Plant species produce different types of allelopathic chemicals in nature;however,little is known about the differential regulation of plant allelopathy.Because allelopathy caused by p-hydroxybenzoic acid(pHBA)is one ...Plant species produce different types of allelopathic chemicals in nature;however,little is known about the differential regulation of plant allelopathy.Because allelopathy caused by p-hydroxybenzoic acid(pHBA)is one of the main obstacles to continuous cropping of Populus×euramericana ‘Neva’,we examined gene expression dynamics in Neva leaves induced by pHBA.The expression of genes related to photosynthesis and respiration changed,while mRNA involved in regulating gene expression during allelopathy was degraded.Some miRNAs that are involved in plant allelopathy target crucial genes for regulating reactive oxygen species.Moreover,coexpression regulatory networks were constructed based on profiles of the identified miRNA-target interactions and the differentially expressed miRNA-target pairs.These findings provide a mechanistic framework for understanding allelopathy in plants.展开更多
The purpose of the present study was to establish a regeneration procedure for Populus × euramericana ＇Neva＇ by using in vitro shoots tips and leaves. For sterilization, 0.1% （w/v） mercuric chloride （HgCl2）...The purpose of the present study was to establish a regeneration procedure for Populus × euramericana ＇Neva＇ by using in vitro shoots tips and leaves. For sterilization, 0.1% （w/v） mercuric chloride （HgCl2） solution for 8 to 10 min was the optimal treatment for this poplar cultivation. The effects of benzyladenine （BA） and α-naphthaleneacetic acid （NAA） added to Murashige and Skoog （MS） medium were tested on organogenesis. The highest regeneration rate and numbers of shoots/explant from shoot tips （96.7%, 9.8） and leaves （90.0%, 8.7） were obtained on the half-strength MS medium supplemented with 0.5 mg/L BA and 0.1 mg/L NAA. The optimal medium for in vitro rooting of shoots was on a half-strength MS medium containing 1 mg/L indolebutyric acid （IBA） with the highest rooting frequency （93.3%） and numbers of roots/explant （8.2）. For acclimatization, in vitro rooted plantlets were transferred to plastic cups containing vermiculite and peat （1： 1）. After acclimatization, transplanted plantlets grew well in a shade house. Therefore, we believe that this efficient plant regeneration protocol especially by leaf explants is very important for in vitro clonal propagation of Populus×euramericana ＇Neva＇.展开更多
The physical-mechanical properties of Populus x canadensis Moench and Populus x euramericana （Dode） Guinier cv. Gelrica were studied to provide theoret- ical and scientific bases for the directional breeding and eff...The physical-mechanical properties of Populus x canadensis Moench and Populus x euramericana （Dode） Guinier cv. Gelrica were studied to provide theoret- ical and scientific bases for the directional breeding and efficient use of artificial forests with P. canadensis and P. euramericana Gelrica. The results showed the air-dried density, basic density of P. canadensis were 0.468 g/cm3 and 0.372 g/cm3, respectively; the shrinkage coefficient of radial, tangential and volume were 0.133%, 0.270% and 0.553%, respectively;the modulus of elasticity in static bending, the bending strength and the compressive strength parallel to grain were 9 302.99 MPa, 79.69 MPa and 40.32 Mpa, respectively. As for the P. euramericana Gelrica, the air-dried density, basic densitywere 0.453 and 0.355 g/cm3, respectively; the shrink- age coefficient of radial, tangential and volume were 0.205%, 0.304% and 0.554%, respectively; the modulus of elasticity in static bending, the bending strength and the compressive strength parallel to grain were 9 014.44, 55.87 and 33.09 Mpa respectively. Comprehensive analysis of the indicators showed that the properties of P. canadensis were better than those of P.euramericana Gelrica.展开更多
Five Populus x euramericana wood samples representing three different sites were selected and nearinfrared （NIR） spectra were obtained. For these sections, basis weight, brightness and three mechanical properties （...Five Populus x euramericana wood samples representing three different sites were selected and nearinfrared （NIR） spectra were obtained. For these sections, basis weight, brightness and three mechanical properties （tensile index, tearing index and bursting index） were determined by standard analytical methods. Calibrations were developed for each paper property using the NIR spectra, data on paper properties, using partial least squares （PLS） regression. The results show that the coefficients of correlation of calibration and validation for basis weight were 0.8824 and 0.8299, respectively; the standard error of calibration （SEC） and prediction （SEP） were 1.150 and 1.170, respectively. In testing for brightness, the correlation coefficient of calibration was 0.9621 and for validation 0.9612, while the SEC and SEP were 0.997 and 1.300, respectively; paper brightness and NIR spectroscopy were highly correlated. NIR spectroscopy can be used to predict tensile, tearing and bursting indices of paper samples rapidly. We found that the paper properties fitted by NIR and GB methods were highly correlated. The coefficients of correlation of calibration and validation for basis weight exceeded 0.8000, while the SEC and SEP were very small. These results reveal that the five paper properties of Populus x euramericana and those predicted by the NIR model were highly correlated. We conclude that the NIR models can be used for the prediction of paper properties.展开更多
