In the past, utilization of bamboo resources in China has been traditionally dominated by direct consumption of local farmers as minor forest products with weak linkage with market. In recent years, the over-supply of...In the past, utilization of bamboo resources in China has been traditionally dominated by direct consumption of local farmers as minor forest products with weak linkage with market. In recent years, the over-supply of grains and rapid degradation of agricultural environment call for alternative crops that can be developed through integrating the environmental plantation with the market demands. Closely associated with forestry and agriculture, bamboo is able to deal with the new challenges which Chinas agriculture is facing. Of 534 documented bamboo species in China, 153 species produce edible-shoots and of which 56 species are recommended for agricultural plantation; 139 species provide timbers and of which 58 species recommended; 116 species can be splited as good strips for weaving and of which 22 species recommended; 88 species are considered as garden bamboos and of which 34 species recommended; 45 species are able to produce paper pulp and of which 18 species recommended.展开更多
The effects of five amendments such as acetic acid(AA), citric acid (CA), ethylenediamine tetraacetic acid (EDTA), sepiolite and phosphogypsum on growth and metal uptake of giant reed (Arundo donax L.) grown o...The effects of five amendments such as acetic acid(AA), citric acid (CA), ethylenediamine tetraacetic acid (EDTA), sepiolite and phosphogypsum on growth and metal uptake of giant reed (Arundo donax L.) grown on soil contaminated by arsenic (As), cadmium (Cd) and lead (Pb) were studied. The results showed that the shoot biomass of giant reed was enhanced by 24.8% and 15.0%, while superoxide mutase and catalase activities slightly varied when adding 5.0 mmol/kg CA and 2.5 mol/kg EDTA to soil as compared to the control, respectively. The concentrations of As, Cd and Pb in shoots were remarkably increased by the addition of 2.5 mmol/kg AA and CA, 5.0 mmol/kg EDTA, and 4.0 g/kg sepiolite as compared to the control. The accumulations of As and Cd were also significantly enhanced in the above condition, while the shoot Pb accumulation was noticeably enhanced by amending with 4.0 g/kg sepiolite and 8.0 g/kg phosphogysum, respectively. The results suggested that AA, CA and sepiolite could be used as optimum soil amendments for giant reed remediation system.展开更多
Six phytoecdysterones have been isolated from the n-BuOH portion of Cucubalus baccifer L., a Chinese folk medicinal plant. Their structures were elucidated as ecdysterone (1), 24(28)-ecdysterone (2), 22-deoxyecdystero...Six phytoecdysterones have been isolated from the n-BuOH portion of Cucubalus baccifer L., a Chinese folk medicinal plant. Their structures were elucidated as ecdysterone (1), 24(28)-ecdysterone (2), 22-deoxyecdysterone (3), 25-hydroxypanuosterone (4), rubrosterone (5) and 2,22-dideoxyecdysterone 3 beta -O-beta -D-glucopyranoside (6) respectively on the basis of spectroscopic and chemical methods. Among them compound 6 was a new phytoecdysterone glycoside and 1-5 were first obtained from this plant.展开更多
A new compound (1) named as winchic acid and eight known ones were isolated from the stem barks of Winchia colophylla A. DC. (collected in Xishuangbanna, Yunnan Province of China). The new compound 1 was identified as...A new compound (1) named as winchic acid and eight known ones were isolated from the stem barks of Winchia colophylla A. DC. (collected in Xishuangbanna, Yunnan Province of China). The new compound 1 was identified as 3beta-hydroxy-27-(4-hydroxy-3-methoxy-E-cinnamoyloxy)-lup-20(29)-en-28-oic acid on the basis of 1D and 2D NMR experiments. The eight known compounds were determined to be lupenone, lupenyl acetate, betulinic acid, alpha-amyrin acetate, ursolic acid, ptiloepoxide, beta-amyrin and cycloeucalenol, respectively.展开更多
In order to improve the development step of bamboo industry, the pest investigation was done in Yunnan Province from 2000, and 1 500 specimens were collected. Basing on the investigation and the date of recordation, t...In order to improve the development step of bamboo industry, the pest investigation was done in Yunnan Province from 2000, and 1 500 specimens were collected. Basing on the investigation and the date of recordation, there had 224 species pests, belonging to 7 orders and 49 families. Among the pest, most done harm to the bamboo slightly, except Omphisa sp., Pantana phyllostachysae and Cyrtotrachelus buqueti. The disease and pest of bamboo should be investigated in whole province systematically.展开更多
