The Mutagenic Effects Of Space Flight And ⁷Li³⁺ Ions Beams On Pepper Seeds

Pepper (Capsicum annuum L.) is one of the most important vegetable crops, which has a long history as a condiment to us. There is much vitamin C, protein, carotene and sugar in fruit of pepper, which make its powerful function of nutrition and health for us, it is a indispensable vegetable for people.In this study, we used the pepper seeds which were induced by space flight and ⁷Li³⁺ ion beams as experimental material. Space flight induced inheritance regularity of the important traits and mutation mechanism of pepper was studied with cytogenetic and molecular genetic method. And provided material for pepper genetic Breeding. The main findings are as follows:(1) Pepper seeds were induced by space-flight and ⁷Li³⁺ ion beams, the mitotic indexs of the root tip cells were significantly higher than controls, which indicated that the space flight and ⁷Li³⁺ ion beams could improve the mitotic index of pepper root tip cells.(2) Compared with the control root tip cells of pepper, root tip cells of pepper induced by space flight had a higher frequency of chromosome aberrations and micronuclei, which indicated that space flight had mutagenic effects on the root cells of pepper. The micronucleus and chromosome aberration rate in pepper root tip cells with ⁷Li³⁺ ion beams were significantly higher than the controls, and while the ⁷Li³⁺ ion beam dose were increased, the micronuclei frequency and the rate of chromosomal aberration were increased.(3) Space flight and ⁷Li³⁺ ion beams on leaves of pepper genomic DNA lines were analyzed with ISSR technique. In the 33 ISSR primers, 13 primers amplified polymorphism straps which were clear, reproducible and specific. ISSR analysis showed that the pepper progenies had significant DNA polymorphism by space flight, polymorphic of contemporary pepper is highest, indicating that the mutagenic effects of contemporary is strongest. And the polymorphism in 50Gy-M₂ by ⁷Li³⁺ ion beams was more frequency than 30Gy-M₂, which indicated that the DNA polymorphism of pepper was by ⁷Li³⁺ ion beam treatment was increased with the ion beam dose rate increased.(4) Space flight and ⁷Li³⁺ ion beams on pepper leaves were analyzed with comet assay technique. The results show that space flight induced the DNA content of tail (Tail DNAâ„…), tail moment (TM) and olive tail moment (OTM) of pepper increased significant compared with the control, and the difference was significant (P<0.01). After 30Gy and 50Gy ⁷Li³⁺ ion beams induced, the Tail DNAâ„…, TM and OTM value of pepper cells has significant differences compared with control at 0.01 level. The Tail DNAâ„…, TM and OTM was increased with the dose of ⁷Li³⁺ ion beams treatment increased, which showed a good dose-response relationship. DNA break was more serious with ⁷Li³⁺ ion beams dose increased in certain ⁷Li³⁺ ion beam dosage range.