lines investigated here was extremely resistant to drought under both ambient and elevated carbon dioxide.