By analyzing the importance of influencing factors and conducting a comparative study of the effects of different sorting algorithms, a new method is proposed that is suitable for classifying the growth state of a nat...By analyzing the importance of influencing factors and conducting a comparative study of the effects of different sorting algorithms, a new method is proposed that is suitable for classifying the growth state of a natural Metasequoia glyptostroboides Hu and W.C. Cheng population. We studied 2817 M. glyptostroboides trees over 100 years old and analyzed their growth state by measuring 15 factors from stumpage, site condition, and environmental data. The dimensionality of all factors were reduced using the random forest algorithm, and we classified the remaining factors using the following algorithms: random forest, back-propagation(BP) neural networks, and support vector machine(SVM). The applicability of each sorting algorithm was analyzed. When all the d factors are used for classification and modeling, the model's overall accuracy,kappa coefficient and test accuracy were 85.5%, 0.739 and 85.8%, respectively. By reducing the dimensionality of the factors using the random forest algorithm, 11 factors most strongly influenced the classifications of the growth state of the Metasequoia population: diameter at breast height,height, crown width, age from stumpage data; longitude,latitude, elevation, slope aspect, gradient and slope position from the site condition data; and the edge of the field from the environmental data. For classifying the Metasequoia population, the random forest algorithm has the highest overall accuracy at 87.2%, which is 3.4 and 2.3% higher than the BP neural networks and SVM algorithms,respectively. The SVM algorithm is superior to the random forest algorithm with respect to classifying the state of mortality. The combination of the random forest and SVM algorithms and their combined information can be used to classify and predict the growth state of this natural M.glyptostroboides population to provide a scientific basis for its effective protection.展开更多
Objective:To examine the individual and synergistic anti-listcrial effect of nisin and leaf essential oil of Metasequoia glyptostroboides(M.glyptostroboides) against one of the leading foodhorne pathogens Listeria mon...Objective:To examine the individual and synergistic anti-listcrial effect of nisin and leaf essential oil of Metasequoia glyptostroboides(M.glyptostroboides) against one of the leading foodhorne pathogens Listeria monocytogenes(L.monocytogenes) ATCC 19116 in milk samples.Methods:The whole(8%),low(1%) and skim(no fat content) milk samples were inoculated with L.monocytogenes ATCC 19116 along with leaf essential oil of M.glyptostroboides or nisin alone as well in eomhinations.Results:In this study,the leaf essential oil at the concentrations of 2% and 5% revealed strong anti-listerial effect against L.monocytogenes ATCC 19116 in all categories of milk samples.Nisin at the concentrations of 250 and 500 IU/mL displayed a strong inhibitory effect against ATCC 19116 as compared to the control group.Additionally,synergistic combinations of leaf essential oil(1%) and nisin(62.5,125.250 and 500 IU/mL) also had a remarkable anti-listerial synergism in all the tested milk samples including whole,low and skim milk after 14 days.Conclusions:As a major finding,the leaf essential oil of M.glyptostroboides might he a useful candidate for using in food industry to control the growth of foodhorne pathogenic bacteria as confirmed by its potent anti-listerial Synergistic effect with nisin against L.monocytogenes ATCC 19116 in different milk samples.展开更多
Seeds of 23 relic Metasequoia glyptostroboides trees were randomly collected from their original, natural opulations found in Lichuan City, Hubei Province, China. The seed characteristics and growth of their three-yea...Seeds of 23 relic Metasequoia glyptostroboides trees were randomly collected from their original, natural opulations found in Lichuan City, Hubei Province, China. The seed characteristics and growth of their three-year-old rogenies were investigated. Results show that the average intra-family coefficient of variation （CV） in height growth of ：he 23 three-year-old families was 14.53%, slightly higher than that of the inter-family CV （14.02%）. Correspondingly, hese two parameters for root-collar diameter growth were 15.44% and 13.15%. The 23 relic mother trees were ignificantly differed in their general combining abilities （GCA） and relative effect values of GCA （RGCA） of height growth and root-collar diameter growth over the three years. Both height and root-collar diameter growth had high amily heritability in this seedling stage. After eliminating two inferior families, i.e., 15 and 46, 2.21% of genetic gain in he ght growth was obtained and 1.50% in root-collar diameter growth. It was also significantly different in crown size and number of branches among the 23 three-year-old seedling families. From a cluster analysis we concluded that eight families, i.e., 23, 28, 29, 30, 31, 33, 35 and 44 displayed superior GCA and RGCA in both height and root-collar diameter growth. Therefore, these relic mother trees displayed their potential as parents in seed orchards. With the exception of family 23, the other seven superior families were all collected at Guihua Village, Zhonglu Town, Lichuan City, which has been identified as an optimum district of M. glyptostroboides for seed collection.展开更多
