Effects Of Epichlo? Endophytes On Rhizosphere Soil Nematodes In Achnatherum Inebrians And Festuca Sinensis

To clarify the effects of Epichlo? endophytes on soil nematodes and plant-parasitic nematodes, by using Achnatherum inebrians and Festuca sinensis as target plants, two communities, Epichlo? endophyte-infected(E+) and endophyte-free(E-), were built up. Community characteristics of soil nematodes in plant rhizosphere soil were compared between E+ and E- plants, including individual density, generic number, Shannon-Wiener(H′), Pielou(J), Margalef index(SR), maturity index(MI), plant parasite index(PPI) and PPI/MI ratio. Inhibition ratio of hatching Hererodera glycines egg and Meloidogyne incognita egg masses in extracts and root exudates of E+ and E- A. inebrians were measured. The main objectives of this study were to determine the relationships of grasses-endophytes and nematodes. Results showed as follows:1. To determine Epichlo? endophytes on characteristics of rhizosphere soil nematode communities in A. inebrians, nematodes were isolated and identified. A total of 11889 soil nematodes individuals were collected, belonging to 37 genera, 22 families, 6 orders and 2 classes. The results indicated that the individual density of predators/omnivores nematode of E+ was significantly(P<0.05) higher than that of EA. inebrians. The generic number, H′, J and SR of soil nematodes had significant(P<0.05) difference in different month scale. The MI of soil nematodes of E+ was significantly(P<0.05) higher than that of E-, whereas the PPI and PPI/MI ratio were significantly(P<0.05) lower than those of E-. In a word, Epichlo? endophytes could improve the individual density, and decrease generic number of soil nematodes. In addition, Epichlo? endophytes had significant(P<0.05) difference on the composition of functional groups of soil nematodes, especially on plant-parasitic nematodes.2. To determine Epichlo? endophyte on characteristics of rhizosphere soil nematodes community in F. sinensis, nematodes were isolated and identified. A total of 2895 soil nematodes individuals were collected, belonging to 26 genera,13 families, 4 orders and 2 classes. The results indicated that the individual density of plant-parasites of E+ were significantly(P<0.05) lower than that of E-, but the individual density of predators/omnivores of E+ were significantly(P<0.05) higher than that of E- which were at 5-10 cm deep soil. The individual density of soil nematodes and plant-parasites of E+ were significantly(P<0.05) higher than that of E- at 10-15 cm deep soil. In a word, Epichlo? endophyte had significant(P<0.05) effects on individual density of plant-parasites and predators/omnivores, but had no significant(P>0.05) effects on diversity and functional groups of soil nematodes.3. By measuring inhibition rate of H. glycines egg and M. incognita egg masses hatching in extracts and root exudates of A. inebrians. The results showed that the inhibition rates of H. glycines egg and M. incognita egg masses hatching of E+ were significantly(P<0.05) higher than those of E- treated with different concentrations(12.5 g/L、25 g/L、50 g/L; 6.25 g/L、12.5 g/L 25 g/L), respectively, of stem extracts. In addition, the inhibition rate of H. glycines egg of E+ was significantly(P<0.05) higher than that of E- treated with different concentrations(6.25 g/L、12.5 g/L and 25 g/L), respectively, of seed extracts. Besides, both root exudates of E+ and E- A. inebrians had certain inhibition effects to H. glycines egg and M. incognita egg masses, but no significant(P>0.05) difference. In a word, Epichlo? endophytes of A. inebrians could affect the hatching effects on H. glycines egg and M. incognita egg masses.