期刊文献+
共找到89篇文章
< 1 2 5 >
每页显示 20 50 100
Studies on the Morphologic Characteristics and Economic Traits of Different Ploidy Materials of Ramie
1
作者 YANChun-geng CAORui-fang +2 位作者 LIZong-dao ZHENGSi-xiang CUIGuo-xian 《Agricultural Sciences in China》 CAS CSCD 2003年第5期502-506,共5页
Different ploidy ramie materials were studied via microscopic observation on stem sections and macerated fiber cells. Morphologic differences between different ploidy plants were analyzed. Average bark area percentage... Different ploidy ramie materials were studied via microscopic observation on stem sections and macerated fiber cells. Morphologic differences between different ploidy plants were analyzed. Average bark area percentages in ramie stem transection of haploids, tetraploids, diploids and triploids were 28. 91, 27. 05, 26. 97 and 24.77% respectively. Average percentages of fiber layer area of diploids, haploids, tetraploids and triploids were 16.80, 16. 58, 15.52 and 13.78% respectively. Average fiber cell diameter and cell wall thickness were increased along with the increase of the ploidy of the plants. Average fiber length of diploids, triploids and haploids were 8. 49, 7. 96 and 6. 93 cm respectively. Average L/B (length/breadth) of diploids, triploids and haploids were 2 470. 7, 2 390. 6 and 1 616.3 respectively. Average breadths of fiber of haploids, diploids and triploids were 29. 30, 33. 87 and 49. 20μm respectively. However, there were relatively large variations in the above characteristics among the ramie materials of the same ploidy levels. Field performance of different ploidy plants was also investigated. As the chromosome ploidy increasing, there was a tendency of declining in shoot number per plant and increasing in stem diameter. Average shoots per plant of haploids, diploids, triploids and tetraploids were 5.83, 5.30, 3.77 and 3. 65 whereas their average stem diameters were 0.66, 0. 67, 0. 74 and 0. 76 cm respectively. Triploids were the tallest, while haploids were the shortest. Triploids had strong growth vigour, diploids and tetraploids had moderate growth vigour, while haploids appeared to be lack of growth vigour. Cold stress tolerance of tetraploids were the strongest, diploid had the moderate tolerance, while haploids and triploids were the least tolerant to cold stress. Both haploids and triploids were sterile. 展开更多
关键词 Ramie [Boehmeria nivea (L. )Gaud] morphological characteristics Economical traits Chromosome ploidy
下载PDF
First record of abnormal body coloration in a rockfish Sebastes koreanus(Scorpaenoidei:Sebastidae)from coastal water of China based on morphological characteristics and DNA barcoding
2
作者 Ang LI Huan WANG +1 位作者 Changting AN Shufang LIU 《Journal of Oceanology and Limnology》 SCIE CAS CSCD 2024年第2期640-646,共7页
The first record of abnormal body coloration in Sebastes koreanus Kim and Lee,1994,from the Yellow Sea of China,was documented based on morphological characteristics and DNA barcoding.The two rockfish specimens were c... The first record of abnormal body coloration in Sebastes koreanus Kim and Lee,1994,from the Yellow Sea of China,was documented based on morphological characteristics and DNA barcoding.The two rockfish specimens were collected from the coastal waters of Qingdao,China,and the whole body and all fins of them were red.Of the two red-colored rockfish,there were tiny deep red spots on each fin,2 red radial stripes behind and below the eyes and 1 large deep red blotch on the opercula,while the similar stripe and spot patterns are also present in the S.koreanus specimens with normal body coloration.The countable characteristics of the two specimens are in the range of the morphometry of S.koreanus.To further clarify the species identity and taxonomic status of the two specimens,DNA barcode analysis was carried out.The genetic distance between the red-colored rockfish and S.koreanus was 0,and the minimum net genetic distances between the red-colored rockfish and other Sebastes species except for S.koreanus were 3.0%,which exceeds the threshold of species delimitation.The phylogenetic analysis showed that the DNA barcoding sequences of the two red-colored rockfish clustered with the S.koreanus sequences.The above results of DNA barcode analysis also support that the two red-colored rockfish could be identified as the species of S.koreanus.The mechanism of color variation in S.koreanus is desirable for further research and the species could be an ideal model to study the color-driven speciation of the rockfishes. 展开更多
关键词 abnormal body coloration Sebastes koreanus coastal water of China Yellow Sea morphological characteristics DNA barcoding