[Objectives]This study was conducted to isolate and investigate the endophytic fungi with antimicrobial activity from the healthy leaves and bark of Metasequoia glyptostroboides Hu&W.C.Cheng regarded as an importa...[Objectives]This study was conducted to isolate and investigate the endophytic fungi with antimicrobial activity from the healthy leaves and bark of Metasequoia glyptostroboides Hu&W.C.Cheng regarded as an important medicinal plant in China.[Methods]Endophytic fungi with visible antimicrobial activity were isolated from the healthy leaves and bark of M.glyptostroboides,and primarily screened using Escherichia coli and Staphylococcus aureus as test microorganisms.[Results]Three isolates with relatively higher antimicrobial activity,labeled as MG-01,MG-02,MG-09,were selected for study.Molecular and morphological analysis indicated that the three isolated endophytes belong to Penicillium sp.The ethyl acetate(EtOAc)extracts of the three endophytes were obtained and subjected to the disk diffusion assay,using E.coil,S.aureus,Pseudomonas aeruginosa,Enterococcus faecalis,Monilia albicanas,and Bacillus subtilis as test microorganisms.The minimum inhibitory activity(MIC)of the endophyte with relatively highest antimicrobial activity was determined using two-fold broth micro-dilution method.All the endophytes showed a broad spectrum antimicrobial activity.Among the three endophytes,the strain MG-09 exhibited relatively highest antimicrobial activity with the zones of inhibition(ZOI)ranging from 14.15 to 24.07 mm and MIC ranging from 416.67 to 65.11μg/ml.[Conclusions]The endophytic fungi colonized in M.glyptostroboides are capable of producing effective antimicrobial compounds which may be a potential source for drug discovery and biocide production.展开更多
Leaves of a Metasequoia glyptostroboides tree in Paomu Village,Longshan County,Hunan Province(Paomu Tree)possess"Even Type"cuticles and frill-margined stomata similar to those of fossil Metasequoia by far kn...Leaves of a Metasequoia glyptostroboides tree in Paomu Village,Longshan County,Hunan Province(Paomu Tree)possess"Even Type"cuticles and frill-margined stomata similar to those of fossil Metasequoia by far known but different from all other living Metasequoia trees(common trees).Paomu Tree is thus hypothesized as the real"living fossil",which has been supported by preliminary DNA analyses.展开更多
Plant growth and productivity are negatively affected by soil salinity.This study investigated the effects of the rhizosphere-promoting bacterium,Bacillus paramycoides JYZ-SD5,and the ectomycorrhizal fungus,Schizophyl...Plant growth and productivity are negatively affected by soil salinity.This study investigated the effects of the rhizosphere-promoting bacterium,Bacillus paramycoides JYZ-SD5,and the ectomycorrhizal fungus,Schizophyllum commune Be,on the growth of Metasequoia glyptostroboides under salt stress.Changes in biomass,root growth,root ion distribution and in vivo enzyme activities were determined under different treatments(Be,JYZ-SD5,and Be+JYZ-SD5).The results show that all inoculations increased chlorophyll content,shoot length and root diameter with or without salt stress,and the effect of Be+JYZ-SD5was the strongest.JYZ-SD5 and Be+JYZ-SD5 treatments significantly increased root length,surface area,bifurcation number,tip number,main root length and diameter under salt stress.Normal chloroplast structures developed under both single and double inoculations.Relative to the control,root activities of M.glyptostroboides in the Be,JYZSD5,and Be+JYZ-SD5 treatments increased by 31.3%,17.2%,and 33.7%.All treatments increased the activities of superoxide dismutase(SOD),peroxidase(POD),Na^(+)-K^(+)-ATPase and Ca^(2+)-Mg^(2+)-ATPase.The strongest effect was by Be+JYZ-SD5.Analysis of root ion distribution showed that,under salt stress,Na^(+)and K^(+)decreased and were concentrated in the epidermis or cortex.Na/K ratios also decreased.The Be+JYZ-SD5 treatment increased betaine by 130.3%and 97.9%under 50 mM and 100 mM salt stress,respectively.Together,these changes result in the activation of physiological and biochemical processes involved in the mitigation of salinity-induced stress in M.glyptostroboides.展开更多
