THE EFFECTS OF RISING TEMPERATURE ON CELL VIABILITY, RELATIVE WATER CONTENT AND PROLINE ACCUMULATION OF PLANTSChalkoo Sameena and Akhtar Sabina
Gases emissions due to human activities are substantially adding to the existing concentration of greenhouse gases, particularly carbon dioxide, methane, CFC at nitrous oxides. Different global circulation models predict that greenhouse gases will gradually increase worlds average ambient temperature. According to a report of the intergovernmental panel on climate change (IPCC), global mean temperature will rise 0. 3% oC per decade reaching to approximately 1 and 3% oC above the present value by years 2025 and 2100, respectively and leading to global warming. Heat stress due to high ambient temperature is a serious threat to crop production worldwide. So, keeping the above in view a research program was planned, and an attempt was made to study the eco-physiological parameters and how these contribute in mitigating the adverse effect of heat stress in potato crop. For this, potato cultivars of diverse nature, namely heat susceptible Kufri Ashoka andheat tolerant Kufri Surya were evaluated for eco- physiological attributes namely cell viability, Relative water content, and Proline content. The experiments were conducted in plastic pots which were exposed at predetermined range of temperature that is 20, 30 and 40. Sampling was done at 45, 60 and 75 days after planting (DAP) and one plant/pot was used for taking observations. Significant differences were noticed in tolerant and susceptible cultivars. It was noticed that Kufri Surya maintained a higher Proline and relative water content at all growth stages under all temperature regimes included in the present study. In Kufri Ashoka the metabolic injury was almost double the injury experienced by Kufri Surya. The results in cell viability test indicated that genotypic differences exist in Kufri Ashoka and Kufri Surya. In overall performance, the higher relative water content, cell viability and higher leaf proline in Kufri Surya suggest that through these traits individually as well as in coordination this Genotype could sustain its functional integrity and deviated least during heat stress. Therefore selection of potato cultivars early in clonal generations, on the basis of these criteria/traits may expedite and help to develop more heat tolerant potato cultivars and thereby can equip potato production system better for the projected climate change inevitable due to global warming.