There are three distinct genetic systems in higher plants,the dominant nuclear genome and the semi-autonomous organelle genomes(plastids and mitochondria).In contrast to the conserved plastid genome(plastome),the plan...There are three distinct genetic systems in higher plants,the dominant nuclear genome and the semi-autonomous organelle genomes(plastids and mitochondria).In contrast to the conserved plastid genome(plastome),the plant mitochondrial genome(mitogenome)is characterized by an intriguing“evolutionary paradox”distinguished by a remarkably low mutation rate but with a significantly high rearrangement rate(Palmer and Herbon,1988;Lai et al.,2022).展开更多
The palynomorph assemblage of lake sediments younger than 51.9 kaBP from Wulagai Gobi in Inner Mongolia was analyzed to reconstruct the vegetation and climate. From 51.9 to 30.6 kaBP, the vegetation was arid to semi-a...The palynomorph assemblage of lake sediments younger than 51.9 kaBP from Wulagai Gobi in Inner Mongolia was analyzed to reconstruct the vegetation and climate. From 51.9 to 30.6 kaBP, the vegetation was arid to semi-arid grassland with only slight changes. According to the palynomorphs, trees and shrubs were very rare. The large number and diversity of algae indicate the presence of a lake. Quantitative climatic conditions were reconstructed using the Best Analogues Method. The results indicate that the annual mean temperature was higher than that at present. The combination of temperature and annual precipitation suggests a change in the climate from cool dry to warm dry and then cool humid. Our results show that the annual precipitation values were mostly higher than that at present but were lower than 400 mm. It infers that the study area was already within the arid to semi-arid regions but with a stronger influence of the summer monsoon during 51.9 to 30.6 kaBP than at present. With slight differences mainly in time scale, the changing trend of the annual temperature curve is consistent with the other climatic records from Antarctica, Greenland, Hulu Cave （East China）, and the Tibetan Plateau during the last glacial period. From 30.6 kaBP to present, very few palynomorphs were detected in the samples. Hence, no information about the vegetation and climate could be extracted. Combined with other studies during Late Pleistocene, we presume that the reason for the lack of pollen during this period was caused by an abrupt temperature fall after 30.6 kaBP or that the lacustrine conditions were unsuitable for pollen deposition. It was probably incurred by the oxidation on land prior to deposition. But for those samples only with algae, it might be caused by the fact that algae could finish their life history in a very short time in a seasonal lake.展开更多
The evolution of the Asian monsoon from the Late Oligocene to the Early Miocene is poorly understood.Here,we first reconstruct the precipitation data of central Tibet during 26–16 million years ago(Ma),applying the c...The evolution of the Asian monsoon from the Late Oligocene to the Early Miocene is poorly understood.Here,we first reconstruct the precipitation data of central Tibet during 26–16 million years ago(Ma),applying the coexistence approach to sedimentary pollen data,and detect an intensified Asian monsoon with1.35 Ma and0.33 Ma cycles.Paleoclimate modeling is used to show the importance of paleogeographic location in the development of the paleomonsoon.In addition,the results of spectral analysis suggest that the fluctuations in the Asian monsoon during 26–16 Ma can be attributed to the long-period cyclicities in obliquity(1.2 Ma).These findings provide climate data that can be used to understand the Asian monsoon evolution during the Late Oligocene to Early Miocene and highlight the effects of paleogeographic patterns and long-period orbital forcings on the tectonic-scale evolution of the Asian monsoon.展开更多
The present article deals with the use of tree barks as a natural trap for airborne spores and pollen grains in China.The study carried out at the southern part of Beijing Botanical Garden,Institute of Botany,Chinese ...The present article deals with the use of tree barks as a natural trap for airborne spores and pollen grains in China.The study carried out at the southern part of Beijing Botanical Garden,Institute of Botany,Chinese Academy of Sciences has yielded a variety of palynomorphs mostly belonging to tree taxa.New methodologies for extraction of palynomorphs from tree barks have been suggested.Bark samples were collected from three taxa,i.e.,Paulownia fortunei Hemsl.(Scrophulariaceae),Quercus dentata Thunb.(Fagaceae),and Picea meyeri Rehder&E.H.Wilson(Pinaceae)having different bark morphologies.P.fortunei with a comparatively soft and fissured bark is believed to have a greater potential for trapping airborne spores and pollen grains compared to the stiff and less fissured barks of Q.dentata and the scaly bark of P.meyeri.Old barks yield better data in terms of quantity and quality of trapped pollen and spores.The present study throws new light on the modern pollen rain,spore-pollen dispersal,and their deposition in and aroundBeijing Botanical Garden,and other different parts of China.展开更多
基金The work is supported by the Natural Science Foundation of Jiangsu Province(BK20220414)the Natural Science Foundation of the Higher Education Institutions of Jiangsu Province(22KJB220003).
