Effects of NaCl stress on seed germination of different varieties of pepper

Taking 3 widely cultured pepper(Capsicum frutescens) varieties including Longjiao 2, Longjiao 3 and Longjiao 5 as study objects, the effects of different concentration of NaCl solution treatments(0, 30, 60, 90, 120, 180 mmolL-1 on seed germination of these 3 pepper varieties were studied. The results indicated that, with the increasing of concentration of NaCl solutions, the germination rate, germination energy and germination index of 3 pepper varieties decreased, while the salt injury index decreased. Longjiao 3 had the strongest salt tolerance since the germination rate of Longjiao 3 was 60.64% when the concentration of NaCl solution was 180 mmolL-1. Salty stress had no effect on the time needed before germination of 3 pepper varieties, but the germination peak delayed with the increasing of concentration of NaCl solution, when the concentration of NaCl was higher than 90 mmolL-1. With the increasing of concentration of NaCl solution, the activities of POD, SOD and CAT in leaves of 3 pepper varieties appeared a trend of firstly increased and then descended. The steepest rise was observed in Longjiao 3, while Longjiao 2 had a minimum rise. The MDA content in leaves of 3 pepper varieties were all increased with the increasing of concentration of NaCl solution. Longjiao 2 had a maximum rise on MDA, while Longjiao 3 had a minimum rise on MDA. All of above results indicated that, the capability of germination and salt tolerance of these 3 pepper were Longjiao 3Longjiao 5Longjiao 2.