Recent advances in spectral sensing techniques and machine learning(ML)methods have enabled the estimation of plant physiochemical traits.Nitrogen(N)is a primary limiting factor for terrestrial forest growth,but tradi...Recent advances in spectral sensing techniques and machine learning(ML)methods have enabled the estimation of plant physiochemical traits.Nitrogen(N)is a primary limiting factor for terrestrial forest growth,but traditional methods for N determination are labor-intensive,time-consuming,and destructive.In this study,we present a rapid,non-destructive method to predict leaf N concentration(LNC)in Metasequoia glyptostroboides plantations under N and phosphorus(P)fertilization using ML techniques and unmanned aerial vehicle(UAV)-based RGB(red,green,blue)images.Nine spectral vegetation indices(VIs)were extracted from the RGB images.The spectral reflectance and VIs were used as input features to construct models for estimating LNC based on support vector machine,ran-dom forest(RF),and multiple linear regression,gradient boosting regression and classification and regression trees(CART).The results show that RF is the best fitting model for estimating LNC with a coefficient of determination(R2)of 0.73.Using this model,we evaluated the effects of N and P treatments on LNC and found a significant increase with N and a decrease with P.Height,diameter at breast height(DBH),and crown width of all M.glyptostroboides were analyzed by Pearson correlation with the predicted LNC.DBH was significantly correlated with LNC under N treat-ment.Our results highlight the potential of combining UAV RGB images with an ML algorithm as an efficient,scalable,and cost-effective method for LNC quantification.Future research can extend this approach to different tree species and different plant traits,paving the way for large-scale,time-efficient plant growth monitoring.展开更多
Metasequoia （Metasequoia glyptostroboides Hu et Cheng） is an important but endangered tree species. In a sense, the course of protection of the metasequoia can be considered a miniature of the history of the protect...Metasequoia （Metasequoia glyptostroboides Hu et Cheng） is an important but endangered tree species. In a sense, the course of protection of the metasequoia can be considered a miniature of the history of the protection of rare Chinese plants over the past 50 years. The approval and establishment of the National Class Nature Reserve for metasequoia is a milestone in this course. A thorough understanding of this course is beneficial to design the correct future protection plans and for taking effective measures. In this paper the entire protection course of metasequoia is reviewed, three detailed measures are proposed according to the present situation and existing problems and discussed as follows. 1） We should reinforce unceasingly the establishment of National Nature Reserves of metasequoia, put emphasis on the protection of the original natural mother trees （ONMTs） of metasequoia, design far- sighted projects to protect the ONMTs and strictly implement and enforce the regulations or laws regarding the protection of meta- sequoia. The establishment and functions of the organization should meet the demands of protecting the ONMTs and developing metasequoias. The budget should support and the quality of the personnel assigned to this task should satisfy the protection and de- velopment of the ONMTs. We should also promote the complete protection of the ONMTs at the same time and strengthen the pro- tection and restoration of the ONMTs and their ecosystem in the Xiaohe valley, Lichuan County, Hubei Province, one of the natural concentration areas of ONMTs in the world. 2） A gene bank should be established for comprehensive protection of the genes of ex- isting original mother trees of metasequoia. 3） The key is to study the theoretical fundamentals of restoration and re-establishment of natural vegetation of metasequoia in the Xiaohe valley to harmonize the relation among environmental departments, forestry sectors, academies of sciences and other educational or research units, to carry out scientific research and strengthen academic exchanges to promote jointly the protection and utilization of metasequoia and other natural resources in China.展开更多
Metasequoia glyptostroboides(M.glyptostroboides)is a unique plant species related to relic flora in China.It plays a positive role in afforestation and its long-term protection with high paleoclimate research value.Ho...Metasequoia glyptostroboides(M.glyptostroboides)is a unique plant species related to relic flora in China.It plays a positive role in afforestation and its long-term protection with high paleoclimate research value.However,due to the nutrients-supply deficiency,it is a big challenge to cultivate the high-quality seedlings of M.glyptostroboides.In this study,a pot experiment in a greenhouse environment was carried out to identify the effect of N-exponential fertilization on the growth and nutrient distribution of M.glyptostroboides seedling.The M.glyptostroboides rooted seedlings with 12-month growth were chosen.Different N fertilizer levels with conventional fertilization(CF:5.0 g seedling^(−1)),exponential fertilization including EF1,EF2,EF3 and EF4 were determined.The relevant growth indexes were measured after 210-day growth.The results indicated that non-significant differences in seedlings’height and ground diameter were found among the above treatments(P>0.05);At the same time,N-exponential fertilization promoted the M.glyptostroboides’s biomass in different organs(P<0.05),with the maximum total biomass under EF3 treatment.The N accumulation in root and stem of the N-exponential fertilization treatments were increased in to some extent(P<0.05).The maximum N accumulation was also found under EF3 treatment.Therefore,steady-state nutrition and superior growth performance of M.glyptostroboides could be obtained by N-exponential fertilization of 5.0 g cutting^(−1).展开更多