下载PDF
Analysis of morphological characteristics of gravels based on digital image processing technology and self-organizing map 被引量:1
3
作者 XU Tao YU Huan +4 位作者 QIU Xia KONG Bo XIANG Qing XU Xiaoyu FU Hao 《Journal of Arid Land》 SCIE CSCD 2023年第3期310-326,共17页
A comprehensive understanding of spatial distribution and clustering patterns of gravels is of great significance for ecological restoration and monitoring.However,traditional methods for studying gravels are low-effi... A comprehensive understanding of spatial distribution and clustering patterns of gravels is of great significance for ecological restoration and monitoring.However,traditional methods for studying gravels are low-efficiency and have many errors.This study researched the spatial distribution and cluster characteristics of gravels based on digital image processing technology combined with a self-organizing map(SOM)and multivariate statistical methods in the grassland of northern Tibetan Plateau.Moreover,the correlation of morphological parameters of gravels between different cluster groups and the environmental factors affecting gravel distribution were analyzed.The results showed that the morphological characteristics of gravels in northern region(cluster C)and southern region(cluster B)of the Tibetan Plateau were similar,with a low gravel coverage,small gravel diameter,and elongated shape.These regions were mainly distributed in high mountainous areas with large topographic relief.The central region(cluster A)has high coverage of gravels with a larger diameter,mainly distributed in high-altitude plains with smaller undulation.Principal component analysis(PCA)results showed that the gravel distribution of cluster A may be mainly affected by vegetation,while those in clusters B and C could be mainly affected by topography,climate,and soil.The study confirmed that the combination of digital image processing technology and SOM could effectively analyzed the spatial distribution characteristics of gravels,providing a new mode for gravel research. 展开更多
关键词 self-organizing map digital image processing morphological characteristics multivariate statistical method environmental monitoring
下载PDF
Morphological characteristics and atomic evolution behavior of nanojoints in Ag nanowire interconnect network
4
作者 Jianlei Cui Xiaoying Ren +5 位作者 Xuesong Mei Zhengjie Fan Chenchen Huang Zhijun Wang Xiaofei Sun Wenjun Wang 《International Journal of Extreme Manufacturing》 SCIE EI CAS CSCD 2023年第2期254-264,共11页
Ag nanowires(AgNWs)have shown great application value in the field of flexible electronics due to their excellent optical and electrical properties,and the quality of its joints of AgNWs in the thin film network direc... Ag nanowires(AgNWs)have shown great application value in the field of flexible electronics due to their excellent optical and electrical properties,and the quality of its joints of AgNWs in the thin film network directly plays a key role in its performance.In order to further improve the joint quality of AgNWs under thermal excitation,the thermal welding process and atomic evolution behavior of AgNWs were investigated through a combination of in situ experimental and molecular dynamics simulations.The influence of processing time,temperature,and stress distribution due to spatial arrangement on nanojoints was systematically explored.What is more,the failure mechanisms and their atomic interface behavior of the nanojoints were also investigated. 展开更多
关键词 Ag nanowires NANOCONTACTS morphological characteristics atomic configuration MD simulation
下载PDF
Morphological comparison and molecular marker screening of three Skeletonema species found in Changjiang(Yangtze)River Basin
5
作者 Jingwen HU Yuxin YI +4 位作者 Zhengxin YANG John Patrick KOCIOLEK Pan YU Quanxi WANG Qingmin YOU 《Journal of Oceanology and Limnology》 SCIE CAS CSCD 2024年第3期923-942,共20页
