The development of needle resin ducts of Pinus elliottii was studied using electron microscope. The results indicate that the resin duct development encompasses at least three distinctive development stages: the s...The development of needle resin ducts of Pinus elliottii was studied using electron microscope. The results indicate that the resin duct development encompasses at least three distinctive development stages: the stage of initial cells, the stage of middle lamellae expansion and intercellular space appearance, and the stage of cavity enlargement and the resin duct formation. During the whole development stages, all kinds of organells in the duct cells show different ultrastructural features and regularity, among them the plastids' changing is the most striking one. On the basis of analysing the ultrastructural features of developing resin duct cells, the pattern of duct cavity formation, possible sites of resin synthesis, the manner and way of the resin elimination from the protoplast are discussed.展开更多
Quantitative trait locus （QTL） detection was carried out for growth traits in 122 F1 progenies of Pinus elliottiivar. elliottii （PEE） x tR caribaea var. hondurensis （PCH） hybrid. The PCH male parent linkage map ...Quantitative trait locus （QTL） detection was carried out for growth traits in 122 F1 progenies of Pinus elliottiivar. elliottii （PEE） x tR caribaea var. hondurensis （PCH） hybrid. The PCH male parent linkage map contained 108 mark- ers in 16 linkage groups, while the PEE female parent contained 93 markers in 19 linkage groups. Sequence-related amplified polymorphism （SRAP）, microsatellite （SSR）, expressed sequence tag polymorphism （ESTP） and inter-simple sequence repeat （ISSR） were selected from an existing linkage map. Growth traits investigated were height at age five （HT05） and six years （HT06）, diameter at breast height at age five （DBH05） and six years （DBH06） and annual growth from age five to six years of height （AGHT） and diameter at breast height （AGDBH）. KruskaI-Wallis and interval mapping approaches were used to estimate levels of significance, the number of QTLs, the percentage of the phenotypic varia- tion explained by each of QTLs and their positions on the genetic linkage maps. Twenty six QTLs with significance levels p 〈 0.05 were detected on the parental maps for the six growth traits, which explained more than 15% of the phenotypic variation, suggesting an existence of major-effect genes. Several QTLs had the pleiotropy controlling more than one sin- gle growth trait. Overall, the proportion of phenotypic variation explained by QTLs ranged from 5.9% to 40.6% for HT05 and HT06, from 6.6% to 42.0% for DBH05 and DBH06 and from 5.8% to 22.3% for AGHT and AGDBH. The results from this study provide a basis for marker-aided selection （MAS） in PEE x PCH hybrids.展开更多
A solid understanding of the efficiency of early selection for fiber dimensions is a prerequisite for breeding slash pine(Pinus elliottii Engelm.)with improved properties for pulp and paper products.Genetic correlatio...A solid understanding of the efficiency of early selection for fiber dimensions is a prerequisite for breeding slash pine(Pinus elliottii Engelm.)with improved properties for pulp and paper products.Genetic correlations between size of fibers,wood quality and growth properties are also important.To accomplish effective early selection for size of fibers and evaluate the impact for wood quality traits and ring widths,core samples were collected from360 trees of 20 open-pollinated Pinus elliottii families from three genetic trials.Cores were measured by SilviScan,and the age trends for phenotypic values,heritability,early-late genetic correlations,and early selection efficiency for fiber dimensions,such as tangential and radial fiber widths,fiber wall thickness and fiber coarseness,and their correlations with microfibril angle(MFA),modulus of elasticity(MOE),wood density and ring width were investigated.Different phenotypic trends were found for tangential and radial fiber widths while fiber coarseness and wall thickness curves were similar.Age trends of heritability based on area-weighted fiber dimensions were different.Low to moderate heritability from pith to bark(~0.5)was found for all fiber dimension across the three sites except for tangential fiber width and wall thickness at the Ganzhou site.Early-late genetic correlations were 0.9 after age of 9 years,and early selection for fiber dimensions could be effective due to strong genetic correlations.Our results showed moderate to strong positive genetic correlations for modulus of elasticity and density with fiber dimensions.The effects on fiber dimensions were weak or moderate when ring width or wood quality traits were selected alone.Estimates of efficiency for early selection indicated that the optimal age for radial fiber width and fiber coarseness was 6-7 years,while for tangential fiber width and wall thickness was 9-10 years.展开更多
