Betulin, oleanolic acid, and betulinic acid are naturally occurring pentacyclic triterpenoids that have significant medicinal value. Considerable amounts of these triterpenoids are available in the outer bark of white...Betulin, oleanolic acid, and betulinic acid are naturally occurring pentacyclic triterpenoids that have significant medicinal value. Considerable amounts of these triterpenoids are available in the outer bark of white birch. In this study, we used ultrasound-assisted extraction （UAE） to extract triterpenoids from birch bark rapidly and with high efficiency. Using high performance liquid chro- matography （HPLC）, three types of triterpenoids were separated and detected. We examined the differences among triterpenoids extracted from diploid versus tetra- ploid white birch. Then, we used factor analysis to screen out tetraploid white birches with comprehensively excel- lent performance. The results indicate that the optimum conditions for extraction include the use of ethanol as an extraction solvent, a solid-to-liquid ratio of 0.1 g/10 ml, ultrasonic power set at 100 W, a temperature of 60 ℃ and an extraction time of 15 min. A reversed-phase C18 col- umn （4.6 mm × 250 mm × 5 μm） with a column tem- perature of 30 ℃ and the mobile phase composed of A （acetonitrile） and B （0.1% aqueous phosphoric acid, v/v） at a flow rate of 0.5 ml/min were used, and the detection wavelength was 195 nm. No significant difference wasobserved between diploid and tetraploid white birch in terms of the content of three types of triterpenoids （at a confidence level of 0.05）. As triterpenoid content, height, and DBH （diameter at breast height） are strongly interre- lated, we used factor analysis to evaluate all individuals, and we screened out six plus trees with excellent com- prehensive characters.展开更多
MADS-box transcription factors show highly diverse regulatory functions in a wide variety of organisms. In this study, we characterized a MADS-box gene （BpMADS12） from the white birch （Betula platyphylla Suk）. Thi...MADS-box transcription factors show highly diverse regulatory functions in a wide variety of organisms. In this study, we characterized a MADS-box gene （BpMADS12） from the white birch （Betula platyphylla Suk）. This gene is a member of the suppressor of overexpression of CO 1/tomato MADS 3 class of MADS-box genes. We generated lines overexpressing BpMADS12 and found that these had higher levels of lignin compared to that observed in nontransgenic lines. Transcriptome anal- ysis revealed numerous changes in gene expression patterns. In total, 8794 differentially expressed genes were identified, including 5006 upregulated unigenes and 3788 downregulated unigenes in BpMADS-overexpression lines. Differentially expressed genes involved in the pathways for lignin and brassinosteroid biosynthesis were significantly enriched and may have contributed to phenotypic changes. The results from a quantitative RT-PCR analysis were consistent those obtained with the transcriptome analysis.Our transcriptome analysis, in combination with measure- ment of lignin level, indicated that BpMADS12 promotes lignin synthesis through regulation of key enzymes in response to brassinosteroid signaling. These results suggest that this MADS-box protein is crucial to all subsequent structural events and provide a good foundation for studies aiming to elucidate the developmental mechanisms underlying formation of wood.展开更多
Influences of temperature, humidity, and CO2 concentration on the photosynthesis and respiration of three-year-oldBetula platyphylla was investigated. Light compensation point, saturation point and CO2 compensation po...Influences of temperature, humidity, and CO2 concentration on the photosynthesis and respiration of three-year-oldBetula platyphylla was investigated. Light compensation point, saturation point and CO2 compensation point were also determined. The results showed that the optimal temperature of photosynthesis and dark respiration was 24 °C and 30 °C, respectively, at ambient CO2. When relative humidity was 80%,Betula platyphylla could maintain strong photosynthesis. There was no significant correlation between respiration and relative humidity. The light compensation and saturation point was 25 μmol·m?2·s?1 and 1 375 μmol·m?2·s?1, respectively. The CO2 compensation point was 180 μL·L?1. The results showed thatBetula platyphylla still had potential to assimilate CO2 when CO2 concentration was above 2 400 μL·L?1.展开更多
