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Temperature responsiveness of seedlings maximum relative growth rate in three Mediterranean Cistus species
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作者 Giacomo Puglielli Alessandra Spoletini +1 位作者 Giuseppe Fabrini Loretta Gratani 《Journal of Plant Ecology》 SCIE CSCD 2017年第2期331-339,共9页
Aims Relative growth rate(RGR)is an indicator of the extent to which a species is using its photosynthates for growth and it is affected by environmental factors,including temperature.Nevertheless,most of plant growth... Aims Relative growth rate(RGR)is an indicator of the extent to which a species is using its photosynthates for growth and it is affected by environmental factors,including temperature.Nevertheless,most of plant growth studies have been carried out at a single growth temperature or at different temperature treatments,resulting in the lack of information on the relationship between RGR and chang-ing mean daily air temperature.We analyzed the temporal changes in RGR during early growth stages in three Cistus species grown outdoor in a common garden from seeds of different provenances.Moreover,we wanted to define the relationship between daily changes in RGR and mean daily air temperature for the considered provenances.The hypothesis that intra-specific temporal variations in RGR can reflect differences in the behavior to maximize RGR(RGRmax)in response to temperature was tested.Methods Seedlings of C.salvifolius,C.monspeliensis and C.creticus subsp.eriocephalus were grown outdoor in the experimental garden of the Sapienza University of Rome under a Mediterranean climate.We analyzed early growth with non-linear growth models and calcu-lated function-derived RGRs as the derivative with respect to time of the parameterized functions used to predict height divided by cur-rent height.The relationships between function-derived RGRs and mean daily air temperature were analyzed by linear and non-linear models,which were ranked according to their standard errors and correlation coefficients.The temperature dependency of RGRmax per each provenance was evaluated through the relationship between RGRmax and the coefficients of the best regression model obtained.Important Findings A parameter that could summarize the temperature dependency of RGR up to RGRmax during the early growth stages for the selected provenances was defined.This allowed us to highlight that a greater RGR temperature responsiveness was related to a delay in the time to reach RGRmax independently by the species.Nevertheless,a greater temperature sensitivity of RGR lead to a reduced maximum height which reflects a negative trade-off between the length of the developmental phases and the extent of RGR temperature respon-siveness.Thus,variations in temperature responsiveness of RGR up to RGRmax have a significant role in shaping the early growth for the investigated species.Our findings quantitatively define provenance dependent strategies by which the selected species cope with daily air temperature variations during early growth. 展开更多
关键词 early growth stage non-linear growth models function-derived relative growth rate local adaptation
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Effects of Sand Burial on the Survival, Growth, and Biomass Allocation in Semi-shrub Hedysarum laeve Seedlings 被引量:14
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作者 张称意 于飞海 董鸣 《Acta Botanica Sinica》 CSCD 2002年第3期337-343,共7页
Hedysarum laeve Maxim. (Leguminosae) is one of the major species used frequently in revegetation of dune_field in the sandlands of the northern part of China by means of aerial sowing. Seedlings of the species after e... Hedysarum laeve Maxim. (Leguminosae) is one of the major species used frequently in revegetation of dune_field in the sandlands of the northern part of China by means of aerial sowing. Seedlings of the species after emergence above the sand surface may be buried in sand to various depths during its establishment in late spring and early summer. A study was made to examine the effects of sand burial at different levels of 0 (control), 33%, 67%, 100% and 133% of their shoot height, on the survivorship, growth, and biomass allocation pattern of H. laeve seedlings (one and two weeks old after emergence). When burial depth was up to 100% of their shoot height, about 70% seedlings died; and the burial at depth of 133% of their shoot height led to death of all seedlings. When seedlings was buried at depth of 33% and 67% of their shoot height, respectively, after six_week growth, their biomass of whole plant, blade, and root and relative growth rate were higher than the unburied counterparts. The seedlings in both 33% and 67% sand burial treatments did not significantly change their biomass allocation pattern comparing with the unburied ones. Furthermore, the number of leaves and shoot height of the seedlings in both 33% and 67% sand burial treatments were not significantly different from those of unburied individuals, respectively. The newly born leaves of the surviving seedlings, in 33%, 67%, and 100% burial treatments, during the period of experiment, were significantly more than those in control. 展开更多
关键词 Hedysarum laeve sandland sand burial SEEDLING growth SURVIVAL biomass allocation relative growth rate
