[Objective] This study was to investigate the effect of atrazine stress on the growth of Pennisetum hydridum. [Method] Pot experiments were conducted to study the effects of atrazine stress (20, 50, 100, 200, 500 mg...[Objective] This study was to investigate the effect of atrazine stress on the growth of Pennisetum hydridum. [Method] Pot experiments were conducted to study the effects of atrazine stress (20, 50, 100, 200, 500 mg/kg) on plant height, biomass, root-shoot ratio and chlorophyll content of P. hydridum. [Results] Low level of atrazine stress (20 and 50 mg/kg) showed no significant effects on plant height and biomass of P. hydridum. Moderate level of atrazine stress (100 and 200 mg/kg) did not show significant effect on plant height, but did on the biomass of P. hydridum. Biomass of P. hydridum stressed by 100 and 200 mg/kg of atrazine was decreased by 34.1% and 36.4% compared with control, respectively. High level of atrazine stress (500 mg/kg) brought significant decrease in plant height(by 40.6%) and biomass(20.0%) of P. hydridum. All levels of atrazine stress showed no significant effects on root-shoot ratio and chlorophyll content of P. hydridum. [Conclusion] Pennisetum hydridum has strong tolerance to atrazine stress.展开更多
Bacterial community presumably plays an essential role in inhibiting pathogen colonization and maintaining the health of scallop larvae, but limiting data are available for Yesso scallop (Patinopecten yessoensisis Ja...Bacterial community presumably plays an essential role in inhibiting pathogen colonization and maintaining the health of scallop larvae, but limiting data are available for Yesso scallop (Patinopecten yessoensisis Jay, 1857) larval development stages. The aim of this study was to characterize and compare the bacterial communities associating with Yesso scallop larval development at fertilized egg S l, trochophora S2, D-shaped larvae S3, umbo larvae S4, and juvenile scallop S5 stages by Illumina high-throughput sequencing. Genomic DNA was extracted from the larvae and their associating baetera, and a gene segment covering V3-V4 region of 16S rRNA gene was amplified and sequenced using an Illumina Miseq sequencer. Overall, 106760 qualified sequences with an average length of 449 bp were obtained. Sequences were compared with those retrieved from 16S rRNA gene databases, and 4 phyla, 7 classes, 15 orders, 21 families, 31 genera were identified. Proteobacteria was predominant phylum, accounting for more than 99%, at all 5 larval development stages. At genus level, Pseudomonas was dominant at stages S1 (80.60%), S2 (87.77%) and S5 (68.71%), followed by Photobacterium (17.06%) and Aeromonas (1.64%) at stage S1, Serratia (6.94%), Stenotrophomonas (3.08%) and Acinetobacter (1.2%) at stage S2, Shewanella (25.95%) and Pseudoalteromonas (4.57%) at stage S5. Moreover, genus Pseudoal- teromonas became dominant at stages S3 (44.85%) and S4 (56.02%), followed by Photobacterium (29.82%), Pseudomonas (11.86%), Aliivibrio (8.60%) and Shewanella (3.39%) at stage S3, Pseudomonas (18.16%), Aliivibrio (14.29%), Shewanella (4.11%), Psychro- monas (4.04%) and Psychrobacter (1.81%) at stage S4. From the results, we concluded that the bacterial community changed sig- nificantly at different development stages of Yesso Scallop larvae.展开更多
The relationship between vegetation greening and climate change remains unclear due to its complexity, especially in drylands. Against the background of global warming, arid and semi-arid areas, including mid-latitude...The relationship between vegetation greening and climate change remains unclear due to its complexity, especially in drylands. Against the background of global warming, arid and semi-arid areas, including mid-latitude deserts, are most sensitive to climate change. In recent decades, the mechanisms underlying the relationship between vegetation greening and climate change have been widely discussed in the literature. However, the influence of vegetation greening in high latitudes on regional climate has not been fully studied. In this paper, a two-dimensional energy balance model was used to study the influence of greening in high latitudes on mid-latitude deserts. The authors found that when greening occurs in high latitudes, the mid-latitude desert recedes at the south boundary, while the polar ice belt and low-latitude vegetation belt both expand. Simultaneously, greening in high latitudes can induce a negative temperature anomaly in northern latitudes and a positive temperature anomaly in southern latitudes. The mid-latitude desert expands at its north and south boundaries until the CO2 concentration reaches 600 ppm(saturated state). The greening in high latitudes could result in a lower global-mean temperature in the ‘saturated’ state, due to the stronger cooling in high latitudes.展开更多
