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The Effect of Elevated CO2 on Tomato Plant Lateral Root Growth

Wang, H., Xiao, W., Niu, Y., Jin, C., Chai, R., Tang, C. and Zhang, Y. 2013. Nitric oxide enhances development of lateral roots in tomato (Solanum lycopersicum L.) under elevated carbon dioxide. Planta 237: 137-144.
Introducing their study, Wang et al. (2013) say "it has been reported that tomato plants grown under elevated CO2 have greater total root length, root surface area, root diameter, root volume and number of lateral roots than those under ambient CO2, leading to a greater root system," citing Wang et al. (2009). And they indicate that "as a result, elevated CO2 significantly increased the uptake of N, P, K, Ca, Mg and micronutrients (Cu, Fe, Mn and Zn)," which in turn was found to have promoted "plant growth and development (Prior et al., 1998)."

In a study designed to further explore this phenomenon, Wang et al. (2013) assessed the lateral root production of 19-day-old tomato (Solanum lycopersicum) seedlings grown in basal nutrient solution for an additional four days under hydroponic conditions in the laboratory at atmospheric CO2 concentrations of either 350 or 800 ppm.

Consistent with the findings of Wang et al. (2009), the seven scientists found that the number of lateral roots increased by 75% under elevated CO2 compared to ambient CO2 and that the length of the roots increased as well.

Figure 1. Left panel: Photos of the lateral root region of a tomato plant grown under ambient (350 ppm) or elevated (800 ppm) CO2 for 4 days (left panel). Right panel: The lateral root number of tomato plants treated for 4 days with ambient (350 ppm) or elevated (800 ppm) CO2. Adapted from Wang et al. (2013).

With more and longer lateral roots in a future CO2-enriched atmosphere, tomato plants (and likely other plants as well) should be better equipped to take up both major and micro nutrients from the soils in which they grow, making them both bigger and better and more apt to produce larger and more nutritious fruit ... and more of it.

Additional References
Prior, S.A., Torbert, H.A., Runion, G.B., Mullins, G.L., Rogers, H.H. and Mauney, J.R. 1998. Effects of carbon dioxide enrichment on cotton nutrient dynamics. Journal of Plant Nutrition 21: 1407-1426.

Wang, Y., Du, S.T., Li, L.L., Huang, L.D., Fang, P., Lin, X.Y., Zhang, Y.S. and Wang, H.L. 2009. Effect of CO2 elevation on root growth and its relationship with indole acetic acid and ethylene in tomato seedlings. Pedosphere 19: 570-576.

Archived 18 June 2013