In our recent investigations of diatom diversity,we studied three species,namely,Skeletonema costatum,Skeletonema subsalsum,and Skeletonema potamos.Although they have been found frequently in Changjiang(Yangtze)River ... In our recent investigations of diatom diversity,we studied three species,namely,Skeletonema costatum,Skeletonema subsalsum,and Skeletonema potamos.Although they have been found frequently in Changjiang(Yangtze)River Basin,their morphological and molecular identification is difficult in taxonomy.Therefore,to integrate morphological and molecular biological approaches,we compared systematically their morphological characters and performed phylogenetic analysis.Twelve strains of Skeletonema were collected and isolated from Shanghai and Jiangsu,China,and their morphological characteristics were examined by light microscopy(LM)and the scanning electron microscopy(SEM).Based on morphological comparison,we determined that S.potamos is easy to distinguish from the other two species.The heavily silicified areolae,undulated or cleft distal ends of terminal fultoportula processes(TFPPs),absence of basal pores of fultoportula processes(FPPs),the rootlike protrusions of FPPs,and no interlocking connection are the stable characteristics that can be used to identify S.potamos.However,there are only two features that can distinguish S.costatum from S.subsalsum,namely the location of terminal rimoportulae(TRPs)and the distal shape of TFPPs.In addition,we amplified and sequenced nine common genetic markers from the strains,from which 101 sequences were obtained,constructed phylogenetic trees based on the nine genes and evaluated that seven genes can be used to identify S.potamos,and revealed that S.subsalsum is the closest known relative of S.costatum,and only ATP synthetase beta-subunit gene(atp B)is able to distinguish them from each other,which strongly support that it is an effective molecular marker for Skeletonema.This work provided a theoretical basis for the taxonomic study of Skeletonema. 展开更多
关键词 SKELETONEMA Changjiang River morphological change distinguishing morphological characteristics molecular marker
下载PDF
Morphological and cytological assessments reveal pollen degradation causes pollen abortion in cotton cytoplasmic male sterility lines
6
作者 PEI Qingyu LIU Jinshan +10 位作者 GUO Chunping MA Xiaomei LIU Xiaoyan YOU Chunyuan LIN Hairong LI Zhibo ZHAO Ruihai ZHU Bo WU Yuanlong PAN Zhenyuan NIE Xinhui 《Journal of Cotton Research》 CAS 2024年第3期266-276,共11页
Background Understanding the mechanism of male sterility is crucial for producing hybrid seeds and developing sterile germplasm resources.However,only a few cytoplasmic male sterility(CMS)lines of cotton have been pro... Background Understanding the mechanism of male sterility is crucial for producing hybrid seeds and developing sterile germplasm resources.However,only a few cytoplasmic male sterility(CMS)lines of cotton have been produced due to several challenges,like inadequate variation of agronomic traits,incomplete sterility,weak resilience of restorer lines,and difficulty in combining strong dominance.Therefore,the morphological and cytological identification of CMS in cotton will facilitate hybrid breeding.Results Two F_(2) segregating populations of cotton were constructed from cytoplasmic male sterile lines(HaA and 01A,maternal)and restorer lines(HaR and 26R,paternal).Genetic analysis of these populations revealed a segregation ratio of 3:1 for fertile to sterile plants.Phenotypic analysis indicated no significant differences in traits of flower bud development between sterile and fertile plants.However,sterile plants exhibited smaller floral organs,shortened filament lengths,and anther atrophy on the flowering day in comparison with the fertile plants.When performed scanning electron microscopy(SEM),the two F_(2) populations revealed morphological variations in the anther epidermis.Cellular analysis showed no significant differences in pollen development before pollen maturation.Interestingly,between the pollen maturation and flowering stages,the tapetum layer of sterile plants degenerated prematurely,resulting in abnormal pollen grains and gradual pollen degradation.Conclusion The results of this study suggest that fertility-restoring genes are controlled by a single dominant gene.Sterile plants exhibit distinctive floral morphology,which is characterized by stamen atrophy and abnormal anthers.Pollen abortion occurs between pollen maturity and flowering,indicating that premature tapetum degradation may be the primary cause of pollen abortion.Overall,our study provides a theoretical basis for utilizing CMS in hybrid breeding and in-depth investigation of the dominant configuration of cotton hybrid combinations,mechanisms of sterility,and the role of sterile and restorer genes. 展开更多
关键词 COTTON Cytoplasmic male sterility Genetic analysis morphological characteristics Pollen development
下载PDF
Morphological Characteristics Analysis of 11 Broom Sorghum Varieties 被引量:1
7
作者 乌艳红 李志明 +8 位作者 辛晓平 孙德欣 吕宁 乌仁图亚 娜日娜 赵建平 王军 韩晓华 李峰 《Agricultural Science & Technology》 CAS 2009年第1期15-18,42,共5页