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Species divergence in seedling leaf traits and tree growth response to nitrogen and phosphorus additions in an evergreen broadleaved forest of subtropical China 被引量:3
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作者 Xuemin Ye Wensheng Bu +3 位作者 Xiaofei Hu Bin Liu Kuan Liang Fusheng Chen 《Journal of Forestry Research》 SCIE CAS CSCD 2023年第1期137-150,共14页
Tree competitiveness generally depends on trait plasticity in response to environmental change.The effects of nitrogen(N)and phosphorus(P)on leaf trait variability by species is poorly understood,especially in China’... Tree competitiveness generally depends on trait plasticity in response to environmental change.The effects of nitrogen(N)and phosphorus(P)on leaf trait variability by species is poorly understood,especially in China’s subtropical forests.This study examined the seedling leaf traits and net primary productivity of all trees>5 cm DBH of two dominant species,Schima superba and Castanopsis carlesii,in an evergreen broadleaved forest fertilized with nitrogen(+N),phosphorus(+P),and nitrogen plus phosphorus(N+P).The effect of N on seedling leaf traits was stronger than P,while fertilization in general was species dependent.Leaf mass per unit area decreased with N for S.superba seedlings but not for C.carlesii.Leaf N,P,and N/P ratios changed with N addition for both species.All four N fractions of carboxylation,bioenergetics,cell wall,and other N metabolites in C.carlesii leaves responded significantly to fertilization,while only the cell wall in S.superb a leaves responded.Other leaf functional traits,including light-saturated photosynthetic rates,water,N,and P use efficiencies,chlorophyll and non structural carbohydrate contents increased with N addition in S.superb a and by P addition in C.carlesii.Canopy closure at the stand-level increased due to N.Litter biomass and relative growth rate of S.superb a was not affected by any treatments,while both for C.carlesii significantly decreased with N+P addition.Collectively,nutrient limitation may vary at a small scale among species in a subtropical forest based on their responses of seedling traits and net primary productivity to fertilization.Seedling traits are not correlated with the net primary productivity of larger trees except for N fractions,because low light conditions induced by fertilization reduces the proportion of N allocated to photosynthesis in seedlings.In addition,acclimation differences of tree species may increase the uncertainty of community succession. 展开更多
关键词 ECOPHYSIOLOGY Fertilization acclimation N fractions Nutrient limitation Photosynthesis relative growth rate
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Effect of Rare Earth Elements on Quantity Growth of Crops 被引量:1
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作者 张自立 常江 +3 位作者 汪成胜 柴绍明 韩修明 李瑞 《Journal of Rare Earths》 SCIE EI CAS CSCD 2002年第4期299-301,共3页
The effects of rare earth on the growth of rice, rape and soybean in three kinds of soils were studied with the method supposed by Economic Co-operation and Development organization (OECD), and the EC50(median growth... The effects of rare earth on the growth of rice, rape and soybean in three kinds of soils were studied with the method supposed by Economic Co-operation and Development organization (OECD), and the EC50(median growth concentration)values were obtained. The inhibition of RE on the growth of rice and rape in red soil and on the growth of soybean in yellow fluvo-aquic soil is higher with stronger poison effects. Compared with other heavy metals such as Hg, Cd, Pb, As, the poison of RE on crops is weaker. 展开更多
关键词 rare earths relative growth quantity half effect concentration
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Effect of NaNO_3 Concentrations on the Growth and Fatty Acid Compositions of Nitzschia closterium and Chaetoceros gracilis* 被引量:1
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作者 梁英 麦康森 孙世春 《Marine Science Bulletin》 CAS 2003年第1期69-74,共6页
Fatty acid compositions of two strains of marine diatoms Nitzschia closterium ( MACC B222 ) and Chaetoceros gracilis ( MACC B13 ) have been examined. The microalgae have been grown at different initial NaNO3 concentr... Fatty acid compositions of two strains of marine diatoms Nitzschia closterium ( MACC B222 ) and Chaetoceros gracilis ( MACC B13 ) have been examined. The microalgae have been grown at different initial NaNO3 concentrations ( 75, 375, 750, 1 125, 1 500, 1 875 mg/L ) and harvested at the late exponential phase. The results by one factor analysis of variance show that the NaNO3 concentrations have no significant influence on the relative growth rate of two strains of marine diatoms; the influence of NaNO3 concentrations on the fatty acids differs from species to species. The major fatty acids of two --diatom strains are 14:0, 16:0, 16:1n7 and 20:5n3 ( EPA ) , B13 also has high percentage -of 20:4n6 ( 6.0 ~ 9.1% ). 展开更多
关键词 Nitzschia closterium Chaetoceros gracilis NaNO3 relative growth rate fatty acid
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Growth performance and scale insect infestation of Shorea leprosula in a common garden experimental plot
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作者 Chin Hong Ng Kevin Kit Siong Ng +3 位作者 Soon Leong Lee Rempei Suwa Chai Ting Lee Lee Hong Tnah 《Journal of Forestry Research》 SCIE CAS CSCD 2023年第3期781-792,共12页