Study on Chlorophyll a (Chl. a) distribution and bloom patterns is essential in the upwelling areas that constitute the main fishery grounds of Vietnam. Based on high resolution satellite imagery and monthly in-situ...Study on Chlorophyll a (Chl. a) distribution and bloom patterns is essential in the upwelling areas that constitute the main fishery grounds of Vietnam. Based on high resolution satellite imagery and monthly in-situ data in period from 2007 to 2008, the spatial and temporal variations ofChl, a in the upwelling region including algal blooms have been detected. Anomalies of higher Chl. a concentration and bloom patterns occurred at different periods, locations, and bloom shapes in coastal waters of Southern Center of Vietnam. The appearances of these bloom are related to four difference reasons, such as: (i) Their locations coincided to main center of upwelling phenomena that usually occur during southwest monsoon (SWM); (ii) Effect of northeast monsoon (NEM) that brings and attaches the nutrient into the coast and created "floating" algae bloom patches in coastal zones; (iii) The algae blooms can be potentially associated with Harmful Algae Bloom (HAB) during the SWM or local eddies during NEM and (iv) Their appearances are also as a result of distinctive nutrient inflow fi'om Mekong delta and pumping of nutrients by internal waves in coastal shallow waters.展开更多
Leaf longevity is an important adaptive strategy that allows plants to maximize photosynthetic carbon gain.Due to the difficulty of identifying overwintering bud scars and distinguishing the age sequence of twigs,leaf...Leaf longevity is an important adaptive strategy that allows plants to maximize photosynthetic carbon gain.Due to the difficulty of identifying overwintering bud scars and distinguishing the age sequence of twigs,leaf longevity is rarely studied in Cupressaceae species,which further limits our understanding of the leaf economic spectrum (LES) for these populations.Here,we investigated the leaf longevity,as well as mass-based leaf nitrogen concentration (N;),of Juniperus saltuaria at different canopy heights for both subalpine and alpine timberline forests in the Sergymla Mountains,southeastern Tibet.We found that the mean leaf longevity was 4.2±1.2 years,and overall it did not differ significantly between different elevations.Along the vertical profiles of juniper canopies,the leaf longevity did not reflect a linear trend.With increasing leaf longevity,N;showed declining trends.We further analyzed the relationship between leaf longevity and the corresponding length of green twigs,and found that the length of green twigs could only explain 1%-3%of the variation in leaf longevity,indicating that the length of green twigs is a poor predictor for the variation in leaf longevity.In summary,for the J.saltuaria species in timberline or nearby subalpine forests,the effects of elevation and canopy depths on leaf longevity are minor,and the leaf trait analysis is in accordance with the prediction of LES.展开更多
Hyperspectral remote sensing makes it possible to non-destructively monitor leaf chlorophyll content (LCC). This study characterized the geometric patterns of the first derivative reflectance spectra in the red edge...Hyperspectral remote sensing makes it possible to non-destructively monitor leaf chlorophyll content (LCC). This study characterized the geometric patterns of the first derivative reflectance spectra in the red edge region of rapeseed (Brassica napus L.) and wheat (Triticum aestivum L.) crops. The ratio of the red edge area less than 718 nm to the entire red edge area was negatively correlated with LCC. This finding allowed the construction of a new red edge param- eter, defined as red edge symmetry (RES). Compared to the commonly used red edge parameters (red edge position, red edge amplitude, and red edge area), RES was a better predictor of LCC. Furthermore, RES was easily calculated using the reflectance of red edge boundary wavebands at 675 and 755 nm (R675 and R755) and reflectance of red edge center wavelength at 718 nm (R718), with the equation RES = (R71s - R675)/(R755 - R675). In addition, RES was simulated effectively with wide wavebands from the airborne hyperspectral sensor AVIRIS and satellite hyperspectral sensor Hyperion. The close relationships between the simulated RES and LCC indicated a high feasibility of estimating LCC with simulated RES from AVIRIS and Hyperion data. This made RES readily applicable to common airborne and satellite hyperspectral data derived from AVIRIS and Hyperion sources, as well as ground-based spectral reflectance data.展开更多
基金Supported by Natural Science Foundation of Yunnan Province(2010CD058)~~
文摘[Objective] This study was to investigate the effect of atrazine stress on the growth of Pennisetum hydridum. [Method] Pot experiments were conducted to study the effects of atrazine stress (20, 50, 100, 200, 500 mg/kg) on plant height, biomass, root-shoot ratio and chlorophyll content of P. hydridum. [Results] Low level of atrazine stress (20 and 50 mg/kg) showed no significant effects on plant height and biomass of P. hydridum. Moderate level of atrazine stress (100 and 200 mg/kg) did not show significant effect on plant height, but did on the biomass of P. hydridum. Biomass of P. hydridum stressed by 100 and 200 mg/kg of atrazine was decreased by 34.1% and 36.4% compared with control, respectively. High level of atrazine stress (500 mg/kg) brought significant decrease in plant height(by 40.6%) and biomass(20.0%) of P. hydridum. All levels of atrazine stress showed no significant effects on root-shoot ratio and chlorophyll content of P. hydridum. [Conclusion] Pennisetum hydridum has strong tolerance to atrazine stress.