Traditionally,plant distribution is thought to be closely related to environmental factors.But recently,it is found that Populus,quite different from other plant taxa,adapted to negative environmental changes,and succ...Traditionally,plant distribution is thought to be closely related to environmental factors.But recently,it is found that Populus,quite different from other plant taxa,adapted to negative environmental changes,and successfully migrated to different climate zones from its origin places of warm temperate zone.Conversely,Metasequoia is gradually tending to extinction from the Miocene to Quaternary.Based on above contrary cases,two response patterns of plant to negative environmental changes are proposed.One is active adaptation represented by Populus,the other is passive adaptation represented by Metasequoia.The plants of passive strategy characterized for desert prevention might be easily replaced by those of active strategy characterized for desert utilization.Fast growing plants,such as Populus with characteristics of drought and salt tolerance,wind and sand resistance,are selected in Tarim Basin in southern Xinjiang,China,as a good example of desert utilization in the construction of new highways and towns,not only serve as farmland shelterbelt in sandy area.In addition,Populus with high-altitude and cold adaptation has also been selected as an ideal tree planted in Xizang.Therefore,the idea of using Populus as one of the preferred pioneer trees to colonize Mars is proposed.展开更多
The substructure of pollen exine in Cedrus deodara (Roxb.) Loud, and Metasequoia glyptostroboides Hu et Cheng has been examined with an atomic force microscope (AFM). The results indicate that the exine substructure u...The substructure of pollen exine in Cedrus deodara (Roxb.) Loud, and Metasequoia glyptostroboides Hu et Cheng has been examined with an atomic force microscope (AFM). The results indicate that the exine substructure units containing sporopollenin in two species are similar in shape, which are granular, but slightly different in size. In Cedrus the substructure unit of pollen exine appears to be 56-99 nm long and 42-74 nm wide, while in Metasequoia it appears to be 81-118 nm long and 43-98 nm wide. It has been observed that the subunits of pollen exine in Cedrus arranged tightly to form short-rod-like or spheroidal pollen exine units, several or more than ten of which formed an island-like structure. There are various spaces among these island-like structures which are interconnected to occupy the entire pollen exine. In Metasequoia, the subunits of pollen exine also arranged tightly with a distribution tendency of cluster of 3-10, however, no obvious boundary exists among these clusters. From our展开更多
Redwood trees(Sequoioideae),including Metasequoia glyptostroboides(dawn redwood),Sequoiadendron giganteum(giant sequoia),and Sequoia sempervirens(coast redwood),are threatened and widely recognized iconic tree species...Redwood trees(Sequoioideae),including Metasequoia glyptostroboides(dawn redwood),Sequoiadendron giganteum(giant sequoia),and Sequoia sempervirens(coast redwood),are threatened and widely recognized iconic tree species.Genomic resources for redwood trees could provide clues to their evolutionary relationships.Here,we report the 8-Gb reference genome of M.glyptostroboides and a comparative analysis with two related species.More than 62%of the M.glyptostroboides genome is composed of repetitive sequences.Clade-specific bursts of long terminal repeat retrotransposons may have contributed to genomic differentiation in the three species.The chromosomal synteny between M.glyptostroboides and S.giganteum is extremely high,whereas there has been significant chromosome reorganization in S.sempervirens.Phylogenetic analysis of marker genes indicates that S.sempervirens is an autopolyploid,and more than 48%of the gene trees are incongruent with the species tree.Results of multiple analyses suggest that incomplete lineage sorting(ILS)rather than hybridization explains the inconsistent phylogeny,indicating that genetic variation among redwoods may be due to random retention of polymorphisms in ancestral populations.Functional analysis of ortholog groups indicates that gene families of ion channels,tannin biosynthesis enzymes,and transcription factors for meristem maintenance have expanded in S.giganteum and S.sempervirens,which is consistent with their extreme height.As a wetland-tolerant species,M.glyptostroboides shows a transcriptional response to flooding stress that is conserved with that of analyzed angiosperm species.Our study offers insights into redwood evolution and adaptation and provides genomic resources to aid in their conservation and management.展开更多
SNAPSHOTS OF CHINA Send us your photographs and let us know what lies behind them at contacts@chinafrica.cn Autumn Allure Autumn colours reach their peak in the Metasequoia forest in the Hongze Lake Wetland Scenic Are...SNAPSHOTS OF CHINA Send us your photographs and let us know what lies behind them at contacts@chinafrica.cn Autumn Allure Autumn colours reach their peak in the Metasequoia forest in the Hongze Lake Wetland Scenic Area in Sihong,Jiangsu Province,attracting numerous visitors on 9 November.展开更多
