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A Preferential Translocation of Carbon into Cucumber Fruit at Elevated CO2 Levels

Paper Reviewed
Dong, J., Xu, Q., Gruda, N. Chu, W., Li, X. and Duan, Z. 2018. Elevated and super-elevated CO2 differ in their interactive effects with nitrogen availability on fruit yield and quality of cucumber. Journal of the Science of Food and Agriculture 98: 4509-4516.

In an interesting study published recently in the Journal of the Science of Food and Agriculture, Dong et al. (2018) grew cucumbers in a controlled-environment glasshouse at three atmospheric CO2 concentrations and two nitrogen application levels for a period of 49 days. The CO2 concentrations included ambient (400 ppm), elevated (800 ppm) and super-elevated (1200 ppm) during daylight hours (0800 to 1700 hours), while the two soil nitrogen applications included low (0.06 g N kg-1 soil) and high (0.24 g N kg-1 soil).

As one might expect, both elevated and super-elevated CO2 stimulated the growth and biomass of the stems, old leaves, new leaves and the entire plant, at values ranging from 5 to 33 percent. But what really caught our eye was the CO2-induced growth response of the edible fruit portion. In this instance, fruit biomass increased by approximately 35 percent under low nitrogen conditions in both elevated and super-elevated CO2 air, whereas it rose by a whopping 71 and 107 percent in super-elevated and elevated CO2 air, respectively, under high soil nitrogen conditions.

What is truly amazing about the above observation is the fact that a 107 percent increase in fruit biomass resulted under conditions where the total biomass increase of the plant averaged only 33 percent. This means that under elevated and super-elevated CO2, greater amounts of carbon were translocated into the fruit from other organs compared to that which occurred in ambient CO2 conditions. And since it is the fruit that matters (because it is what we humans consume), these findings are great news for those who grow and consume cucumbers!

Posted 17 October 2018