Many tree planting programmes have long been initiated to increase forest cover to mitigate the effects of global climate change.Successful planting requires careful planning at the project level,including using suita... Many tree planting programmes have long been initiated to increase forest cover to mitigate the effects of global climate change.Successful planting requires careful planning at the project level,including using suitable species with favourable traits.However,there is a paucity of improvement data for tropical tree species.An experimental common garden of Shorea leprosula was established to study traits related to growth performance which are key factors in planting success.Seedlings of S.leprosula were collected from nine geographical forest reserves.To study the effects of genetic variation,seedlings were planted in a common environment following a randomized complete block design.From performance data collected 2017‒2019,one population showed the highest coefficient for relative height growth,significantly higher than most of the other populations.Interestingly,this population from Beserah also exhibited the lowest coefficient for scale insect infestation.This study provides preliminary results on growth performance and susceptibility to scale insect infestation in S.leprosula and the first common garden experiment site conducted on dipterocarp species.It lays a foundation for future genome-wide studies. 展开更多
关键词 Root collar diameter Height Scale insect relative growth rate DIPTEROCARP
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Phytoremediation of Rocky Slope Surfaces: Selection and Growth of Pioneer Climbing Plants
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作者 WANG Zhong-Qiang WU Liang-Huan +1 位作者 S. ANIMESH ZHU Yuan-Hong 《Pedosphere》 SCIE CAS CSCD 2009年第4期541-544,共4页
INTRODUCTION As a result of the massive construction following rapid economic growth in China, extraction of building materials from mountain resources has left behind many quarries. Those quarries usually have rocky ... INTRODUCTION As a result of the massive construction following rapid economic growth in China, extraction of building materials from mountain resources has left behind many quarries. Those quarries usually have rocky surfaces and steep slopes. The existence of rocky slopes is not only a safety hazard but also increases soil erosion and affects landscape aesthetics. Natural restoration of vegetation on rocky slope surfaces is a very slow process, which might require hundreds of years, and is not considered an acceptable restoration strategy (Cullen et al., 1998). Phytoremediation methods have been widely considered as a better option for vegetation establishment on rocky slope surfaces (Muzzi et al., 1997). 展开更多
关键词 relative growth rate survival rate vegetation restoration
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Predicting Compensatory Growth and Reproduction in Agricultural Weeds Using a Plant's Growth Rate Trajectory: A Test with Defoliation of Abutilon theophrasti
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作者 David Alexander Wait 《Journal of Agricultural Science and Technology(A)》 2016年第4期255-260,共6页
A plant's capacity to compensate for pest damage as a function of resource availability needs to be predictable in order to apply biocontrol agents effectively. In this research, it was hypothesized that a weedy plan... A plant's capacity to compensate for pest damage as a function of resource availability needs to be predictable in order to apply biocontrol agents effectively. In this research, it was hypothesized that a weedy plant species' capacity to compensate for defoliation is related to how resource availability affects a plant's growth trajectory. Growth rate trajectory is defined as the percent change in relative growth rate or the slope of a plant's relative growth rate. 90 Abutilon theophrasti, a common weed species, in cultivated fields of corn and soybean, grew in a greenhouse for 70 d under three nitrogen (N) fertilization treatments. "Unfertilized" plants were not fertilized, "bulk" fertilized plants received 0.6 g N on day 15 and "exponential" fertilized plants received a total of 0.6 g N supplied at an exponential rate of 10% per day with a starting concentration of 0.02 g N on day 15. On day 25, 15 plants in each N treatment had 75% of total leaf area removed. Biomass and reproductive compensation were determined after 50 d and 70 d of growth. Results showed that bulk plants had the greatest absolute growth, but also the greatest decline in growth rates and the least capacity for compensation. Unfertilized plants had the lowest absolute growth, but declines in growth rates were similar to bulk plants with only a slightly greater compensatory capacity. Exponential plants had intermediate absolute growth, but the least decline in growth rates and the greatest capacity for compensation. This experiment indicates that a plant's growth rate trajectory, and not high or low relative growth rates or N availability per se, can be used to predict a weedy plant's capacity to compensate for herbivory, and has implications for biocontrol of weedy species. 展开更多
关键词 BIOCONTROL compensatory growth HERBIVORY nitrogen fertilization relative growth rate reproductive allocation.
