Increasing drought periods due to climate change will severely affect crop yield in many parts of the world. Therefore, understanding how certain plant species can tolerate drought better than others might be crucial for future food security. The plant Oudneya afrianca can be found in Libyan, Tunisian, Algerian and Moroccan Sahara deserts and is well adapted to drought conditions. These occur, when the soil has less water than it can actually hold after excess water has drained away (field capacity). In the presented paper, Oudneya afrianca was used to study coping mechanisms of plants under moderate (4 days watering to 50 % field capacity) and severe drought (8 days watering to 25 % field capacity). Furthermore, experiments looked at how plants recover from this water stress. Results show that drought tolerance in Oudneya afrianca involves accumulation of so-called reactive oxygen species. Plants produce these substances under stressful conditions to activate protective mechanisms and increase survival. Furthermore, drought increased antioxidant concentration (especially that of ascorbate [ASC] and glutathione [GSH]) in Oudneya africana. Antioxidants and the so-called ascorbate-glutathione cycle can remove reactive oxygen species and a higher activity is a signal of drought tolerance. The balance between reactive oxygen species, antioxidants and efficiency of the ASC-GSH cycle is a key factor in the tolerance to long-term drought in Oudneya africana. In addition, medium drought stress for a longer time has a stronger negative effect than severe drought stress for a short period. Antioxidants and changes in certain steps during the photosynthesis process can help the plant survive during drought recovery. However, there might be additional, yet un-identified changes in the plant metabolism during long-term drought, which need more research.

For further information

Read the Environmental and Experimental Botany original research article which this summary is based on ‘Drought tolerance in a Saharian plant Oudneya africana: Role of antioxidant defences’ (March 2015).

Visit the profile of the research ambassador, Antje Fiebig, who wrote this summary.

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