Machilus maomingensis Jin et Tang,sp.nov.from the Eocene Youganwo Formation of the Maoming Basin,South China,is studied in detail from the perspective of the leaf architecture and the excellently preserved cuticle.The...Machilus maomingensis Jin et Tang,sp.nov.from the Eocene Youganwo Formation of the Maoming Basin,South China,is studied in detail from the perspective of the leaf architecture and the excellently preserved cuticle.The leaf margin is entire,the primary venation is pinnate;6 to 8secondary veins are present and the major secondary venation is eucamptodromous.Stomata are paracytic and occur on the lower epidermis.Trichome bases are unicellular.Oil cells are present in the upper epidermis.The new fossil species described has features of the Lauraceae,particularly of the extant genus Machilus Rumphius ex Nees,and it is most similar to Machilus chinensis（Bentham）Hemsley,an extant species distributed in southern China and Vietnam.Hence,Machilus maomingensis sp.nov.is inferred to live in a warm and humid climate.The discovery of the present fossil indicates that Machilus has existed in South China from at least the Eocene.展开更多
The potential geographic distribution and favorable climatic conditions of Machilus thunbergii under current and future predicted climates in China are predicted based on MaxEnt model and ArcGIS software. The results ...The potential geographic distribution and favorable climatic conditions of Machilus thunbergii under current and future predicted climates in China are predicted based on MaxEnt model and ArcGIS software. The results show that the AUC values in different time periods and emission seniors are more than 0.9, which indicates the prediction is excellent. Precipitation of the coldest quarter, precipitation of the driest month, annual precipitation, mean diurnal range, and temperature annual range are the most important environmental factors affecting the distribution of Machilus thunbergii. At present, the suitable areas of Machilus thunbergii are mainly concentrated in the eastern subtropics of China, with a total area of 118.47 × 104 km2. The medium-suitability area and the high-suitability area are concentrated in Wuyi Mountains, Luoxiao Mountains, Xuefeng Mountains, Nanling and east of Taiwan Mountains. With the change of climate, the suitable area increases, and the medium-suitability area and high-suitability area migrate and expand to the east, and the low-suitability area expands slightly to the west and north. So, the simulated distribution of Machilus thunbergii should be one of priorities, when instigating in-situ conservation. The research results can provide a theoretical reference for the popularization and planting of Machilus thunbergii.展开更多
The soil drought stress experiment in different durations (no watering within 3d, 6d, 9d, 11d individually) was conducted to study the drought-resistant capacity of one-year-old seedlings for the native tree species (...The soil drought stress experiment in different durations (no watering within 3d, 6d, 9d, 11d individually) was conducted to study the drought-resistant capacity of one-year-old seedlings for the native tree species (Machilus yunnanensis) in Yunnan Province and the introduced tree species (Cinnamomum camphora). The leaf water potential, chlorophyll content, proline content and plasma membrane permeability for two species seedlings were measured in different soil drought conditions. The results showed that, on the 9th day of drought stress, the leaf water potential of two species decreased obviously, whereas the free proline content and plasma membrane permeability increased sharply. On the 11th day, the leaf water potential of C. camphora seedlings was lower than that of M. yunnanensis seedlings; the plasma membrane permeability in C. camphora seedling leaves increased much more than that in M. yunnanensis seedling leaves, which showed that the injury to the former by soil drought stress was more severe than that to the latter. The free proline content in M. yunnanensis seedling leaves continued to increase on the 11th day, but that in the C. camphora seedling leaves started to drop obviously, indicating that the reduction of osmotic regulation substance in C. camphora seedling leaves after the 11th day was unable to maintain the osmotic balance between the plasma system and its surroundings and the water loss occurred inevitably. Comprehensively, M. yunnanensis seedlings enhanced the drought-resistance in the course of soil drought stress by maintaining higher leaf water potential and by increasing osmotic regulation substance to promote cell plasma concentration and maintain membrane structure integrity so as to reduce water loss. The subordination function index evaluated with fuzzy mathematic theory also showed that the drought-resistant capacity of M. yunnanensis seedlings was stronger than that of C. camphora seedlings.展开更多
Machilus spp.are mostly valuable timber and economic tree species,widely used in many fields such as artificial afforestation,landscaping,furniture and building materials,chemicals and medicine.In this article,the dis...Machilus spp.are mostly valuable timber and economic tree species,widely used in many fields such as artificial afforestation,landscaping,furniture and building materials,chemicals and medicine.In this article,the distribution,uses and domestic resources of Machilus Nees are summarized.Focus is placed on the analysis of propagation methods,including seed propagation,cutting propagation and tissue culture propagation.The research status and existing problems are summarized,and the future research focus on the propagation technology of Machilus Nees is prospected,with a view to provide theoretical references for the efficient breeding of high-quality seedlings and comprehensive promotion and application of Machilus spp.and contribute to the conservation and sustainable use of wild resources.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.41210001)State Key Laboratory of Palaeobiology and Stratigraphy (Nanjing Institute of Geology and Palaeontology,CAS) (Grant No.123110)+1 种基金the Fundamental Research Funds for the Central Universities(Grant No.161gjc28)the Scientific Research Fund,Hongda Zhang,Sun Yat-sen University
文摘Machilus maomingensis Jin et Tang,sp.nov.from the Eocene Youganwo Formation of the Maoming Basin,South China,is studied in detail from the perspective of the leaf architecture and the excellently preserved cuticle.The leaf margin is entire,the primary venation is pinnate;6 to 8secondary veins are present and the major secondary venation is eucamptodromous.Stomata are paracytic and occur on the lower epidermis.Trichome bases are unicellular.Oil cells are present in the upper epidermis.The new fossil species described has features of the Lauraceae,particularly of the extant genus Machilus Rumphius ex Nees,and it is most similar to Machilus chinensis（Bentham）Hemsley,an extant species distributed in southern China and Vietnam.Hence,Machilus maomingensis sp.nov.is inferred to live in a warm and humid climate.The discovery of the present fossil indicates that Machilus has existed in South China from at least the Eocene.
