Biological Effects Of Low Energy N~+ Implantation On Chili Pepper

In order to investigate the effects of low energy N+ ion implantation on biochemical characteristics of Chili Pepper, the experimental material was “Shanjiao 2012” that were provided by chili group of college of horticulture Northwest A & F University. We implanted low energy N+ ion(10Ke V) into the dry seeds of “Shanjiao 2012”with the biological modified ion implantation equipment, and the injected doses were 20×1014 N+/cm2, 40×1014 N+/cm2, 60×1014 N+/cm2, 80×1014 N+/cm2, 100×1014 N+/cm2, 120×1014 N+/cm2. The experiment were divided into three groups: CK1 was the normal seeds, CK2 was processed by vacuum, another group was processed by low energy ions. The latter two processing had the same time. In this study, in order to provide basis for ion beam mutation breeding of chili pepper, the effects on percentage of seeds germination, physiological and biochemical parameters, antioxidant enzyme activity, agronomic characters, photosynthetic characteristics and fruit quality were studied. The main results are as follows:1. Along with doses of N+ ions increasing, the germination percentage of chili pepper was decreased continuously in the radiation energy of 20 Ke V and 25 Ke V, on the other hand, “double saddle” line appeared in germination percentage of the energy of 10 Ke V and 15 Ke V. Those show that ion implantation was not completely inhibited, on the contrary, it had effectively stimulating the germination to some extent. According to the germination percentage of chili pepper with the different energy and doses, the final choice was the energy of 10 Ke V, and the injected doses were 20×1014 N+/cm2, 40×1014 N+/cm2, 60×1014 N+/cm2, 80×1014 N+/cm2, 100×1014 N+/cm2, 120×1014 N+/cm2. By means of regression analysis, the median lethal dose(LD50)of ion beam chili pepper seeds was about between 80×1014 N+/cm2 and 100×1014 N+/cm2.2. Varying with the increase of nitrogen ion implantation does, the content of chlorophyll was higher than that in two controls, the maximum appeared in 120×1014 N+/cm2, and malondialdehyde(MDA) content raised first, declined second and the raised again, the minimum appeared in 80×1014 N+/cm2. On the other hand, soluble protein content in the pepper seedlings was lower than that in two controls.3. Varying with the increase of nitrogen ion implantation does, the activities of superoxide dismutase(SOD), peroxidase(POD), catalase(CAT)and ascorbate peroxidase(APX) increased first and then decreased. When the implantation dose was 80×1014 N+/cm2, the activities of SOD, POD and CAT were maximum. The maximum of APX activity appeared in 60×1014 N+/cm2.4. By N+ ion implantation, the plant height and stem thicknes of chili pepper were determined dynamically in four times, the results show that middle and high doses of N+ ion implantation(80×1014 N+/cm2) had certain inhibition at the same time of growth. There were differences in internode bifurcate of most of the treatments, they included two bifurcation and three. The plant spreading of every treatments were significantly smaller than that of CK1. When the implantation dose was 100×1014 N+/cm2, the node of first flower were significantly lowered than that of CK1 and CK2.Twigs per plant of dose of 80×1014 N+/cm2, 120×1014 N+/cm2 were significantly more than that of two controls and other processing.5. Varying with the increase of nitrogen ion implantation does, Photosynthetic rate(Pn) of chilli pepper raised first, declined second and the raised again, and it was related to the content of chlorophyll. On the contrary, the concentration of intercellular CO2(Ci)declined first, raised second and the declined again. That was because Pn has inverse relation to Ci. At the same time, stomatal conductance(Gs) raised first, declined second and the raised again. Because the transpiration rate(Tr) and stomatal conductance(Gs) has direct proportional relation, the trend of change on transpiration rate(Tr) was consistent with Gs.6. By N+ ion implantation, When the implantation dose was 40×1014 N+/cm2, fruit length and weight of chili pepper were significantly higher than two controls, and those of other treatments were also higher than that of controls. This show that ion implantation can lead to the yield increasing effect of chili pepper. Varying with the increase of nitrogen ion implantation does, the contents of dry matter of chili pepper were similar between two controls and six processing. In addition to the dose 100×1014 N+/cm2, the content of soluble sugar of other each processing were lower than two controls, and the minimum appeared in 60×1014 N+/cm2. On the contrary, along with doses of Nitrogen ions increasing, the vitamin C content of all processing were higher than two control groups, and the maximum appeared in 80×1014 N+/cm2.