[Objective] To provide a theoretical basis for high-yield breeding of broom sorghum.[Method] Using 11 kinds of broom sorghum collected at home as research objects, the differences in morphological characteristics of b... [Objective] To provide a theoretical basis for high-yield breeding of broom sorghum.[Method] Using 11 kinds of broom sorghum collected at home as research objects, the differences in morphological characteristics of broom sorghum were compared through the survey of some indicators, such as plant height, tillering, inflorescence, stem node, stem-leaf ratio, yield, and so on. [Result] The 11 kinds of broom sorghum were different in morphological characteristics with large amplitude of plant height; zygl-1, zygl-6, zygl-8 and zygl-9 were appropriate for fixed broom type; zygl-9 had the highest integrated production. [Condusion] The study laid the foundation for further exploring breeding, cultivation and promotion of broom sorghum. 展开更多
关键词 Broom sorghum morphological characteristic ANALYSIS
下载PDF
Building Morphological Characteristics and Their Effect on the Wind in Beijing 被引量:6
8
作者 苗世光 李萍阳 王晓云 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2009年第6期1115-1124,共10页
An urban boundary layer model (UBLM) is improved by incorporating the effect of buildings with a sectional drag coefficient and a height-distributed canopy drag length scale. The improved UBLM is applied to simulate... An urban boundary layer model (UBLM) is improved by incorporating the effect of buildings with a sectional drag coefficient and a height-distributed canopy drag length scale. The improved UBLM is applied to simulate the wind fields over three typical urban blocks over the Beijing area with different height-towidth ratios. For comparisons, the wind fields over the same blocks are simulated by an urban sub-domain scale model resolving the buildings explicitly. The wind fields simulated from the two different methods are in good agreement. Then, two-dimensional building morphological characteristics and urban canopy parameters for Beijing are derived from detailed building height data. Finally, experiements are conducted to investigate the effect of buildings on the wind field in Beijing using the improved UBLM. 展开更多
关键词 building morphological characteristics urban boundary layer model urban canopy model
下载PDF
Morphological Characteristics of Precipitation Areas over the Tibetan Plateau Measured by TRMM PR 被引量:2
9
作者 Yilun CHEN Aoqi ZHANG +2 位作者 Yunfei FU Shumin CHEN Weibiao LI 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2021年第4期677-689,共13页
The multidimensional morphological characteristics(including scale, horizontal shape and 3 D morphology) of precipitation areas over the Tibetan Plateau in summer were studied using 15 years(1998–2012) of observation... The multidimensional morphological characteristics(including scale, horizontal shape and 3 D morphology) of precipitation areas over the Tibetan Plateau in summer were studied using 15 years(1998–2012) of observational data from the precipitation radar onboard the Tropical Rainfall Measuring Mission satellite. As the scale of the precipitation area increased from 20 to 150 km, the near-surface rain rate(RRav) of the precipitation area increased by up to 78%(from ~1.12 to ~2 mm h~(-1)). Linear precipitation areas had the lowest median RRav(~1 mm h~(-1) over the eastern Tibetan Plateau),whereas square-shaped precipitation areas had the highest median RRav(~1.58 mm h~(-1) over the eastern Tibetan Plateau).The 3D morphology was defined as the ratio of the average vertical scale to the average horizontal scale, where a large value corresponds to thin and tall, and a small value corresponds to plump and short. Thin-and-tall precipitation areas and plump-and-short precipitation areas had a greater median RRav, whereas the precipitation areas with a moderate 3D morphology had the lowest median RRav. The vertical structure of the precipitation-area reflectivity was sensitive to both size and 3D morphology, but was not sensitive to the horizontal shape. The relationship between RRav and the morphological characteristics was most significant over the southern slopes of the Tanggula Mountains and the Tibetan Plateau east of 100°E. The morphological characteristics of precipitation areas are therefore closely related to the intensity of precipitation and could potentially be used to forecast precipitation and verify numerical models. 展开更多
关键词 precipitation areas morphological characteristics Tibetan Plateau TRMM PR
下载PDF
Morphological characteristics in the area off eastern Taiwan Island and their tectonic implications 被引量:1
10
作者 LIUBaohua ZHENGYanpeng +2 位作者 WUJinlong HANGuozhong ZHANGDeyu 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2004年第3期449-461,共13页
