Preliminarily Studies On The Mutation Effects Of Return Satellite Flight And Variation Mechanism On Hot Pepper (Capsicum Annuum L.)

Hot pepper (Capsicum annuum L.) is a very important vegetable in our life. It is as fresh food and the processing raw material. In this paper, five cultivars and the offsprings of cultivar '5-12' were employed to study the changes in seeds germination, botanical characters, protein contents and DNA mutation. The main purpose is to find the mechanism of space condition on hot pepper mutation and providing the material for hot pepper's heredity breeding. The main results were as follows:(1) The results showed that the germination potentiality and germination rate of hot pepper seed after boarding return satellite were changed, however, the changes varied with cultivars. During the seed germination, the soluble protein and MDA content decreased, but SOD activities increased. SOD activity of treated seeds was higher than that of the control during the ultimate period of germination of cultivars '5-08', '5-10', '5-11', '5-12'. However, SOD activity of treated seeds of cultivar '5-09' was lower than that of the control. From 1d to 4d of germination of cultivar'5-11', the SOD activity increased 37.58%, but the control only increased 16.00%. Moreover, APX, G-POD and CAT activities were changed as well during seed germination. All assayed items of cultivar '5-08' and '5-09' were lower than control. The direction of variation was negative. Whereas the assayed items of other three cultivars were higher than control and the direction of variation was advantageous.(2) It was found that the botanical characters, such as the time from transplant to bloom of the first flower, number of leaves on which the first inflorescence emerged, plant height, lateral branch numbers, flower characters of the fifth branch, fruit characters and fruit numbers per plant, were changed after boarding on the return satellite. However, these changes varied with cultivars. The offsprings of cultivar '5-12' were tested in detail. The results showed that the time from transplant to bloom of the first flower and first inflorescence were enhancer than that of control, but the plant height, flower of the fifth branch and lateral branch numbers were lower than that of the control. It was also found that the width of leaves of the first branch was bigger than that of control. Number of fruits per plant was decreased, but the fruit characters, such as fruit length, fruit width and average weight of fruit was bigger than that of the control.(3) Proteins of SP₁^SP₄ leaves of cultivar '5-12' were analyzed by SDS-PAGE. The results showed that protein bands were rich. There were obvious difference between the offsprings andcontrol. There were two new protein bands of SP₂^SP₄ as compared with the control, and the molecular weight was 15.0KD and 27.0KD respectively. At the same time, DNA of SP₁^SP₄ leaves of cultivar '5-12' were analyzed with RAPD technique. Among 45 primers used in this experiment, 6 primers expanded bands and 5 primers generated special DNA bands. Totally, the rates of DNA mutation were S23=7.2%, S27=1.6%, S33=2.4%, S62=3.2%, S68=13.6%. This indicated that gene mutation has had a sudden change or chromosomic exchange, flaw.