The Study On Changing Laws Of Lycopene Contents Of Watermelon And The Effects Of High Hydrostatic Pressure Treatment On The Seeds

Citrullus lanatus, a species in the family Cucurbitaceae which originated from African tropical grassland is annual herbaceous species. The cultivation history of Citrullus lanatus is long,there are about two thousands Citrullus lanatus germplasm resources and the regional distribution of which is widely. Cultivating new Citrullus lanatus variety was restricted for the limited genetic basis, the new breeding methods are necessitated. The High Hydrostatic Pressure mutation breeding method is a new technology which combined high pressure physics and biology and agricultural breeding,and that which has broad promising prospects in the future.We chose Citrullus lanatus as research materials in this paper, we used Ultraviolet Spectrophotometer to test the content of lycopene in different ploidy (4x, 3x, 2x and F1 hybridization ) ripe Citrullus lanatus fruit and study the law,and that establish the convenient and accurate determination system to analysis the relationship between the content of lycopene and the ploidy and fruit color of Citrullus lanatus, taking the biological effect theory of high hydrostatic pressure as basis,using high hydrostatic pressure experimental equipment and the water as pressure transmission media, then we used different high hydrostatic pressure (50MPa, 100MPa, 150MPa) to treat Citrullus lanatus seeds(dry seeds or germinating seed) for about 20min to research the effects of high hydrostatic pressure treatment to the seedling rate of Citrullus lanatus and the photosynthetic pigment content of Citrullus lanatus young seedling and the peroxidase activity and the agronomic characters of Citrullus lanatus . The main results are shown as follows:1. The lycopene content difference was significant in different Citrullus lanatus materials, the law of lycopene content in different Citrullus lanatus ploidy is: triploid is highest, tetraploid takes second place, F1 hybridization and diploid is the lowest; it is a positive correlation between the lycopene content and the degree of the red color of fruit, there is very little lycopene in yellow flesh Citrullus lanatus.2. The seedling rate of the groups (dry seeds or germinating seed) which were treated by high hydrostatic pressure was significant declined, the analysis of variance showed that compared with the control that the seedling rate difference of the treated seeds was significant in the 95% confidence level.3. The content of chlorophyll and carotenoid of the treated groups were lower than the control, the growth of the treated groups was inhibited too, but The content of chlorophyll and carotenoid of the treated groups was increased gradually at late growth stage and promoted the growth, compared with the control the peroxidase activity of the treated groups was elevated significant and enhanced the stress resistance.4. High pressure is an important influencing factor for plant growth, the Citrullus lanatus seeds was treated by high pressure can significantly influence the agronomic characters of Citrullus lanatus, yield increase in Citrullus lanatus , shorten mature period, improving quality characters.The results above illustrated that there was a positive correlation between the lycopene content and the color of fruit; the mutation by high hydrostatic pressure not only improve the quality of the Citrullus lanatus, but also shorten mature period, so this is an efficient new pathway for Citrullus lanatus mutation breeding.