Study On The Pollination Biology Of The State Key Protected Species Emmenopterys Henryi Oliv.

Emmenopterys henryi, which belongs to the Emmenopterys, Rubiaceae, is native to China. It is one of the national first-level precious plants and the second-level protected species in China.Therefore It is important to study the measurements for protection of it.By field investigation and lab experiments, we have rudimentary research on seven populations (Dashuichong,Songmaochong and Houtouwa) in different habitats in Liankangshan nature reserve of Xin County in Henan province,covering the following features,i.e. population flowering opening, pollen viability, stigma receptivity,kinds of the pollinating insects, the pollinating behavior, frequency and the efficiency of the pollinating insects, pollen-ovule ratio,out-crossing index, nature and artificial pollination treatments on pollen germination rate. Based on the research we further analyzed the endangered reasons and proposed the corresponding protective measures.Following are the results:(1)Floral characteristics and flowering habit. The flower of Emmenopterys henryi is bisexual and herkogamy. Each inflorescence is covered with 18~30 flowers. The flowerescence of a single one spans 5 to 6 days, the flowerescence of a single plant spans 15 to 16 days,in which many flowers were blooming in the same time;Among the population, the flowerescence spans from early July to August, the flowerings of different population had no big difference, but based on the same population the synchronism of flowers was low.Population florescences were earlier in lower elevation than in higher elevation.(2)Pollen quality The pollen's dispersing lasts 6 to 7 days from 1day before blooming to 5-6 day after blooming, the outbreak dispersing is focusing in 1 to 2 days. The single flower has great pollen quantity, 256752±55523; in 1-3 days after the dispersing,pollen viability is above 80%, the highest viability was 97%,indicating that pollen quality may not be the key factor leading to the endangered status of this species.There were fertile and sterile pollens, the fertile ones are round sphere, sterile ones are anomalous circle caky.The abortion rate was increasing gradually in the florescence. (3)Stigma receptivity Both the flowering morphology dynamics of a single flower and test for stigma receptivity indicated that the mature period of pistils was later than the stamens. Stigma was acceptive only on the second to third day after flowering.There is only 0.5-1d overlapping time between pistils and stamens. Meanwhile, stigma receptivity can be influenced by temperature, illumination and humidity.(4)Breeding system features The breeding system would be facultative xenogamy by the Pollen-ovule ratio=1862 of Emmenopterys henryi. By its out-crossing index=3 the breeding system of this species is likely to self-compatible and needs pollinators sometimes during the pollinating process. The result of the treatments of emasculated, bagged and without artificial pollination shows that Emmenopterys henryi does not have apomixes. These three results are coincident.So the breeding system of Emmenopterys henryi can be determined to be self-compatible and needs pollinators.(5)Characteristics of pollinating insects The results about the pollination biology characteristics of Emmenopterys henryi were revealed through the field observation.The flowers are visited by 17 species of insects which belong to Hymenoptera, Lepicoptera , Coleoptera , Blattaria and Tthysanoptera in the experiment. And there are 10 kinds of insects belonging to Hymenoptera, accounting for 66.7%. The visiting time and frequency of each insect is different. The main pollinators are Apis cerana Fabricius,Daimio tethys, Campsomeris prismatica.The results of field observation show that the activities of insects are influenced by temperature and weather. What's more, with the altitude increasing, the kinds of insects are decreasing.Because pollination insufficiency and continuous rain cause natural fertility to be low,the pollination of the species is not successful. So on the pollination, pollination medium insufficiency and population dispersing are the endangered main reasons of Emmenopterys henryi.