Floral Characteristics And Pollination Biology Of Endangered Plant Magnolia Sinensis

Floral characteristics and pollination biology are the focus of modern ecology,In particular,it is of great significance for the protection of endangered species.This paper was based on the Magnolia sinensis of natural distribution in the DaChuan town in LuShan as the research object,Studying on Magnolia sinensis floral comprehensive feature,pollination ecology of different altitude gradients of 1800 m,2000m,2200 m,2400 m by position observation?microscropic observation,the results of the study have verified preliminarily the endangered mechanisms of Magnolia sinensis,in order to pretect the Magnolia sinensis in wild environment,and offer scientific basis for recovery.The results were showed as follows:1.Magnolia sinensis flowering in the early middle of 5,in the late middle of 5 into the full bloom,middle June flowering end,total flowering duration around 35 d,since the difference of temperature at different altitudes,the flowering time was different,altitude 2400 m delayed 14-17 d than 1800 m,The duration of flowering at different altitudes was the same for 17-19 d;the opening process of single flower can be divided into bud stage,flower opening,full blooming,and flower withering,bud stage duration 7-8 d,the flowering duration of single flower was 4-5 d,the flowering duration of flowers at different altitudes are same.2.The flower diameter of altitude 2000 m and 2200 m was significantly higher than the altitude of 1800 m and 2400 m(p<0.05);Rod shaped torus,there was no significant difference in the length of each elevation(p>0.05);tepals 9,the size of the tepals in elevation of 2200 m was significantly higher than that of the 1800 m and the 2400 m(p<0.05);The number of pistils and stamens in the altitude of 1800 m(83.50±10.52,41.50±4.32)was significantly higher than(p<0.05)2400 m(66±11.40,3 3.25±2.06),shows that with the increase of altitude,Magnolia sinensis reduced sexual function input.3.Magnolia sinensis has the characteristics of dichogamy,the pistil is first ripe,on the first day and the first day of flowering,a large amount of mucus was produced on the surface of stigma and the stigma has the best receptivity,after loose powder,the stigma receptivity decreased,and the pollen and stigma had high activity time at the same time is short;stamens not crack in flowering day,it cracks in second to third days,the pollen vigor is high,the pollen vitality of the first day is more than 85%up to 93%,with the increase of the opening process,the vitality gradually declined,pollen viability was maintained until the fourth day of loose powder;Magnolia sinensis has the characteristics of herkogamy,with the delay of flowering time,gynoecium gradually rise,at the altitude of 1800 m and 2000 m,herkogamy were most significant,respectively,at the first day of 9.16±0.39 mm and 9.99±0.01 mm increased to fifth days of 19.72±0.17 mm and 19.69±0.19 mm.4.Principal component analysis on the floral syndrome parameters at different altitudes of Magnolia sinensis,two main components were extracted,the first principal component flower diameter contribution rate was 66.749%,the second principal component torus length contribution rate was 23.852%,the total contribution rate was 90.601%.According to the comprehensive model,the score at 2200 m altitude was 1.94,and the comprehensive evaluation score was the first,which showed the best flower show,so it was more suitable to grow at an altitude of 2200 m.5.Magnolia sinensis OCI value is 4.The pollination method of Magnolia sinensis is outcrossing and self-part compatibility,need pollinators.Through the calculation of P/O value of different altitudes,the P/O is 3024.6-14000,according to the Cruden standard(2108.0-195525.0),it was concluded that the pollination method of Magnolia sinensis was obligate outcrossing,need pollinators.6.A total of 12 specie of flower visiting insects were observed at Magnolia sinensis,main flower visiting insects is Bombus ningpoensis,Apis cerana Fabricius and Syrphidae,the total number of visits was about 322 times.The visiting peak time of visiting insects at different altitudes was concentrated at 10:00-11:00 a.m.and 13:00-14:00 p.m.7.Magnolia sinensis most important cross pollination insects is Bumblebee,it were observed 170 visits,accounting for about 52.80%of the total,it main floral sites was stamens and pistils.Different altitude Bumblebee pollinator frequency is different,the temperature of high altitude is low,so the frequency of visiting insects is low,Bumblebee at an altitude of 1800 m and 2000 m visiting frequencies(7.105±1.38 second· h-1 and 7.075±0.05 second·h-1)was significantly higher than that of 2200 m and 2400 m visiting frequencies(1.57±0.73 second·h-1 and 0.50±0.04 second·h-1)(P<0.05).