On the basis of bathymetric data and other geological and geophysical data obtained during the first survey conducted by Chinese Mainland in the area off eastern Taiwan Island from May to June in 2000, the morphologic... On the basis of bathymetric data and other geological and geophysical data obtained during the first survey conducted by Chinese Mainland in the area off eastern Taiwan Island from May to June in 2000, the morphological features of the region, the tectonic control to the seafloor topography and their tectonic implication are studied and discussed. The results have revealed that both the slope zone of the Ryukyu arc and the Ryukyu Trench present a typical morphotectonic characteristics controlled by the trench-arc system in the West Pacific Ocean. At the slope of eastern Taiwan Island the isobathic lines parallel to the coastline and distribute densely in nearly N-S direction and the slope gradient of topography is large. Such a unique feature is attributed to the collision of the Luzon arc and Eurasia continent. In the Huatung Basin, turbidity fans and submarine canyons are well developed, the formations of which are mainly related to the steep topography of the slope of the Luzon arc and the abundant supply of sediments. These submarine canyons are controlled by basement highs and strike-slip faults. On eastern side and western side of the Gagua Ridge, both the water depth and morphological features are different, but the basement of Gagua Ridge belongs to the Huatung Basin. The eastern side of the Gagua Ridge (123°12′E) corresponds to the boundary of two plates with different ages. In the West Philippine Basin, linear ridges and troughs in a NW trending are identified, which are dissected by a NE trending transform fault. According to the seafloor topography features, the direction of the transform fault and the magnetic anomaly lineations, the seafloor of this region was formed during 60-45 Ma B. P. when the West Philippine Basin was spreading along NE-SW relative to the present orientation. 展开更多
关键词 Taiwan Island morphological characteristics tectonic implications
下载PDF
Observation of Morphological Characteristics on Rhbdophaga SP
11
作者 张玉美 姚骏 +2 位作者 潘学峰 郭永生 林华峰 《Agricultural Science & Technology》 CAS 2011年第11期1649-1652,共4页
[Objective] The research aimed at describing morphological characteristics of Rhbdophaga SP. [Method] The morphological characteristics of gall midges (Rhbdophaga SP) on salix, which distributed along lake area of H... [Objective] The research aimed at describing morphological characteristics of Rhbdophaga SP. [Method] The morphological characteristics of gall midges (Rhbdophaga SP) on salix, which distributed along lake area of Huaihe river in Huoqiu Country, were observed from March, 2008 to June, 2010, and larval instars, larval duration and pupal duration were also divided. [Result] Morphological characteristics of Rhbdophaga SP were described in detail, and the larvae were divided into three instars based on the development and molting with the greatly varied shapes and sizes. The pupa is free pupa, and the development of a pupa was divided into four stages, pre-pupal stage, early pupal stage, mid-pupal stage and late puapl stage. [Conclusion] Results were referential for further research of Rhbdophaga SP. 展开更多
关键词 Salix integra Linn Rhbdophaga SP morphological characteristics
下载PDF
Analysis of genotype differences of rice response to low Zn^(2+) activity and some morphological characteristics 被引量:5
12
作者 WANG Renmin, Dept of Agro YANG Xiao’e and YANG Yuai, Dept of Agri Chemistry, ZheJiang Agri Univ, Hangzhou 310029, China 《Chinese Rice Research Newsletter》 1998年第3期11-12,共2页
Zinc deficiency is one of the most widespreadmicro-nutritional disorder for rice. To solve the problem, screening Zn-efficient cultivars isan available method and understanding geno-
关键词 Analysis of genotype differences of rice response to low Zn activity and some morphological characteristics root
下载PDF
Morphological Characteristics of the Long-legged Chafer Hoplia spectabilis Medvedev(Coleoptera: Scarabaeoidea) at Various Developmental Stages
13
作者 Guo Jianpu Nong Xiangqun Wang Feng 《Plant Diseases and Pests》 CAS 2015年第3期25-29,共5页
