Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 7/23/2003
Publication Date: 7/23/2003
Citation: Duraes, F., Shanahan, J.F., Russell, W.K., Oneill, P.M., Magalhaes, P.C., Oliveira, A.C. 2003. Chlorophyll fluorescence analysis of maize under drought and nitrogen stress conditions. Agronomy Abstracts. #457971. CDROM
Technical Abstract: The objective of this study was to determine the dry matter, grain yield and photosynthetic responses of contrasting maize genotypes to water (W) and nitrogen (N) stresses. The two contrasting inbred lines of B73 (water stress susceptible) and N7A (stress tolerant), and their F1 hybrid were grown in the greenhouse. Plants were grown under two water levels (well-watered and water-stressed) and three N levels (25, 50, 75, ppm N nutrient solution). Leaf chlorophyll content was measured for several growth stages using a SPAD chlorophyll meter. On these same dates leaf CO2 assimilation (A) and several chlorophyll fluorescence (CF) parameters, including maximum fluorescence (Fm), were determined for both dark adapted and fully illuminated leaves using the LI-COR model 6400 photosynthesis system. Total dry mater (DM) and final grain yield (GY) were also measured at maturity. Maximum fluorescence (Fm) was found to be a more powerful indicator of N or W stress under full illumination than under dark conditions. Treatment variation in A was closely associated with variation in final DM and GY, particularly during flowering, and variation in A was in turn highly correlated with variation in electron transport rate. Measurement of leaf chlorophyll content, A, CF, and final GY revealed that N7A and its hybrid with B73 maintained a distinct advantage over B73 under W and N stress conditions.