The embryogenesis, pollen germination, floral character and seed physiology of the endangered plant Manglietia aromatica Dandy were investigated. Based on this study, this species has very low seed set rate. The abort...The embryogenesis, pollen germination, floral character and seed physiology of the endangered plant Manglietia aromatica Dandy were investigated. Based on this study, this species has very low seed set rate. The abortion rate of functional megaspores in all the ovules is 27.9%, the egg cell abortion rate of mature embryo sacs is up to 80%, and the germination rate of pollen grains is as low as nearly 0.01%. In addition, the floral structure appears to be another limited factor for the effective pollination of this species. The endangerment mechanism of this species seems to be comprehensive. Human's destroying actions are the direct factors that have made the population degenerate quickly; low reproductive ability and the destroyed environments are the main reasons that prevent the population from renovating and spreading. Therefore, the conservation measures suggested by this study are to research the breed technology, artificial population renovating, in situ conservation, and ex situ conservation.展开更多
Manglietia patungensis is an endangered species distributed aggregately in evergreen broad-leaved forest communities in Southwest China. A controlling experiment was employed to test the effects of soil type and shade...Manglietia patungensis is an endangered species distributed aggregately in evergreen broad-leaved forest communities in Southwest China. A controlling experiment was employed to test the effects of soil type and shade degree on seed germination and seedling establishment by using four soil types and three shade treatments with five replicates. Results showed that the germination rate of M. patungensis seeds was relatively low ranging from 19% to 31%. Shade degree and soil type had no significant effect on seed germination rate, but influenced germination dynamics. Both shade degree and soil type treatments significantly affected seedling survival and seedling growth. Seedling survival rate increased with increasing light density. Increased light also promoted biomass accumulation and root development of seedlings. The biomass of the seedlings under full light condition increased 72% comparing with the seedlings under 80% shade degree. Root depth, root area and cross number increased with the increase of light density. Seedlings on farmland soil survived better than that on other three kinds of soil. The seedling survival rate in the farmland soil reached 91.4%, but was reduced to 80.3%, 78.0% and 52.8% in old-field soil, sandy soil and forest soil respectively. Total biomass, aboveground biomass and root biomass of seedlings in forest soil was the highest, followed by seedlings in sandy and old-field soils respectively, and seedlings in farmland soil ranked the least. Some suggestions were finally put forward for the conservation of M. patungensis based on the research results.展开更多
Manglietia ventii is a wild plant species with extremely small populations endemic to Yunnan,mainly distributed in southeast Yunnan.Due to the continuous deterioration of natural habitats,excessive felling and utiliza...Manglietia ventii is a wild plant species with extremely small populations endemic to Yunnan,mainly distributed in southeast Yunnan.Due to the continuous deterioration of natural habitats,excessive felling and utilization of human beings,and the decline of breeding ability,the number of individuals in the population has decreased significantly.Through field investigation and literature review,the research status of M.ventii in systematics,conservation ecology,reproductive biology,genetic diversity,endangered mechanism and resource protection at home and abroad are systematically reviewed.And the future research direction is prospected.It is necessary to strengthen the research on the basic characteristics of M.ventii,explore the transmission route of M.ventii and deepen the development and utilization of resources,in order to provide a theoretical support for the protection and sustainable utilization of germplasm resources of M.ventii,and provide a reference for the protection of other wild plant species with extremely small populations.展开更多
文摘The embryogenesis, pollen germination, floral character and seed physiology of the endangered plant Manglietia aromatica Dandy were investigated. Based on this study, this species has very low seed set rate. The abortion rate of functional megaspores in all the ovules is 27.9%, the egg cell abortion rate of mature embryo sacs is up to 80%, and the germination rate of pollen grains is as low as nearly 0.01%. In addition, the floral structure appears to be another limited factor for the effective pollination of this species. The endangerment mechanism of this species seems to be comprehensive. Human's destroying actions are the direct factors that have made the population degenerate quickly; low reproductive ability and the destroyed environments are the main reasons that prevent the population from renovating and spreading. Therefore, the conservation measures suggested by this study are to research the breed technology, artificial population renovating, in situ conservation, and ex situ conservation.
文摘目的明确3种木莲属濒危药用植物叶绿体基因组密码子的使用偏好性,揭示影响其密码子使用偏性的因素,为后续研究奠定基础。方法利用CodonW1.4.2、EMBOSS、SPSS19.0软件对木兰科木莲属植物粗梗木莲Manglietia crassipes Law、大果木莲Manglietia grandis Hu et Cheng、毛果木莲Manglietia ventii N.V.Tiep叶绿体基因组的密码子偏好性进行分析。结果3种木莲属濒危药用植物叶绿体基因组密码子的第3位碱基GC平均含量为30.23%~32.50%,有效密码子数(ENC)均大于35%,表明其密码子的偏性较弱。中性绘图、ENC-plot和PR2-plot分析表明,3种木莲属濒危药用植物叶绿体基因组密码子使用偏性主要受自然选择的影响,也有部分基因受突变压力的影响。利用相对同义密码子使用度(RSCU)筛选出GUU、GUA、UCA、CCA、GCA等43个最优密码子,其中有35个以A/U结尾。结论3种木莲属濒危药用植物叶绿体基因组密码子偏好使用A/U结尾,其密码子使用偏性主要受自然选择影响,可为基因表达和基因载体选择等研究提供依据。
文摘Manglietia patungensis is an endangered species distributed aggregately in evergreen broad-leaved forest communities in Southwest China. A controlling experiment was employed to test the effects of soil type and shade degree on seed germination and seedling establishment by using four soil types and three shade treatments with five replicates. Results showed that the germination rate of M. patungensis seeds was relatively low ranging from 19% to 31%. Shade degree and soil type had no significant effect on seed germination rate, but influenced germination dynamics. Both shade degree and soil type treatments significantly affected seedling survival and seedling growth. Seedling survival rate increased with increasing light density. Increased light also promoted biomass accumulation and root development of seedlings. The biomass of the seedlings under full light condition increased 72% comparing with the seedlings under 80% shade degree. Root depth, root area and cross number increased with the increase of light density. Seedlings on farmland soil survived better than that on other three kinds of soil. The seedling survival rate in the farmland soil reached 91.4%, but was reduced to 80.3%, 78.0% and 52.8% in old-field soil, sandy soil and forest soil respectively. Total biomass, aboveground biomass and root biomass of seedlings in forest soil was the highest, followed by seedlings in sandy and old-field soils respectively, and seedlings in farmland soil ranked the least. Some suggestions were finally put forward for the conservation of M. patungensis based on the research results.
基金Supported by National Natural Science Foundation of China(31960069).
文摘Manglietia ventii is a wild plant species with extremely small populations endemic to Yunnan,mainly distributed in southeast Yunnan.Due to the continuous deterioration of natural habitats,excessive felling and utilization of human beings,and the decline of breeding ability,the number of individuals in the population has decreased significantly.Through field investigation and literature review,the research status of M.ventii in systematics,conservation ecology,reproductive biology,genetic diversity,endangered mechanism and resource protection at home and abroad are systematically reviewed.And the future research direction is prospected.It is necessary to strengthen the research on the basic characteristics of M.ventii,explore the transmission route of M.ventii and deepen the development and utilization of resources,in order to provide a theoretical support for the protection and sustainable utilization of germplasm resources of M.ventii,and provide a reference for the protection of other wild plant species with extremely small populations.