The content of total sugar, sucrose, fructose and protein in the leaves of3-yr.-old Betula platyphylla was measured after the treatment by three exogenous sugar solutions(sucrose, fructose, glucose) and three high con...The content of total sugar, sucrose, fructose and protein in the leaves of3-yr.-old Betula platyphylla was measured after the treatment by three exogenous sugar solutions(sucrose, fructose, glucose) and three high concentrations of CO_2 (700, 1 400, 2 100 μL/L·L^(-1))for about a month in 1998. The results showed that spraying three exogenous sugar solutionsincreased markedly the content of sugar and protein of leaves under 700 μL·L^(-1) and 1 400μL·L^(-1) CO_2 The effect of spraying exogenous sucrose solution was the best among the threeexogenous sugars. The treatment of spraying exogenous sugar solution and 2 100 μL·L^(-1) CO_2constrained the accumulation of total sugar and protein of leaves. There was no difference inprotein content of leaves when spraying glucose and fructose solutions under 700 μL·L^(-1) and 1400 μL·L^(-1) CO_2. The treatment of 2 100 μL·L^(-1) CO_2 concentration significantly increasedthe contents of total sugar, sucrose, fructose, and protein of leaves compared with that of the 700μL·L^(-1) and 1 400 μL·L^(-1) CO_2 except the plants spraying fructose solution. There waspositive correlation between the content of sugar of leaves and CO_2 concentration when sprayingsame exogenous sugar solution.展开更多
Estimating genetic parameters of parental lines through progeny testing and choosing good hybrid parents are important for genetically improving seed orchard trees.In this study, 24 tetraploid progeny seedlings were u...Estimating genetic parameters of parental lines through progeny testing and choosing good hybrid parents are important for genetically improving seed orchard trees.In this study, 24 tetraploid progeny seedlings were used as experimental materials, which came from test cross design：six tetraploid Betula platyphylla lines（Q33, Q13, Q103,Q19, Q83 and Q14） as female parents and four individual B. platyphylla diploid lines（F3, F4, F9 and F11） as male parents were crossed. Variance analysis of height, diameter, height-to-diameter ratio, and internodal distance showed that the differences between hybrid combinations reached highly significant levels. Using multi-objective decisionmaking, we performed a comprehensive assessment of the various hybrid combinations. Using a selection rate of 20 % of the standard, five hybrids were selected;their genetic gains in average height, diameter, height-todiameter ratio, and internodal distance were 20.95, 6.07,13.07 and 8.96 %, respectively. We also analyzed the combining ability and genetic parameter effect values of parents and hybrid combinations. The combined analysis revealed that Q13, Q103, Q33 and Q83 were superior females; F3, F4, and F9 were superior males; and F3 × Q13, F4 × Q83 and F9 × Q33 were superior hybrid combinations. The heights and diameters of these progenies were 22.49 and 11.48 % greater than average,respectively.展开更多
Female inflorescence of Betula platyphylla was sampled at an interval of eachtwo days to analyze the background of gene expression in floral phase. On the basis of SMARTstrategy, the driver cDNA was obtained from tota...Female inflorescence of Betula platyphylla was sampled at an interval of eachtwo days to analyze the background of gene expression in floral phase. On the basis of SMARTstrategy, the driver cDNA was obtained from total RNA of the last sample and the tester cDNA wasfrom that of the others by RT-PCR which were subsequently used to construct a subtracted cDNAlibrary. The result of the ESTs (expression sequence tags) blastX showed that the genes in thesubtracted cDNA library could be mainly clustered into 5 groups related to metabolism,transportation and signal transduction, cell cycle, stress response, and regulation. Therelationship between gene expression and development was also discussed.展开更多
We analyzed the germination traits (germination rate, germination potential, and germination index) of seeds from 23 half-sib families of birch (Betula platyphylla). The germination rates of the 23 families ranged fro...We analyzed the germination traits (germination rate, germination potential, and germination index) of seeds from 23 half-sib families of birch (Betula platyphylla). The germination rates of the 23 families ranged from 38.57 to 76.50%. Seeds from the eight families germinating at the highest rates were then used for germination experiments under salt stress. Germination rate, germination potential, and germination index of these eight half-sib families decreased with increasing salt concentrations. The effects of four different hormones (6-benzylaminopurine, 6BA;gibberellin, GA3;naphthalene acetic acid, NAA;and melatonin) at various concentrations on the germination of seeds from the eight half-sib birch families under salt stress were investigated. Treatments with 6BA and GA3 alleviated the effects of salt stress on seed germination, whereas treatments with NAA and melatonin aggravated the effects of salt stress. The most effective treatments for alleviating the effects of salt stress on birch seed germination were 10 mg/L 6BA and 300 mg/L GA3. This study provides practical information for screening birch families for salt tolerance at the seed germination stage, and for cultivation of birch in saline environments.展开更多