基金financial support from Zhang Zidao Sland Group Co.,Ltd. for the project (99801214)
文摘Bacterial community presumably plays an essential role in inhibiting pathogen colonization and maintaining the health of scallop larvae, but limiting data are available for Yesso scallop (Patinopecten yessoensisis Jay, 1857) larval development stages. The aim of this study was to characterize and compare the bacterial communities associating with Yesso scallop larval development at fertilized egg S l, trochophora S2, D-shaped larvae S3, umbo larvae S4, and juvenile scallop S5 stages by Illumina high-throughput sequencing. Genomic DNA was extracted from the larvae and their associating baetera, and a gene segment covering V3-V4 region of 16S rRNA gene was amplified and sequenced using an Illumina Miseq sequencer. Overall, 106760 qualified sequences with an average length of 449 bp were obtained. Sequences were compared with those retrieved from 16S rRNA gene databases, and 4 phyla, 7 classes, 15 orders, 21 families, 31 genera were identified. Proteobacteria was predominant phylum, accounting for more than 99%, at all 5 larval development stages. At genus level, Pseudomonas was dominant at stages S1 (80.60%), S2 (87.77%) and S5 (68.71%), followed by Photobacterium (17.06%) and Aeromonas (1.64%) at stage S1, Serratia (6.94%), Stenotrophomonas (3.08%) and Acinetobacter (1.2%) at stage S2, Shewanella (25.95%) and Pseudoalteromonas (4.57%) at stage S5. Moreover, genus Pseudoal- teromonas became dominant at stages S3 (44.85%) and S4 (56.02%), followed by Photobacterium (29.82%), Pseudomonas (11.86%), Aliivibrio (8.60%) and Shewanella (3.39%) at stage S3, Pseudomonas (18.16%), Aliivibrio (14.29%), Shewanella (4.11%), Psychro- monas (4.04%) and Psychrobacter (1.81%) at stage S4. From the results, we concluded that the bacterial community changed sig- nificantly at different development stages of Yesso Scallop larvae.
基金This work was jointly supported by the Strategic Priority Research Program of the Chinese Academy of Sciences[grant number XDA2006010301]the National Natural Science Foundation of China[grant numbers 41521004,41705047,and 41875083]+1 种基金the Foundation of the Key Laboratory for Semi-Arid Climate Change of the Ministry of Education in Lanzhou University from the Fundamental Research Funds for the Central Universities[grant numbers lzujbky-2017-bt04 and lzujbky-2017-70]the China 111 Project[grant number B13045].
文摘The relationship between vegetation greening and climate change remains unclear due to its complexity, especially in drylands. Against the background of global warming, arid and semi-arid areas, including mid-latitude deserts, are most sensitive to climate change. In recent decades, the mechanisms underlying the relationship between vegetation greening and climate change have been widely discussed in the literature. However, the influence of vegetation greening in high latitudes on regional climate has not been fully studied. In this paper, a two-dimensional energy balance model was used to study the influence of greening in high latitudes on mid-latitude deserts. The authors found that when greening occurs in high latitudes, the mid-latitude desert recedes at the south boundary, while the polar ice belt and low-latitude vegetation belt both expand. Simultaneously, greening in high latitudes can induce a negative temperature anomaly in northern latitudes and a positive temperature anomaly in southern latitudes. The mid-latitude desert expands at its north and south boundaries until the CO2 concentration reaches 600 ppm(saturated state). The greening in high latitudes could result in a lower global-mean temperature in the ‘saturated’ state, due to the stronger cooling in high latitudes.