Fermentation of the succulent bamboo shoots of Bambusa balcooa Roxb. resulted in an enrichment of phytosterols from 0.12% to 0.62% dry weight as compared to that of the fresh unfermented samples. The bacterial strains...Fermentation of the succulent bamboo shoots of Bambusa balcooa Roxb. resulted in an enrichment of phytosterols from 0.12% to 0.62% dry weight as compared to that of the fresh unfermented samples. The bacterial strains responsible for higher accumulation of phytosterols during fermentation of the bamboo shoots have been isolated and further extraction and purification of the crude phytosterols (isolated from the fermented samples) were done by TLC, UV, NMR, IR and Mass spectral analysis. The isolated phytosterols (β-sitos-terols) were then subjected to microbial transformation which yielded a considerable amount of androsta-1, 4-diene-3,17-dione (ADD) in the incubation mixture in presence of metabolic inhibitors (α, α'-dipyridyl and sodium arsenate).展开更多
The pyrolysis of phytoremediated giant reed(Arundo donax)biomass could cause secondary pollution of heavy metals.The stabilization of heavy metals in the pyrolysis process with external materials such as Al2O3,CaCO3,F...The pyrolysis of phytoremediated giant reed(Arundo donax)biomass could cause secondary pollution of heavy metals.The stabilization of heavy metals in the pyrolysis process with external materials such as Al2O3,CaCO3,FeCl3and NaOH,wasstudied.The results showed that37%As and97%Cd in biochar were stabilized when giant reed powder was pyrolyzed at250°Cwith5%Al2O3for2h.Furthermore,59%Pb in biochar was stabilized at400°C with5%CaCO3for1h.Under biochar produced inoptimized pyrolysis conditions,Cd mainly existed in a residual fraction,while Pb and As mainly existed in oxidizable fraction inBCR analysis.In XRD analysis,As was only found in Ca2As2O7;Cd in biochar mainly existed in Cd(AlCl4)2,CdPbO3or CdSO3;and Pb mainly existed as Pb3O2SO4.展开更多
Bamboos are widely distributed in mainland Southeast Asia and have abundant biomass. They are characterized by prolonged vegetative growth and semelparity. Where bamboos are dominant, their synchronous flowering and d...Bamboos are widely distributed in mainland Southeast Asia and have abundant biomass. They are characterized by prolonged vegetative growth and semelparity. Where bamboos are dominant, their synchronous flowering and death has a major impact on forest vegetation. Although the small-scale dynamics of this process have become clearer in recent years, the history, geographical scale and synchronicity of bamboo flowering over broad areas remains unknown. This study focused on the flowering history of six bamboo species, Bambusa tulda, Cephalostachyum virgatum, Dendrocalamus hamiltonii, Dendrocalamus membranaceus, Indosasa sinica and Oxytenanthera parvifolia, over 40 years across a broad area of northern Laos. We also examined the synchronicity of flowering in D. membranaceus. We visited 49 villages in northern Laos and surveyed knowledgeable inhabitants about bamboo flowering history. The timing, scale and synchronicity of gregarious flowering varied among species. D. hamiltonii and D. membranaceus showed higher flowering synchronicity than other species. All the species except I. sinica had both sporadic and gregarious flowering traits, and showed conspicuous variability in their flowering scale. The flowering bamboo population at two gregarious flowering sites for D. membranaceus was surveyed. While thisspecies had the highest synchronicity in this study, its synchronicity was lower than other species in previous studies worldwide. We found that the gregarious flowering of bamboos in northern Laos over the last 40 years showed lower synchronicity than bamboo flowering reported in other areas of the world. The historical dynamics and scale of bamboo flowering must be further clarified to understand the vegetation composition of this area.展开更多
