This study represents a geographical approach to morphological variation of cones, needles and seeds in natural dragon spruce （Picea asperata Mast.） populations across western China and the relationship between morp...This study represents a geographical approach to morphological variation of cones, needles and seeds in natural dragon spruce （Picea asperata Mast.） populations across western China and the relationship between morphological traits and weather variation for the origins of populations. Significant differences were found for all cone, needle and seed traits among populations and trees within populations. The coefficients of variation in 2 higher latitude populations were higher than those in other populations in all traits except for needle width and seed width. Fairly high within-population variability was also detected for cone dry weight, seed dry weight and needle traits in this study. Cone length, cone width, cone dry weight, seed scale length, seed scale width and seed wing length were strongly positively intercorrelated. Seed length and seed dry weight showed a significantly positive correlation with seed wing length. And needle width showed a significant negative correlation with cone traits, seed scale length, seed wing length and seed length. The higher the annual mean temperature, the higher the average cone length. This study also revealed a negative linear dependence on latitude： the higher the latitude, the lower the population average seed length. Seed dry weight was positively and linearly related with altitude.展开更多
Abundant sphaeroidal acritarch Leiosphaeridia asperata,with vesicle size ranging from 13 to 360 μm,occurred in the Proterozoic Liulaobei Formation shales in Huainan,Anhui Province.TEM/SEM studies of these sphaeroidal...Abundant sphaeroidal acritarch Leiosphaeridia asperata,with vesicle size ranging from 13 to 360 μm,occurred in the Proterozoic Liulaobei Formation shales in Huainan,Anhui Province.TEM/SEM studies of these sphaeroidal acritarchs have revealed complex ultrastructures,including ridges,bands,and possible trilaminar structures(TLS).Ridges,spaced ~1 μm apart,are distributed regularly on the vesicle internal surface of one specimen.Some specimens have alternating electron-dense and electron-tenuous bands that are perpendicular to vesicle walls.Some specimens have trilaminar structures(TLS),while a few others have both bands and TLS.These wall ultrastructures provide evidence that the Liulaobei leiosphaerids are of green microalgae.The variation in wall ultrastructures may represent various stages in a life cycle or developmental phases in the cyst formation analogous to some modern chlorophyceaen microalgae.展开更多
Aims Competition,temperature and nutrient are the most important determinants of tree growth in the cold climate on the eastern Tibetan Plateau.Although many studies have reported their individual effects on tree grow...Aims Competition,temperature and nutrient are the most important determinants of tree growth in the cold climate on the eastern Tibetan Plateau.Although many studies have reported their individual effects on tree growth,little is known about how the interactions of competition with fertilization and temperature affect root growth.We aim to test whether climate warming and fertilization promote competition and to explore the functional strategies of Picea asperata in response to the interactions of these factors.Methods We conducted a paired experiment including competition and non-competition treatments under elevated temperature(ET)and fertilization.We measured root traits,including the root tip number over the root surface(RTRS),the root branching events over the root surface(RBRS),the specific root length(SRL),the specific root area(SRA),the total fine root length and area(RL and RA),the root tips(RTs)and root branching(RB)events.These root traits are considered to be indicators of plant resource uptake capacity and root growth.The root biomass and the nutrient concentrations in the roots were also determined.Important Findings The results indicated that ET,fertilization and competition individually enhanced the nitrogen(N)and potassium(K)concentrations in fine roots,but they did not affect fine root biomass or root traits,including RL,RT,RA and RB.However,both temperature and fertilizationz as well as their interaction,interacting with competition increased RL,RA,RT,RB and nutrient uptake.In addition,the SRL,SRA,RTRS and RBRS decreased un der fertilization,the interaction between temperature and competition decreased SRL and SRA,while the other parameters were not affected by temperature or competition.These results indicate that P.asperata maintains a conservative nutrient strategy in response to competition,climate warming,fertilization and their interactions.Our results improve our understanding of the physiological and ecological adaptability of trees to global change.展开更多
文摘This study represents a geographical approach to morphological variation of cones, needles and seeds in natural dragon spruce （Picea asperata Mast.） populations across western China and the relationship between morphological traits and weather variation for the origins of populations. Significant differences were found for all cone, needle and seed traits among populations and trees within populations. The coefficients of variation in 2 higher latitude populations were higher than those in other populations in all traits except for needle width and seed width. Fairly high within-population variability was also detected for cone dry weight, seed dry weight and needle traits in this study. Cone length, cone width, cone dry weight, seed scale length, seed scale width and seed wing length were strongly positively intercorrelated. Seed length and seed dry weight showed a significantly positive correlation with seed wing length. And needle width showed a significant negative correlation with cone traits, seed scale length, seed wing length and seed length. The higher the annual mean temperature, the higher the average cone length. This study also revealed a negative linear dependence on latitude： the higher the latitude, the lower the population average seed length. Seed dry weight was positively and linearly related with altitude.
基金supported financially by Chinese Academy of Sciences (Grant No. KZCX2-YW-153)National Basic Research Program of China (Grant No. 2006CB806400National Natural Science Foundation of China (Grant Nos. 40772021,40625006)
文摘Abundant sphaeroidal acritarch Leiosphaeridia asperata,with vesicle size ranging from 13 to 360 μm,occurred in the Proterozoic Liulaobei Formation shales in Huainan,Anhui Province.TEM/SEM studies of these sphaeroidal acritarchs have revealed complex ultrastructures,including ridges,bands,and possible trilaminar structures(TLS).Ridges,spaced ~1 μm apart,are distributed regularly on the vesicle internal surface of one specimen.Some specimens have alternating electron-dense and electron-tenuous bands that are perpendicular to vesicle walls.Some specimens have trilaminar structures(TLS),while a few others have both bands and TLS.These wall ultrastructures provide evidence that the Liulaobei leiosphaerids are of green microalgae.The variation in wall ultrastructures may represent various stages in a life cycle or developmental phases in the cyst formation analogous to some modern chlorophyceaen microalgae.
基金supported by National Key Research and Development Project of China(2017YFC0505002)National Natural Science Foundation of China(31400424,31570477).
文摘Aims Competition,temperature and nutrient are the most important determinants of tree growth in the cold climate on the eastern Tibetan Plateau.Although many studies have reported their individual effects on tree growth,little is known about how the interactions of competition with fertilization and temperature affect root growth.We aim to test whether climate warming and fertilization promote competition and to explore the functional strategies of Picea asperata in response to the interactions of these factors.Methods We conducted a paired experiment including competition and non-competition treatments under elevated temperature(ET)and fertilization.We measured root traits,including the root tip number over the root surface(RTRS),the root branching events over the root surface(RBRS),the specific root length(SRL),the specific root area(SRA),the total fine root length and area(RL and RA),the root tips(RTs)and root branching(RB)events.These root traits are considered to be indicators of plant resource uptake capacity and root growth.The root biomass and the nutrient concentrations in the roots were also determined.Important Findings The results indicated that ET,fertilization and competition individually enhanced the nitrogen(N)and potassium(K)concentrations in fine roots,but they did not affect fine root biomass or root traits,including RL,RT,RA and RB.However,both temperature and fertilizationz as well as their interaction,interacting with competition increased RL,RA,RT,RB and nutrient uptake.In addition,the SRL,SRA,RTRS and RBRS decreased un der fertilization,the interaction between temperature and competition decreased SRL and SRA,while the other parameters were not affected by temperature or competition.These results indicate that P.asperata maintains a conservative nutrient strategy in response to competition,climate warming,fertilization and their interactions.Our results improve our understanding of the physiological and ecological adaptability of trees to global change.
