Carbon Dioxide Fertilization Effect:
The atmospheric carbon dioxide concentration is gradually increasing. If this trend remains to continue, then the atmospheric concentration level will become double by the end of the 21st century. With the doubling of this atmospheric carbon dioxide concentration, the growth of many plants particularly, the C3 species under favourable conditions could increase by about 30% on average in short term. The response of plants to elevated concentrations of carbon dioxide is known as the carbon dioxide fertilization effect. Due to this effect, the rate of photosynthesis will increase and the transpiration rate may be reduced and consequently, water use efficiency will increase. This will allow many species to grow successfully in regions of water scarcity. Plants will allocate a greater proportion of photosynthesis to roots. Greater root production is expected to enhance mycorrhizal development and fixation of nitrogen in root nodules. However, the beneficial effect of increased carbon dioxide may not be realized because of the negative effects of global warming.