Vol. 11, Issue 7 (2022)

Author(s):
Shreevani GN, Sreenivas AG and Beladhadi RV

Abstract:
A central issue in ecology is to determine how environmental variations associated with global climate change; especially changing atmospheric carbon dioxide (CO₂) and temperatures affect trophic interactions in various ecosystems, more so on the physiology of the plant system. In this regard, an investigation on phytochemistry of Bt cotton under different climate change treatments viz., elevated CO₂ (550 ± 25 ppm) and temperature (2 ºC rise) was conducted and compared with ambient levels of CO₂ and temperature under open top chambers (OTC’s)at University of Agricultural Sciences, Raichur. The results indicated that climate change in terms of eCO₂ and temperature has favored the growth and development of Bt cotton crop, as it was evidenced by the accelerated growth rates in the form of plant height, number of leaves, leaf area, leaf area index (LAI), leaf water content (LWC) and sympodia. The growth parameters showed positive trend along with the yield parameters and resulted in increased yield in the eCO₂ and temperature treatments. Likewise, biochemical analysis of the Bt cotton plant showed lot of changes wherein, the chlorophyll content, carbon and carbon-based compounds viz., tannins, phenols and sugars significantly increased in the eCO₂ conditions (CO₂ alone and in combinations with temperature) as compared to aCO₂ treatments. On the contrary, nitrogen (N) and N-based compounds viz., proteins and amino acids decreased in the eCO₂ conditions which resulted in change in carbon to nitrogen (C: N) ratio. Climate change typically affected carbon and nitrogen dynamics in Bt cotton, which being a transgenic plant invests some nutrients for the production of specific toxic proteins (i.e., endotoxins). This was evidenced in the present investigations which clearly showed that eCO₂ and temperature treatments decreased Bt toxin production