Abstract
Effect of low-temperature stress on growth and metabolism of 10 varieties of sugar cane (Saccharum spp hybrids) was studied. Results explicitly demonstrated genetic variability in growth and metabolic behaviour of sugar cane varieties which may be due to their relative tolerance to low-temperature stress. The growth attributes, viz., plant height, leaf area, and leaf length of plants showed significant reduction; varieties BO 91, Co 1148, CoLk 9606, CoLk 8102, and CoS 767 showed relatively less reduction compared to varieties, CoLk 8001, CoJ 64, and CoS 97264. Chlorophyll a and b, carotenoids, proline, malondialdehydes (MDA), and B202 increased invariably in all the varieties under low-temperature stress. Specific activity of antioxidant enzymes, viz., catalase, peroxidase, superoxide dismutase, and glutathione reductase also increased in most of the varieties under low temperature conditions. Higher accumulation of proline and carotenoids and increase in specific activity of antioxidant enzymes, viz., catalase (CAT), peroxidase (POX), glutathione reductase (GR), and superoxide dismutase (SOD) and lower increases in MDA and B202 contents were found in some varieties, BO 91, Co 1148, CoLk 9606, CoLk 8102, and CoS 767. Interestingly, these varieties also showed less reduction in growth attributes compared to the rest of the genotypes. These parameters may be responsible for reducing the accumulation of reactive oxygen species during low-temperature stress, and may help sugar cane plants to survive under low-temperature conditions at early stages of growth. These may be used as biochemical traits to characterize sugar cane varieties tolerant to low-temperature stress, and in turn, help sugar cane breeders to develop low-temperature tolerant varieties.
