| Artocarpus hypargyreus Hance,belonging to Moraceae Artocarpus,is an evergreen species,it's one of the state-protected three-grade and endangered plants.The results of the survey showed that the numbers of species of wild populations are dwindling;many populations showed scattered only one and interrupted distribution;the seedlings is rare in forest;the population is recessionary trends.In order to protect and restore resources of Artocarpus hypargyreus Hance,it is the urgent matter to study the conversation biology of Artocarpus hypargyreus Hance and reveal the endangered mechanism.Five populations throughout the entire distribution of the species were chosen,the endangered mechanism was studied by Reproductive phenology,Breeding System,Distribution of reproductive component,Seed Characteristics, Physiological characteristics of seed germination,Seed reserves in soil seed bank,Distribution of seeds and Spread pattern,Structural characteristics of community,Interspecies relationship and Genetic diversity.At the same time,the technology of Ex situ conservation was studied by seed breeding and cutting propagation and tissue culture.Based on these results,the results could be summarized as follows.1 Its outcrossing index was 5,the breeding system was outcrossing,part was self-compatible and sometimes demand for pollinators;its Pollen-ovule ration was 1248,facultative xenogamy.Used gravity-glass-slice method to make sure its anemophily mode.Phenology observations showed that the situation of flowering was flowering occurred simultaneously to a large number flowering at the same time and form of self-pollination to protect the reproductive success.The results of reproduction component showed that the female inflorescence more than 80 per cent distributed in the upper canopy,about 70%of male inflorescence distributed in the lower part of canopy,fruit guitar kind of the low rate of up to 15.5%.2 The results of characteristics of seeds showed that the weight of a thousand seeds of Artocarpus hypargyreus Hance was 98.37g,the seed crosswise diameter was 0.32-0.41cm,the seed longitudinal diameter was 0.65-0.75cm,the color of seed skin was sepia,Embryo was white and plumule was small.The quality of seeds was poor,the seeds of life were only 40.1%,there were high proportion of air tablets and decay,respectively 32.5%and 12.0%;its seed had the dormancy phenomenon.The germination percentage was only 4.5%if seeds were immediately planted after picked.Under the natural state the germination percentage was low,Also has 10.6%after the pretreatment,it could relieve seed dormancy through the high temperature and humidity bedding treatment,could raise the seed-germination percentage greatly,the laboratory germination percentage reached 70.6%and the threshing ground germination percentage reached 68.6%.3 The seed germination physiology research indicated that the peel included suppresses material, and caused the germination percentage low in natural stat.In the seed germination process the activeness of the peroxide enzyme and the catalase and the dehydrogenase changed not in a big way.Soaking seeds with the 300mg·L-1GA3 solution could enhance the enzyme effectively activeness,obviously raises the seed-germination percentage.4 The results studied on soil seed bank showed that the seed bank of Artocarpus hypargyreus Hance had less reserves,the largest reserves was 31.9/m2,large number of seeds(about 80%) stored in the litter layer,the seed distribution pattern had obvious clusters,almost all of seed distributed in the crown scope.5 The results of study on structure and dynamics of the population showed that the age structure of populations showed only a few young individuals,the large number of individual ageing, population trends showed recession;the survival curve of the population appeared to be a type of Deevey-Ⅱ,in the age classⅤtoⅥpopulation had highest mortality,after age classⅥthe mortality was smooth,it was a phenomenon that a population that had less number of young individuals and the large number of individual ageing was endangered.The determination of spatial distribution pattern of Artocarpus hypargyreus Hance had good consistency by using six aggregate indices,distribution of the overall population was gathered.6 The inter-specific correlation of Artocarpus hypargyreus Hance in the tree layers and shrub layers with other species were studied by using X2 tests and association coefficients(AC).The results showed that the interspecific correlations of Artocarpus hypargyreus Hance to other species were very similar,there was no relationship between Artocarpus hypargyreus Hance and other species,Artocarpus hypargyreus Hance was an incidental or rare species,as habitats or its own reasons,it could not be community building species or dominant species in the existing environmental conditions.7 The result of heredity multiple RAPD analysis indicated that the population of Artocarpus hypargyreus Hance had the high heredity multiplicity,the percentage of polymorphic loci was 87.78%.Shannon's information index was 0.2319,and Nei's gene diversity was 0.1660.The coefficient gene differentiation(GST)was 0.7378,and the gene flowing(Nm)was 0.1251.It showed that the gene flowing was limited seriously,its hereditary change had 73.78%to exist in the population,only then 26.22%occurred in the population.The cluster result of heredity distance between population's was consistent with the geographic latitude position by the UPGMA cluster analysis,heredity distance was increased by the geography distance increases.8 The seed of Artocarpus hypargyreus Hance had the dormancy phenomenon.It could significantly promote seed to germinate and improve the germination rate and speed germination by the treatment that seed mixed with sand in the high temperature and humidity place.The year growth rule of the seedling presented obviously "slow,fast,slow",the height and diameter growth presented the peak in July and August and September.the growth quantity of fast-growing time accounted for the total growth 60-70%.With the power function model estimated the height's and diameter's growth quantity in each periods,its correlation coefficient and the fitting were highest.9 The affect of cuttings survival rate of Artocarpus hypargyreus Hance was extremely obvious on cutting time and mother tree age and concentration of ABT;the affect of cuttings survival rate was obvious on seedbed matrix;the affect of cuttings survival rate was not obvious on strip length.The cutting effect of Softwood strip was good in July.Selecting the low age strip,coordinating 100mgL-1ABT could obtain the high cutting survival rate on the seedbed matrix to use the river sand.10 The young tender stem was suitable in tissue culture of Artocarpus hypargyreus Hance.the suitable start culture medium combination was Improves MS+6-BA2a mg·L-1+NAAbmg·L-1; the suitable multiplication culture medium combination was Improves MS+6-BA2a′mg·L-1+ NAA1b′mg·L-1+Sucrose 30g·L-1;the combination 1/4MS+IBA3cmg·L-1+NAA3b″mg·L-1 was suitable to rooting.On the basis of above results,it is suggested that there are two aspects for the endangered mechanisms of Artocarpus hypargyreus Hance.For a one thing,it is the internal factor,because individual quantity are few,inbreeding and self-compatibility are serious,it causes the seed quantity to be few,seed quality is bad;the seed additional ripening process cannot obtain the appropriate temperature and the moisture content;the peel suppresses the seed to germinate;the accumulation of the seed distribution pattern is not good for population to expand;between the population the gene exchange are few,the small population splits up seriously,the heterozygosity is low in the population,and its compatibility is weak.On the other hand,it is external factor, habitat fragmentation and over-digging for medicinal use have led to the extinction of a great number of populations;the climatic change causes the flowering season does not meet and the animal takes food of the fruit these factors have led to the limit seed for regeneration.;all over results have limited community's development so Ex situ conservation is the main way for restoration and expansion of Artocarpus hypargyreus Hance population.Carries on the artificial propagation through the multi-population sample,especially takes a sample in the high heredity multiplicity population to carry on the cutting and the tissue culture,it can expand and renewal the existing population.At the same time,through breaks the seed dormancy,creates the condition to raise the seed-germination percentage,carries on sowing seeds in the big spatial scope,these measures can increase seedling quantity in the population,and create gene exchanging and reorganization condition,further protects its heredity multiplicity,stable and strength population quantity.
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