Preliminary Studies On Biological Characteristics Of Plumbago Auriculata

Plumbago auriculata belonged to plumbaginaceae plumbago species, originated in South Africa. The vitality of the species with high ornamental value, population, the effect was very good, which have great development value in landscape application. But there had been no one to delve into the biology and landscape application. In Chengdu region P. auriculata has a good growing condition, ecological adaptability and ornamental values, thus having great potential in the actual landscape application. To promote the application of P. auriculata, the seed biological features, flowering biological characteristics, pollination and seed setting characteristics were studied systematically. The main results obtained in this study were as follows:(1) P. auriculata mature seed are brown with a high maturity and deep color, so the seed collecting can be determined based on seed color. The thousand-seed weight is8.84g, an average of113seeds up to1g. P. auriculata’s testa thin and the germ close to chalazal, these characteristics were conducive to the P. auriculata seed breakthrough seed coat and germination, and P. auriculata seed does not have dormancy characteristic. So accelerating germination and other special processing before sowing is not necessary. According to the P. auriculata studied on seed germination characteristics of results, before germination P. auriculata seeds should generally be soaked24h, the optimum temperature for germination was25℃, seed storage methods can choose the conventional storage.(2) P. auriculata flowering by late May to Mid-October. L-type single flower florescence for5days, S-type for4days. L-type plants of a single inflorescence florescence about10days, S-type, compared with about8days; L-type plants per plant florescence about36days, S-type, compared with about32days.(3) P. auriculata which have two types of pollen and stigma morphology with large differences. P values and E values of the S-type pollen were significantly higher than the L-type pollen. L-shaped stigma was significantly longer than the S-type, The style diameter was significantly greater than the S-type. L-type pollen exine exine ornamentation is tightly packed and uniform, S-type pollen is relatively loose and uneven; L-shaped strumae property neglect S-type, and L-shaped strumae property has a handle.(4) P. auriculata’s breeding type was outcrossing, and has a high flowering synchrony index, is0.89, but the relative flowering intensity was not high, not conducive to attract insects and reproductive success, P. auriculata was a typical style heterotypic plants, and has a self-incompatibility, so, the lack of pollinators lead to low seed setting rate.(5) P. auriculata can be used in the petals open (in this case the stigma has been stretched and has a strong pollinated sexual, and the anthers not crack) take loose2h-3h pollen artificial emasculation heterotype pollen processing, can improve the P. auriculata seed setting rate, to solve the realistic problem of seed yield less.(6) P. auriculata grant heterotype pollen seed setting rate was much higher than that of natural seed setting rate, so, artificial pollination is an important technical to solve the problem of scarcity of the high price of seed.