基金supported by Study on Spatial Environmental Effect Model and Forestation Decision Support System for Forest Vegetation in Beijing(6161001)
文摘By analyzing the importance of influencing factors and conducting a comparative study of the effects of different sorting algorithms, a new method is proposed that is suitable for classifying the growth state of a natural Metasequoia glyptostroboides Hu and W.C. Cheng population. We studied 2817 M. glyptostroboides trees over 100 years old and analyzed their growth state by measuring 15 factors from stumpage, site condition, and environmental data. The dimensionality of all factors were reduced using the random forest algorithm, and we classified the remaining factors using the following algorithms: random forest, back-propagation(BP) neural networks, and support vector machine(SVM). The applicability of each sorting algorithm was analyzed. When all the d factors are used for classification and modeling, the model's overall accuracy,kappa coefficient and test accuracy were 85.5%, 0.739 and 85.8%, respectively. By reducing the dimensionality of the factors using the random forest algorithm, 11 factors most strongly influenced the classifications of the growth state of the Metasequoia population: diameter at breast height,height, crown width, age from stumpage data; longitude,latitude, elevation, slope aspect, gradient and slope position from the site condition data; and the edge of the field from the environmental data. For classifying the Metasequoia population, the random forest algorithm has the highest overall accuracy at 87.2%, which is 3.4 and 2.3% higher than the BP neural networks and SVM algorithms,respectively. The SVM algorithm is superior to the random forest algorithm with respect to classifying the state of mortality. The combination of the random forest and SVM algorithms and their combined information can be used to classify and predict the growth state of this natural M.glyptostroboides population to provide a scientific basis for its effective protection.
文摘Objective:To examine the individual and synergistic anti-listcrial effect of nisin and leaf essential oil of Metasequoia glyptostroboides(M.glyptostroboides) against one of the leading foodhorne pathogens Listeria monocytogenes(L.monocytogenes) ATCC 19116 in milk samples.Methods:The whole(8%),low(1%) and skim(no fat content) milk samples were inoculated with L.monocytogenes ATCC 19116 along with leaf essential oil of M.glyptostroboides or nisin alone as well in eomhinations.Results:In this study,the leaf essential oil at the concentrations of 2% and 5% revealed strong anti-listerial effect against L.monocytogenes ATCC 19116 in all categories of milk samples.Nisin at the concentrations of 250 and 500 IU/mL displayed a strong inhibitory effect against ATCC 19116 as compared to the control group.Additionally,synergistic combinations of leaf essential oil(1%) and nisin(62.5,125.250 and 500 IU/mL) also had a remarkable anti-listerial synergism in all the tested milk samples including whole,low and skim milk after 14 days.Conclusions:As a major finding,the leaf essential oil of M.glyptostroboides might he a useful candidate for using in food industry to control the growth of foodhorne pathogenic bacteria as confirmed by its potent anti-listerial Synergistic effect with nisin against L.monocytogenes ATCC 19116 in different milk samples.
基金supported by the National Natural Science Foundation of China (GrantNo. 31100458)the Fundamental Research Funds for the Central Universities (Nos.2011QC034 and 52204-09073)
文摘Seeds of 23 relic Metasequoia glyptostroboides trees were randomly collected from their original, natural opulations found in Lichuan City, Hubei Province, China. The seed characteristics and growth of their three-year-old rogenies were investigated. Results show that the average intra-family coefficient of variation （CV） in height growth of ：he 23 three-year-old families was 14.53%, slightly higher than that of the inter-family CV （14.02%）. Correspondingly, hese two parameters for root-collar diameter growth were 15.44% and 13.15%. The 23 relic mother trees were ignificantly differed in their general combining abilities （GCA） and relative effect values of GCA （RGCA） of height growth and root-collar diameter growth over the three years. Both height and root-collar diameter growth had high amily heritability in this seedling stage. After eliminating two inferior families, i.e., 15 and 46, 2.21% of genetic gain in he ght growth was obtained and 1.50% in root-collar diameter growth. It was also significantly different in crown size and number of branches among the 23 three-year-old seedling families. From a cluster analysis we concluded that eight families, i.e., 23, 28, 29, 30, 31, 33, 35 and 44 displayed superior GCA and RGCA in both height and root-collar diameter growth. Therefore, these relic mother trees displayed their potential as parents in seed orchards. With the exception of family 23, the other seven superior families were all collected at Guihua Village, Zhonglu Town, Lichuan City, which has been identified as an optimum district of M. glyptostroboides for seed collection.
