Research On The Effects Of Transgenic Apple On Population Of Microbial Community And Pollen Fertility

With the commercialization of the crops, increase of plant species and area and themore enhanced awareness of human security, more and more attention is paid to problemsabout ecological security of genetically modified crops. In this experiment, the geneticalstability of the exogenous gene in receptor’s root system, the residual of exogenous gene insoil, the presence of exogenous gene in culturable microorganisms in soil and the effects oftransgenic plants on rhizosphere microbes were studied on the transgenic plants carryingexogenous CpTI gene subcultured in vitro for thirteen years and planted in the greenhousefor eight years. The results showed that the germination rate and the viability of pollengrains of the transgenic apple were observably lower than the control. The formationprocess of transgenic apple pollen was observed through microscope to find the causes ofthe above phenomenonThe main results are as follows：1The PCR analysis of roots of the129transgenic lines of Gala, Orin and Fujicarrying CpTI gene subcultured in vitro for thirteen years showed that the differentialfragments of exogenous CpTI gene could be found in roots of129transgenic lines, whichshowed that the exogenous gene did not lost in the process of roots formation.2The PCR analysis of the topsoil, rhizospheric soil and rooting zone soil of thetransgenic apple planted in the field for eight years showed that the exogenous CpTI genecould be found in all strains in rhizospheric soil and in the rooting zone soil but only in twostrains in the topsoil. The results showed that there were residues of the exogenous CpTIgene in soil of transgenic plants.3262bacteria strains,189actinomycetes strains and146fungi strains were isolatedfrom the topsoil, rhizosphere and root surface soil where the exogenous gene were detected,the PCR analysis of them showed that there was no exogenous CpTI gene.4The matrix was sterile vermiculite and peat (1:1)with supplements ofbio-fertilizer.The number of bacteria, actinomycetes and fungi isolated from therhizosphere soil of planted transgenic apples (Gala, Orin, Fuji) grown for30d,60d and90d was counted. The results showed that: the number of bacteria and fungi was significantly higher than that in control after30d’s growth; the number of fungi was higher than that ofcontrol, while the number of bacteria of transgenic Orin was significantly lower than thatof control at60thday,; the number of fungi isolated from the soil of transgenic Fuji wassignificantly higher than that of control after90d’s growth, while no significant differenceswere found in the number of bacteria compared to the control; the number ofactinomycetes shared no significant differences with the control.5Paraffin section method was used in the experiment. Buds of transgenic apple werecollected with interval of3days from mid-March to early April, the processof pollen formation was observed through microscope, the results showed that: in theearly period of anther development, sporogenous cells were partly separated from thepollen sac wall, resulting in nutritional deficiencies during pollen development, whichaccounted for the low germination rate and viability of pollen in vitro in the late period ofbud development.