Effects of atrazine on the black community land function and role of microbial ecology

Abstract

By measuring the concentration of atrazine stress and different culture days, the abundance of key genes in soil nitrogen transformation was studied by means of real-time PCR with the increase of atrazine stress time. The abundance of soil nitrogen-fixing function gene (nif-H) increased significantly with the increase of time in the middle and late culture period (15-30 d), indicating that the abundance of soil nitrogen-fixing function gene was promoted; soil ammonia oxidation. The abundance of functional gene (amo A) was reduced at the low concentration of atrazine (0 mg/kg, 20 mg/kg), and then decreased with increasing stress time, while at high concentration of atrazine. Under the treatment of (100mg/kg), with the increase of time, the abundance of soil ammonia oxidation function increased first and then decreased, indicating that the abundance of soil ammonia oxidation function gene was affected in the process of culture. II Based on high-throughput sequencing technology, the results of soil nitrogen fixation and ammonia oxidation community diversity showed that the functional gene diversity of soil samples was affected by the concentration of atrazine and stress time. According to the analysis of soil diversity index, nitrogen-fixing functional genes of soil samples treated with atrazine at 0 mg/kg, 20 mg/kg and 100 mg/kg were tested at the late stage (30 d). The diversity index of (nif-H) was higher than the mid-test (15 d). At the beginning of the experiment (0 d), the ammonia functional gene (amo A) diversity index of soil samples treated with atrazine concentrations of 0 mg/kg, 20 mg/kg and 100 mg/kg was higher than that in the middle of the experiment (15d), studies have shown that the nitrogen and ammonia oxidation functional gene diversity is affected under different concentrations of atrazine stress time. The distribution of the nitrogen-fixing gene (nif-H) and the ammonia-oxidizing functional gene (amo A) in the horizontal sample community structure showed that the nitrogen-fixing gene was in the middle of culture (15 d), and the genus Burkholderia and Rhizobium were earlier than the culture period (0d) indicating that the above two types of nitrogen-fixing microorganisms play a leading role at this stage. Throughout the experiment (0-30 d), the number of nitrogen-fixing functional genes in the blank treatment was higher than 20 mg/kg and 200 mg/kg. The principal component analysis confirmed that the different culture days and different stress concentrations of atrazine had certain effects on the composition of soil nif-H and amo A gene communities.