| Twenty turf samples in Shenzhen were surveyed with line intercept method for weed species in four seasons during a year and the data obtained were analyzed with cluster analysis; Herbicidal activities of corn gluten peptides prepared by different proteases were systematically carried out, the differences of herbicidal activities of corn gluten peptides prepared by different proteases and different hydrolysis times were compared and analysized,and the molecular weight distribution of corn gluten peptides was further measured and determined. And the result shows: 1. Totally 83 species belonging to 25 sections were found in 20 blocks'turfgrass in Shenzhen, of which 65 species are broadleaf weeds and the other 18 species are grass weeds. 2. The turf weeds in Shenzhen are classified into 15 communities. There are 3 communities in spring, 4 communities in summer, autumn, and winter, respectively. Management level and habitat are the important factors affecting weed communities. 3. The ANOVA(P<0.05) analysis shows that the herbicidal activities of peptides changed with hydrolyzing time, using different proteases, namely Alcalase 2.4L, Papain, Flavourzyme?R500MG and NeutraseR?1.5MG to hydrolyze CGM. The optimum hydrolysis time is 6 hours for Flavourzyme, and 3 hours for other three proteases. 4. The ANOVA analysis indicates: compared with Alcalase 2.4L, herbicidal activity of peptides prepared by Papain is not significantly difference (p>0.05), and significantly difference (p<0.05) by Flavourzyme ?R500MG as well as highly significantly difference by Neutrase?R1.5MG (p<0.01). Therefore, the two proteases, Alcalase 2.4L and Papain, can be taken priority to prepare the corn gluten peptides. 5. Using the technologies of ultrafiltration and size exclusion chromatography to measure the molecular weight distribution of peptides, peptides of small molecular weight exhibited higher herbicidal activity than those of large molecular weight, and their average molecular weight is 424.27D. |
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