The long-legged chafer Hoplia spectabilis Medvedev was described in 1952. Its occurrence was rarely reported and the document about its morphological details was not found. However, the chafer did frequently break out... The long-legged chafer Hoplia spectabilis Medvedev was described in 1952. Its occurrence was rarely reported and the document about its morphological details was not found. However, the chafer did frequently break out at Buha River valley in Tianjun county, Qinghai province, China since 2005. In this paper, we present a comprehensive description and illustrations of morphological characteristics of H. spectabilis from local collection, including developmental stages of adult, egg, larva and pupa. Among them, characteristics of the larva and pupa, the male genitalia as well as the difference between male and female are described for the first time. The morphological data will be quite useful for identification and characterization of the chafer, a poorly known species. It will also be an important basis for the chafer control when it breaks out. 展开更多
关键词 Hoplia spectabilis Medvedev morphological characteristics ADULT EGG Larva PUPA
下载PDF
Effects of Silica on Serum Phospholipid,Lipid Peroxide and Morphological Characteristics of Rat Lung
14
作者 GUO WEI-XIN LI GUO-HUA +1 位作者 ZHENG SHU-QIN AND LIN ZHONG-NING(Department of Hygiene, Fujian Medical College,Fuzhou 350004, China) 《Biomedical and Environmental Sciences》 SCIE CAS CSCD 1995年第2期169-175,共7页
The effects of instilled silica have been studied on the serum-phospholipid (PL), lipid peroxide (LPO) and histopathology of rat lung up to 140 days from the first day of instillation. Silica induced relatively higher... The effects of instilled silica have been studied on the serum-phospholipid (PL), lipid peroxide (LPO) and histopathology of rat lung up to 140 days from the first day of instillation. Silica induced relatively higher serum-PL throughout the experiment. The level of LPO also increased appreciably. They presented positive linear correlation. The early lesion was acute alveolitis with silica particles. These lesions became silicotic nodules on the 30th day, which then were enlarged gradually and fused by fibrosis. Alveolar macrophages (AM) were activated and surface structure was damaged. These results indicate that instilled sillca can induce lipid peroxidation of cell membrane and selective accumulation of lung PL 展开更多
关键词 AM CELL Effects of Silica on Serum Phospholipid Lipid Peroxide and morphological characteristics of Rat Lung
下载PDF
Morphological Characteristics and Nutrient Content of Fine Roots of 2-Year-Old and 3-Year-Old Eucalyptus grandis Plantation
15
作者 Xiaoyu DUAN Xianwei LI +2 位作者 Liuling ZHOU Weishuang WANG Hui CHEN 《Agricultural Biotechnology》 CAS 2012年第6期9-14,共6页
[ Objective] This study aimed to explore the morphological characteristics and nutrient content of f'me roots of 2-year-old and 3-year-old Euca/yptus grand/s plantation and investigate the correlation. [ Method] Fine... [ Objective] This study aimed to explore the morphological characteristics and nutrient content of f'me roots of 2-year-old and 3-year-old Euca/yptus grand/s plantation and investigate the correlation. [ Method] Fine roots of 2-year-old and 3-year-old Eucalyptus grandis plantation were collected as experimental materials, to determine the root diameter (D), root length (L), specific root length (SRL) and contents of major nutrient elements N, P, K, Ca, Mg and C of fine roots (level 1 -5), study the morphological characteristics and major nutrient element content and investigate the correlation. [ Result] The results showed that morphological differences of fine roots ( level 1 - 5 ) of Eucalyptus grandis plantation were great with the increase of root order, to be specific, D and L increased and SRL decreased with the increasing root order; SRL, L and D of 3-year-old Eucalyptus grauclis plantation were greater than those of 2-year-old Euca/yptus grand/s plantation. Contents of N, Ca, Mg and C of fine roots of 2-year-old and 3-year-old Eucalyptus grandis plantation showed consistent orders with the increase of root order: N and Mg contents were reduced, while Ca and C contents were enhanced; P and K contents varied with different forest ages; both 2-year-old and 3-year- old Eucalyptus grandis showed an order of C 〉 K 〉 Ca (Mg) 〉 N. Major nutrient element content and morphological characteristics of Eucalyptus grand/s fine roots (level 1 -5 ) were extremely significantly correlated (P 〈0.01 ), SRL, L and D could be adopted as reference indices to evaluate nutrient status of Eucalyptus grand/s. Required nutrients and fine root morphology of Eucalyptus grandis plantation changed with the increase of forest age, and the nutrient cycling and energy flow patterns also changed; major nutrient dements in fine roots of 2-year-old and 3-year-old Eucalyptus grandis plantation transferred in a different order from the growth order, therefore N fertilizer could be applied to improve the growth of fine roots. [ Condusion] This study laid the foundation for understanding the fine root morphology and nutrient variation pattern of Eucalyptus grandis plantation and enriching the response and adaptation mechanism theory of roots to environment, pos- sessing important reference significance for the sustainable development of Eucalyptus grand/s plantation. 展开更多
