Author
SNIDER, JOHN - University Of Georgia | |
CHASTAIN, DARYL - University Of Georgia | |
MEEKS, CALVIN - University Of Georgia | |
COLLINS, GUY - North Carolina State University | |
Sorensen, Ronald - Ron | |
PERRY, CALVIN - University Of Georgia |
Submitted to: Journal of Plant Physiology
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 6/11/2015 Publication Date: 6/15/2015 Citation: Snider, J.L., Chastain, D.R., Meeks, C.D., Collins, G.D., Sorensen, R.B., Perry, C.D. 2015. Predawn respiration rates during flowering are highly predictive of yield response in Gossypium hirsutum when yield variability is water-induced. Journal of Plant Physiology. 183:114-120. Interpretive Summary: Previous research has shown that respiratory carbon evolution by leaves under abiotic stress is suspected as one of the major limitation to crop productivity. However, respiration rates of fully expanded leaves are positively associated with plant growth rates. Given the substantial sensitivity of plant growth to drought, it was hypothesized that predawn respiration rates (RPD) would be 1) more sensitive to drought than photosynthetic processes and 2) highly predictive of water-induced yield variability in Gossypium hirsutum. Two studies (at Tifton and Camilla Georgia) addressed these hypotheses. At Tifton, drought was imposed beginning at the onset of flowering (first flower) and continuing for three weeks (peak bloom) followed by a recovery period, and predawn water potential, respiration rates, net photosynthesis and maximum quantum yield of photosystem II (Fv/Fm) were measured throughout the study period. At Camilla, plants were exposed to five different irrigation regimes throughout the growing season, and average water potential and respiration rates were determined between first flower and peak bloom for all treatments. For both sites, fiber yield was assessed at crop maturity. The relationships between water potential, respiration rates, and yield were assessed via non-linear regression. The interactive effects of water potential and respiration rates on fiber yield was assessed using response-surface analysis. It was concluded for field-grown G. hirsutum that 1) respiration rate is exceptionally sensitive to progressive drought (more so than net photosynthesis or photosystem II), 2) average respiration rates from first flower to peak bloom is highly predictive of water-induced yield variability, and 3) average water potential during flowering alters yield response to respiration rate. Technical Abstract: Respiratory carbon evolution by leaves under abiotic stress is implicated as a major limitation to crop productivity; however, respiration rates of fully expanded leaves are positively associated with plant growth rates. Given the substantial sensitivity of plant growth to drought, it was hypothesized that predawn respiration rates (RPD) would be 1) more sensitive to drought than photosynthetic processes and 2) highly predictive of water-induced yield variability in Gossypium hirsutum. Two studies (at Tifton and Camilla Georgia) addressed these hypotheses. At Tifton, drought was imposed beginning at the onset of flowering (first flower) and continuing for three weeks (peak bloom) followed by a recovery period, and predawn water potential ('PD), RPD, net photosynthesis (AN) and maximum quantum yield of photosystem II (Fv/Fm) were measured throughout the study period. At Camilla, plants were exposed to five different irrigation regimes throughout the growing season, and average 'PD and RPD were determined between first flower and peak bloom for all treatments. For both sites, fiber yield was assessed at crop maturity. The relationships between 'PD, RPD and yield were assessed via non-linear regression, and the interactive effects of 'PD and RPD on fiber yield was assessed using response-surface analysis. It was concluded for field-grown G. hirsutum that 1) RPD is exceptionally sensitive to progressive drought (more so than AN or Fv/Fm), 2) average RPD from first flower to peak bloom is highly predictive of water-induced yield variability, and 3) average 'PD during flowering alters yield response to RPD. |