Comparison Of Zooplankton And Gastropod Biodiversity Between Organic And Conventional Paddy Fields

China as the dominant country of rice farming and consuming in the world,the demand of rice is huge.As developing of the economic and rising of the living standard,the health consciousness and environmental consciousness of human are raising.The quality of the life is also improving.The demand of organic production is steadily on the increase.And the planting area of the organic rice is also rapidly increasing.But the ecological and environmental effects of the organic rice farming are still unclear and urgently needed evaluation.This article assessed the biodiversity of two kinds of untargeted organisms-zooplanktons and gastropods-in species and genetic levels,in order to demonstrate the effects brought by organic and conventional rice farming.The main results of this article obtained were followed:1?Using 5 plot sampling method,totally 235 zooplanktons of Daphnia,Moina,Cyclops and Microcyslops were found in organic paddy fields and 70 of Daphnia,Moina and Microcyslops were found in conventional paddy fields.The density and average genus abundance of zooplankton fauna in organic paddy fields are significantly higher than in the conventional paddy fields(p<0.05).The Shannon-Wiener index(H'o=1.302),Simpson index(Do=0.713)and Margalef index(do=0.326)are also significantly higher than these indices in conventional paddy fields(H'c=0.749,Dc=0.494,dc=0.320).These results show than the biodiversity of zooplankton fauna in organic paddy fields is higher than in the conventional paddy fields.2?There were 103 gastropods of 5 species i.e.Bellamya aeruginosa,Radix swinhoei,Cipangopaludina cathayensis,Bithynia fuchsiana,Bithynia misella in organic paddy fields while 92 gastropods of B.aeruginosa,R.swinhoei,C.cathayensis in conventional paddy fields were found using 5 plot sampling method.The Shannon-Wiener index(H'o=1.161),Simpson index(Do=0.622)and Margalef index(do=0.986)of the gastropod fauna in organic paddy fields are significantly higher than the fauna's in the conventional paddy fields(H'c=0.480,Dc=0.379,dc=0.391)(p<0.05).The results of the comparison of two gastropod faunas in different kinds of paddy fields indicated that the biodiversity of the gastropod fauna in organic paddy fields is higher than the fauna in the conventional paddy fields.3?Using RAPD and mitochondrial molecular markers to investigate the genetic diversity of the R.swinhoei faunas which is the domain species in two kinds of paddy field.Two molecular markers all demonstrated that the genetic diversity of R.swinhoei fauna in the organic paddy fields is higher than in the conventional paddy fields.Genetic diversity indices of the R.swinhoei communities in organic paddy fields were all higher than in the conventional paddy fields.These result indicted the organic farming could increase and protect the genetic diversity of the gastropod in molecular level.4?We downloaded 17249 EST sequences of 4 genus i.e.Bellamya,Oncomelania,Lymnaea and Physa and detected the SSR motifs located in these sequences.There are 476 sequences contained 526 SSR motifs.After annotated the function of the sequences contained the SSR motifs,54 sequences were annotated.Totally 425 primers were designed for these EST-SSRs.27 pairs of primer were random selected and using two kinds of species of Bellamya(Bellamya purificata&Bellamya aeruginosa)as templates to verify the feasibility of this EST-SSR mining method.42.9%of primers got form the sequences of Bellamya were amplified productions in Bellamya aeruginosa and the rate in Bellamya purificata was 50%.No production were got using primers belonged to other genus.These EST-SSR markers could be used for assessing the genetic diversity of gastropod community and may overcome the defect of low transformation ability of the genomic SSRs between different gastropod species.Through the comparison of zooplankton and gastropod faunas' biodiversity in organic and conventional paddy fields,show the organic farming could raise and protect the biodiversity of the untargeted organisms.EST-SSRs got in this article provide very useful resources to investigate the genetic diversity of gastropod community.And these untargeted organisms have huge potential to assess and monitor the environment.