Betula platyphylla Sukaczev tetraploids have significantly larger leaf, fruit and stoma (gigantic phenotype) than diploids of the same species;however, the mechanism underlying this difference remains unclear. Tetrapl...Betula platyphylla Sukaczev tetraploids have significantly larger leaf, fruit and stoma (gigantic phenotype) than diploids of the same species;however, the mechanism underlying this difference remains unclear. Tetraploid B. platyphylla transcriptome data have indicated that the expression of genes related to indole-3-acetic acid (IAA) biosynthesis and signal transduction was altered after genome duplication. IAA exerts pleiotropic effects on growth and development by inducing the expression of Aux/IAA. We identified 20 Aux/IAA genes (BpIAA1– BpIAA20) in B. platyphylla distributed across 10 chromosomes. Multiple alignment and motif analyses revealed that nine BpIAA proteins shared all four conserved domains. Phylogenetic analysis indicated that Aux/IAA families were divided into four subfamilies and that there were two pairs of BpIAA sister genes. The BpIAAs were differentially expressed in diploids and tetraploids. Moreover, the expression levels of the nine BpIAA genes were specifically up-regulated in tetraploids from June to September compared with May (except August 5th) in tetraploids, while they were down-regulated in diploids. IAA levels were more than twofold higher in tetraploids than diploids during the vegetative season. These results indicate that genome duplication of B. platyphylla caused the up-regulated of genes involved in IAA synthesis, and the increased concentration of IAA may induce the constitutive expression of 20 BpIAA genes. Therefore, the significant changes in the expression patterns of the BpIAAs contributed to the gigantic phenotype of tetraploids to some extent. Our research sheds light on the phenotypic variations observed in B. platyphylla tetraploids.展开更多
The transcription factor BplMYB46 has been identified as a regulator of abiotic stress responses and promoter of secondary wall deposition in Betula platyphylla.To investigate the downstream targets of BplMYB46,the ex...The transcription factor BplMYB46 has been identified as a regulator of abiotic stress responses and promoter of secondary wall deposition in Betula platyphylla.To investigate the downstream targets of BplMYB46,the expression profiles of genes in stems from BplMYB46-overexpressing(OE)and BplMYB46-silencing(SE)plants were studied.In OE stems,952 genes were upregulated,and 1469 were downregulated in comparison to SE stems.In a KEGG pathway enrichment analysis of differentially expressed genes(DEGs),1387 differentially expressed genes were annotated for 117 metabolic pathways.DEGs were abundant for metabolic pathway,secondary metabolite biosynthesis,plant hormone signal transduction,phenylpropanoid and flavonoid biosynthesis.DEGs were implicated lignin or cellulose biosynthesis,cell wall modification,xylem development,disease resistance,stress responses,and anthocyanin biosynthesis.These results suggested that BplMYB46 regulates cell wall development and stress resistance by affecting the expression of these genes.Our study further elucidates the mechanism by which BplMYB46 mediates abiotic stress responses and secondary cell wall biosynthesis in birch.展开更多
For the first time in this paper the forests of Betula platyphylla in Daxing’an Mountains are Subdivided by phytosociological methods. Three community types of B. platyphylla forest have been differentiated, e.g., Rh...For the first time in this paper the forests of Betula platyphylla in Daxing’an Mountains are Subdivided by phytosociological methods. Three community types of B. platyphylla forest have been differentiated, e.g., Rhododendron dahuricum-Betula platyphylla Corylus, Corylus heterophylla-Betula platyphylla community and Arternisia stolonifera-Betula platyphylla community. The distributed elevation, stand height, differential species, major composition species of tree layer, shrub layer and herb layer for each community were detail展开更多
The stem analysis of Betula platyphylla in natural forest at the Maoershan Forest Experimental Station of Northeast Forestry Universitu. showed that the growth variation of the trees. including height and diameter bre...The stem analysis of Betula platyphylla in natural forest at the Maoershan Forest Experimental Station of Northeast Forestry Universitu. showed that the growth variation of the trees. including height and diameter breast height decreaseswith the increase of the age. There is the turning point for the growth variation of the tree from acute change to relative sta-bility when the trees are in eighteen years old. There are signiticant difttrences among the height. diameter and volumegrowth of the trees at that time. Theretbre. the optimal age for carly seleetion of this species in natural stands is eighteenyears old (18 a). Diameter is used as main index for eary seleclion and height growth as auxiliary one.展开更多