文摘The potential geographic distribution and favorable climatic conditions of Machilus thunbergii under current and future predicted climates in China are predicted based on MaxEnt model and ArcGIS software. The results show that the AUC values in different time periods and emission seniors are more than 0.9, which indicates the prediction is excellent. Precipitation of the coldest quarter, precipitation of the driest month, annual precipitation, mean diurnal range, and temperature annual range are the most important environmental factors affecting the distribution of Machilus thunbergii. At present, the suitable areas of Machilus thunbergii are mainly concentrated in the eastern subtropics of China, with a total area of 118.47 × 104 km2. The medium-suitability area and the high-suitability area are concentrated in Wuyi Mountains, Luoxiao Mountains, Xuefeng Mountains, Nanling and east of Taiwan Mountains. With the change of climate, the suitable area increases, and the medium-suitability area and high-suitability area migrate and expand to the east, and the low-suitability area expands slightly to the west and north. So, the simulated distribution of Machilus thunbergii should be one of priorities, when instigating in-situ conservation. The research results can provide a theoretical reference for the popularization and planting of Machilus thunbergii.
基金This research was supported by Research Fund of Southwest Forestry College (200510)
文摘The soil drought stress experiment in different durations (no watering within 3d, 6d, 9d, 11d individually) was conducted to study the drought-resistant capacity of one-year-old seedlings for the native tree species (Machilus yunnanensis) in Yunnan Province and the introduced tree species (Cinnamomum camphora). The leaf water potential, chlorophyll content, proline content and plasma membrane permeability for two species seedlings were measured in different soil drought conditions. The results showed that, on the 9th day of drought stress, the leaf water potential of two species decreased obviously, whereas the free proline content and plasma membrane permeability increased sharply. On the 11th day, the leaf water potential of C. camphora seedlings was lower than that of M. yunnanensis seedlings; the plasma membrane permeability in C. camphora seedling leaves increased much more than that in M. yunnanensis seedling leaves, which showed that the injury to the former by soil drought stress was more severe than that to the latter. The free proline content in M. yunnanensis seedling leaves continued to increase on the 11th day, but that in the C. camphora seedling leaves started to drop obviously, indicating that the reduction of osmotic regulation substance in C. camphora seedling leaves after the 11th day was unable to maintain the osmotic balance between the plasma system and its surroundings and the water loss occurred inevitably. Comprehensively, M. yunnanensis seedlings enhanced the drought-resistance in the course of soil drought stress by maintaining higher leaf water potential and by increasing osmotic regulation substance to promote cell plasma concentration and maintain membrane structure integrity so as to reduce water loss. The subordination function index evaluated with fuzzy mathematic theory also showed that the drought-resistant capacity of M. yunnanensis seedlings was stronger than that of C. camphora seedlings.
基金Forestry Science and Technology Innovation Project of Guangdong Province(14KJCX005-02).
文摘Machilus spp.are mostly valuable timber and economic tree species,widely used in many fields such as artificial afforestation,landscaping,furniture and building materials,chemicals and medicine.In this article,the distribution,uses and domestic resources of Machilus Nees are summarized.Focus is placed on the analysis of propagation methods,including seed propagation,cutting propagation and tissue culture propagation.The research status and existing problems are summarized,and the future research focus on the propagation technology of Machilus Nees is prospected,with a view to provide theoretical references for the efficient breeding of high-quality seedlings and comprehensive promotion and application of Machilus spp.and contribute to the conservation and sustainable use of wild resources.
