The Selection Of Pepper PGPR And The Application Effect In Soilless Cultivition

This paper studied the selection of pepper Plant growth-promoting rhizobacteria (PGPR) and the application effect of pepper PGPR in pepper's soiless cultivation. Four bacterial strains that could promote pepper's growth were selected from forty. Then different concentration of pepper PGPR and different nutrient solution were setted to study the effect on the peppers growth and development,yield and quality. The colonization density of rhizosphere were also studied in this paper. The aim is to find the optimum pepper PGPR and nutrient solution and their optimal concentration in pepper's soiless cultivation. The results are as follows:1. In the 40 Rhizosphere bacteria, G15-7,A21-4,R2-1 and L24-1 can not only improve the seed germination rate, germinating potential and promote the increase of taproot and hypocotyl in the seed germination experiment ,but also significantly promote the growth of pepper in seeding stage without watering any nutrient solution. Of them, the influence of A21-4 treatments on pepper's morphological indexes was the greatest, and the height ,stem diameter,leaves number and the root volume were respectively increased 23%,31% 27%,83% compared with CK. G15-7 is Paenibacillus polymyxa, A21-4 is Serratia plymuthica. R2-1 is Bacillus subtilis. L14-2 is Pseudomonas chlororaphis.2.The treatments that watered pepper PGPR G15-7,A21-4,R2-1,L24-1, to a certain extent, could improve the physiological and morphological index of pepper. And there was a centain relationship with the concentration of PGPR. The effect of Bacillus subtilis R2-1 on promoting pepper's growth is the most significantly one. In addition, Paenibacillus polymyxa G15-7 Serratia plymuthica A21-4 and Pseudomonas chlororaphis L14-2, in 10~9cfu/ml concentration, could also improve the chlorophyll content of pepper. G15-7,in 10~9cfu/ml concentration, could improve the root activity of pepper significantly too.3.G15-7,A21-4,R2-1 and L24-1 all have the power of rhizosphere colonization and the higher concentration, the higher colonization density. But the Colonization density reduced as time went on and the Colonization density in roots reduced more slowly than that in substrates. On the 30th day after treatment, the colonization density of A21-4 and R2-1,both in substrates and roots , reached 10~4cfu/g.4. With all treatments watering Bacillus subtilis R2-1 in 10~9cfu/ml ,the height,stem diameter and freash weight of pepper,watered ShanQi nutrient solution was better than watered Shangdong agricultural university or Holland nutrient solution in seedling stage. And watered ShanQi nutrient solution was more helpful for the colonization of Bacillus subtilis R2-1 than watered the other two nutrient solution.5 In the pot experiment, all treatments were watered Bacillus subtilis R2-1 in 10~9cfu/ml but watered ShanQi nutrient solution in different concentration. Watered 3/2 times ShanQi nutrient solution was superior to watered 1/2 times in growth indices ,yield and quality of pepper. The chlorophyll content of pepper leaves and root vigor,watered 3/2 times ShanQi nutrient solution was superior to watered 1times,but as to the yield and quality ,there were no significant differences between them. So considering the principle of economizing fertilizer and Economic benefits, it's better to choose the 1 times ShanQi nutrient solution in the production process.