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A Doubling of Tuber Dry Matter for a Doubling of Atmospheric CO2

Paper Reviewed
Lahijani, M.J.A., Kafi, M., Nezami, A., Nabati, J., Mehrjerdi, M.Z., Shahkoomahally, S. and Erwin, J. 2018. Variations in assimilation rate, photoassimilate translocation, and cellular fine structure of potato cultivars (Solanum Tuberosum L.) exposed to elevated CO2. Plant Physiology and Biochemistry 130: 303-313.

Given the positive effects that have been observed from atmospheric CO2 enrichment on the growth and biomass of plants, it is only prudent to determine the variation in the magnitude of such benefits on different crop cultivars so that farmers can select and grow those cultivars which will provide the largest yield increases per unit of CO2 rise in the years and decades ahead.

Focusing on two potato (Solanum Tuberosum) cultivars (Agria and Fontane), Lahijani et al. (2018) conducted just such an analysis. Their investigation included growing virus-free plantlets of both cultivars in controlled environment chambers under ambient (400 ppm) or elevated (800 ppm) CO2 conditions for a period of 90 days. All plants received adequate water, fertilization and light during the course of the study.

Not surprisingly, the experiment revealed that elevated CO2 stimulated plant photosynthesis and biomass. As shown in the figure below, leaf, stem and tuber dry matter were, respectively, 28.1%, 27.8% and a whopping 165.6% higher in the Agria cultivar at 800 ppm CO2 compared to that observed at ambient CO2 levels. Similar findings were observed for the Fontane cultivar, which experienced CO2-induced leaf, stem and tuber dry matter increases of 31.1%, 56.8% and 95.0%, respectively. With respect to which of the cultivars is the better one to grow in the future, it would appear that Fontane has a slight edge; in viewing the tuber dry matter (i.e., the edible portion of the plant), it produced around 0.25 g more per plant under elevated CO2 conditions than Agria, although this difference was not statistically significant.

Whichever cultivar farmers choose to utilize, one thing is clear -- the future 95% and 165% CO2-induced tuber dry matter increases anticipated for Fontane and Agria potato cultivars will certainly help to improve the food security of many nations that heavily rely on such below-ground crops to feed their citizens.

Figure 1. Leaf dry matter (A), stem dry matter (B), and tuber dry matter (C) of potato cultivars grown at ambient (400 ppm; blue shaded bars) or elevated (800 ppm; green shaded bars) CO2. Source: Lahijani et al. (2018).

Posted 24 April 2019