The longleaf pine(Pinus palustris Mill.)ecosystem is an endangered ecosystem in the southeastern USA,and efforts to restore the species are ongoing.However,in recent decades,the region has experienced drastic fluctuat...The longleaf pine(Pinus palustris Mill.)ecosystem is an endangered ecosystem in the southeastern USA,and efforts to restore the species are ongoing.However,in recent decades,the region has experienced drastic fluctuations between wet and dry growing season conditions from year to year,and it is not fully understood how these fluctuations have influenced the growth of P.palustris.To address this topic,we cored P.palustris trees in woodlands of southwest Georgia and used dendrochronology techniques to determine how climate fluctuations have influenced the growth and drought resilience of P.palustris.We also cored slash pine(Pinus elliottii Engelm.)trees in the same woodlands to compare growth between species.While P.palustris growth was less impacted by adverse climate conditions compared to P.elliottii,the strength of correlations between P.palustris growth and temperature,precipitation,and Palmer Drought Severity Index(PDSI)changed over time.In recent decades,climate conditions during the growing season became more influential on P.palustris growth than the previous year's conditions.This is concerning given that drought severity during the growing season has been increasing.Our results also indicate that P.palustris was less resilient to droughts during the 2000s and 2010s than to those of the 1950s.Under this new climate paradigm,our results suggest that P.palustris might be more susceptible to growth reductions and less resistant to droughts than once expected.This work highlights the importance of understanding the impact of novel climate conditions on P.palustris and has implications for restoration efforts,such as using silvicultural treatments that reduce tree vulnerability to drought(e.g.,thinning)and promote other climate-adapted species in mixture with P.palustris.展开更多
Slash Pine(Pinus elliottii) is an introduced tree species that can adapt different site types. Since 1970s, in order to enrich the tree species resource, Slash Pine was planted on the cut_over area of Casuarina equise...Slash Pine(Pinus elliottii) is an introduced tree species that can adapt different site types. Since 1970s, in order to enrich the tree species resource, Slash Pine was planted on the cut_over area of Casuarina equisetifolia protection forest in Chishan Protection Forest Farm of Dongshan County, Fujian Province. It could prevent soil fertility from degeneration, improve forest productivity and provide fundamental data for soil ecological management to study the soil nutrient content and enzyme activities of different age stands of Slash Pine. The effect of Slash Pine on fertility of coastal sandy land was studied in this paper. The results showed that it would make the soil acid to plant Slash Pine on the cut_over area of C.equisetifolia protection forest Compared, because the pH value was declined as the growth of Slash Pine stand, and it declined to 3.96(0～20*!cm) and 3.87(20～40*!cm) when Slash Pine stand was 26*!a; Compared with the second generation coastal protection forest of C.equisetifolia the nutrients content in the soil of 26*!a Slash Pine stand were lower than that in the soil of the second generation forest, especially for available P, available K, and total N. The CEC in soil layer of 0～20*!cm was obviously effected by Slash Pine. In this soil layer, the CEC was increased as the growth of Slash Pine stands, and it was as 1.22 times as the content in the soil of the second generation forest. There was no obvious effect on urease activity, but the activities of phosphataese, polyphenol oxidase, and peroxidase were declined by planted Shash Pine on the cut_over area of Casuarina protection forest.展开更多
文摘The development of needle resin ducts of Pinus elliottii was studied using electron microscope. The results indicate that the resin duct development encompasses at least three distinctive development stages: the stage of initial cells, the stage of middle lamellae expansion and intercellular space appearance, and the stage of cavity enlargement and the resin duct formation. During the whole development stages, all kinds of organells in the duct cells show different ultrastructural features and regularity, among them the plastids' changing is the most striking one. On the basis of analysing the ultrastructural features of developing resin duct cells, the pattern of duct cavity formation, possible sites of resin synthesis, the manner and way of the resin elimination from the protoplast are discussed.
基金financially supported by the National Natural Science Foundation of China (No. 30671706)
文摘Quantitative trait locus （QTL） detection was carried out for growth traits in 122 F1 progenies of Pinus elliottiivar. elliottii （PEE） x tR caribaea var. hondurensis （PCH） hybrid. The PCH male parent linkage map contained 108 mark- ers in 16 linkage groups, while the PEE female parent contained 93 markers in 19 linkage groups. Sequence-related amplified polymorphism （SRAP）, microsatellite （SSR）, expressed sequence tag polymorphism （ESTP） and inter-simple sequence repeat （ISSR） were selected from an existing linkage map. Growth traits investigated were height at age five （HT05） and six years （HT06）, diameter at breast height at age five （DBH05） and six years （DBH06） and annual growth from age five to six years of height （AGHT） and diameter at breast height （AGDBH）. KruskaI-Wallis and interval mapping approaches were used to estimate levels of significance, the number of QTLs, the percentage of the phenotypic varia- tion explained by each of QTLs and their positions on the genetic linkage maps. Twenty six QTLs with significance levels p 〈 0.05 were detected on the parental maps for the six growth traits, which explained more than 15% of the phenotypic variation, suggesting an existence of major-effect genes. Several QTLs had the pleiotropy controlling more than one sin- gle growth trait. Overall, the proportion of phenotypic variation explained by QTLs ranged from 5.9% to 40.6% for HT05 and HT06, from 6.6% to 42.0% for DBH05 and DBH06 and from 5.8% to 22.3% for AGHT and AGDBH. The results from this study provide a basis for marker-aided selection （MAS） in PEE x PCH hybrids.
