Influence of elevated CO2 concentration on salt and drought resistance mechanisms of a C3 (Chenopodium quinoa) and a C4 (Atriplex nummularia) xero-halophyte
Final Report Abstract
For the very first time it could be shown that elevated atmospheric CO2 concentration increases the salt resistance not only of C3, but also of C4 plant species, but due to different type specific mechanisms. The C3 species C. quinoa benefits directly from elevated CO2 via an enhanced photosynthesis and energy supply, which reduces oxidative stress. In the C4 species A. nummularia, CO2 enrichment ameliorates ion toxicity and nutrient imbalance and indirectly ameliorates oxidative stress (non-stomatal feedback down-regulation of photosynthesis via a reduced electron transport rate). CO2 enrichment counteracts exactly the respective major growth constraints of the two plant species/types under hyperosmotic conditions, which helps to detect the plans´ vulnerabilities more clearly than if they were grown only under ambient CO2. Therefore we recommend plant cultivation under elevated CO2 as a very useful (but still neglected) tool/model for “stress diagnosis” in plants. The results of the study imply that both plant types will be suited for cultivation on dry and saline soils in a future with rising atmospheric CO2 concentration and by this way can help to mitigate the consequences of global climate change and counteract its causes. Based on the existing literature, we hypothesized that the salt and drought resistance of the C3 species C. quinoa is more enhanced by elevated CO2 than the one of the C4 species A. nummularia. To our surprise, this does not seem to be the case, and both plant types benefit from CO2 enrichment. However, the different type specific mechanisms make it difficult to directly compare and validate (quantify) the impact of elevated CO2 on the resistance of the two plant types. The topic “sustainable use of cash crop halophytes” in the context of global changes is well suited for reports in public media, especially against the background that many plant species (not only C3, but also C4 plants) will benefit from elevated atmospheric CO2 concentration.
Publications
- (2015): Elevated atmospheric CO2 concentration leads to different salt resistance mechanisms in a C3 (Chenopodium quinoa) and a C4 (Atriplex nummularia) halophyte. Env. Exp. Bot. 118, 67-77
Geißler, N., Hussin, S., El-Far, M. & Koyro, H.-W.
(See online at https://doi.org/10.1016/j.envexpbot.2015.06.003) - Effect of elevated atmospheric CO2 concentration on the salt resistance of C3 and C4 halophytes. 2nd International Conference on “Physiological, Biochemical and Molecular Arguments for Salt tolerance”, October 12th – 14th 2015, Doha
Koyro, H.-W.
- Effect of elevated CO2 concentration on gas exchange and antioxidant defence mechanisms of a C3 (Chenopodium quinoa) and a C4 (Atriplex nummularia) halophyte. Abstract book and poster presentation, Botanikertagung, August 30th - September 3rd 2015, Freising
Geißler, N. & Koyro, H.-W.
- Effect of NaCl salinity and elevated CO2 concentration on ion relations and osmotic adjustment of a C3 (Chenopodium quinoa) and a C4 (Atriplex nummularia) halophyte. Abstract book and poster presentation, GfÖ Annual Meeting, August 31st - September 4th 2015, Göttingen
Geißler, N., Süßel, F. & Koyro, H.-W.
