Studies On Plant Reproductive Ecology Of Platycrater Arguta Sieb.et Zucc.

Platycrater arguta is a perennial shrub endemic and precious to China,which represents the temperate deciduous forests of Sino-Japanese floristic region.The species has great values in ornamental and scientific research.But in the field investigation shows that the species population distribution presented plaques,take more fruit and setting rate is high,the low seed germination rate,population characteristics such as effective update is given priority to with asexual reproduction.In order to understand the P.arguta appearance of these phenomena,and lead to narrow its population distribution area and a small number of endangered reasons.This research through to the 5 P.arguta communitives in Jiangxi province,including Maotoushan,Tongboshan,Yangjifeng,Longhushan and Wufushan about population habitat distribution types and distribution pattern,breeding system,pollination ecology characteristics,seed germination and plant asexual reproduction characteristic research.Discusses the reason that in the wild populations are becoming scarce and the cause of the endangered mechanism,providing theoretical basis for the protection of the P.arguta.About the species of community distribution of habitat characteristics,flowering phenology,flower characteristics,breeding system and pollination ecology research results show that:Five P.arguta communities in Jiangxi province,are mainly distributed in the walls of the running water,drought,shade degrees higher places in valleys or on the slope-composite niche and other special habitats.P.arguta populations are generally for the cluster distribution,but tends to uniform distribution and random distribution.May be due to the requirements of the species to habitat is extremely high,especially the ecological factors,such as water and light sensitivity to the abnormal changes of habitat,more easily lead to its endangered.The web is a cyme of P.arguta,flowering time is 6~8 month,single flower blossoms lasts 2~3d,the whole inflorescence lasts about 10 d,population blossom last about 20 d,flowering phenology the unimodal curve model,population for centralized flowering pattern,this pattern is beneficial to attract pollinators,increase the probability of reproductive success.In the flowering process of P.arguta shows: stigma and anther is separation of space position,also has on the same height,and capital to be send out before the pollen;Its hybrid index is equal to 3 or 4,pollen and ovule ratio of 2520-3100,combined with the result of bagging experiment can determine the breeding system belongs to different cross-linking is given priority to,partial selfing affinity,need pollinators or belong to selfing affinity,sometimes need to the type of pollinators.These two approaches may be the collaborative adaptation to environmentalchange.The existence of selfing guarantee increase reproductive success,but will reduce the adaptability of offspring,and its pollen easy to drop on their own stigma the resulting pollen competition may be the cause of the endangered species.In the process of P.arguta flowering,main pollinators are Bombus sp.,Apis florea Fabricius,Andrena cammelia Wu,Episyrphus balteata De Geer,Megachile remota Smith,Athyma jina Moore,Zemeros flegyas Cramer,Coeliccia didyma Selys,etc.Effective pollinators are Bombus sp.,Apis florea,Andrena cammelia.Butterflies,flies and part of the bees are invalid pollinators.Insect pollination behavior related to nectar secretion,fertile flower color and male flower color.When male flower color changed from green to white,to be able to attract pollinators and increase the pollinating insects pollination frequency,which is beneficial to reproductive success.Due to the little kinds of pollinators,when pollination is homologous strain cross pollination phenomenon they may cause its endangered on reproductive,this may be the another reason.Through P.arguta seed germination experiment research that the seeds to be less seed dormancy,energy is low,about 44.6%,low seed germination rate was only12.5%,with the increase of time,germination rate falling,in the field investigation never found a youth plant or little less.Seeds of P.arguta under the condition of natural ecological fitness is low,the number of grow seedlings is small,it is restricted factors affecting population natural regeneration.Aiming at the problems above all,you can take corresponding protection strategies:(1)to take on the protection strategy.(2)using tissue rapid propagation technology of breeding,then transplanted to the natural environment.