基金the National Science Foundation of China(Grant No.31970038)the Science Public Welfare Fund Projects of Zhejiang Province(Grant No.2017C32050)。
文摘[Objectives]This study was conducted to isolate and investigate the endophytic fungi with antimicrobial activity from the healthy leaves and bark of Metasequoia glyptostroboides Hu&W.C.Cheng regarded as an important medicinal plant in China.[Methods]Endophytic fungi with visible antimicrobial activity were isolated from the healthy leaves and bark of M.glyptostroboides,and primarily screened using Escherichia coli and Staphylococcus aureus as test microorganisms.[Results]Three isolates with relatively higher antimicrobial activity,labeled as MG-01,MG-02,MG-09,were selected for study.Molecular and morphological analysis indicated that the three isolated endophytes belong to Penicillium sp.The ethyl acetate(EtOAc)extracts of the three endophytes were obtained and subjected to the disk diffusion assay,using E.coil,S.aureus,Pseudomonas aeruginosa,Enterococcus faecalis,Monilia albicanas,and Bacillus subtilis as test microorganisms.The minimum inhibitory activity(MIC)of the endophyte with relatively highest antimicrobial activity was determined using two-fold broth micro-dilution method.All the endophytes showed a broad spectrum antimicrobial activity.Among the three endophytes,the strain MG-09 exhibited relatively highest antimicrobial activity with the zones of inhibition(ZOI)ranging from 14.15 to 24.07 mm and MIC ranging from 416.67 to 65.11μg/ml.[Conclusions]The endophytic fungi colonized in M.glyptostroboides are capable of producing effective antimicrobial compounds which may be a potential source for drug discovery and biocide production.
文摘Leaves of a Metasequoia glyptostroboides tree in Paomu Village,Longshan County,Hunan Province(Paomu Tree)possess"Even Type"cuticles and frill-margined stomata similar to those of fossil Metasequoia by far known but different from all other living Metasequoia trees(common trees).Paomu Tree is thus hypothesized as the real"living fossil",which has been supported by preliminary DNA analyses.
基金supported by the National Key Research and Development Program of China (2017YFD0600104)the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD)。
文摘Plant growth and productivity are negatively affected by soil salinity.This study investigated the effects of the rhizosphere-promoting bacterium,Bacillus paramycoides JYZ-SD5,and the ectomycorrhizal fungus,Schizophyllum commune Be,on the growth of Metasequoia glyptostroboides under salt stress.Changes in biomass,root growth,root ion distribution and in vivo enzyme activities were determined under different treatments(Be,JYZ-SD5,and Be+JYZ-SD5).The results show that all inoculations increased chlorophyll content,shoot length and root diameter with or without salt stress,and the effect of Be+JYZ-SD5was the strongest.JYZ-SD5 and Be+JYZ-SD5 treatments significantly increased root length,surface area,bifurcation number,tip number,main root length and diameter under salt stress.Normal chloroplast structures developed under both single and double inoculations.Relative to the control,root activities of M.glyptostroboides in the Be,JYZSD5,and Be+JYZ-SD5 treatments increased by 31.3%,17.2%,and 33.7%.All treatments increased the activities of superoxide dismutase(SOD),peroxidase(POD),Na^(+)-K^(+)-ATPase and Ca^(2+)-Mg^(2+)-ATPase.The strongest effect was by Be+JYZ-SD5.Analysis of root ion distribution showed that,under salt stress,Na^(+)and K^(+)decreased and were concentrated in the epidermis or cortex.Na/K ratios also decreased.The Be+JYZ-SD5 treatment increased betaine by 130.3%and 97.9%under 50 mM and 100 mM salt stress,respectively.Together,these changes result in the activation of physiological and biochemical processes involved in the mitigation of salinity-induced stress in M.glyptostroboides.
基金supported by the“Pioneer”and“Leading Goose”R&D Program of Zhejiang(2022C02053)National Natural Science Foundation of China(NSFC)(32201632).