White birch(Betula platyphylla)is precious material for pulpwood and widely distributed in 14 provinces of China.Previous study indicated that inhibited expression of a gene encoding an auxin amide synthase,BpGH3.5,in...White birch(Betula platyphylla)is precious material for pulpwood and widely distributed in 14 provinces of China.Previous study indicated that inhibited expression of a gene encoding an auxin amide synthase,BpGH3.5,in transgenic plants reduced the level of IAA–amino acid conjugation,resulting in more free IAA,thereby better growth of birch.Utilizing transgenic-B pGH3.5 lines to increase wood production in a wide range of environments is the goal for breeders.In three field trials here,we measured tree height,diameter at breast height,and volume of 16 BpGH3.5-transgenic 7-year-old white birch lines(including 12 antisense strand lines and 4 overexpression lines)and a wild-type white birch line from three sites that varied greatly in their environmental conditions.To select elite BpGH3.5-transgenic lines for each target environment,we used an additive main effects and multiplicative interaction model to analyze genotype by environment interaction,growth adaptability and stability.The selection criteria for elite transgenic lines were set as the average volume plus 0.75 times the standard deviation for the tested lines at each test site.Results showed that the effect of line and site for height was highly significant(P<0.01),and the effect of line×site was significant(P<0.05);selected as the elite lines were FG12,FG13 and FG27 at the Maoershan Experimental Forest Farm,FG13 and FG32 at the Shidaohe Forest Farm,and FG3 and FG31 at the Ecological Experiment Forest Farm.These seven high-yield,stable lines can now be tested in production trials or adjacent trial areas with similar environmental conditions,while the high-yield,unstable lines should be tested in production trials in areas deemed suitable for their growth.These results provide guidance on which released transgenic elite lines will grow best in a wide range of conditions.展开更多
Betula platyphylla and Betula costata are important species in mixed broadleaved-Korean pine(Pinus koraiensis)forests.However,the specific ways in which their growth is affected by warm temperatures and drought remain...Betula platyphylla and Betula costata are important species in mixed broadleaved-Korean pine(Pinus koraiensis)forests.However,the specific ways in which their growth is affected by warm temperatures and drought remain unclear.To address this issue,60 and 62 tree-ring cores of B.platyphylla and B.costata were collected in Yichun,China.Using dendrochronological methods,the response and adaptation of these species to climate change were examined.A“hysteresis effect”was found in the rings of both species,linked to May–September moisture conditions of the previous year.Radial growth of B.costata was positively correlated with the standardized precipitation-evapotranspiration index(SPEI),the precipitation from September to October of the previous year,and the relative humidity in October of the previous year.Growth of B.costata is primarily restricted by moisture conditions from September to October.In contrast,B.platyphylla growth is mainly limited by minimum temperatures in May–June of both the previous and current years.After droughts,B.platyphylla had a faster recovery rate compared to B.costata.In the context of rising temperatures since 1980,the correlation between B.platyphylla growth and monthly SPEI became positive and strengthened over time,while the growth of B.costata showed no conspicuous change.Our findings suggest that the growth of B.platyphylla is already affected by warming temperatures,whereas B.costata may become limited if warming continues or intensifies.Climate change could disrupt the succession of these species,possibly accelerating the succession of pioneer species.The results of this research are of great significance for understanding how the growth changes of birch species under warming and drying conditions,and contribute to understanding the structural adaptation of mixed broadleaved-Korean pine(Pinus koraiensis)forests under climate change.展开更多
Glutathione-S-transferase(GST,EC2.5.1.18)multifunctional protease is important for detoxification,defense against biotic and abiotic stresses,and secondary metabolic material transport for plant growth and development...Glutathione-S-transferase(GST,EC2.5.1.18)multifunctional protease is important for detoxification,defense against biotic and abiotic stresses,and secondary metabolic material transport for plant growth and development.In this study,71 members of the BpGST family were identified from the entire Betula platyphylla Suk.genome.Most of the members encode proteins with amino acid lengths ranging from 101 to 875 and were localized to the cytoplasm by a prediction.BpGSTs can be divided into seven subfamilies,with a majority of birch U and F subfamily members according to gene structure,conserved motifs and evolutionary analysis.GST family genes showed collinearity with 22 genes in Oryza sativa L.,and three genes in Arabidopsis thaliana;promoter cis-acting elements predicted that the GST gene family is functional in growth,hormone regulation,and abiotic stress response.Most members of the F subfamily of GST(BpGSTFs)were expressed in roots,stems,leaves,and petioles,with the most expression observed in leaves.On the basis of the expression profiles of F subfamily genes(BpGSTF1 to BpGSTF13)during salt,mannitol and ABA stress,BpGSTF proteins seem to have multiple functions depending on the type of abiotic stress;for instance,BpGSTs may function at different times during abiotic stress.This study enhances understanding of the GST gene family and provides a basis for further exploration of their function in birch.展开更多
