| Forest region in Daxingan and Xiaoxingan Mountains is the most abundant diversity of forest plant germplasm resources region with the same latitude. But the forest vegetation’s secondarization, artificialization and habitat fragmented are increasing seriously at present. Very delicate catalogue information that was studied for long term in history has been lost accuracy. So, we are going to carry out a plan that the Daxingan and Xiaoxingan Mountains forest plant germplasm resources are surveyed in details, which plays an important role on germplasm resources protection in the area. We carried out the grid method to layout and survey509samples in this area in four years. The main conclusions are as follows:There are63kinds of trees germplasm resources,78kinds of shrubs germplasm resources,532kinds of herb germplasm resources in total samples. Among them, occasional and rare species that appear more frequently than the common and dominant ones, which reflected the blance of plant germplasm resources in this area. Plant germplasm resources abundant degree varied from forest community types. Overall, the species number of germplasm resources in the second growth forest are higher than ancient forest and coniferous plantation, and that in the hardwood kind of plantation germplasm resources are closed to natural secondary forest. The main trees germplasm resources all revealed a phenomenon that the numbers of mature and old individual are too poor. Habitats fragmented lead to the reproductive group of the plant germplasm resources being isolated, and because small populations play a random drift role, meaning the capacity of the genetic has certain loss.Although the survey whose sample quantity, sample area is rare in the regional survey history. But comparing to a history of nearly one hundred years of investigation, we have still shows insufficient, we found it that samples surveyed are short in germplasm resources numbers. Even so, the samples investigated covered33nanyang administrative units, and county forest plant germplasm resources richness still show overall law that they are influenced by geographical space.That means:With the longitude increasing and latitude reducing, abundance goes up. Among them, the edge of the forest areas are away from the general rule for agriculture and other factors.According to analysis sample data of Larix gmelinii forest, Quercus mongolica forest and Betula platyphylla forest, which3common community types in Daxing’an and Xiaoxing’an Mountains, we indicated that, the tree layer, the shrub layer and herb layer’s shannon index is significantly effected by the longitude, latitude and water hot conditions. In general, it is contrary to the latitude altering trend, but longitude, average temperature, and precipitation changing trend is the same. But Larix gmelinii forest shrub layer, Quercus mongolica forest shrub layer and herb layer, and Betula platyphylla forest herb layer’s shannon index showed not only with latitude falling and trend rising, also with an average temperatures increasing and trend declining. It shows that sample dry degree directly influence the abundance of the plant germplasm resources. The number of building group of kinds decreases or disappears and soil water ability drops, which leads to shade-tolerance, wet-hobby plant germplasm resources severely damaged.This paper further analysis the interspecific relationships between the building group of kinds and rare plants (totally20species,190double species). The results showed that rare and endangered plants strongly depend on the building group of kinds. It further prove Daxing’an and Xiaoxing’an Mountains forest plant germplasm resources that is in form of dangerous not only be directly effected by the harvest, but also build a especially closed relationship to building group of kinds cut. Therefore, rare and endangered plant germplasm resource’s recovery, in addition to reduce the pressure of harvest, we must restore the health status of building group of kinds. |
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