Magnolia sinica is one of the most threatened trees endemic to Southeast Yunnan.Based on our investigations,only 52 individuals and eight populations are found in the wild.M.sinica has been categorized as Critically E...Magnolia sinica is one of the most threatened trees endemic to Southeast Yunnan.Based on our investigations,only 52 individuals and eight populations are found in the wild.M.sinica has been categorized as Critically Endangered on the IUCN Red List and identified as a "Plant Species with Extremely Small Populations(PSESP)".Its fruit/seed set is very low and seedlings are rarely found in the wild.It is hypothesized that it may encounter obstacles to reproductive success.This study,therefore,focuses on its reproductive biology,knowledge of which is essential for effective conservation.Flowers of this species are protogynous and nocturnal,and possess a two-day rhythm of sexual presentation.For the first night of anthesis,the flowers are in the pistillate stage during which tepals open at dusk and close approx.1 h later(except for the open outer ones).They remain closed until the next afternoon,when flowers,now in the staminate stage,re-open and remain so until the tepals drop.Nocturnal beetles enter into the flowers and remain trapped throughout the night as the flower closes,during which time they feed on tepals.Pollen-gathering bees are found to visit the re-opened flowers and the beetles are released during this stage.Two species of Pleocomidae and Curculionidae beetles appear to be effective pollinators.M.sinica is a self-compatible,pollinator-dependent species,and its fruit/seed set can be significantly increased by hand-pollination.No functional seed dispersers have been found in its extant natural habitats.These findings suggest that it may face both pollination and seed disperser insufficiencies in its current fragmented habitats,which may account for its low regeneration.Here we propose conservation strategies based on our findings.展开更多
A new tetrastilbene named carasinol D （1） was isolated from the roots of Caragana sinica. Its structure was elucidated by spectroscopic analysis. Compound 1 was obtained from carasinol B （2） by an acid-catalyzed c...A new tetrastilbene named carasinol D （1） was isolated from the roots of Caragana sinica. Its structure was elucidated by spectroscopic analysis. Compound 1 was obtained from carasinol B （2） by an acid-catalyzed conversion.展开更多
In order to efficiently explore and use woody biomass,six lignin fractions were isolated from dewaxed Caragana sinica via successive extraction with organic solvents and alkaline solutions.The lignin structures were c...In order to efficiently explore and use woody biomass,six lignin fractions were isolated from dewaxed Caragana sinica via successive extraction with organic solvents and alkaline solutions.The lignin structures were characterized by Fourier transform infrared spectroscopy(FT-IR) and 1D and 2D Nuclear Magnetic Resonance(NMR).FT-IR spectra revealed that the "core" of the lignin structure did not significantly change during the treatment under the conditions given.The results of 1H and 13C NMR demonstrated that the lignin fraction L2,isolated with 70% ethanol containing 1% NaOH,was mainly composed of β-O-4 ether bonds together with G and S units and trace p-hydroxyphenyl unit.Based on the 2D HSQC NMR spectrum,the ethanol organosolv lignin fraction L1,extracted with 70% ethanol,presents a predominance of β-O-4′ aryl ether linkages(61% of total side chains),and a low abundance of condensed carbon-carbon linked structures(such as ββ′,β-1′,and β-5′) and a lower S/G ratio.Furthermore,a small percentage(ca.9%) of the linkage side chain was found to be acylated at the γ-carbon.展开更多
The objectives of this study were to investigate the effects of successive continuous generation （SCG） cuttings of Buxus sinica var. parvifolia on the rejuvenation of ortets at the hormone level, detect levels of in...The objectives of this study were to investigate the effects of successive continuous generation （SCG） cuttings of Buxus sinica var. parvifolia on the rejuvenation of ortets at the hormone level, detect levels of indoleacetic acid （IAA）, abscisic acid （ABA）, isopentenyladenosine （iPA）, zeatin riboside （ZR） and gibberellin4 （GA4） during the rooting process of different generations by means of enzyme-linked immunosorbent assay （ELISA） technology and statistically analyze the rooting characteristics of cuttings. The results show that, the root systems of subsequent generations （generation 1998, 2000） developed satisfactorily, only a few initial generation （generation 1990, 1994） cuttings rooted and the root growth was inhibited. Around the period of callus formation and root projection through the epidermis, there was a marked, regular variation in the levels of IAA, ABA and GA4 between the initial generations and subsequent generations.展开更多