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Impacts of Date Palm Seeds (Phoenix dactyliferous L.) on Growth Indices and Nutrient Utilization of Common Carp Cyprinus carpio L,
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作者 Vian Mohammed Ahmed Nasreen Mohialddin Abdulrahman +6 位作者 Sarwar Abubaker HamaAmeen Bakhan Rafiq Hassan Abu Baker Kamil Abbas Baxan Akram Hussen Idres Shexa Hamad Sana Abdulla Karem Kale Mamand Aziz 《Journal of Agricultural Science and Technology(B)》 2017年第4期280-284,共5页
This study was carried out to study the effect of adding different levels of date palm seed (Phoentix dactyliJProus) powder in the diet of common carp (Cyprinus carpio) at fish laboratory of Animal Production Depa... This study was carried out to study the effect of adding different levels of date palm seed (Phoentix dactyliJProus) powder in the diet of common carp (Cyprinus carpio) at fish laboratory of Animal Production Department, College of Agricultural Sciences, Sulaimani University, Sulaimani, Iraq. The actual experimental feeding trials were conducted for 70 d and the adaptation period for 21 d. A total of 81 common carp fingerlings weighted 62 ± 2 g were divided into three experimental groups. The control treatment T1 was with 0 g date palm seed, T2 with 2.5 g date palm seed per kg diet and T3 with 5 g date palm seed per kg diet. Each treatment was in three replicates in which three common carp fingerlings were stocked in each aquarium which fed the experimental diets twice daily. The results indicated that weight gain (WG) and specific growth rate (SGR) in the third treatment (T3) group were significantly higher than those of fish fed control diets. T2 consumed more diet than other treatments with 306.940 g with higher feed conversion ratio (FCR); T3 was higher significantly in food efficiency. No significant (P 〈 0.05) differences obtained from consumed protein while the protein efficiency ratio was significantly higher in T3 with 319.323. Control was higher significantly in flesh weight without viscera with the third treatment; in flesh weight without head and viscera each the control and the second treatment was significantly higher than the third treatment. As a conclusion, the date palm seeds powder have a positive effect on growth performance of common carp. 展开更多
关键词 Weight gain specific growth rate relative growth rate feed conversion ratio food efficiency protein efficiency ratio date palm seeds common carp.
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Carbon Dioxide Concentrations and Light Levels on Growth and Mineral Nutrition of Juvenile Cacao Genotypes
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作者 Virupax C. Baligar Marshall K. Elson +3 位作者 Alex-Alan F. Almeida Quintino R. de Araujo Dario Ahnert Zhenli He 《American Journal of Plant Sciences》 2021年第5期818-839,共22页
In many countries cacao (</span><i><span style="font-family:Verdana;">Theobroma cacao</span></i><span style="font-family:Verdana;"> L.) is invariably grown as an... In many countries cacao (</span><i><span style="font-family:Verdana;">Theobroma cacao</span></i><span style="font-family:Verdana;"> L.) is invariably grown as an understory crop in agroforestry types of cropping systems and subjected to low levels photosynthetic photon flux density (PPFD) due to presence of large number of upper story shade trees with poorly managed canopy structure. In recent years carbon dioxide concentration in the atmosphere is steadily increasing and it is unclear what impact this will have on performance of cacao grown under shade of upper story shade trees. A climatically controlled greenhouse experiment was undertaken to evaluate the effects of ambient and elevated carbon dioxide (400 and 700 μmol&middot;mol</span><sup><span style="font-family:Verdana;">-1</span></sup><span style="font-family:Verdana;">) and three levels of PPFD (100, 200, and 400 μmol&middot;m</span><sup><span style="font-family:Verdana;">-2</span></sup><span style="font-family:Verdana;">&middot;s</span><sup><span style="font-family:Verdana;">-1</span></sup><span style="font-family:Verdana;">) on growth, and macro- and micronutrient use efficiency of three genetically contrasting cacao genotypes (CCN 51, VB 1117 and NO 81). Intraspecific variations were observed in cacao genotypes for growth parameters at ambient to elevated carbon dioxide and low to adequate levels of PPFD. With the exceptions of total root length and leaf area, irrespective of carbon dioxide and PPFD levels, all three genotypes showed significant differences in all the growth parameters. For all the cacao genotypes, increasing PPFD from 100 to 400 μmol&middot;m</span><sup><span style="font-family:Verdana;">-2</span></sup><span style="font-family:Verdana;">&middot;s</span><sup><span style="font-family:Verdana;">-1</span></sup><span style="font-family:Verdana;"> and carbon dioxide from 400 to 700 μmol&middot;mol</span><sup><span style="font-family:Verdana;">-1</span></sup><span style="font-family:Verdana;"> increased overall growth parameters such as leaf, shoot and root biomass accumulation, stem height, leaf area, relative growth rate and net assimilation rate. Irrespective of carbon dioxide and PPFD, invariably genotypes differed significantly in macro-micronutrient uptake parameters such as concentration, uptake, influx, transport and use efficiency. With few exceptions, raising PPFD from 100 to 400 μmol&middot;m</span><sup><span style="font-family:Verdana;">-2</span></sup><span style="font-family:Verdana;">&middot;s</span><sup><span style="font-family:Verdana;">-1</span></sup><span style="font-family:Verdana;"> and carbon dioxide from 400 to 700 μmol&middot;mol</span><sup><span style="font-family:Verdana;">-1</span></sup><span style="font-family:Verdana;"> increased nutrient use efficiency for all the cacao genotypes. Elevated carbon dioxide and adequate PPFD are benefi</span><span style="font-family:Verdana;">cial in improving cacao growth and mineral nutrient uptake and use efficiency. 展开更多