基金financially supported by National Forestry Department Public Benefit Research Foundation of China(201204302)
文摘Betulin, oleanolic acid, and betulinic acid are naturally occurring pentacyclic triterpenoids that have significant medicinal value. Considerable amounts of these triterpenoids are available in the outer bark of white birch. In this study, we used ultrasound-assisted extraction （UAE） to extract triterpenoids from birch bark rapidly and with high efficiency. Using high performance liquid chro- matography （HPLC）, three types of triterpenoids were separated and detected. We examined the differences among triterpenoids extracted from diploid versus tetra- ploid white birch. Then, we used factor analysis to screen out tetraploid white birches with comprehensively excel- lent performance. The results indicate that the optimum conditions for extraction include the use of ethanol as an extraction solvent, a solid-to-liquid ratio of 0.1 g/10 ml, ultrasonic power set at 100 W, a temperature of 60 ℃ and an extraction time of 15 min. A reversed-phase C18 col- umn （4.6 mm × 250 mm × 5 μm） with a column tem- perature of 30 ℃ and the mobile phase composed of A （acetonitrile） and B （0.1% aqueous phosphoric acid, v/v） at a flow rate of 0.5 ml/min were used, and the detection wavelength was 195 nm. No significant difference wasobserved between diploid and tetraploid white birch in terms of the content of three types of triterpenoids （at a confidence level of 0.05）. As triterpenoid content, height, and DBH （diameter at breast height） are strongly interre- lated, we used factor analysis to evaluate all individuals, and we screened out six plus trees with excellent com- prehensive characters.
基金financially supported by the National Science and Technology Program of China during the 12th Five-Year Plan Period(No.2013AA102704)the National Natural Science Foundation of China(NO:31200510)
文摘MADS-box transcription factors show highly diverse regulatory functions in a wide variety of organisms. In this study, we characterized a MADS-box gene （BpMADS12） from the white birch （Betula platyphylla Suk）. This gene is a member of the suppressor of overexpression of CO 1/tomato MADS 3 class of MADS-box genes. We generated lines overexpressing BpMADS12 and found that these had higher levels of lignin compared to that observed in nontransgenic lines. Transcriptome anal- ysis revealed numerous changes in gene expression patterns. In total, 8794 differentially expressed genes were identified, including 5006 upregulated unigenes and 3788 downregulated unigenes in BpMADS-overexpression lines. Differentially expressed genes involved in the pathways for lignin and brassinosteroid biosynthesis were significantly enriched and may have contributed to phenotypic changes. The results from a quantitative RT-PCR analysis were consistent those obtained with the transcriptome analysis.Our transcriptome analysis, in combination with measure- ment of lignin level, indicated that BpMADS12 promotes lignin synthesis through regulation of key enzymes in response to brassinosteroid signaling. These results suggest that this MADS-box protein is crucial to all subsequent structural events and provide a good foundation for studies aiming to elucidate the developmental mechanisms underlying formation of wood.
基金This paper was supported by the National Natural Science Foundation of China (No. 39970627) and the Key Project of State Department of Science Technology (2002BA515B05).
文摘Influences of temperature, humidity, and CO2 concentration on the photosynthesis and respiration of three-year-oldBetula platyphylla was investigated. Light compensation point, saturation point and CO2 compensation point were also determined. The results showed that the optimal temperature of photosynthesis and dark respiration was 24 °C and 30 °C, respectively, at ambient CO2. When relative humidity was 80%,Betula platyphylla could maintain strong photosynthesis. There was no significant correlation between respiration and relative humidity. The light compensation and saturation point was 25 μmol·m?2·s?1 and 1 375 μmol·m?2·s?1, respectively. The CO2 compensation point was 180 μL·L?1. The results showed thatBetula platyphylla still had potential to assimilate CO2 when CO2 concentration was above 2 400 μL·L?1.