基金supported financially by the NSFC-Yunnan joint fund to support key projects to W.B.Sun(Grant no.U1302262)the Young Academic and Technical Leader Raising Foundation of Yunnan Province to G.Chen(2015HB091)
文摘Magnolia sinica is one of the most threatened trees endemic to Southeast Yunnan.Based on our investigations,only 52 individuals and eight populations are found in the wild.M.sinica has been categorized as Critically Endangered on the IUCN Red List and identified as a "Plant Species with Extremely Small Populations(PSESP)".Its fruit/seed set is very low and seedlings are rarely found in the wild.It is hypothesized that it may encounter obstacles to reproductive success.This study,therefore,focuses on its reproductive biology,knowledge of which is essential for effective conservation.Flowers of this species are protogynous and nocturnal,and possess a two-day rhythm of sexual presentation.For the first night of anthesis,the flowers are in the pistillate stage during which tepals open at dusk and close approx.1 h later(except for the open outer ones).They remain closed until the next afternoon,when flowers,now in the staminate stage,re-open and remain so until the tepals drop.Nocturnal beetles enter into the flowers and remain trapped throughout the night as the flower closes,during which time they feed on tepals.Pollen-gathering bees are found to visit the re-opened flowers and the beetles are released during this stage.Two species of Pleocomidae and Curculionidae beetles appear to be effective pollinators.M.sinica is a self-compatible,pollinator-dependent species,and its fruit/seed set can be significantly increased by hand-pollination.No functional seed dispersers have been found in its extant natural habitats.These findings suggest that it may face both pollination and seed disperser insufficiencies in its current fragmented habitats,which may account for its low regeneration.Here we propose conservation strategies based on our findings.
基金This project is supported by the National Natural Science Foundation of China （No. 39270800）；the Major Subject of the Science and Technology Commission of Shanghai Municipality （No. 06DZ19709）.
文摘A new tetrastilbene named carasinol D （1） was isolated from the roots of Caragana sinica. Its structure was elucidated by spectroscopic analysis. Compound 1 was obtained from carasinol B （2） by an acid-catalyzed conversion.
基金Major State Basic Research Projects of China(973-2010CB732204)Specific Programs in Graduate Science and Technology Innovation of Beijing Forestry University(BLYJ201110)
文摘In order to efficiently explore and use woody biomass,six lignin fractions were isolated from dewaxed Caragana sinica via successive extraction with organic solvents and alkaline solutions.The lignin structures were characterized by Fourier transform infrared spectroscopy(FT-IR) and 1D and 2D Nuclear Magnetic Resonance(NMR).FT-IR spectra revealed that the "core" of the lignin structure did not significantly change during the treatment under the conditions given.The results of 1H and 13C NMR demonstrated that the lignin fraction L2,isolated with 70% ethanol containing 1% NaOH,was mainly composed of β-O-4 ether bonds together with G and S units and trace p-hydroxyphenyl unit.Based on the 2D HSQC NMR spectrum,the ethanol organosolv lignin fraction L1,extracted with 70% ethanol,presents a predominance of β-O-4′ aryl ether linkages(61% of total side chains),and a low abundance of condensed carbon-carbon linked structures(such as ββ′,β-1′,and β-5′) and a lower S/G ratio.Furthermore,a small percentage(ca.9%) of the linkage side chain was found to be acylated at the γ-carbon.
基金the National Natural Science Foundation of China （Grant No. 30070633）.
文摘The objectives of this study were to investigate the effects of successive continuous generation （SCG） cuttings of Buxus sinica var. parvifolia on the rejuvenation of ortets at the hormone level, detect levels of indoleacetic acid （IAA）, abscisic acid （ABA）, isopentenyladenosine （iPA）, zeatin riboside （ZR） and gibberellin4 （GA4） during the rooting process of different generations by means of enzyme-linked immunosorbent assay （ELISA） technology and statistically analyze the rooting characteristics of cuttings. The results show that, the root systems of subsequent generations （generation 1998, 2000） developed satisfactorily, only a few initial generation （generation 1990, 1994） cuttings rooted and the root growth was inhibited. Around the period of callus formation and root projection through the epidermis, there was a marked, regular variation in the levels of IAA, ABA and GA4 between the initial generations and subsequent generations.