关键词 Eucalyptus grandis Fine root Root order Nutrient elements morphological characteristics
下载PDF
Spatial Layout and Morphological Characteristics of the Waterfront Settlements in Northern Jiangxi
16
作者 DENG Huan 《Journal of Landscape Research》 2018年第4期30-34,共5页
The stmctufe types of the waterfront settlements in the north of Jiangxi Province were analyzed. According to the relationship between location and water, die waterfront setdements in northern Jiangxi were classifi... The stmctufe types of the waterfront settlements in the north of Jiangxi Province were analyzed. According to the relationship between location and water, die waterfront setdements in northern Jiangxi were classified into tiiree categofies. The structuial commonalities of the three kinds of waterfront settlements were cleady interpreted. On this basis and combined with the field research data and relevant data, the characteristics of the waterfront setdements in northern Jiangxi were summarized: treating water as the main skeleton, choosing location by the distance £com watet, magnetic effect and organic textute. The characteiistic space of watetfront settLemeiits found in the investigation process was classified and elaborated, which has certain reference significance for tiie space study of waterfront settlements. 展开更多
关键词 Northern Jiangxi Waterfront setdements Spatial layout morphological characteristics
下载PDF
Morphological and Biological Characteristics of Rhynchaenus empopulifolis in Tai’an,China
17
作者 Xie Na 《Plant Diseases and Pests》 CAS 2021年第1期27-30,共4页
Rhynchaenus empopulifolis is a defoliator harming poplar,and its occurrence is reported in Tai’an area for the first time.Through indoor rearing and forest investigation,the morphological,biological and damage charac... Rhynchaenus empopulifolis is a defoliator harming poplar,and its occurrence is reported in Tai’an area for the first time.Through indoor rearing and forest investigation,the morphological,biological and damage characteristics of R.empopulifolis in Tai’an were observed,and color pictures of each instar and local characteristics of adult as well as damage symptoms were provided,in order to lay a theoretical basis for rapid identification and precise control of R.empopulifolis. 展开更多
关键词 Rhynchaenus empopulifolis morphological characteristics Biological characteristics Damage status
下载PDF
Morphological characteristics and DNA barcoding of Pampus echinogaster(Basilewsky, 1855)
18
作者 LI Yuan ZHANG Yan +3 位作者 GAO Tianxiang HAN Zhiqiang LIN Longshan ZHANG Xiumei 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2017年第12期18-23,共6页
The morphological similarities of Pampus fishes have led to considerable confusion in species-level identification,and no accurate information on neotype or DNA barcoding of Pampus echinogaster is available. Two hundr... The morphological similarities of Pampus fishes have led to considerable confusion in species-level identification,and no accurate information on neotype or DNA barcoding of Pampus echinogaster is available. Two hundred and seven specimens of P. echinogaster were collected from the coastal waters of Dandong, Dongying, Qingdao,Nantong, Zhoushan, Wenzhou, Changle, Taiwan, and Wakayama(Japan), from June 2010 to April 2013. The diagnostic characteristics of P. echinogaster are as follows: dorsal fin VIII-XI-43–51, anal fin V-VIII-43–49, pectoral fin 22–27, caudal fin 19–22, pelvic fin absent; first gill rakers sparse, slender(pointed), 3–4+12–16=15–20; vertebrae39–41; transverse occipital canal on top of head moderately small, wavy ridges not reaching upper origin of pectoral fin; ventral branch of lateral line canal spare, shorter than dorsal branch of lateral line canal. By combining congener sequences of the cytochrome oxidase I(COI) gene from Gen Bank, two absolute groups were detected among all specimens, which further indicated that two valid species were present based on genetic differences in amino acid sequences and the distance between the groups. The sequences of Group 1 can be regarded as DNA barcoding of P. echinogaster. The correct morphological redescription and DNA barcoding of P.echinogaster are presented here to provide a guarantee for efficient and accurate studies, a theoretical basis for classification, and enable appropriate fishery management and conservation strategies for the genus Pampus in the future. 展开更多
