Effects Of Methionine-selenium On Physiological Characteristics, Selenium Content And Quality Of Muskmelon

This paper explored the regulation functions on the growth and physiological characteristics and the enrichment effect of selenium (Se) in muskmelon(Cucumis melo L.) with methionine-selenium (Met-Se) treated, though two ways by Met-Se added into soil or sprayed on leaves, as well as the effects of Se dynamic distribution in muskmelon were explored by the method of Met-Se sprayed on leaves.The results were as follows:1. Effects of Met-Se added in soil on physiological characteristics, quality and Se content of Muskmelon4,10 and 16 mg·kg-1 Se treated all could lead to an obvious increase in pigment content, photosynthetic rate, growth and yield. Met-Se added into soil all could improve Se content in sarcocarp significantly, and met the selenium-rich standard, but inorganic Se in sarcocarp with 16 mg·kg-1 Se treated was too high to hazard for human health, while the organic Se in sarcocarp with 4 and 10 mg·kg-1 Se treated which occupy total Se content more than 80%, could meet human being needs for Se security supplement, and 10 mg·kg-1 Se treated was better for the effect of Se supplement. Soil add Met-Se also improve the quality of fruit, and the contents of soluble sugar, protein and free anomic acid in fruit of 10 mg·kg-1 Se treated was the highest, compared with control the content of them increased by 14.82%, 49.88% and 23.42%, respectively, so the optimum Se concentration for soil was 10 mg·kg-1. Further study found that, although the content of nitrate and nitrite in sarcocarp were raised with the increasing of soil Se concentration, but the sarcocarp nitrite content of 4,10 and 16 mg·kg-1 Se treated were 1.499,1.907 and 2.131 mg·kg-1, respectively, all far below the national standard limit (20 mg·kg-1). the total Se content in different tissues and organs, including root, stem, petiole, blade, epicarp, mesocarp and seed were raised with soil Se concentration increasing, Mainly distributed in seed and root.2. Effects of Met-Se sprayed on leaves on physiological characteristics, quality and Se content of MuskmelonSarcocarp Se content of Met-Se treated with Se concentration of 15,30 and 60 mg·kg-1 all met the selenium-rich standard; and Met-Se treated with Se concentration of 30 mg·L-1 has the best effect on fruit quality improvement.In spraying time test, Met-Se solution sprayed for 1-3 times led to an obvious increase in pigment content, photosynthetic rate (Pn), growth volume and yield. Met-Se sprayed on leaves improved sarcocarp Se content significantly, and met the selenium-rich standard, but inorganic Se in sarcocarp with Met-Se treated for 3 times was too high to hazard for human health, while the organic Se in sarcocarp with 1 and 2 times Met-Se treated which occupy total Se content more than 80%, could meet human being needs for Se security supplement, and 2 times Met-Se treated was better for the effect of Se supplement; They were also improve the fruit quality, and the contents of soluble sugar, protein and free anomic acid in fruit of 2 times Met-Se treated was the highest, compared with control the content of them increased by 9.14%,31.72% and 33.90%, respectively, so the optimum method of Met-Se sprayed was Met-Se solution with Se concentration of 30 mg·L-1 spraying 2 times. Further study found that, although the content of nitrate and nitrite in sarcocarp were raised with the increasing of Met-Se spraying times, but the content of nitrite inl,2 and 3 Met-Se treated sarcocarp were 1.525,1.654 and 1.745 mg·kg-1, respectively, all far below the national standard limit (20 mg·kg-1). The total Se content in different tissues and organs, including root, stem, petiole, blade, epicarp, mesocarp and seed were raised with the sprayed times added, Mainly distributed in seed and blade.3. Effect of Se distributed in different tissues and organs of muskmelon with Met-Se sprayed on leavesAfter Met-Se Sparyed on leaves, The forms of Se existed in muskmelon was given priority with organic Se; the bottom blade Se content was the highest among the bottom tissues and organs of muskmelon including stem, petiole, blade and root, as well as the upside blade, which Se content was the highest among the upside tissues and organs of muskmelon including stem, petiole, and blade, and the seed Se content was the highest among the tissues and organs of fruit.It could increase the organic Se content in pericarp as well as the inorganic Se by Met-Se sprayed; the inorganic Se6+ content was higher in epicarp than in mesocarp, while the organic Se and inorganic Se4+ content was higher in mesocarp than in epicarp.