Effects Of Selenium On Physiology Of Potato Under Cold Stress

The potato (Solarium tuberosum L.) is an important crop for foodstuff, vegetable and industrial raw materials, and it is an adaptable, high-yield, wide usage crop which has developed a complete industrial chain consisting of cultivation, R&D, processing, and marketing. Cold is a important environmental factor that affects the growth and yield of potato, especially0℃below freezing would cause serious damage to the potato plants, and even lead to death of the whole plant. Therefore, improving the hardiness of plants has great significance in agricultural production. Numerous studies show that selenium plays an important role in the resistance of plant towards cold stress, but it has few studies on the effects of selenium to cold resistance of potato still. In this experiment, Favorita microtuber was used as materials to analyze the effects of selenium on potato under cold stress. The main results were as follows:1The effects of selenium on chlorophyll, soluble protein and the relative conductivity under cold stress(1) Under cold stress, compared with CK, application with10mg-L-1sodium selenite improved the content of chlorophyll, chlorophyll a, chlorophyll b and soluble protein, decreased the damage to the cell membrane system by reducing the relative conductivity. The results indicated that selenium could alleviate the cold damage towards potato in some extent.(2) In selenium concentration test, selenium improved the leaf soluble protein and chlorophyll content effectively, the chlorophyll content was largest accumulated in the selenium concentration of20mg-L-1. And the leaf relative conductivity increased first then decreased with the increasing of selenium concentration. The results indicated that the best foliar spray of selenium concentration is20mg-L"1.2The effects of selenium on antioxidant enzymes of potato under cold stress(1) Under cold stress, compared with CK, application with10mg-L-1sodium selenite improved the activity of POD and CAT, decreased the content of MDA. The results showed that selenium influenced the antioxidant enzymes of potato, enhanced free radical scavenging ability, improved the resistant of potato towards cold stress. (2) In selenium concentration test, application with30mg·L-1sodium selenite increased the activity of SOD and GSH-Px, The activity of POD and CAT increased at the10mg·L-1, MDA levels showed a downward trend with the increasing of selenium concentration, and MDA content reached a minimum at the3Omg·L-1, reached the significant difference level compared with the CK. The results showed that selenium influenced the antioxidant enzymes of potato, enhanced free radical scavenging ability, improved the resistant of potato towards cold stress.3The effects of selenium on GSH-Px gene expression levels under cold stressQuantitative PCR analysis was used to obtain the gene expression of GSH-Px under cold stress. In selenium treatment plants, the largest increased gene expression of GSH-Px in3h of cold stress, and the expression levels increased first then decreased with the increasing time of cold stress, whereas no significant change in CK. The results showed that selenium may play a crucial role in GSH-Px gene expression.