关键词 morphological characteristics DNA barcoding Pampus echinogaster genetic differentiation transverse occipital canal
下载PDF
Leaf stable carbon isotope composition in Picea schrenkiana var. tianschanica in relation to leaf physiological and morphological characteristics along an altitudinal gradient
19
作者 ZHANG Hui-wen WU Zhen XIAO Hong-lang 《Journal of Mountain Science》 SCIE CSCD 2016年第7期1217-1228,共12页
To understand the effects of leaf physiological and morphological characteristics on δ13C of alpine trees, we examined leaf δ13C value, LA, SD, LNC, LPC, LKC, Chla+b, LDMC, LMA and Narea in one-year-old needles of P... To understand the effects of leaf physiological and morphological characteristics on δ13C of alpine trees, we examined leaf δ13C value, LA, SD, LNC, LPC, LKC, Chla+b, LDMC, LMA and Narea in one-year-old needles of Picea schrenkiana var. tianschanica at ten points along an altitudinal gradient from 1420 m to 2300 m a.s.l. on the northern slopes of the Tianshan Mountains in northwest China. Our results indicated that all the leaf traits differed significantly among sampling sites along the altitudinal gradient(P<0.001). LA, SD, LPC, LKC increased linearly with increasing elevation, whereas leaf δ13C, LNC, Chla+b, LDMC, LMA and Narea varied non-linearly with changes in altitude. Stepwise multiple regression analyses showed that four controlled physiological and morphological characteristics influenced the variation of δ13C. Among these four controlled factors, LKC was the most profound physiological factor that affected δ13C values, LA was the secondary morphological factor, SD was the third morphological factor, LNC was the last physiological factor. This suggested that leaf δ13C was directly controlled by physiological and morphological adjustments with changing environmental conditions due to the elevation. 展开更多
关键词 Alpine trees Leaf Carbon isotope composition Physiological characteristics morphological characteristics Altitudinal variation
下载PDF
Fine Root Distribution Characteristics of Populus cathayana Plantations at Different Ages in Alpine Sandy Land
20
作者 Xiangdong YANG 《Plant Diseases and Pests》 CAS 2023年第4期1-6,10,共7页
[Objectives]The paper was to study the fine root distribution characteristics of Populus cathayana plantations at different ages in alpine sandy land.[Methods]With 5,10,15,20,and 25 years old P.cathayana plantation in... [Objectives]The paper was to study the fine root distribution characteristics of Populus cathayana plantations at different ages in alpine sandy land.[Methods]With 5,10,15,20,and 25 years old P.cathayana plantation in the eastern margin of Gonghe Basin,Qinghai Province as the research objects,fine roots were collected by root core drilling method,and the differences of fine root biomass,root length density,average diameter and root tip number at the soil depths of 0-20,20-40,40-60,60-80 and 80-100 cm were analyzed.[Results]The total biomass density of P.cathayana plantation was mainly distributed in the soil layer of 0-60 cm,accounting for 76%of the entire soil layer,and its value increased with the increase in forest age.With the increase in different forest ages,the root length density,average diameter and root tip number of living fine roots in the soil layer of 0-60 cm accounted for 74%-81%of the entire soil layer,and the proportions in the soil layers of 60-80 and 80-100 cm were 9%-11%.The biomass density,root length density,average diameter and root tip number of living and dead fine roots of P.cathayana plantation increased with the increase of forest age.The root length density,average diameter and root tip number of P.cathayana fine roots showed a linear function change trend with the growth of forest age,which could be described by the linear function equation y=ax+b(a>0).The analysis results showed that the root length density,average diameter and root tip number of P.cathayana were significantly correlated with the total biomass density of fine roots,and the root length density and average diameter had an extremely positive correlation with the total biomass density.[Conclusions]In the future,P.cathayana plantation should be properly tended to promote the development of fine roots and maximize its ecological benefits. 展开更多
关键词 Populus cathayana plantation BIOMASS Fine root distribution morphological characteristics
下载PDF
上一页 1 2 5 下一页 到第
使用帮助 返回顶部