Influence of elevated CO2 concentration on salt and drought resistance mechanisms of a C3 (Chenopodium quinoa) and a C4 (Atriplex nummularia) xero-halophyte
The study intends to answer the question if elevated atmospheric CO2 concentration has a different effect on the salt and drought resistance of closely related C3 and C4 xero-halophytic crops which are suited for saline agriculture. We suppose that elevated CO2 concentration significantly enhances biomass production, water relations (such as water use efficiency), photosynthesis (ETR/Atotal-ratio), ion nutrition and therewith drought and salt resistance of the C3 plant Chenopodium quinoa, while it has only a slightly positive effect on the C4 plant Atriplex nummularia. This hypothesis is tested by growing the mentioned species at different levels of NaCl salinity and drought stress close to the welting point under ambient (400ppm) and elevated (540 ppm) CO2 concentration in open top chambers (OTC). We intend to compare and correlate various eco-physiological parameters such as plant growth, gas exchange, chlorophyll fluorescence, water potential, composition of ions and organic substances (compatible solutes).
The addressed topic is of major importance especially in arid areas. Global climate change goes along with rising atmospheric concentration of trace gases such as CO2 as well as desertification and water deficiency. The utilisation of alternative water resources such as saline irrigation has devastating effects on conventional agriculture with salt excluding glycophytes because it exacerbates soil salinisation and drought. The results of the project will provide a basis for the future sustainable use of salt including C3 and C4 xero-halophytes on dry and/or saline soils, which can mitigate the cause and the consequences of climate change.
Eisa, S., Hussin, S., Geißler, N. & Koyro, H.-W. (2012): Effect of NaCl salinity on water relations, photosynthesis and chemical composition of Quinoa (Chenopodium quinoa Willd.) as a potential cash crop halophyte. Aust. J. Crop Sci. 6, 357-368.
Hussin, S., Geißler, N. & Koyro, H.-W. (2013): Effect of NaCl salinity on Atriplex nummularia (L.) with special emphasis on carbon and nitrogen metabolism. Acta Physiol. Plant. 35, 1025-1038.
Geißler, N., Lieth, H. & Koyro, H.-W. (2014): Cash crop halophytes – the ecologically and economically sustainable use of naturally salt resistant plants in the context of global changes. In: Ahmad, P. & Wani, M.R. (Eds.): Physiological mechanisms and adaptation strategies in plants under changing environment. pp. 145-162. Springer, New York.