Nematpour, A.,
Eshghizadeh, H.R.
and Abraheh, M.
2019
Interactive effects
of CO2 and
nitrogen supply
on growth and
physiological traits
of millet cultivars
under drought stress.
Archives of Agronomy and Soil Science 44:
doi.org/10.1080/03650340.2019.1631450.
NOTE:
Nematpour et al. (2019) say it is "essential to gain a better understanding of the interactive effects of elevated CO2 levels and drought stress on crop yield in order to ensure future food security."
The two millet cultivars included common millet (Panicum miliaceum cv. Pishahang) and foxtail millet (Setaria italica cv. Bastan).
SUMMARY:
Drought stress resulted in negative impacts on the two millet cultivars.
Elevated CO2 was shown to "to ameliorate the adverse effects of drought stress by reducing reactive oxygen species generation, which ultimately reduced the need for antioxidant enzymes."
Increased atmospheric CO2 stimulated plant growth under both adequate water and water-stressed conditions
This was well known for plants with the C3 photosynthetic pathway.
As a C4 plant, millet also benefitted to a similar degree to that observed in most C3 plants.
This is great news for those who grow yhis crop on arid and semi-arid regions.
DETAILS:
Elevated CO2 enhanced chlorophyll content, leaf area, and root dry weight under both well-watered and drought-stressed conditions, but the enhancements were slightly greater under well-watered conditions.
These parameters were enhanced by 38, 43, 42 and 47% for chlorophyll a, chlorophyll b, leaf area and root dry weight, respectively, under well-watered conditions and by 27, 23, 10 and 35% under drought-stressed conditions, again respectively.
Shoot dry weights, reported as a mean for both cultivars, increased by 26% due to CO2 enrichment.
Three agronomists from Iran investigated the interactive effects of CO2, drought and nitrogen supply on two millet cultivars.
Their work was conducted in a controlled-environment greenhouse at the College of Agriculture, Isfahan University of Technology, Isfahan, Iran.
CO2 treatments included ambient (390 ppm) and elevated (700 ppm), nitrogen (N) treatments included no N added and 85 mg N kg-1 soil applied, and the two water treatments were irrigation after 40% depletion of available soil water (adequate water) and irrigation after 75% water depletion of available soil water (water stress), which drought stress was only applied after the plant reach full establishment at the four-leaf stage.