2000 Vol. 21, No. 5
2000, 21(5): 337-342.
The testicular structure and reproductive cycle of ovoviviparous teleost,Sebastiscus marmoratus was studied in this paper.The testes of S.marmoratus are lobular type.In August and September of every year,the testes are at the stage of spermatogonic proliferation,when primary spermatogonia divide and develop into secondary spermatogonia,which and Sertoli cells form spermatogenic cysts.From October to next January,the testis enters spermatogenesis.During this stage,germ cells in the spermatogenic cysts develop into sperms gradually.February till July is the stage of sperm degeneration and absorption,when there are only primary spermatogonia and some remains of sperms.During reproductive time,sperms are transferred to urinogenital papilla via vasa efferentia and vasa deferentia,and enter the female reproductive tracts by the way of internal fertilization.
The impact of different concentrations of Zn[2+] on the ultrastucture of hepatopancreas in larval (zoea Ⅳ) of Chinese crab,Eriocheir sinensis was studied after being exposed for 96 h by using transmission electronic microscope.The result demonstrated that significant ultrastructural changes,which occurred in hepatopancreas cells,were found after exposed above 200 μg/L Zn[2+].When compared with control group (31.8 μg/L Zn[2+]).B cells have numerous vacuoles or a large vacuole with a number of insoluble Zn electronic dense granules (EDG) in membrane-lined types.When the mature B cells are extruded from the epithelium of the hepatopancreas tubules,these EDGs in vacuole will be released as the vacuoles which have burst.The EDGs will be found in the lumen.The production of EDGs in the lumen and the vacuole of B cell have been correlated directly with the ambient concentration of Zn[2+].The EDGs in lumen then may be removed via the gut and excreted directly to outside and they are insoluble.The cytoplasm of R cells are often disoganized,vacuolized and form large vacuoles.The R cell are seriously damaged.The cytoplasm of E cell have large amount of vacuoles,which may be resulted from the degeneration of swollen mitochondrion.This shows that the E cells have lost their ability to differentiate to other cells.When the concentration of Zn[2+] is high (1031.8 μg/L Zn[2+]),the structure of hepatopancreas will be seriously destroyed and no cell structure can be found. This observation suggested that formation of EDG in B cells was an important cellular detoxifying mechanism,in which Zn[2+] or other heavy metal were incorporated into intracellular insoluble form (may be metal-protein complexes).These are harmless to the tissue and cell.Pathological effects occur in tissues when the rate of influx of a toxicant,such as Zn[2+],exceeds rate of detoxification and excretion.In this experiment,the effect was found to be the damage of R and E cell,even the all cells in hepatopancreas.
We report data on sexual dimorphism in body size and head size and female reproduction for Sphenomorphus indicus from Hangzhou,Zhejiang,eastern China.The skink is sexually dimorphic in both body and head size,and females are larger in body size but smaller in head size.Except for neonates that did not exhibit sexual dimorphism in head size,males had larger heads than did females.When SVL was kept constant,we found that juvenile and adult males did not differ in head size but juvenile females had larger heads than did adult females.Heads of neonates were relatively the largest,implying the importance of larger heads for an individuals ability to use larger prey.The smallest reproductive female was 67.7 mm SVL,and all females larger than this size produced a single litter per season.Litter size,litter mass and neonate mass varied from 3 to 11 (mean=7.2) offspring,1.30 to 5.19 (mean=3.34) g and 0.36 to 0.58 (mean=0.48) g,respectively.Litter size determined by counting the number of yolked follicles and oviductal eggs outnumbered that by counting the number of neonates by 1.0 offspring.Neonate mass was independent of maternal SVL,and litter size was independent of maternal conditions.Both litter size and litter mass were positively correlated with maternal SVL,and there was a marginally positive correlation between relative clutch mass and maternal SVL.An inverse relationship between neonate mass and litter size was found in S.indicus,suggesting a trade-off between the two variables.Our data indicate that selection should favor larger body size in S.indicus,as females can increase their reproductive output through production of more offspring by increasing body size.Moreover,adult females partition relatively less resources into head growth but more into carcass growth,thereby leaving a larger space for producing more offspring.
2000, 21(5): 355-360.
Habitat selection of mainland serow (Capricornis sumatraensis) was studied in Tangjiahe Natural Reserve,Qingchuan County of Sichuan Province from March 1998 to February 1999.The results showed as follows:The main ecological factors notably influenced on habitat selection of mainland serow in spring were human disturbance,vegetation type,tree dispersion,tree density,slope,rock dispersion,tree size and slope position.The main ecological factors notably influenced on habitat selection of mainland serow in winter were human disturbance,vegetation type,slope position,canopy,water source,tree dispersion,tree density,tree size,shrub size,rock dispersion,slope aspect and animal dispersion.The separation of habitat selection of mainland serow in spring and winter showed mainly in the ecological factors,slope,elevation,tree size,tree dispersion,shrub dispersion,rock dispersion,vegetation type,slope position,canopy and water source.
2000, 21(5): 361-366.
