东北中部地区水稻不同生育时期低温处理下生理变化及耐冷性比较

摘要：研究水稻不同生育时期低温条件下各种生理指标的变化，选育耐低温水稻新品种，对于东北地区的水稻生产具有重要意义。以东北中部地区目前主要栽培的15个主要栽培水稻品种为实验材料，利用人工气候箱进行低温处理，分析苗期、孕穗期、抽穗期和灌浆期4个不同生育时期各个品种过氧化物酶（POD）、丙二醛（MDA）、脯氨酸和叶绿素4种生理指标含量变化与耐低温系数之间的关系。同时利用不同生理指标隶属函数的加权平均值（D值）对不同水稻品种的抗冷性进行分类划分。结果表明，每个生育时期的低温处理下，过氧化物酶（POD）、脯氨酸、叶绿素均呈下降趋势，丙二醛（MDA）则呈上升趋势，并且4种指标的变化幅度与水稻耐低温系数之间呈极显著相关性（P＜0.01），各种指标的加权平均值（D值）与抗低温系数之间相关系数达到极显著，并且高于每一个单一指标。因此，D值可以更有效的对水稻进行抗低温评价和分级。

Comparison between physiological properties and cold tolerance under low temperature treatment during different growing stages of rice in northeast central region of China

Abstract: In northeastern China, chilling damage is the main threat to rice production. The selection and breeding of cold tolerant rice varieties is an important goal. Research into the differing physiologies of rice strains grown under low temperature conditions can give guidance for the breeding of cold-tolerant varieties. A better understanding is needed of the physiological variation exhibited by rice during different growth stages, under exposure to low temperature stress. We selected fifteen major rice varieties that are grown in the central northeast of China for analysis under controlled environmental conditions. Following the climatic characteristics of the region and the temperature demands of rice at different developmental stages, we simulated natural temperature variation with an artificial weather box; set to provide four daily temperature gradients. A control variety was planted in the natural environment. We examined the relationship between the cold tolerance coefficient (the ratio of yields under low temperature compared with the control), and levels within the leaves of peroxidase (POD), malondialdehyde (MDA), proline (Pro), and chlorophyll, during the seedling, booting, heading and grain filling stages of development. This relationship has been shown to be related to the cold tolerance of the plants. Using the weighted average of subordinate function values (D value), of these four physiological indices, the relative cold tolerance shown by each variety was determined. We found that during each growth stage the POD, proline and chlorophyll levels decreased. This was in contrast to MDA levels; these were observed to increase. The subordinate function changes in the four indices are significantly correlated with the cold tolerance coefficient (p<0.01). At seedling, booting, heading and grain filling stages, we were able to use the above four physiological indicators to create an index of subordinate functions. From large to small these were Pro; MDA; POD; chlorophyll; MDA; chlorophyll; Pro; POD; chlorophyll; MDA; POD; Pro and MDA; chlorophyll; Pro; POD. Quantitative analysis of the cold tolerance characters of each variety was conducted using these subordinate functions; and the contribution of each index to the cold tolerance of each variety was analyzed. The D value of the four indices not only has a significant correlation with the cold tolerance coefficient but is also higher than the result of each index. In conclusion, the D value can be used to effectively evaluate and classify the low temperature tolerance of rice. It can provide an new method of screening for low temperature tolerance in rice breeding. The changes in the physiological indices observed, when plants were subjected to different periods of low temperature stress, accurately reflect the cold tolerance of rice, and can be used to effectively classify rice varieties according to their cold tolerance.