文摘Recent advances in spectral sensing techniques and machine learning(ML)methods have enabled the estimation of plant physiochemical traits.Nitrogen(N)is a primary limiting factor for terrestrial forest growth,but traditional methods for N determination are labor-intensive,time-consuming,and destructive.In this study,we present a rapid,non-destructive method to predict leaf N concentration(LNC)in Metasequoia glyptostroboides plantations under N and phosphorus(P)fertilization using ML techniques and unmanned aerial vehicle(UAV)-based RGB(red,green,blue)images.Nine spectral vegetation indices(VIs)were extracted from the RGB images.The spectral reflectance and VIs were used as input features to construct models for estimating LNC based on support vector machine,ran-dom forest(RF),and multiple linear regression,gradient boosting regression and classification and regression trees(CART).The results show that RF is the best fitting model for estimating LNC with a coefficient of determination(R2)of 0.73.Using this model,we evaluated the effects of N and P treatments on LNC and found a significant increase with N and a decrease with P.Height,diameter at breast height(DBH),and crown width of all M.glyptostroboides were analyzed by Pearson correlation with the predicted LNC.DBH was significantly correlated with LNC under N treat-ment.Our results highlight the potential of combining UAV RGB images with an ML algorithm as an efficient,scalable,and cost-effective method for LNC quantification.Future research can extend this approach to different tree species and different plant traits,paving the way for large-scale,time-efficient plant growth monitoring.
基金support from Beijing Forestry University, the help provided by Dr. Ma Jinshuang, Research Taxonomist at the Brooklyn Botanical Gar-den and by Mr. Li Yujie of the Planning and Design Academy of the Forest Products Industry of the State Forestry Administration
文摘Metasequoia （Metasequoia glyptostroboides Hu et Cheng） is an important but endangered tree species. In a sense, the course of protection of the metasequoia can be considered a miniature of the history of the protection of rare Chinese plants over the past 50 years. The approval and establishment of the National Class Nature Reserve for metasequoia is a milestone in this course. A thorough understanding of this course is beneficial to design the correct future protection plans and for taking effective measures. In this paper the entire protection course of metasequoia is reviewed, three detailed measures are proposed according to the present situation and existing problems and discussed as follows. 1） We should reinforce unceasingly the establishment of National Nature Reserves of metasequoia, put emphasis on the protection of the original natural mother trees （ONMTs） of metasequoia, design far- sighted projects to protect the ONMTs and strictly implement and enforce the regulations or laws regarding the protection of meta- sequoia. The establishment and functions of the organization should meet the demands of protecting the ONMTs and developing metasequoias. The budget should support and the quality of the personnel assigned to this task should satisfy the protection and de- velopment of the ONMTs. We should also promote the complete protection of the ONMTs at the same time and strengthen the pro- tection and restoration of the ONMTs and their ecosystem in the Xiaohe valley, Lichuan County, Hubei Province, one of the natural concentration areas of ONMTs in the world. 2） A gene bank should be established for comprehensive protection of the genes of ex- isting original mother trees of metasequoia. 3） The key is to study the theoretical fundamentals of restoration and re-establishment of natural vegetation of metasequoia in the Xiaohe valley to harmonize the relation among environmental departments, forestry sectors, academies of sciences and other educational or research units, to carry out scientific research and strengthen academic exchanges to promote jointly the protection and utilization of metasequoia and other natural resources in China.
基金the Natural Science Fundation of Zhejiang Province(LY20C160004).
文摘Metasequoia glyptostroboides(M.glyptostroboides)is a unique plant species related to relic flora in China.It plays a positive role in afforestation and its long-term protection with high paleoclimate research value.However,due to the nutrients-supply deficiency,it is a big challenge to cultivate the high-quality seedlings of M.glyptostroboides.In this study,a pot experiment in a greenhouse environment was carried out to identify the effect of N-exponential fertilization on the growth and nutrient distribution of M.glyptostroboides seedling.The M.glyptostroboides rooted seedlings with 12-month growth were chosen.Different N fertilizer levels with conventional fertilization(CF:5.0 g seedling^(−1)),exponential fertilization including EF1,EF2,EF3 and EF4 were determined.The relevant growth indexes were measured after 210-day growth.The results indicated that non-significant differences in seedlings’height and ground diameter were found among the above treatments(P>0.05);At the same time,N-exponential fertilization promoted the M.glyptostroboides’s biomass in different organs(P<0.05),with the maximum total biomass under EF3 treatment.The N accumulation in root and stem of the N-exponential fertilization treatments were increased in to some extent(P<0.05).The maximum N accumulation was also found under EF3 treatment.Therefore,steady-state nutrition and superior growth performance of M.glyptostroboides could be obtained by N-exponential fertilization of 5.0 g cutting^(−1).