A study was conducted to investigate culms density and size, seed size and production rate in Melocanna baccifera stands disturbed by biotic pressure and fire. Results revealed that culms density, number and size of s...A study was conducted to investigate culms density and size, seed size and production rate in Melocanna baccifera stands disturbed by biotic pressure and fire. Results revealed that culms density, number and size of seeds produced in the bamboo stands were significantly affected by frequent fire and excessive biotic pressure (collection of young shoots for vegetables and mature culms). The culm density and seed production rate decreased significantly in the stand subjected to excessive biotic pressure. An increasing exposure of culms to sun light was responsible for the above decrease. Seed production rate significantly increased in case of culms subjected to fire in comparison to the control. It indicated that fire stimulated the seed production in M. baccifera stand.展开更多
The pot experiments were conducted to study the effects of intercropping with Pseudostellaria maximowicziana,Malachiumaquaticum and Stellaria media on Cd accumulation of Cyphomandra betacea seedlings.Compared with the...The pot experiments were conducted to study the effects of intercropping with Pseudostellaria maximowicziana,Malachiumaquaticum and Stellaria media on Cd accumulation of Cyphomandra betacea seedlings.Compared with the monoculture,intercropping with Caryophyllaceae endarachneyllaceae accumulator plants decreased the biomass of C.betacea seedlings,and also reduced the photosynthetic pigment contents in C.betacea seedlings,which involve chlorophyll a,chlorophyll b,total chlorophyll and carotenoid.Intercropping with P.maximowicziana and M.aquaticum increased the Cd contents in shoots of C.betacea seedlings,which increased by 65.02%and 25.61%,respectively,compared with the monoculture.Intercropping with S.media reduced the Cd contents in shoots of C.betacea seedlings,which were reduced by 4.68%compared with the monoculture.When intercropping with C.betacea seedlings,the Cd accumulation amounts of 3 Caryophyllaceae accumulator plants were ranked as S.media>P.maximowicziana>M.aquaticum.Intercropping with S.media could effectively reduce Cd accumulation of C.betacea seedlings under Cd-contaminated soil condition.展开更多
Plants show different growth responses to N sources supplied with either NH4^+ or NO3^-. The uptake of different N sources also affects the rhizosphere pH and therefore the bioavallability of soil phosphorus, particu...Plants show different growth responses to N sources supplied with either NH4^+ or NO3^-. The uptake of different N sources also affects the rhizosphere pH and therefore the bioavallability of soil phosphorus, particularly in alkaline soils. The plant growth, P uptake, and P availability in the rhizosphere of oat (Arena nuda L.) grown in hydroponics and in soil culture were investigated under supply with sole NH4^+-N, sole NO3-N, or a combination. Sole NO^- -fed oat plants accumulated more biomass than sole NH4^+ -fed ones. The highest biomass accumulation was observed when N was supplied with both NH^+ -N and NO3^- -N. Growth of the plant root increased with the proportion of NO3^- in the cultural medium. Better root growth and higher root/shoot ratio were consistently observed in NO3^- fed plants. However, root vigor was the highest when N was supplied with NO3^- +NH4^+. NH4^+ supply reduced the rhizosphere pH but did not affect P uptake by plants grown in soils with CaHPO4 added as P source. No P deficiency was observed, and plant P concentrations were generally above 2 g kg^-1. P uptake was increased when N was supplied partly or solely as NO3^--N, similarly as biomass accumulation. The results suggested that oat was an NO3-preferring plant, and NO3^- -N was essential for plant growth and the maintenance of root absorption capacity. N supply with NH4^+ -N did not improve P nutrition, which was most likely due to the absence of P deficiency.展开更多