关键词 relative growth Rate Net Assimilation Rate Mineral Nutrient Influx and Transport Mineral Nutrient Uptake Efficiency
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Nitrogen Fertilization on Maize Sowing:Plant Growth and Seed Vigor
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作者 Cristian Troyjack Joao Roberto Pimentel +10 位作者 Itala Thaísa Dubal Padilha Ruddy Alvaro Veliz Escalera Lanes Beatriz Acosta Jaques Felipe Koch Manoela Andrade Monteiro Gustavo Henrique Demari Vinicius Jardel Szareski Ivan Ricardo Carvalho Luis Osmar Braga Schuch Tiago Zanatta Aumonde Tiago Pedó 《American Journal of Plant Sciences》 2018年第1期83-97,共15页
The management of fertilization in maize plants is a preponderant factor in the search for higher yields and obtaining quality seeds. In this sense, the study of nitrogen (N) management is predominant in improving the... The management of fertilization in maize plants is a preponderant factor in the search for higher yields and obtaining quality seeds. In this sense, the study of nitrogen (N) management is predominant in improving the efficiency of its application. The objective of this study was to evaluate the growth, partition assimilation and vigor expression of maize seeds submitted at different doses of nitrogen applied at sowing. The treatments were constituted by different doses of nitrogen fertilization at sowing, being: 25%, 50%, 75% and 100% of the recommended dose for the crop, according to the recommendation of nitrogen fertilization. The plants were collected at regular intervals of 21 days after sowing until the end of the growth cycle. For the analysis of growth and partition of dry matter between the organs, the accumulation of dry matter and leaf area was measured. The experimental design was randomized blocks in a 4 × 7 factorial scheme (four N rates at sowing and seven collection times with three replications). The maize plants under the influence of nitrogen fertilization at sowing presented differential growth and distinct responses in the assimilated partition between their structures, with the intensity dependent on the dose used. Plants grown using 75% of the recommended dose of N at sowing had a higher relative growth rate, with more pronounced effects compared to the other doses. The expression of maize seed vigor increases to an increase of 82.5% N at sowing. 展开更多
关键词 Emergence Speed Net Assimilation Rates relative growth Rates Zea mays L. VIGOR
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Analytically Derived Wind Wave Growth Relations 被引量:11
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作者 GUAN Changlong(管长龙) +1 位作者 SUN Qun(孙群) 《China Ocean Engineering》 SCIE EI 2002年第3期359-368,共10页
By the use of the 3/2 power law presented by Toba combined with the significant wave energy balance equation for wind wave, wind wave growth at a limited fetch is analytically investigated. The new wind wave growth re... By the use of the 3/2 power law presented by Toba combined with the significant wave energy balance equation for wind wave, wind wave growth at a limited fetch is analytically investigated. The new wind wave growth relations (WWGRs) are analytically derived with sheltering coefficient and wind drag coefficient as parameters. The geometrical average of observational values of sheltering coefficient and the arithmetic average of observational values of wind drag coefficient are applied to determine the new WWGRs. Comparisons with existing empirical WWGRs are made. 展开更多
关键词 wind wave wind wave growth relation 3/2 power law
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Interaction between insulin-like growth factor binding protein-related protein 1 and transforming growth factor beta 1 in primary hepatic stellate cells 被引量:3
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作者 Xiu-Qing Li Qian-Qian Zhang +3 位作者 Hai-Yan Zhang Xiao-Hong Guo Hui-Qin Fan Li-Xin Liu 《Hepatobiliary & Pancreatic Diseases International》 SCIE CAS CSCD 2017年第4期395-404,共10页
BACKGROUND: We previously showed that insulin-like growth factor binding protein-related protein 1 (IGFBPrP1) is a novel mediator in liver fibrosis. Transforming growth factor beta 1 (TGF beta 1) is known as the stron... BACKGROUND: We previously showed that insulin-like growth factor binding protein-related protein 1 (IGFBPrP1) is a novel mediator in liver fibrosis. Transforming growth factor beta 1 (TGF beta 1) is known as the strongest effector of liver fibrosis. Therefore, we aimed to investigate the detailed interaction between IGFBPrP1 and TGF beta 1 in primary hepatic stellate cells (HSCs). METHODS: We overexpressed TGF beta 1 or IGFBPrP1 and inhibited TGF beta 1 expression in primary HSCs for 6, 12, 24, 48, 72, and 96 hours to investigate their interaction and observe the accompanying expressions of a-smooth muscle actin (alpha-SMA), collagen I, fibronectin, and phosphorylated-mothers against decapentaplegic homolog 2/3 (p-Smad2/3). RESULTS: We found that the adenovirus vector encoding the TGF beta 1 gene (AdTGF beta 1) induced IGFBPrP1 expression while that of alpha-SMA, collagen I, fibronectin, and TGF beta 1 increased gradually. Concomitantly, AdIGFBPrP1 upregulated TGF beta 1, alpha-SMA, collagen I, fibronectin, and p-Smad2/3 in a time-dependent manner while IGFBPrP1 expression was decreased at 96 hours. Inhibition of TGF beta 1 expression reduced the IGFBPrP1-stimulated expression of alpha-SMA, collagen I, fibronectin, and p-Smad2/3. CONCLUSIONS: These findings for the first time suggest the existence of a possible mutually regulation between IGFBPrP1 and TGF beta 1, which likely accelerates liver fibrosis progression. Furthermore, IGFBPrP1 likely participates in liver fibrosis in a TGF beta 1-depedent manner, and may act as an upstream regulatory factor of TGF beta 1 in the Smad pathway. 展开更多