基金supported by the National Natural Science Foundation of China(No.32260407)Science and Technology Leader Foundation of Jiangxi Province(No.20212BCJ23011)National Natural Science Foundation of China(No.31860220 and 32160385)。
文摘A solid understanding of the efficiency of early selection for fiber dimensions is a prerequisite for breeding slash pine(Pinus elliottii Engelm.)with improved properties for pulp and paper products.Genetic correlations between size of fibers,wood quality and growth properties are also important.To accomplish effective early selection for size of fibers and evaluate the impact for wood quality traits and ring widths,core samples were collected from360 trees of 20 open-pollinated Pinus elliottii families from three genetic trials.Cores were measured by SilviScan,and the age trends for phenotypic values,heritability,early-late genetic correlations,and early selection efficiency for fiber dimensions,such as tangential and radial fiber widths,fiber wall thickness and fiber coarseness,and their correlations with microfibril angle(MFA),modulus of elasticity(MOE),wood density and ring width were investigated.Different phenotypic trends were found for tangential and radial fiber widths while fiber coarseness and wall thickness curves were similar.Age trends of heritability based on area-weighted fiber dimensions were different.Low to moderate heritability from pith to bark(~0.5)was found for all fiber dimension across the three sites except for tangential fiber width and wall thickness at the Ganzhou site.Early-late genetic correlations were 0.9 after age of 9 years,and early selection for fiber dimensions could be effective due to strong genetic correlations.Our results showed moderate to strong positive genetic correlations for modulus of elasticity and density with fiber dimensions.The effects on fiber dimensions were weak or moderate when ring width or wood quality traits were selected alone.Estimates of efficiency for early selection indicated that the optimal age for radial fiber width and fiber coarseness was 6-7 years,while for tangential fiber width and wall thickness was 9-10 years.
基金funded through a Ph D scholarship (2021.05104.BD) funded by the Portuguese Foundation for Science and Technology (FCT)a Fulbright grant with the support of FCTsupported by The Jones Center at Ichauway
文摘The longleaf pine(Pinus palustris Mill.)ecosystem is an endangered ecosystem in the southeastern USA,and efforts to restore the species are ongoing.However,in recent decades,the region has experienced drastic fluctuations between wet and dry growing season conditions from year to year,and it is not fully understood how these fluctuations have influenced the growth of P.palustris.To address this topic,we cored P.palustris trees in woodlands of southwest Georgia and used dendrochronology techniques to determine how climate fluctuations have influenced the growth and drought resilience of P.palustris.We also cored slash pine(Pinus elliottii Engelm.)trees in the same woodlands to compare growth between species.While P.palustris growth was less impacted by adverse climate conditions compared to P.elliottii,the strength of correlations between P.palustris growth and temperature,precipitation,and Palmer Drought Severity Index(PDSI)changed over time.In recent decades,climate conditions during the growing season became more influential on P.palustris growth than the previous year's conditions.This is concerning given that drought severity during the growing season has been increasing.Our results also indicate that P.palustris was less resilient to droughts during the 2000s and 2010s than to those of the 1950s.Under this new climate paradigm,our results suggest that P.palustris might be more susceptible to growth reductions and less resistant to droughts than once expected.This work highlights the importance of understanding the impact of novel climate conditions on P.palustris and has implications for restoration efforts,such as using silvicultural treatments that reduce tree vulnerability to drought(e.g.,thinning)and promote other climate-adapted species in mixture with P.palustris.
文摘Slash Pine(Pinus elliottii) is an introduced tree species that can adapt different site types. Since 1970s, in order to enrich the tree species resource, Slash Pine was planted on the cut_over area of Casuarina equisetifolia protection forest in Chishan Protection Forest Farm of Dongshan County, Fujian Province. It could prevent soil fertility from degeneration, improve forest productivity and provide fundamental data for soil ecological management to study the soil nutrient content and enzyme activities of different age stands of Slash Pine. The effect of Slash Pine on fertility of coastal sandy land was studied in this paper. The results showed that it would make the soil acid to plant Slash Pine on the cut_over area of C.equisetifolia protection forest Compared, because the pH value was declined as the growth of Slash Pine stand, and it declined to 3.96(0～20*!cm) and 3.87(20～40*!cm) when Slash Pine stand was 26*!a; Compared with the second generation coastal protection forest of C.equisetifolia the nutrients content in the soil of 26*!a Slash Pine stand were lower than that in the soil of the second generation forest, especially for available P, available K, and total N. The CEC in soil layer of 0～20*!cm was obviously effected by Slash Pine. In this soil layer, the CEC was increased as the growth of Slash Pine stands, and it was as 1.22 times as the content in the soil of the second generation forest. There was no obvious effect on urease activity, but the activities of phosphataese, polyphenol oxidase, and peroxidase were declined by planted Shash Pine on the cut_over area of Casuarina protection forest.