文摘Study on Chlorophyll a (Chl. a) distribution and bloom patterns is essential in the upwelling areas that constitute the main fishery grounds of Vietnam. Based on high resolution satellite imagery and monthly in-situ data in period from 2007 to 2008, the spatial and temporal variations ofChl, a in the upwelling region including algal blooms have been detected. Anomalies of higher Chl. a concentration and bloom patterns occurred at different periods, locations, and bloom shapes in coastal waters of Southern Center of Vietnam. The appearances of these bloom are related to four difference reasons, such as: (i) Their locations coincided to main center of upwelling phenomena that usually occur during southwest monsoon (SWM); (ii) Effect of northeast monsoon (NEM) that brings and attaches the nutrient into the coast and created "floating" algae bloom patches in coastal zones; (iii) The algae blooms can be potentially associated with Harmful Algae Bloom (HAB) during the SWM or local eddies during NEM and (iv) Their appearances are also as a result of distinctive nutrient inflow fi'om Mekong delta and pumping of nutrients by internal waves in coastal shallow waters.
基金The Key Scientific and Technological Research Projects in Tibet Autonomous Region (XZ202101ZY0005G)The Second Tibetan Plateau Scientific Expedition and Research (STEP) Program (2019QZKK0301-1)。
文摘Leaf longevity is an important adaptive strategy that allows plants to maximize photosynthetic carbon gain.Due to the difficulty of identifying overwintering bud scars and distinguishing the age sequence of twigs,leaf longevity is rarely studied in Cupressaceae species,which further limits our understanding of the leaf economic spectrum (LES) for these populations.Here,we investigated the leaf longevity,as well as mass-based leaf nitrogen concentration (N;),of Juniperus saltuaria at different canopy heights for both subalpine and alpine timberline forests in the Sergymla Mountains,southeastern Tibet.We found that the mean leaf longevity was 4.2±1.2 years,and overall it did not differ significantly between different elevations.Along the vertical profiles of juniper canopies,the leaf longevity did not reflect a linear trend.With increasing leaf longevity,N;showed declining trends.We further analyzed the relationship between leaf longevity and the corresponding length of green twigs,and found that the length of green twigs could only explain 1%-3%of the variation in leaf longevity,indicating that the length of green twigs is a poor predictor for the variation in leaf longevity.In summary,for the J.saltuaria species in timberline or nearby subalpine forests,the effects of elevation and canopy depths on leaf longevity are minor,and the leaf trait analysis is in accordance with the prediction of LES.
基金Supported by the Program for New Century Excellent Talents in University of China(No.NCET-08-0797)the National Natural Science Foundation of China(No.30871448)+1 种基金the Natural Science Foundation of Jiangsu Province,China(No.BK2008330)the Program for the Creative Scholars of Jiangsu Province,China(No.BK20081479)
文摘Hyperspectral remote sensing makes it possible to non-destructively monitor leaf chlorophyll content (LCC). This study characterized the geometric patterns of the first derivative reflectance spectra in the red edge region of rapeseed (Brassica napus L.) and wheat (Triticum aestivum L.) crops. The ratio of the red edge area less than 718 nm to the entire red edge area was negatively correlated with LCC. This finding allowed the construction of a new red edge param- eter, defined as red edge symmetry (RES). Compared to the commonly used red edge parameters (red edge position, red edge amplitude, and red edge area), RES was a better predictor of LCC. Furthermore, RES was easily calculated using the reflectance of red edge boundary wavebands at 675 and 755 nm (R675 and R755) and reflectance of red edge center wavelength at 718 nm (R718), with the equation RES = (R71s - R675)/(R755 - R675). In addition, RES was simulated effectively with wide wavebands from the airborne hyperspectral sensor AVIRIS and satellite hyperspectral sensor Hyperion. The close relationships between the simulated RES and LCC indicated a high feasibility of estimating LCC with simulated RES from AVIRIS and Hyperion data. This made RES readily applicable to common airborne and satellite hyperspectral data derived from AVIRIS and Hyperion sources, as well as ground-based spectral reflectance data.