关键词 insulin-like growth factor binding protein related protein 1 transforming growth factor in primary hepatic stellate cells alpha-smooth muscle actin extracellular matrix Smad pathway
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Beijing's Steady Growth in Foreign Economic Relations and Trade
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作者 Xiao Qiang Staff reporter 《China's Foreign Trade》 1996年第5期18-18,共1页
In 1995,Beijing’s foreign economic andtrade sector continued to deepen itsrestructuring,give play to its advantagesand overcome its difficulties,and maintainedsustained development in foreign trade,theutilization of ... In 1995,Beijing’s foreign economic andtrade sector continued to deepen itsrestructuring,give play to its advantagesand overcome its difficulties,and maintainedsustained development in foreign trade,theutilization of foreign investment and foreigncooperation. The year 1995 saw an import andexport volume of US$4.23 billion,5.4 percentup from the previous year,including animport volume of US$1.74 billion,down 8percent,exports of US$2.49 billion,17.3percent up from the previous year,whichsurpasses the required US$2.3 billion ofexports by the municipal government.Specialforeign trade companies and industrial andtrade companies had exports of US$1.441billion,4.8 percent up from the previousyear,accounting for 57.9 percent of the 展开更多
关键词 USA TING Beijing’s Steady growth in Foreign Economic Relations and Trade
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Seedling dynamics differ between canopy species and understory species in a tropical seasonal rainforest,SW China
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作者 Libing Pan Xiaoyang Song +2 位作者 Wenfu Zhang Jie Yang Min Cao 《Plant Diversity》 SCIE CAS CSCD 2024年第5期671-677,共7页
We used 11 years of census data from 450 seedling quadrats established in a 20-ha forest dynamics plot to study seedling dynamics in tree species of a tropical seasonal rainforest in Xishuangbanna,southwestern China.W... We used 11 years of census data from 450 seedling quadrats established in a 20-ha forest dynamics plot to study seedling dynamics in tree species of a tropical seasonal rainforest in Xishuangbanna,southwestern China.We found that overall seedling recruitment rate and relative growth rate were higher in the rainy season than in the dry season.Both the recruitment rate of seedlings from canopy tree species(two species)and the relative growth rate of seedlings from understory species(nine species)were higher in the rainy season than in the dry season.However,in the rainy season,the recruitment rate of seedlings was higher for canopy tree species than for understory tree species.In addition,relative growth rate of seedlings was higher in the canopy species than in understory seedlings in the dry season.We also observed that,in both rainy and dry seasons,mortality rate of seedlings was higher for canopy species than for understory species.Overall,canopy tree species appear to have evolved a flexible strategy to adapt to the seasonal changes of a monsoon climate.In contrast,understory tree species seem to have adopted a conservative strategy.Specifically,these species mainly release seedlings in the rainy season and maintain relatively stable populations with a lower mortality rate and recruitment rate in both dry and rainy seasons.Our study suggests that canopy and understory seedling populations growing in forest understory may respond to future climate change scenarios with distinct regeneration strategies. 展开更多
关键词 Tropical forest Tree seedling SEASONALITY RECRUITMENT Mortality relative growth rate
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Relative position of seeds driven the seedling growth are mediated by root-leaf traits
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作者 Jing Zhu Xue-Lin Wang +5 位作者 Xing Jin Lan Jiang Hong-Yu Lin Yang Hu Jin-Fu Liu Zhong-Sheng He 《Journal of Plant Ecology》 SCIE CSCD 2024年第2期24-35,共12页
Variations in plant traits are indicative of plant adaptations to forest environments,and studying their relationships with tree growth provides valuable insights into forest regeneration.The spatial arrangement of pl... Variations in plant traits are indicative of plant adaptations to forest environments,and studying their relationships with tree growth provides valuable insights into forest regeneration.The spatial arrangement of plant seeds within the forest litter or soil critically infuences the variations of root-leaf traits,thereby affecting the adaptive strategies of emerging seedlings.However,our current understanding of the impacts of individual root-leaf traits on seedling growth in different relative position,and whether these traits together affect growth,remains limited.This study focuses on the dominant tree species,Castanopsis kawakamii,within the Sanming C.kawakamii Nature Reserve of China.The present experiment aimed to examine the variations in root-leaf traits of seedling,focus on the relative positions of seeds within different layers:beneath or above