| The purpose of this paper is to reveal the effects of hypomagnetic field space (HMFS) closing to the geomagnetism vanished on the embryo development and the ability to learning and memory. By observing the embryo developing process and the behavior of learning and memory of day-old chicks, we try to explore the influence of HMFS on animal's ontogenesis and high neural activation. Incubated in HMFS, the developing characteristics of chick's embryo were compared with those in normal geomagnetic field. Thus we obtained some index such as the hatching rate, dead-embryo rate, health rate and cripple rate; and using a wildly accepted learning and memory model, we analyzed the ability to learning and remembering of the chicks, and thus the behavioral evidences about the effect of HMFS were gained. In addition, the timing biological effects of HMFS were deteced by brief period or alternate exposing. In the meantime, a histological technique was engaged to explore the influence of HMFS on neuron conformation. The result shows that, the hatching rate, the body/egg weight index, the water dissipate rate from the tiny pores of eggshell and the average hatching periods from HMFS had no significant differences comparing to those from control groups. However, the cripple rate, dystocia rate and the average incubating time difference increased by 11.9%,8.4% and 4.4 times than that in control groups, respectively. In addition, the main incubating periods increased by 2.2 h than ynat in control groups. The result indicated that the HMFS had some negative effects on the developing characteristic of chick's embryo, that is, not only more abnormal individuals come into being, and also the holistic hatching time had been influenced. This predicts that the responses of organisms to the HMFS might have biggish individual differences. Those results revealed that geomagnetic field disappearing may have some negative effects on human beings, and therefore, geomagnetic field disappearing is an important factor that must be considered in the plan about navigation carrying-men in outer space and emigration to outer space. With the one-trial passive avoidance task (OTPAT) model of day-old chicks, our experiment showed that, the retained curve in OTPAT of day-old chicks hatching from natural geomagnetic field (control groups, CG) is consistent with the acknowledged three-phase model. The two dips are at the 20 min and the 60 min, and the average avoidance rates (AR) of the curve to the red bead were extremely high. The OTPAT retained curve of day-old chicks hatching from hypomagnetic field space (experimental groups, EG) also presents the marked timing effect. The two dips were at the 25 min and the 50 min, the avoidance rates to the red bead (ARR) in the short- and intermediate-term memory was 74.1% on average, which was resembled to that in control group. However, the long-term memory represented an obvious fluctuation. Compared with that in CG, ARR and the deviation coefficient in EG were decreased by 25.3% and increased by 1.3 times, respectively. That is to say, both the memory ability and stability in the experimental chicks declined. The result indicated that the hypomagnetic field space has a negative effect on the development of chick brain function, and that could have lasted to birth after.While the incubating eggs were exposed to short-term HMFS, we inspected the effect on the embryo developing and learning and memory. The result showed, at the majority cases of short-term exposure, compared to the CG and EG, the hatching rate was increased; the dystocia rate was obviously lower than that in EG, but have no difference compared to that in CG; and the cripple rate had no significant varieties, excepted for the group exposed to HMFS at the last stage of the incubation. In that group, the cripple rate was significant higher than that in CG, but has no difference with EG. All the results indicated that the negative effect of HMFS may be a long-term effect; short-term exposing had not too serious influence, and sometimes it...
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