A hydroponics experiment was aimed at identifying the lead(Pb) tolerance and phytoremediation potential of Moso bamboo(Phyllostachys pubescens) seedlings grown under different Pb treatments. Experimental results i...A hydroponics experiment was aimed at identifying the lead(Pb) tolerance and phytoremediation potential of Moso bamboo(Phyllostachys pubescens) seedlings grown under different Pb treatments. Experimental results indicated that at the highest Pb concentration(400 μmol/L), the growth of bamboo seedlings was inhibited and Pb concentrations in leaves, stems, and roots reached the maximum of 148.8, 482.2, and 4282.8 mg/kg, respectively. Scanning electron microscopy revealed that the excessive Pb caused decreased stomatal opening, formation of abundant inclusions in roots, and just a few inclusions in stems. The ultrastructural analysis using transmission electron microscopy revealed that the addition of excessive Pb caused abnormally shaped chloroplasts, disappearance of endoplasmic reticulum, shrinkage of nucleus and nucleolus, and loss of thylakoid membranes. Although ultrastructural analysis revealed some internal damage, even the plants exposed to 400 μmol/L Pb survived and no visual Pb toxicity symptoms such as necrosis and chlorosis were observed in these plants. Even at the highest Pb treatment, no significant difference was observed for the dry weight of stem compared with controls. It is suggested that use of Moso bamboo as an experimental material provides a new perspective for remediation of heavy metal contaminated soil owing to its high metal tolerance and greater biomass.展开更多
he internal genetic clock of semelparous mast-flowering bamboo species creates gregarious regions of flowering and death, thus leading to fuel-load accumulation that potentially promotes fire(Fire-Cycle Hypothesis)....he internal genetic clock of semelparous mast-flowering bamboo species creates gregarious regions of flowering and death, thus leading to fuel-load accumulation that potentially promotes fire(Fire-Cycle Hypothesis). Higher abundance of bamboo could be expected to provide greater fuel loads after flowering. Here, we investigated the possible link between bamboo dominance and fire occurrence. As the main food source for the giant panda in the Qinling Mountains of China, Bashania fargesii(Farges Canebrake) and Fargesia qinlingensis(Arrow Bamboo) dominate lower(1000–1900 m) and higher elevations(1800–2700 m), respectively. Four soil profiles(elevation ranging from 1240 to 2170 m) in areas of known recent bamboo flowering events(~1980) and adjacent non-flowering sites were assessed for phytoliths and charcoal. Characteristic phytoliths were chosen to describe bamboo dynamics, and charcoal particles were extracted from the soil to reconstruct fire history. Carbon 14 dating of soil charcoal samples was conducted using an accelerator mass spectrometry technique. In addition, we chose two depths(28–52 and 90–100 cm) in one Bashania profile(B. fargesii forest) and one Fargesia profile(F. qinlingensis forest) for phytolith dating. Our findings indicate that bamboo has been a dominant component of these ecosystems almost for the entire profile; some 6400 yrs for Bashania and ca. 10000 yrs for the Fargesia. It is also clear from the charcoal and phytolith data that bamboo abundance and recent mast flowering were significantly related to fire occurrence for lower elevation Bashania while the higher elevation Fargesia was not. One of the four profiles had chronological charcoal records throughout and the oldest charcoal aged was ~1410 yr BP, suggesting an anthropogenic origin. The mixing of phytolith and charcoal made it unrealistic to describe temporal dynamics of bamboo and fire events, and thus our interpretation is cognizant of the dating discrepancies and conservative(less-speculative). Due to the long history of bamboo and much shorter history of fire within the profile, our data lend little evidence to the Fire-Cycle Hypothesis.展开更多
文摘In the past, utilization of bamboo resources in China has been traditionally dominated by direct consumption of local farmers as minor forest products with weak linkage with market. In recent years, the over-supply of grains and rapid degradation of agricultural environment call for alternative crops that can be developed through integrating the environmental plantation with the market demands. Closely associated with forestry and agriculture, bamboo is able to deal with the new challenges which Chinas agriculture is facing. Of 534 documented bamboo species in China, 153 species produce edible-shoots and of which 56 species are recommended for agricultural plantation; 139 species provide timbers and of which 58 species recommended; 116 species can be splited as good strips for weaving and of which 22 species recommended; 88 species are considered as garden bamboos and of which 34 species recommended; 45 species are able to produce paper pulp and of which 18 species recommended.