The absorption and enrichment of heavy metal elements by leaves of Populus×euramericana cv.’Neva’ were analyzed through content assessing of heavy metal elements in soils of three forest lands at Fangshan Distr...The absorption and enrichment of heavy metal elements by leaves of Populus×euramericana cv.’Neva’ were analyzed through content assessing of heavy metal elements in soils of three forest lands at Fangshan District in the southern suburb of Beijing. These forest lands with P.×euramericana cv. ’Neva’plantation were around with the various sources of pollution such as cement mill,stone mill, sewage and garbage.Some of heavy metal elements such as Cd,Pb,Cu,and Zn were found in the soil samples and leaves of P.×euramericana cv.’Neva’ grown on the three forest lands which were investigated.The results of investigation showed that the soils of three forest lands were polluted with Pb, Cd,Cu and Zn in varying degrees.The contents of Pb,Cu and Zn in soils were significantly different among the three forest lands,whereas the average content of Cd(0.077 6 mg·kg<sup>-1</sup>) was less but that of Pb,Cu,and Zn(37.61,26.25 and 90.3 mg·kg<sup>-1</sup> ) were more than the average background value of Beijing.The contents of Pb,Cd,Cu and Zn in leaves of P.×euramericana cv.’Neva’ were different among three forestlands.With the changes of heavy metal contents in soil samples,there was no regularity on the changes of different heavy metal contents in leaves of P.×euramericana cv.’Neva’ grown on different forest land.P.×euramericana cv.’Neva’ can absorb and accumulate Pb,Cd,Cu and Zn in soil but showed different capacities of absorption and accumulation with the order of Cd】Zn】Cu】Pb.Especially,its absorption and accumulation capacity for Cd was strong with maximum enrichment factor higher than 16 and showed high accumulation on low background,whereas its enrichment capacities for Pb and Cu were relatively poorer with average enrichment factor of less than 1.At different forest lands,there existed great difference on absorption capacity of P.×euramericana cv.’Neva’ with the same heavy metal.展开更多
基金the National Public Welfare Industry Research Project of China(201504406)National Natural Science Foundation of China(31770706)+1 种基金National Natural Science Foundation of China(31870379)Science Research Projects of Facility Horticulture Laboratory of Universities in Shandong(2018YY031)。
文摘Plant species produce different types of allelopathic chemicals in nature;however,little is known about the differential regulation of plant allelopathy.Because allelopathy caused by p-hydroxybenzoic acid(pHBA)is one of the main obstacles to continuous cropping of Populus×euramericana ‘Neva’,we examined gene expression dynamics in Neva leaves induced by pHBA.The expression of genes related to photosynthesis and respiration changed,while mRNA involved in regulating gene expression during allelopathy was degraded.Some miRNAs that are involved in plant allelopathy target crucial genes for regulating reactive oxygen species.Moreover,coexpression regulatory networks were constructed based on profiles of the identified miRNA-target interactions and the differentially expressed miRNA-target pairs.These findings provide a mechanistic framework for understanding allelopathy in plants.
文摘The purpose of the present study was to establish a regeneration procedure for Populus × euramericana ＇Neva＇ by using in vitro shoots tips and leaves. For sterilization, 0.1% （w/v） mercuric chloride （HgCl2） solution for 8 to 10 min was the optimal treatment for this poplar cultivation. The effects of benzyladenine （BA） and α-naphthaleneacetic acid （NAA） added to Murashige and Skoog （MS） medium were tested on organogenesis. The highest regeneration rate and numbers of shoots/explant from shoot tips （96.7%, 9.8） and leaves （90.0%, 8.7） were obtained on the half-strength MS medium supplemented with 0.5 mg/L BA and 0.1 mg/L NAA. The optimal medium for in vitro rooting of shoots was on a half-strength MS medium containing 1 mg/L indolebutyric acid （IBA） with the highest rooting frequency （93.3%） and numbers of roots/explant （8.2）. For acclimatization, in vitro rooted plantlets were transferred to plastic cups containing vermiculite and peat （1： 1）. After acclimatization, transplanted plantlets grew well in a shade house. Therefore, we believe that this efficient plant regeneration protocol especially by leaf explants is very important for in vitro clonal propagation of Populus×euramericana ＇Neva＇.
