|
Wild Cistanche deserticola Y. C. Ma was listed in Appendix II and endangered after years of abuse. Cultivation of C. deserticola was encouraged to meet market demand. Seed production was the premise of cultivation, and the study of pollination characteristics was important to seed production. C. deserticola in Ningxia planting bases was investigated for the species and activity of pollination insects, etc, in order to provide science foundation for the seed breeding. The main research results were as follows:1.Species of flower visitors of C. deserticolaFlower visitors of C. deserticola was captured and indentified during 2008 and 2010. A total number of 35 species of insects included 6 orders and 13 families were recognized as the flower visitors of C. deserticola. Among them, the species account of Hymenoptera and Diptera insects, was 23 and 5, respectively, Hemiptera, Coleoptera, Lepidoptera, was each 2, respectively, the rest 1 specie belong to Thysanoptera.24 species were identified as pollinators, of which Apis mellifera L. Anthophora erschowi, Anthophora altacia Radoszkowski, Anthophora plagiata Illiger, Anthophora patruelis Cockerell, Andrena cineraria L. were principal pollinators.2. The daily activity of major pollinators of C. deserticolaThe activity of flower visitors on 34 individuals was cameraed by Digital monitoring system in 2009 and 2010. The activity of pollinators could be classified two kinds, activited frequently in the morning and evening, at noon. The pollinators numbers of A. mellifera L., A. erschowi, A. altacia Radoszkowski, A. plagiata Illiger, A. patruelis Cockerell, A. cineraria L. were studied, with the maximum of 3.04,0.92, 1.2,0.64,0.57,0.64 and the minimum of 0.39,0,0.95,0.61,0,0 in sunny day.The numbers of above pollinators visiting flowers were also studied, with the maximum of 5.22,1.40,2.75,1.68,0.77,1.65 and the minimum of 1.30,0,0.63,0.69, 0,0 in each flower. The time of pollinating visiting flowers were variable, A.patruelis Cockerell>A. mellifera L.> A. altacia Radoszkowski>A.erschowi>A. plagiata Illiger>A. cineraria L. The visiting time was 12.53s,10.07s,7.16s,7.11s, 6.35s,5.75s, respectively.A. mellifera L. was dominated pollinator. The numbers of pollinators and visiting flowers, the visiting time had significantly positive correlation for each other. The meteorological data of planting base in years 2009 and 2010 showed the change tendency of temperature, humidity, solar radiation was similar. The numbers of A. mellifera L.and temperature had a significantly positive correlation.3.The volatile compounds in C.deserticola inflorescenceInflorescence volatile compounds of 3 individuals were collected, respectively in budding stage, initial bloom stage and full bloom stage during 2010, which composition and content were analysed by GC-MS.The composition and content of volatile compounds in inflorescence at different flower period was variable. Forty volatile components were identified from inflorescence of C. deserticola. The main components in buds were hydrocarbons and green leaf volatiles. Some components were characteristic in buds and disappeared or decreased in flowers. The relative contents of some components gradually increased with the buds blooming. And some components only emerged in flowers. The higher content of esters and aromatics were found in flowers, which were significantly increased in comparison with the volatile compounds from buds.4.Nectar secretion of C. deserticola and its influence on pollinatorsNectar secretion in 10 individuals of control and bagging, respectively, was compared in 2009 and 2010.The amount of nectar secretion of bagging individuals was most on second day during three days of flowering. Under natural conditions, there were 2 peak periods in one day on 8～10 h and 14～16 h, respectively, the highest secretion were 4.9μl and 4.97μl, respectively. Nectar secretion on 10～12 h was least, with the amount of 3.01μl. However, at this time pollinators were most active, and the number of pollinators and pollinating flowers reached maximum.5. The influence of flower colour on pollinatiorsThe pollinators numbers of 32 individuals in different colours was statisticed.The insects preference of colour was dark violet, violet, light violet, yellow-white, mauve, respectively. Some pollinators also visited yellow flowers, but low frequency to violet flowers, with the numbers of 52.75 to 188.75.6.The quantity properties of flowers characters and its influence on pollinatorsThe research between 31 individual characteristics and pollination frequency in 2009 and 2010, indicated that plant height and nectar secretion, flower diameter and nectar sugar content, corolla tube length and nectar secretion all showed significantly positive correlation. It was also found that numbers of fruit was significantly positively correlated with the number of pollinators, while the number of flower, pollinating time as well. Seed weight was significantly positively correlated with the number of pollinators, the same as pollinating time.7. The influence of different flowers department treatments on pollinatorsIn bloom stage of 2009 and 2010, the major pollinators numbers of 3 individuals with removing stamens, corolla lobe, both perianth and stamens were 17.17,6.00, 16.33,23.33 in one day. It showed the attraction of pollinators was a result of the integrated effects of flowers components, of which pollen and nectar played a important role. The reward of nectar was more attractive than pollen to pollinators.8. Pollen germination in situ of self-and cross-pollinatingPollens in both self-and cross-pollinating were germinated, and there were no significantly difference between both germination percentage at different times. Most pollen tubes by self-pollinating only grew at stigmatic surface in 72 h, however pollen tubes grew into the ovary by cross-pollinating after 72 h.
|