基金Project (2012BAC09B04) supported by National Key Technology Research and Development Program of the Ministry of Science and Technology of ChinaProject (2010-277-027) supported by Science and Technology Foundation of Environmental Protection in Hunan Province,ChinaProject (2011SK3262) supported by Science and Technology Planning of Hunan Province,China
文摘The effects of five amendments such as acetic acid(AA), citric acid (CA), ethylenediamine tetraacetic acid (EDTA), sepiolite and phosphogypsum on growth and metal uptake of giant reed (Arundo donax L.) grown on soil contaminated by arsenic (As), cadmium (Cd) and lead (Pb) were studied. The results showed that the shoot biomass of giant reed was enhanced by 24.8% and 15.0%, while superoxide mutase and catalase activities slightly varied when adding 5.0 mmol/kg CA and 2.5 mol/kg EDTA to soil as compared to the control, respectively. The concentrations of As, Cd and Pb in shoots were remarkably increased by the addition of 2.5 mmol/kg AA and CA, 5.0 mmol/kg EDTA, and 4.0 g/kg sepiolite as compared to the control. The accumulations of As and Cd were also significantly enhanced in the above condition, while the shoot Pb accumulation was noticeably enhanced by amending with 4.0 g/kg sepiolite and 8.0 g/kg phosphogysum, respectively. The results suggested that AA, CA and sepiolite could be used as optimum soil amendments for giant reed remediation system.
文摘Six phytoecdysterones have been isolated from the n-BuOH portion of Cucubalus baccifer L., a Chinese folk medicinal plant. Their structures were elucidated as ecdysterone (1), 24(28)-ecdysterone (2), 22-deoxyecdysterone (3), 25-hydroxypanuosterone (4), rubrosterone (5) and 2,22-dideoxyecdysterone 3 beta -O-beta -D-glucopyranoside (6) respectively on the basis of spectroscopic and chemical methods. Among them compound 6 was a new phytoecdysterone glycoside and 1-5 were first obtained from this plant.
文摘A new compound (1) named as winchic acid and eight known ones were isolated from the stem barks of Winchia colophylla A. DC. (collected in Xishuangbanna, Yunnan Province of China). The new compound 1 was identified as 3beta-hydroxy-27-(4-hydroxy-3-methoxy-E-cinnamoyloxy)-lup-20(29)-en-28-oic acid on the basis of 1D and 2D NMR experiments. The eight known compounds were determined to be lupenone, lupenyl acetate, betulinic acid, alpha-amyrin acetate, ursolic acid, ptiloepoxide, beta-amyrin and cycloeucalenol, respectively.
基金Supported by Key Technologies R&D Programme of the Ministry of Science and Technology of the People’s Republic of China during the Eleventh Five-year Plan(2006BAD19B09)~~
文摘In order to improve the development step of bamboo industry, the pest investigation was done in Yunnan Province from 2000, and 1 500 specimens were collected. Basing on the investigation and the date of recordation, there had 224 species pests, belonging to 7 orders and 49 families. Among the pest, most done harm to the bamboo slightly, except Omphisa sp., Pantana phyllostachysae and Cyrtotrachelus buqueti. The disease and pest of bamboo should be investigated in whole province systematically.
文摘Fermentation of the succulent bamboo shoots of Bambusa balcooa Roxb. resulted in an enrichment of phytosterols from 0.12% to 0.62% dry weight as compared to that of the fresh unfermented samples. The bacterial strains responsible for higher accumulation of phytosterols during fermentation of the bamboo shoots have been isolated and further extraction and purification of the crude phytosterols (isolated from the fermented samples) were done by TLC, UV, NMR, IR and Mass spectral analysis. The isolated phytosterols (β-sitos-terols) were then subjected to microbial transformation which yielded a considerable amount of androsta-1, 4-diene-3,17-dione (ADD) in the incubation mixture in presence of metabolic inhibitors (α, α'-dipyridyl and sodium arsenate).
基金Projects(21577176,41271330) supported by the National Natural Science Foundation of China
文摘The pyrolysis of phytoremediated giant reed(Arundo donax)biomass could cause secondary pollution of heavy metals.The stabilization of heavy metals in the pyrolysis process with external materials such as Al2O3,CaCO3,FeCl3and NaOH,wasstudied.The results showed that37%As and97%Cd in biochar were stabilized when giant reed powder was pyrolyzed at250°Cwith5%Al2O3for2h.Furthermore,59%Pb in biochar was stabilized at400°C with5%CaCO3for1h.Under biochar produced inoptimized pyrolysis conditions,Cd mainly existed in a residual fraction,while Pb and As mainly existed in oxidizable fraction inBCR analysis.In XRD analysis,As was only found in Ca2As2O7;Cd in biochar mainly existed in Cd(AlCl4)2,CdPbO3or CdSO3;and Pb mainly existed as Pb3O2SO4.
