Abstract:

In order to explore the cold tolerance characteristics of rice new male sterile lines and its physiological and biochemical mechanism, the study focused on the identification of cold tolerance and determination of MDA contents, peroxidase activity, and biomass contents at seedling stage through Light incubator culture and the normal methods for determination of malondialdehyde (MDA) content, peroxidase activity, and biomass contents, by using a set of male sterile lines which were with the same cytoplasm derivation and different nucleus derivations and another set of male sterile lines which were with the same nucleus derivation and different cytoplasm derivations. The results showed that, the cold tolerance was classified to 4 types, G huaxiang 2A was most tolerant to cold stress (the first class), whereas Y ruanxiang A was the weakest one for cold tolerance (the ninth class). By comparing the cold tolerance level of the male sterile lines with the same cytoplasm derivation and different nucleus derivations, G huaxiang 2A was the most tolerant, G huaxiang 1A was the second, and G ruanxiang A was the third. It showed that nuclei gene affects the cold tolerance of the sterile lines. By comparing the cold tolerance level of the male sterile lines with the same nuclei derivation and different cytoplasm derivations, WA ruanxiang A was the most tolerant, G ruanxiang A was the second, and Y ruanxiang A was the third. It showed that cytoplasm gene affects the cold tolerance of the sterile lines. The content of MDA, the activity of POD, and the seedling height, number of seedling roots and fresh weight were all related to the cold tolerance of the sterile lines. That is, if a sterile line was more tolerant to cold stress, its relative MDA content was lower, its relative POD activity also was lower, its relative fresh weight of biomass was higher.