The impact of enhanced atmospheric carbon dioxide on yield, proximate composition, elemental concentration, fatty acid and vitamin C contents of tomato (Lycopersicon esculentum)

摘要

The global average temperature has witnessed a steady increase during the second half of the twentieth century and the trend is continuing. Carbon dioxide, a major green house gas is piling up in the atmosphere and besides causing global warming, is expected to alter the physico-chemical composition of plants. The objective of this work was to evaluate the hypothesis that increased CO_2 in the air is causing undesirable changes in the nutritional composition of tomato fruits. Two varieties of tomato (Lycopersicon esculentum) were grown in ambient (400 μmol mol~(-1)) and elevated (1,000 μmol mol~(-1)) concentration of CO_2 under controlled conditions. The fruits were harvested at premature and fully matured stages and analyzed for yield, proximate composition, elemental concentration, fatty acid, and vitamin C contents. The amount of carbohydrates increased significantly under the enhanced CO_2 conditions. The amount of crude protein and vitamin C, two important nutritional parameters, decreased substantially. Fatty acid content showed a mild decrease with a slight increase in crude fiber. Understandably, the effect of enhanced atmospheric CO_2 was more pronounced at the fully matured stage. Mineral contents of the fruit samples changed in an irregular fashion. Tomato fruit has been traditionally a source of vitamin C, under the experimental conditions, a negative impact of enhanced CO_2 on this source of vitamin C was observed. The nutritional quality of both varieties of tomato has altered under the CO_2 enriched atmosphere.