基金supported by JSPS KAKENHI(Grant Number 22241012)
文摘Bamboos are widely distributed in mainland Southeast Asia and have abundant biomass. They are characterized by prolonged vegetative growth and semelparity. Where bamboos are dominant, their synchronous flowering and death has a major impact on forest vegetation. Although the small-scale dynamics of this process have become clearer in recent years, the history, geographical scale and synchronicity of bamboo flowering over broad areas remains unknown. This study focused on the flowering history of six bamboo species, Bambusa tulda, Cephalostachyum virgatum, Dendrocalamus hamiltonii, Dendrocalamus membranaceus, Indosasa sinica and Oxytenanthera parvifolia, over 40 years across a broad area of northern Laos. We also examined the synchronicity of flowering in D. membranaceus. We visited 49 villages in northern Laos and surveyed knowledgeable inhabitants about bamboo flowering history. The timing, scale and synchronicity of gregarious flowering varied among species. D. hamiltonii and D. membranaceus showed higher flowering synchronicity than other species. All the species except I. sinica had both sporadic and gregarious flowering traits, and showed conspicuous variability in their flowering scale. The flowering bamboo population at two gregarious flowering sites for D. membranaceus was surveyed. While thisspecies had the highest synchronicity in this study, its synchronicity was lower than other species in previous studies worldwide. We found that the gregarious flowering of bamboos in northern Laos over the last 40 years showed lower synchronicity than bamboo flowering reported in other areas of the world. The historical dynamics and scale of bamboo flowering must be further clarified to understand the vegetation composition of this area.
基金This study was supported by Ministry of Environ-ment & Forests, Govt. of India for financial assistance in the form of aresearch project
文摘A study was conducted to investigate culms density and size, seed size and production rate in Melocanna baccifera stands disturbed by biotic pressure and fire. Results revealed that culms density, number and size of seeds produced in the bamboo stands were significantly affected by frequent fire and excessive biotic pressure (collection of young shoots for vegetables and mature culms). The culm density and seed production rate decreased significantly in the stand subjected to excessive biotic pressure. An increasing exposure of culms to sun light was responsible for the above decrease. Seed production rate significantly increased in case of culms subjected to fire in comparison to the control. It indicated that fire stimulated the seed production in M. baccifera stand.
文摘The pot experiments were conducted to study the effects of intercropping with Pseudostellaria maximowicziana,Malachiumaquaticum and Stellaria media on Cd accumulation of Cyphomandra betacea seedlings.Compared with the monoculture,intercropping with Caryophyllaceae endarachneyllaceae accumulator plants decreased the biomass of C.betacea seedlings,and also reduced the photosynthetic pigment contents in C.betacea seedlings,which involve chlorophyll a,chlorophyll b,total chlorophyll and carotenoid.Intercropping with P.maximowicziana and M.aquaticum increased the Cd contents in shoots of C.betacea seedlings,which increased by 65.02%and 25.61%,respectively,compared with the monoculture.Intercropping with S.media reduced the Cd contents in shoots of C.betacea seedlings,which were reduced by 4.68%compared with the monoculture.When intercropping with C.betacea seedlings,the Cd accumulation amounts of 3 Caryophyllaceae accumulator plants were ranked as S.media>P.maximowicziana>M.aquaticum.Intercropping with S.media could effectively reduce Cd accumulation of C.betacea seedlings under Cd-contaminated soil condition.
基金Project supported by the National Natural Science Foundation Council of China (No.30660086)the Natural Science Foundation of Inner Mongolia of China (No.200607010302)+2 种基金Hong Kong Research Grants Council (No.2465/05M)Hong Kong University Grants Committee (No.AOE/B-07/99)Hong Kong Baptist University Matching Research Fund.