文摘There are three distinct genetic systems in higher plants,the dominant nuclear genome and the semi-autonomous organelle genomes(plastids and mitochondria).In contrast to the conserved plastid genome(plastome),the plant mitochondrial genome(mitogenome)is characterized by an intriguing“evolutionary paradox”distinguished by a remarkably low mutation rate but with a significantly high rearrangement rate(Palmer and Herbon,1988;Lai et al.,2022).
基金supported by China Geological Survey Projects (Grant Nos. 1212011087116 and 1212011120116)the Basic Research Fund of Institute of Geology, Chinese Academy of Geological Sciences (Grant No. J1109)
文摘The palynomorph assemblage of lake sediments younger than 51.9 kaBP from Wulagai Gobi in Inner Mongolia was analyzed to reconstruct the vegetation and climate. From 51.9 to 30.6 kaBP, the vegetation was arid to semi-arid grassland with only slight changes. According to the palynomorphs, trees and shrubs were very rare. The large number and diversity of algae indicate the presence of a lake. Quantitative climatic conditions were reconstructed using the Best Analogues Method. The results indicate that the annual mean temperature was higher than that at present. The combination of temperature and annual precipitation suggests a change in the climate from cool dry to warm dry and then cool humid. Our results show that the annual precipitation values were mostly higher than that at present but were lower than 400 mm. It infers that the study area was already within the arid to semi-arid regions but with a stronger influence of the summer monsoon during 51.9 to 30.6 kaBP than at present. With slight differences mainly in time scale, the changing trend of the annual temperature curve is consistent with the other climatic records from Antarctica, Greenland, Hulu Cave （East China）, and the Tibetan Plateau during the last glacial period. From 30.6 kaBP to present, very few palynomorphs were detected in the samples. Hence, no information about the vegetation and climate could be extracted. Combined with other studies during Late Pleistocene, we presume that the reason for the lack of pollen during this period was caused by an abrupt temperature fall after 30.6 kaBP or that the lacustrine conditions were unsuitable for pollen deposition. It was probably incurred by the oxidation on land prior to deposition. But for those samples only with algae, it might be caused by the fact that algae could finish their life history in a very short time in a seasonal lake.
基金The authors thank Prof.Chun-Ju Huang from the China University of Geosciences(Wuhan)for a useful discussion.This research was supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(no.XDB26000000)the China National Key Basic Research Program(2014CB954201)+2 种基金the National Natural Science Foundation of China(nos.31570223,41690115,and 32000174)the State Key Laboratory of Systematic and Evolutionary Botany(nos.LSEB2019-1 and LSEB2019-4)and the Chinese Academy of Sciences President’s International Fellowship Initiative(2018VBA0016).
文摘The evolution of the Asian monsoon from the Late Oligocene to the Early Miocene is poorly understood.Here,we first reconstruct the precipitation data of central Tibet during 26–16 million years ago(Ma),applying the coexistence approach to sedimentary pollen data,and detect an intensified Asian monsoon with1.35 Ma and0.33 Ma cycles.Paleoclimate modeling is used to show the importance of paleogeographic location in the development of the paleomonsoon.In addition,the results of spectral analysis suggest that the fluctuations in the Asian monsoon during 26–16 Ma can be attributed to the long-period cyclicities in obliquity(1.2 Ma).These findings provide climate data that can be used to understand the Asian monsoon evolution during the Late Oligocene to Early Miocene and highlight the effects of paleogeographic patterns and long-period orbital forcings on the tectonic-scale evolution of the Asian monsoon.
基金supported by the National Key Basic Research Program of China (2014CB954201)the National Natural Science Foundation of China (41271222)+1 种基金the Chinese Academy of Sciences Visiting Professorship for Senior International Scientists (90004F1005)the visiting scholarship funded by China Scholarship Council (CSC)
文摘The present article deals with the use of tree barks as a natural trap for airborne spores and pollen grains in China.The study carried out at the southern part of Beijing Botanical Garden,Institute of Botany,Chinese Academy of Sciences has yielded a variety of palynomorphs mostly belonging to tree taxa.New methodologies for extraction of palynomorphs from tree barks have been suggested.Bark samples were collected from three taxa,i.e.,Paulownia fortunei Hemsl.(Scrophulariaceae),Quercus dentata Thunb.(Fagaceae),and Picea meyeri Rehder&E.H.Wilson(Pinaceae)having different bark morphologies.P.fortunei with a comparatively soft and fissured bark is believed to have a greater potential for trapping airborne spores and pollen grains compared to the stiff and less fissured barks of Q.dentata and the scaly bark of P.meyeri.Old barks yield better data in terms of quantity and quality of trapped pollen and spores.The present study throws new light on the modern pollen rain,spore-pollen dispersal,and their deposition in and aroundBeijing Botanical Garden,and other different parts of China.