基金This paper was supported by the National Natural Science Foundation of China (No. 39970627) and the Key Project of State Department of Science Technology (2002BA515B05).
文摘The content of total sugar, sucrose, fructose and protein in the leaves of3-yr.-old Betula platyphylla was measured after the treatment by three exogenous sugar solutions(sucrose, fructose, glucose) and three high concentrations of CO_2 (700, 1 400, 2 100 μL/L·L^(-1))for about a month in 1998. The results showed that spraying three exogenous sugar solutionsincreased markedly the content of sugar and protein of leaves under 700 μL·L^(-1) and 1 400μL·L^(-1) CO_2 The effect of spraying exogenous sucrose solution was the best among the threeexogenous sugars. The treatment of spraying exogenous sugar solution and 2 100 μL·L^(-1) CO_2constrained the accumulation of total sugar and protein of leaves. There was no difference inprotein content of leaves when spraying glucose and fructose solutions under 700 μL·L^(-1) and 1400 μL·L^(-1) CO_2. The treatment of 2 100 μL·L^(-1) CO_2 concentration significantly increasedthe contents of total sugar, sucrose, fructose, and protein of leaves compared with that of the 700μL·L^(-1) and 1 400 μL·L^(-1) CO_2 except the plants spraying fructose solution. There waspositive correlation between the content of sugar of leaves and CO_2 concentration when sprayingsame exogenous sugar solution.
基金supported by National Science and Technology Supporting Topics of China(2012BAD01B05)
文摘Estimating genetic parameters of parental lines through progeny testing and choosing good hybrid parents are important for genetically improving seed orchard trees.In this study, 24 tetraploid progeny seedlings were used as experimental materials, which came from test cross design：six tetraploid Betula platyphylla lines（Q33, Q13, Q103,Q19, Q83 and Q14） as female parents and four individual B. platyphylla diploid lines（F3, F4, F9 and F11） as male parents were crossed. Variance analysis of height, diameter, height-to-diameter ratio, and internodal distance showed that the differences between hybrid combinations reached highly significant levels. Using multi-objective decisionmaking, we performed a comprehensive assessment of the various hybrid combinations. Using a selection rate of 20 % of the standard, five hybrids were selected;their genetic gains in average height, diameter, height-todiameter ratio, and internodal distance were 20.95, 6.07,13.07 and 8.96 %, respectively. We also analyzed the combining ability and genetic parameter effect values of parents and hybrid combinations. The combined analysis revealed that Q13, Q103, Q33 and Q83 were superior females; F3, F4, and F9 were superior males; and F3 × Q13, F4 × Q83 and F9 × Q33 were superior hybrid combinations. The heights and diameters of these progenies were 22.49 and 11.48 % greater than average,respectively.
基金This project was supported by National Natural Science Foundation of China (39970627)
文摘Female inflorescence of Betula platyphylla was sampled at an interval of eachtwo days to analyze the background of gene expression in floral phase. On the basis of SMARTstrategy, the driver cDNA was obtained from total RNA of the last sample and the tester cDNA wasfrom that of the others by RT-PCR which were subsequently used to construct a subtracted cDNAlibrary. The result of the ESTs (expression sequence tags) blastX showed that the genes in thesubtracted cDNA library could be mainly clustered into 5 groups related to metabolism,transportation and signal transduction, cell cycle, stress response, and regulation. Therelationship between gene expression and development was also discussed.
基金supported by Grants from the National Natural Science Foundation of China(No.31770712)
文摘We analyzed the germination traits (germination rate, germination potential, and germination index) of seeds from 23 half-sib families of birch (Betula platyphylla). The germination rates of the 23 families ranged from 38.57 to 76.50%. Seeds from the eight families germinating at the highest rates were then used for germination experiments under salt stress. Germination rate, germination potential, and germination index of these eight half-sib families decreased with increasing salt concentrations. The effects of four different hormones (6-benzylaminopurine, 6BA;gibberellin, GA3;naphthalene acetic acid, NAA;and melatonin) at various concentrations on the germination of seeds from the eight half-sib birch families under salt stress were investigated. Treatments with 6BA and GA3 alleviated the effects of salt stress on seed germination, whereas treatments with NAA and melatonin aggravated the effects of salt stress. The most effective treatments for alleviating the effects of salt stress on birch seed germination were 10 mg/L 6BA and 300 mg/L GA3. This study provides practical information for screening birch families for salt tolerance at the seed germination stage, and for cultivation of birch in saline environments.