the litter layer,or within the bare soil layer(without litter).Our fndings provided evidence supporting a coordinated relationship between root and leaf traits,wherein leaf traits varied in conjunction with root traits in the relative positions of seeds.Specifcally,we observed that seedlings exhibited higher values for specifc leaf area and average root diameter,while displaying lower root tissue density.The mixed model explained 86.1%of the variation in root-leaf traits,surpassing the variation explained by the relative positions.Furthermore,soil nitrogen acted as a mediator,regulating the relationship between seedling growth and root-leaf traits,specifcally leaf dry matter content and root tissue density.Therefore,future studies should consider artifcially manipulating tree species diversity based on root-leaf traits characteristics to promote forest recovery. 展开更多
关键词 relative growth rate COORDINATION leaf traits root traits soil nitrogen content seed relative positions
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Phosphatase and tensin homology deleted in chromosome 10,hypoxia-inducible factor-1 alpha gene expression in colorectal adenoma and adenocarcinoma and their relation to vascular endothelial growth factor protein expression
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作者 钱群 《外科研究与新技术》 2005年第3期165-166,共2页
To examine phosphatase and tensin homology deleted in chromosome 10 (PTEN),hypoxia-inducible factor-1 alpha (HIF-1 alpha) gene expressions and their relation to vascular endothelial growth factor(VEGF) protein express... To examine phosphatase and tensin homology deleted in chromosome 10 (PTEN),hypoxia-inducible factor-1 alpha (HIF-1 alpha) gene expressions and their relation to vascular endothelial growth factor(VEGF) protein expression in the patients with human colorectal adenomas and adenocarcinomas.Methods The expression of PTEN,HIF-1 alpha gene was detected by using in situ hybridization,and the VEGF expression levels by immunohistochemistry in colorectal adenomas and primary colorectal adenocarcinoma.Results Strong expression of HIF-1 alpha was detectable in the majority of colorectal dadenocarcinoma,particularly surrounding areas of necrosis in adenocarcinoma.PTEN,HIF-1 alpha mRNA and VEGF protein were positive in 51.6%,67.7% and 59.7% respectively in 62 cases of adenocarcinomas,and 77.8%,44.4% and 33.3% respectively in 18 cases of adenomas.The positive rate of VEGF was higher in the patients with colorectal adenocarcinomas than that in those with adenomas,whereas that of PTEN mRNA was contrary.HIF-1 mRNA expression was correlated significantly with lymph node metastasis,liver metastasis,Duke’s stage and recurrence.During colorectal tumor progression,the expression of HIF-1 alpha mRNA was positively correlated with the VEGF protein expression (χ2= 4.751 ,P<0.05),but negatively with the PTEN mRNA expression(χ2=21.84,P<0.01).Conclusion The absence or low expression of PTEN and the increased levels of HIF-1α and VEGF may paly an important role in carcinogenesis and progression of colorectal carcinoma.These results suggest that VEGF upregulated by HIF-1 alpha gene may be involved in angiogenesis of colorectal adenocarcinoma.4 refs,1 tab. 展开更多
关键词 Phosphatase and tensin homology deleted in chromosome 10 hypoxia-inducible factor-1 alpha gene expression in colorectal adenoma and adenocarcinoma and their relation to vascular endothelial growth factor protein expression
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Regeneration characteristics of gaps and their effect on Abies fargesii forests in the Shennongjia National Nature Reserve,China 被引量:2
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作者 FU Chan-juan LIU Yan-hong XIONG Wen-juan 《Forestry Studies in China》 CAS 2010年第4期206-212,共7页
Abiesfargesii is an evergreen tree species of the Pinaceae family, one of the most important cultivated timber species, endemic to China. It is of great importance for the maintenance of vegetation landscape and the p... Abiesfargesii is an evergreen tree species of the Pinaceae family, one of the most important cultivated timber species, endemic to China. It is of great importance for the maintenance of vegetation landscape and the preservation of endangered animal species. Community regeneration of forest gaps and their effect on A. fargesii forests in the Shennongjia National Nature Reserve were studied based on two-year field survey data. The results show that 1) forest gap regeneration is an important approach for the regeneration of A. fargesii communities; regeneration characteristics in the gaps of the broad-leaved species Betula albo-sinensis Burk. and the shade-tolerant species A. fargesii differed from those of understory species. 2) A. fargesii is most predominant in early gap regeneration but, over time, is gradually replaced by other species. Seedlings less than three years old accounted for 45.7% of all seedlings and only 6.3% of saplings older than seven years. 3) In terms of height and basal diameter in different sized gaps, size of seedlings showed the following trend: medium 〉 small 〉 large 〉 understory; the relative growth rate appeared in the same order. 4) The size of seedlings did not appear different between within-gap positions in medium and small gaps, but the tallest seedlings grew in the south of the large gaps and declined towards the center and north edges. 5) Principal component analysis suggests that the most important factors for the growth and distribution ofA. fargesii seedlings decreased in order of gap size, slope direction, gap microenvironment and tree-shrub-grass cover. 展开更多
