水稻新质型不育系幼苗期耐冷性及其生理生化特性的质核效应

为了探明水稻新质型不育系幼苗期耐冷性特点，以一套同质异核不育系（G软香A，G华香1A，G华香2A）和一套同核异质不育系（G软香A，Y软香A，WA软香A）为材料，采用光照培养箱培养的方法，鉴定和评价了3~4叶期幼苗的耐冷性，并分析了低温胁迫后不育系幼苗丙二醛(MDA)含量、过氧化物酶(POD)活性以及幼苗生物量的变化。结果表明：供试不育系的耐冷性分级可分为4级，其中G华香2A的耐冷性最强（1级），Y软香A的耐冷性最差（9级）。就同质异核不育系而言，G华香2A耐冷性最强，G华香1A次之，G软香A中等，表现出细胞核对耐冷性的效应。就同核异质不育系而言，WA软香A耐冷性强，G软香A耐冷性中等，Y软香A耐冷性极弱，表现出细胞质对耐冷性的效应。因此，水稻不育系的耐冷性受到细胞质和细胞核基因的共同影响。幼苗MDA含量、POD的活性以及幼苗期水稻苗高、根数、鲜重等生物量等性状都与耐冷性有关。耐冷性越强的不育系，经低温处理后其幼苗MDA相对含量越低，POD相对活性越低，生物量相对鲜重越大，即说明耐冷性越强的不育系，经低温处理后较之对照幼苗的MDA含量增加量较小，POD活性增强程度小，生物量下降较少。

Effect of Cytoplasms and Nuclei on Cold Tolerance of Rice New Cytoplasmic Male Sterile Lines and Its Physiological and Biochemical Characteristics at Seedling Stage

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.