Antioxidant enzyme and morphological characteristics of roots of three Nicotiana Tabacum L. genotype seedlings under chilling stress

Abstract

In order to study the morphological and physiological ecological response of root of Flue-cured tobacco seedling after low temperature stress, this experiment was conducted with different stressful period which was 2, 4 and 6 days under 5 to 7°C (day) by the material named Yunyan87, Msk326 and Yunyan85, respectively. The results showed that comparing with favorable temperature (23 to 25°Cday), activities of superoxide dismutase (SOD) and peroxidase (POD) and ascorbate peroxidase (CAT) had different change trends with difference variety, in which three parameters increased for YY87, and except activities of SOD rise for YY85, other parameters decreased after low temperature stress for short-term (2 days) as for K326 and YY85. When low-temperature stress period prolonged, these parameters come to rise gradually. As for morphological parameters, average diagram, surface area and volume of root declined significant after low-temperature stress for 2 days for YY87, while these morphological parameters are similar to normal level if prolonging stress to 6 days. However all morphological parameters are opposite for K326 comparing with YY87. Surface area, volume of root declined to some extent for YY85. These conclusion indicate different morphological and physiological ecological response mechanisms for roots of Flue-cured tobacco seedling of different variety after chilling stress. Key words: Chilling stress, flue-cured tobacco, morphology, physiology, roots.