基金supported by the National Natural Science Foundation of China(Grant Nos.31370660 and 31670673)the 111 Project(B16010)
文摘Betula platyphylla Sukaczev tetraploids have significantly larger leaf, fruit and stoma (gigantic phenotype) than diploids of the same species;however, the mechanism underlying this difference remains unclear. Tetraploid B. platyphylla transcriptome data have indicated that the expression of genes related to indole-3-acetic acid (IAA) biosynthesis and signal transduction was altered after genome duplication. IAA exerts pleiotropic effects on growth and development by inducing the expression of Aux/IAA. We identified 20 Aux/IAA genes (BpIAA1– BpIAA20) in B. platyphylla distributed across 10 chromosomes. Multiple alignment and motif analyses revealed that nine BpIAA proteins shared all four conserved domains. Phylogenetic analysis indicated that Aux/IAA families were divided into four subfamilies and that there were two pairs of BpIAA sister genes. The BpIAAs were differentially expressed in diploids and tetraploids. Moreover, the expression levels of the nine BpIAA genes were specifically up-regulated in tetraploids from June to September compared with May (except August 5th) in tetraploids, while they were down-regulated in diploids. IAA levels were more than twofold higher in tetraploids than diploids during the vegetative season. These results indicate that genome duplication of B. platyphylla caused the up-regulated of genes involved in IAA synthesis, and the increased concentration of IAA may induce the constitutive expression of 20 BpIAA genes. Therefore, the significant changes in the expression patterns of the BpIAAs contributed to the gigantic phenotype of tetraploids to some extent. Our research sheds light on the phenotypic variations observed in B. platyphylla tetraploids.
基金supported by the Doctoral Research Fund of Mudanjiang Normal University(MNUB201504)the National Natural Science Foundation of China(31700587 and31470671)
文摘The transcription factor BplMYB46 has been identified as a regulator of abiotic stress responses and promoter of secondary wall deposition in Betula platyphylla.To investigate the downstream targets of BplMYB46,the expression profiles of genes in stems from BplMYB46-overexpressing(OE)and BplMYB46-silencing(SE)plants were studied.In OE stems,952 genes were upregulated,and 1469 were downregulated in comparison to SE stems.In a KEGG pathway enrichment analysis of differentially expressed genes(DEGs),1387 differentially expressed genes were annotated for 117 metabolic pathways.DEGs were abundant for metabolic pathway,secondary metabolite biosynthesis,plant hormone signal transduction,phenylpropanoid and flavonoid biosynthesis.DEGs were implicated lignin or cellulose biosynthesis,cell wall modification,xylem development,disease resistance,stress responses,and anthocyanin biosynthesis.These results suggested that BplMYB46 regulates cell wall development and stress resistance by affecting the expression of these genes.Our study further elucidates the mechanism by which BplMYB46 mediates abiotic stress responses and secondary cell wall biosynthesis in birch.
文摘For the first time in this paper the forests of Betula platyphylla in Daxing’an Mountains are Subdivided by phytosociological methods. Three community types of B. platyphylla forest have been differentiated, e.g., Rhododendron dahuricum-Betula platyphylla Corylus, Corylus heterophylla-Betula platyphylla community and Arternisia stolonifera-Betula platyphylla community. The distributed elevation, stand height, differential species, major composition species of tree layer, shrub layer and herb layer for each community were detail
文摘The stem analysis of Betula platyphylla in natural forest at the Maoershan Forest Experimental Station of Northeast Forestry Universitu. showed that the growth variation of the trees. including height and diameter breast height decreaseswith the increase of the age. There is the turning point for the growth variation of the tree from acute change to relative sta-bility when the trees are in eighteen years old. There are signiticant difttrences among the height. diameter and volumegrowth of the trees at that time. Theretbre. the optimal age for carly seleetion of this species in natural stands is eighteenyears old (18 a). Diameter is used as main index for eary seleclion and height growth as auxiliary one.