文摘The physical-mechanical properties of Populus x canadensis Moench and Populus x euramericana （Dode） Guinier cv. Gelrica were studied to provide theoret- ical and scientific bases for the directional breeding and efficient use of artificial forests with P. canadensis and P. euramericana Gelrica. The results showed the air-dried density, basic density of P. canadensis were 0.468 g/cm3 and 0.372 g/cm3, respectively; the shrinkage coefficient of radial, tangential and volume were 0.133%, 0.270% and 0.553%, respectively;the modulus of elasticity in static bending, the bending strength and the compressive strength parallel to grain were 9 302.99 MPa, 79.69 MPa and 40.32 Mpa, respectively. As for the P. euramericana Gelrica, the air-dried density, basic densitywere 0.453 and 0.355 g/cm3, respectively; the shrink- age coefficient of radial, tangential and volume were 0.205%, 0.304% and 0.554%, respectively; the modulus of elasticity in static bending, the bending strength and the compressive strength parallel to grain were 9 014.44, 55.87 and 33.09 Mpa respectively. Comprehensive analysis of the indicators showed that the properties of P. canadensis were better than those of P.euramericana Gelrica.
文摘Five Populus x euramericana wood samples representing three different sites were selected and nearinfrared （NIR） spectra were obtained. For these sections, basis weight, brightness and three mechanical properties （tensile index, tearing index and bursting index） were determined by standard analytical methods. Calibrations were developed for each paper property using the NIR spectra, data on paper properties, using partial least squares （PLS） regression. The results show that the coefficients of correlation of calibration and validation for basis weight were 0.8824 and 0.8299, respectively; the standard error of calibration （SEC） and prediction （SEP） were 1.150 and 1.170, respectively. In testing for brightness, the correlation coefficient of calibration was 0.9621 and for validation 0.9612, while the SEC and SEP were 0.997 and 1.300, respectively; paper brightness and NIR spectroscopy were highly correlated. NIR spectroscopy can be used to predict tensile, tearing and bursting indices of paper samples rapidly. We found that the paper properties fitted by NIR and GB methods were highly correlated. The coefficients of correlation of calibration and validation for basis weight exceeded 0.8000, while the SEC and SEP were very small. These results reveal that the five paper properties of Populus x euramericana and those predicted by the NIR model were highly correlated. We conclude that the NIR models can be used for the prediction of paper properties.
文摘The absorption and enrichment of heavy metal elements by leaves of Populus×euramericana cv.’Neva’ were analyzed through content assessing of heavy metal elements in soils of three forest lands at Fangshan District in the southern suburb of Beijing. These forest lands with P.×euramericana cv. ’Neva’plantation were around with the various sources of pollution such as cement mill,stone mill, sewage and garbage.Some of heavy metal elements such as Cd,Pb,Cu,and Zn were found in the soil samples and leaves of P.×euramericana cv.’Neva’ grown on the three forest lands which were investigated.The results of investigation showed that the soils of three forest lands were polluted with Pb, Cd,Cu and Zn in varying degrees.The contents of Pb,Cu and Zn in soils were significantly different among the three forest lands,whereas the average content of Cd(0.077 6 mg·kg<sup>-1</sup>) was less but that of Pb,Cu,and Zn(37.61,26.25 and 90.3 mg·kg<sup>-1</sup> ) were more than the average background value of Beijing.The contents of Pb,Cd,Cu and Zn in leaves of P.×euramericana cv.’Neva’ were different among three forestlands.With the changes of heavy metal contents in soil samples,there was no regularity on the changes of different heavy metal contents in leaves of P.×euramericana cv.’Neva’ grown on different forest land.P.×euramericana cv.’Neva’ can absorb and accumulate Pb,Cd,Cu and Zn in soil but showed different capacities of absorption and accumulation with the order of Cd】Zn】Cu】Pb.Especially,its absorption and accumulation capacity for Cd was strong with maximum enrichment factor higher than 16 and showed high accumulation on low background,whereas its enrichment capacities for Pb and Cu were relatively poorer with average enrichment factor of less than 1.At different forest lands,there existed great difference on absorption capacity of P.×euramericana cv.’Neva’ with the same heavy metal.