关键词 Abiesfargesii REGENERATION GAP relative growth rate
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Influence of form and quantity of chromium on the development and survival of two silkworm(Bombyx mori L.)races 被引量:1
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作者 FrederickB.Tucker WANGKai-xiong +1 位作者 LUShun-lin XULi-jun 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2003年第6期744-748,共5页
Growth inhibitory activity has proven important in Qiufeng×Baiyu and Qingsong×Haoyue silkworm larvae. The consumption of mulberry leaves was reduced in both silkworm races while Qiufeng×Baiyu larvae s... Growth inhibitory activity has proven important in Qiufeng×Baiyu and Qingsong×Haoyue silkworm larvae. The consumption of mulberry leaves was reduced in both silkworm races while Qiufeng×Baiyu larvae showed the higher reduction in leaf consumption. From the results obtained, it was revealed that even at low concentrations of 400 mg/L of either Cr(Ⅲ) or Cr(Ⅵ) ions, growth of Qiufeng × Baiyu and Qingsong × Haoyue was significantly depressed. Depression in relative growth index(RGI) and high death rate in both silkworm races indicated that the different concentrations of the two ions used caused their growth inhibitions. Through linear regression analysis, the EC 50 (concentration of the compound that caused 50% reduction) was interpolated for both tested compounds. EC 50 (mg/L) of Cr (Ⅲ) ions in Qiufeng × Baiyu and Qingsong × Haoyue were 800 and 600 respectively. EC 50 (mg/L) of Cr(Ⅵ) ions in Qiufeng × Baiyu and Qingsong × Haoyue was 600 and 316 respectively. According to the analysis of relative growth index, and an analysis of linear regression technique for measuring the growth of the silkworm races, it was indicated that the form of Cr affected growth rates, growth inhibition responses of the larvae, and toxicological effects. Thus, form and quantity of Cr accumulating in silkworms reared with contaminated leaves are likely to influence their population dynamics. 展开更多
关键词 CHROMIUM relative growth index antifeedant activity BIOASSAY
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Relative effects of different leaf attributes on sapling growth in tropical dry forest 被引量:1
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作者 Ravi K.Chaturvedi A.S.Raghubanshi J.S.Singh 《Journal of Plant Ecology》 SCIE 2014年第6期544-558,共15页
Aims Soil moisture content(SMC)influences establishment,survival and development of plant species and is considered as the most important limiting factor in tropical dry forest(TDF).In this study we attempt to establi... Aims Soil moisture content(SMC)influences establishment,survival and development of plant species and is considered as the most important limiting factor in tropical dry forest(TDF).In this study we attempt to establish the relationship between leaf attributes and of tree saplings in TDF and address the following questions:(i)how are the functional attributes of dominant tree saplings of TDF affected by seasonal changes in SMC at different habitats?,(ii)what is the relationship of functional attributes with each other?,(iii)how are the functional attributes and their plasticity affected by habitat con-ditions?and(iv)can the functional attributes in single or in com-bination predict the growth rate of tree saplings of TDF?The study was conducted on four sites(Hathinala,Gaighat,Harnakachar and Ranitali,listed in order of decreasing SMC)within the tropical dry deciduous forest in northern India.Methods We analysed eight leaf attributes,specific leaf area(SLA);leaf dry matter content(LDMC);leaf nitrogen concentration(leaf N);leaf phosphorus concentration(leaf P);chlorophyll concentration(Chl);mass-based photosynthetic rate(Amass);mass-based stomatal con-ductance(Gsmass);intrinsic water use efficiency(WUEi)and three growth attributes,relative diameter increment(RDI);relative height increment(RHI);relative growth rate(RGR)of the 10 dominant tree saplings(viz.,Acacia catechu,Anogeissus latifolia,Boswellia serrata,Buchanania lanzan,Diospyros melanoxylon,Hardwickia binata,Lagerstroemia parviflora,Lannea coromandelica,Shorea robusta and Terminalia tomentosa)of a TDF and observed the effects of site,season and species for a period of 2 years.Saplings were selected in gradients of deciduousness.Step-wise multiple regression was performed to predict RDI,RHI and RGR from mean values of SMC and leaf attributes.Important Findings All the 11 attributes were interrelated and differed significantly among the 10 saplings.Species response varied across sites and seasons.Across the SMC gradient,the attributes showed variable plasticity that differed across species.Among the 10 saplings,the highly deciduous Boswellia serrata showed the maximum plasticity in seven functional attributes.According to the step-wise multiple regressions,65%variability in RDI and 67%variability in RGR were due to Gsmass,and for RHI,61%variability was due to Amass.SMC and the other attributes,viz.,SLA,Chl,WUEi and LDMC in combination could contribute only for~2-6%of the variability in RDI,RHI and RGR,which indicates that other traits/factors,not accounted in this study are also important in modulating the growth of tree saplings in TDFs.In conclusion,growth of the tree saplings in the tropical dry environment is determined by soil moisture,whereas the response of saplings of different tree species is modulated by alterations in key functional attributes such as SLA,Chl,WUEi and LDMC. 展开更多
关键词 tropical dry forest soil moisture content deciduousness tree saplings leaf attributes relative growth rate
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