The life table of the giant panda was suggested by WEI Fu-Wen in 1989,who mainly based on the skull specimen collected in field and the result of age determination through incisor sections of known age panda specimen.However,in a review of recent literature.We noted 3 errors in analyses,all of which may lead to erroneous inferences (Harris et al.,1993),Therefore.According to the data on the age structures of wild giant pandas in Mingshan and Qinglai Mountains,and the age structure derived from the analysis on the skull specimen as well as the stable age structure in the giant panda populations in the two mountains,the proportions of the giant panda in different classes are calculated by using the relative equation of distribution density function on the ages of animal populations:f(x)=βe[-βx] (Hou et al.,1998).Then,the life table of the giant panda and its relevant numerical indexes were amended through synthesizing the research data and the main conclusions as follows:The mean life expectancy:3.995 years.After a half year of living.The mean life span increase to (10.36±1.15) years.The net reproductive rate (R):1.05734.The mean time of per generation (T):12.156 years.The intrinsic rate of natural increase (r[m]):0.00459033.The finite rate of increase (λ):1.00460040.
The sample plot investigating method was used to research insect communities in three different growth phrase of tropical rain forest (gap phase,building phase,mature phase) of Xishuangbanna in September,1997 and April,1998.The species and individual composition of insect communities were studied,the DMA,J,d,Ds,H index were used for comparing the diversity of insect communities in three habitats.The results showed that the total number of insects collected were 2 455 belonging to 15 orders with Diptera,Hymenoptera and Coleoptera as the dominant groups and Lepidoptera as the normal groups.There were the most number of species and individuals of insect communities in building phase (secondary forest).The richness and dominance of insect communities were the largest in building phase,but the evenness of gap phase was the largest.The Shannon-Wiener diversity index in mature phase was the largest,and it got higher with the increase of growth stage.The species composition similarity between mature phase and building phase of tropical rain forests was the highest,but it was lower between building phase and gap phrase.
This paper reports results of our taxonomic study on subspecies of Chinese white-bellied rat (Niviventer confucianus) collected in southwestern China.The difference of pelage coloration and coefficient of difference (C.D.) on 17 selected cranial and dental variables among samples from this region were analyzed to assess the difference between the sample and the nominate subspecies N.c.confucianus.92 individuals with complete skulls from this region were then submitted to multivariate analyses.The results showed that the samples from Yajiang,western Sichuan and Deqin,northwestern Yunnan,which have once been included in N.c.confucianus,were distinguished from N.c.confucianus and should be respectively considered as two new subspecies.We propose to name them and to describe them respectively as.
By scanning electron microscopy and inductively couple plasma spectrometry (ICP),the ultrastructure and elemental composition of the eggshell of Tibetan Eared-pheasant (Crossoptilon harmani) have been investigated.The average thickness of the surface layer of crystals,the palisade and cone layer and the eggshell membrane are 9.3 μm,307.1 μm and 64.6 μm respectively,Their proportions to the total thickness of the eggshell 2.4%,80.6% and 17% respectively.There are many vesicular holes in palisade layer,and physiological significance such structure may be of significant to air exchange.The shape of eggshell pore on the surface layer of crystals is circle or ellipsis or irregular square.The fracture surface of eggshell pore is funneled-shape.Some granules fill in the upper part of the eggshell pore.The contents of 21 elements in the eggshell is presented in this paper.
2000, 21(5): 387-391.
Morphology and ultrastructure of mature sperm of Thenus orientalis were studied with electron microscopy.Each sperm comprises a nucleus,membrane complex area and acrosomal region.The nucleus limited by a nuclear envelope contains uncondensed chromatin,microtubules and filaments.Five to six radial arms extend from the nucleus,and are stationary as well as packed with microtubules.The membrane complex area,which lies between the nucleus and the acrosomal region,contains numerous lamellar membrane structure and vesicle which originate from the lamellar membrane structure.The acrosomal region includes acrosomal vesicle and periacrosomal material.The acrosome is structurally complex and comprised of acrosomal cap,inner and outer acrosomal material.The periacrosomal material is finely granular with most of it lying at the sides of the acrosomal vesicle.The mode of acrosome reaction of Palinura sperm was also discussed in this paper.
Owing to its high evolution rate,lack of recombination and maternal inheritance,mtDNA has been extensively used in unraveling the genealogical history of our species.By means of restriction enzyme analysis of the whole sequence and direct sequencing of the control region,mtDNA has shed light on the provenance of mod ern human,estimation of past population size and date of expansion event,migration and expansion patterns at a continental level,as well as the microdifferen tiaton and demographic history of single population.In this paper,we reviewed the recent advances of mtDNA studies of the world populations,the improvement of the mathematics model,the congruity and discrepancy between mtDNA and nuclear data,the co-evolution between mtDNA and language,ancient DNA,as well as the arguments about the special genetic characteristics of this genetic marker.
Cryopreservation of animal germplasm is to preserve the germplasm at a very low temperature (-196 ℃) so that it could survive for a long time because its metabolism was inhibited.Sperm and embryos as well as oocytes of many species were successfully cryopreserved since 1949.The number of species whose germplasm could be cryopreserved is increasing to improvement of the technology of cryobiology.However,there are still problems or difficulties for the cryopreservation of animal germplasm,such as low fertile ability of the germplasm,especially most of mammalian oocytes,after cryopreservation.Further study on the mechanism of cryopreservation,finding a better protocol and reducing the cryoinjury are crucial to cryopreservation of animal germplasm.The present paper describes some of the advances in the cryopreservation and outlines the relative merits and limitations as reference for the researchers in this field.
2000, 21(5): 412-415.
Studies on satellite tracking of migratory birds and on satellite image analysis of their habitat were reviewed.The advantage and development of these new technologies were discussed by comparing with traditional methods.Overlaying satellite locations on satellite images is particularly important and powerful to show the route selection and habitat use of migratory birds.However,there are few studies on relevant subjects by combining the two technologies. Finally,we discussed how these studies can contribute to the conservation of migratory birds.
2000, 21(5): 416-418.