基金supported by National Key R&D Program of China during the 14th Five-year Plan Period(2021YFD2200102)Heilongjiang Touyan Innovation Team Program(Tree Genetics and Breeding Innovation Team)。
文摘White birch(Betula platyphylla)is precious material for pulpwood and widely distributed in 14 provinces of China.Previous study indicated that inhibited expression of a gene encoding an auxin amide synthase,BpGH3.5,in transgenic plants reduced the level of IAA–amino acid conjugation,resulting in more free IAA,thereby better growth of birch.Utilizing transgenic-B pGH3.5 lines to increase wood production in a wide range of environments is the goal for breeders.In three field trials here,we measured tree height,diameter at breast height,and volume of 16 BpGH3.5-transgenic 7-year-old white birch lines(including 12 antisense strand lines and 4 overexpression lines)and a wild-type white birch line from three sites that varied greatly in their environmental conditions.To select elite BpGH3.5-transgenic lines for each target environment,we used an additive main effects and multiplicative interaction model to analyze genotype by environment interaction,growth adaptability and stability.The selection criteria for elite transgenic lines were set as the average volume plus 0.75 times the standard deviation for the tested lines at each test site.Results showed that the effect of line and site for height was highly significant(P<0.01),and the effect of line×site was significant(P<0.05);selected as the elite lines were FG12,FG13 and FG27 at the Maoershan Experimental Forest Farm,FG13 and FG32 at the Shidaohe Forest Farm,and FG3 and FG31 at the Ecological Experiment Forest Farm.These seven high-yield,stable lines can now be tested in production trials or adjacent trial areas with similar environmental conditions,while the high-yield,unstable lines should be tested in production trials in areas deemed suitable for their growth.These results provide guidance on which released transgenic elite lines will grow best in a wide range of conditions.
基金the Key Project of the China National Key Research and Development Program(2021YFD2200401)the National Natural Science Foundation of China(42177421 and 41877426)。
文摘Betula platyphylla and Betula costata are important species in mixed broadleaved-Korean pine(Pinus koraiensis)forests.However,the specific ways in which their growth is affected by warm temperatures and drought remain unclear.To address this issue,60 and 62 tree-ring cores of B.platyphylla and B.costata were collected in Yichun,China.Using dendrochronological methods,the response and adaptation of these species to climate change were examined.A“hysteresis effect”was found in the rings of both species,linked to May–September moisture conditions of the previous year.Radial growth of B.costata was positively correlated with the standardized precipitation-evapotranspiration index(SPEI),the precipitation from September to October of the previous year,and the relative humidity in October of the previous year.Growth of B.costata is primarily restricted by moisture conditions from September to October.In contrast,B.platyphylla growth is mainly limited by minimum temperatures in May–June of both the previous and current years.After droughts,B.platyphylla had a faster recovery rate compared to B.costata.In the context of rising temperatures since 1980,the correlation between B.platyphylla growth and monthly SPEI became positive and strengthened over time,while the growth of B.costata showed no conspicuous change.Our findings suggest that the growth of B.platyphylla is already affected by warming temperatures,whereas B.costata may become limited if warming continues or intensifies.Climate change could disrupt the succession of these species,possibly accelerating the succession of pioneer species.The results of this research are of great significance for understanding how the growth changes of birch species under warming and drying conditions,and contribute to understanding the structural adaptation of mixed broadleaved-Korean pine(Pinus koraiensis)forests under climate change.
基金supported by the National Key Research and Development Program of China(No.2021YFD2200304)FundamentalResearch Funds for the Central Universities(2572022DQ08)the National Natural Science Foundation of China(No32171738).
文摘Glutathione-S-transferase(GST,EC2.5.1.18)multifunctional protease is important for detoxification,defense against biotic and abiotic stresses,and secondary metabolic material transport for plant growth and development.In this study,71 members of the BpGST family were identified from the entire Betula platyphylla Suk.genome.Most of the members encode proteins with amino acid lengths ranging from 101 to 875 and were localized to the cytoplasm by a prediction.BpGSTs can be divided into seven subfamilies,with a majority of birch U and F subfamily members according to gene structure,conserved motifs and evolutionary analysis.GST family genes showed collinearity with 22 genes in Oryza sativa L.,and three genes in Arabidopsis thaliana;promoter cis-acting elements predicted that the GST gene family is functional in growth,hormone regulation,and abiotic stress response.Most members of the F subfamily of GST(BpGSTFs)were expressed in roots,stems,leaves,and petioles,with the most expression observed in leaves.On the basis of the expression profiles of F subfamily genes(BpGSTF1 to BpGSTF13)during salt,mannitol and ABA stress,BpGSTF proteins seem to have multiple functions depending on the type of abiotic stress;for instance,BpGSTs may function at different times during abiotic stress.This study enhances understanding of the GST gene family and provides a basis for further exploration of their function in birch.