基金Supported by projects of the Open Research Fund of State Key Laboratory of Modern Paleontology and Stratigraphy,Nanjing Institute of Geology and Palaeontology,CAS(No.213127)the National Natural Science Foundation of China(No.31470324)Higher Education Teaching Reform Project of Shenyang Normal University,2014(No.052/51400301).
文摘Traditionally,plant distribution is thought to be closely related to environmental factors.But recently,it is found that Populus,quite different from other plant taxa,adapted to negative environmental changes,and successfully migrated to different climate zones from its origin places of warm temperate zone.Conversely,Metasequoia is gradually tending to extinction from the Miocene to Quaternary.Based on above contrary cases,two response patterns of plant to negative environmental changes are proposed.One is active adaptation represented by Populus,the other is passive adaptation represented by Metasequoia.The plants of passive strategy characterized for desert prevention might be easily replaced by those of active strategy characterized for desert utilization.Fast growing plants,such as Populus with characteristics of drought and salt tolerance,wind and sand resistance,are selected in Tarim Basin in southern Xinjiang,China,as a good example of desert utilization in the construction of new highways and towns,not only serve as farmland shelterbelt in sandy area.In addition,Populus with high-altitude and cold adaptation has also been selected as an ideal tree planted in Xizang.Therefore,the idea of using Populus as one of the preferred pioneer trees to colonize Mars is proposed.
文摘The substructure of pollen exine in Cedrus deodara (Roxb.) Loud, and Metasequoia glyptostroboides Hu et Cheng has been examined with an atomic force microscope (AFM). The results indicate that the exine substructure units containing sporopollenin in two species are similar in shape, which are granular, but slightly different in size. In Cedrus the substructure unit of pollen exine appears to be 56-99 nm long and 42-74 nm wide, while in Metasequoia it appears to be 81-118 nm long and 43-98 nm wide. It has been observed that the subunits of pollen exine in Cedrus arranged tightly to form short-rod-like or spheroidal pollen exine units, several or more than ten of which formed an island-like structure. There are various spaces among these island-like structures which are interconnected to occupy the entire pollen exine. In Metasequoia, the subunits of pollen exine also arranged tightly with a distribution tendency of cluster of 3-10, however, no obvious boundary exists among these clusters. From our
基金supported by the National Key Research and Development Program of China(2017YFD0600701).
文摘Redwood trees(Sequoioideae),including Metasequoia glyptostroboides(dawn redwood),Sequoiadendron giganteum(giant sequoia),and Sequoia sempervirens(coast redwood),are threatened and widely recognized iconic tree species.Genomic resources for redwood trees could provide clues to their evolutionary relationships.Here,we report the 8-Gb reference genome of M.glyptostroboides and a comparative analysis with two related species.More than 62%of the M.glyptostroboides genome is composed of repetitive sequences.Clade-specific bursts of long terminal repeat retrotransposons may have contributed to genomic differentiation in the three species.The chromosomal synteny between M.glyptostroboides and S.giganteum is extremely high,whereas there has been significant chromosome reorganization in S.sempervirens.Phylogenetic analysis of marker genes indicates that S.sempervirens is an autopolyploid,and more than 48%of the gene trees are incongruent with the species tree.Results of multiple analyses suggest that incomplete lineage sorting(ILS)rather than hybridization explains the inconsistent phylogeny,indicating that genetic variation among redwoods may be due to random retention of polymorphisms in ancestral populations.Functional analysis of ortholog groups indicates that gene families of ion channels,tannin biosynthesis enzymes,and transcription factors for meristem maintenance have expanded in S.giganteum and S.sempervirens,which is consistent with their extreme height.As a wetland-tolerant species,M.glyptostroboides shows a transcriptional response to flooding stress that is conserved with that of analyzed angiosperm species.Our study offers insights into redwood evolution and adaptation and provides genomic resources to aid in their conservation and management.
文摘SNAPSHOTS OF CHINA Send us your photographs and let us know what lies behind them at contacts@chinafrica.cn Autumn Allure Autumn colours reach their peak in the Metasequoia forest in the Hongze Lake Wetland Scenic Area in Sihong,Jiangsu Province,attracting numerous visitors on 9 November.