文摘Plants show different growth responses to N sources supplied with either NH4^+ or NO3^-. The uptake of different N sources also affects the rhizosphere pH and therefore the bioavallability of soil phosphorus, particularly in alkaline soils. The plant growth, P uptake, and P availability in the rhizosphere of oat (Arena nuda L.) grown in hydroponics and in soil culture were investigated under supply with sole NH4^+-N, sole NO3-N, or a combination. Sole NO^- -fed oat plants accumulated more biomass than sole NH4^+ -fed ones. The highest biomass accumulation was observed when N was supplied with both NH^+ -N and NO3^- -N. Growth of the plant root increased with the proportion of NO3^- in the cultural medium. Better root growth and higher root/shoot ratio were consistently observed in NO3^- fed plants. However, root vigor was the highest when N was supplied with NO3^- +NH4^+. NH4^+ supply reduced the rhizosphere pH but did not affect P uptake by plants grown in soils with CaHPO4 added as P source. No P deficiency was observed, and plant P concentrations were generally above 2 g kg^-1. P uptake was increased when N was supplied partly or solely as NO3^--N, similarly as biomass accumulation. The results suggested that oat was an NO3-preferring plant, and NO3^- -N was essential for plant growth and the maintenance of root absorption capacity. N supply with NH4^+ -N did not improve P nutrition, which was most likely due to the absence of P deficiency.
基金supported by the National Natural Science Foundation of China(No.31300520)the Science and Technology Program of Zhejiang Province(No.2014C33043)the Zhejiang Provincial Natural Science Foundation of China(No.LY12C16004)
文摘A hydroponics experiment was aimed at identifying the lead(Pb) tolerance and phytoremediation potential of Moso bamboo(Phyllostachys pubescens) seedlings grown under different Pb treatments. Experimental results indicated that at the highest Pb concentration(400 μmol/L), the growth of bamboo seedlings was inhibited and Pb concentrations in leaves, stems, and roots reached the maximum of 148.8, 482.2, and 4282.8 mg/kg, respectively. Scanning electron microscopy revealed that the excessive Pb caused decreased stomatal opening, formation of abundant inclusions in roots, and just a few inclusions in stems. The ultrastructural analysis using transmission electron microscopy revealed that the addition of excessive Pb caused abnormally shaped chloroplasts, disappearance of endoplasmic reticulum, shrinkage of nucleus and nucleolus, and loss of thylakoid membranes. Although ultrastructural analysis revealed some internal damage, even the plants exposed to 400 μmol/L Pb survived and no visual Pb toxicity symptoms such as necrosis and chlorosis were observed in these plants. Even at the highest Pb treatment, no significant difference was observed for the dry weight of stem compared with controls. It is suggested that use of Moso bamboo as an experimental material provides a new perspective for remediation of heavy metal contaminated soil owing to its high metal tolerance and greater biomass.
文摘he internal genetic clock of semelparous mast-flowering bamboo species creates gregarious regions of flowering and death, thus leading to fuel-load accumulation that potentially promotes fire(Fire-Cycle Hypothesis). Higher abundance of bamboo could be expected to provide greater fuel loads after flowering. Here, we investigated the possible link between bamboo dominance and fire occurrence. As the main food source for the giant panda in the Qinling Mountains of China, Bashania fargesii(Farges Canebrake) and Fargesia qinlingensis(Arrow Bamboo) dominate lower(1000–1900 m) and higher elevations(1800–2700 m), respectively. Four soil profiles(elevation ranging from 1240 to 2170 m) in areas of known recent bamboo flowering events(~1980) and adjacent non-flowering sites were assessed for phytoliths and charcoal. Characteristic phytoliths were chosen to describe bamboo dynamics, and charcoal particles were extracted from the soil to reconstruct fire history. Carbon 14 dating of soil charcoal samples was conducted using an accelerator mass spectrometry technique. In addition, we chose two depths(28–52 and 90–100 cm) in one Bashania profile(B. fargesii forest) and one Fargesia profile(F. qinlingensis forest) for phytolith dating. Our findings indicate that bamboo has been a dominant component of these ecosystems almost for the entire profile; some 6400 yrs for Bashania and ca. 10000 yrs for the Fargesia. It is also clear from the charcoal and phytolith data that bamboo abundance and recent mast flowering were significantly related to fire occurrence for lower elevation Bashania while the higher elevation Fargesia was not. One of the four profiles had chronological charcoal records throughout and the oldest charcoal aged was ~1410 yr BP, suggesting an anthropogenic origin. The mixing of phytolith and charcoal made it unrealistic to describe temporal dynamics of bamboo and fire events, and thus our interpretation is cognizant of the dating discrepancies and conservative(less-speculative). Due to the long history of bamboo and much shorter history of fire within the profile, our data lend little evidence to the Fire-Cycle Hypothesis.