Effects of nitrogen nutritional stress on the morphological and yield parameters of tomato (Solanum lycopersicum L.)     

Gideon O. Okunlol  Olusanya A. Olatunji  Akinjide M. Afolabi  Kolade K. Gbadegesin 《寒旱区科学》2015,7(2):137-145

This investigation was carried out to better understand the effects of nitrogen stress on the growth and yield of tomato(Solanum lycopersicon L.). Seeds of S. lycopersicon(Ife No. 1 variety) were collected from the Osun–State Ministry of Agriculture, Oshogbo, Nigeria and planted in analyzed top soil. The plants were grown for a period of five weeks within which they were supplied with water and kept under optimum environmental conditions that enhanced normal growth. After this period, the plants were subjected to different levels of nitrogen stress which include: plants supplied with distilled water only(n), plants supplied with complete nutrient solution(N), plants supplied with nutrient solution in which nitrogen concentration sources was increased by a factor of 5(N5), and plants supplied with nutrient solution in which nitrogen concentration sources was increased by a factor of 10(N10). Analysis of Variance(ANOVA) results shows that there is no significant effect of stress on the growth and morphological parameters of tomato plants. However, there was a significant effect of nitrogen stress on the yield parameters. Nitrogen stress also caused an increase in the number and size of fruits produced in plants subjected with high nitrogen concentration.  相似文献   

Estimating variation in stomatal frequency at intra-individual,intra-site,and inter-taxonomic levels in populations of the Leonardoxa africana (Fabaceae) complex over environmental gradients in Cameroon     

Walter Finsinger  Thibaut Dos Santos  Doyle McKey 《Comptes Rendus Geoscience》2013,345(7-8):350-359

Variation of stomatal frequency (stomatal density and stomatal index) includes genetically-based, potentially-adaptive variation, and variation due to phenotypic plasticity, the degree of which may be fundamental to the ability to maintain high water-use efficiency and thus to deal with environmental change. We analysed stomatal frequency and morphology (pore length, pore width) in leaves from several individuals from nine populations of four sub-species of the Leonardoxa africana complex. The dataset represents a hierarchical sampling wherein factors are nested within each level (leaves in individuals, individuals in sites, etc.), allowing estimation of the contribution of different levels to overall variation, using variance-component analysis. SI showed significant variation among sites (“site” is largely confounded with “sub-species”), being highest in the sub-species localized in the highest-elevation site. However, most of the observed variance was accounted for at intra-site and intra-individual levels. This variance could reflect great phenotypic plasticity, presumably in response to highly local variation in micro-environmental conditions.  相似文献   

Field survey and modelling of irrigation water quality indices in a Mediterranean island catchment: a comparison between spatial interpolation methods     

Nikolaos Malamos  Demetris Koutsoyiannis 《水文科学杂志》2013,58(10):1447-1467

ABSTRACT

A biannual survey of physico-chemical quality indices of 104 irrigation-water wells located in a cultivated plain of a Mediterranean island catchment was conducted using a multi-parameter probe. The campaign was planned so as to differentiate between the dry and wet seasons. The acquired data constituted the test bed for evaluating the results and the features of four spatial interpolation methods, i.e. ordinary kriging, universal kriging, inverse distance weighted and nearest neighbours, against those of the recently introduced bilinear surface smoothing (BSS). In several cases, BSS outperformed the other interpolation methods, especially during the two-fold cross-validation procedure. The study emphasizes the fact that both in situ measurements and good mathematical techniques for studying the spatial distribution of water quality indices are pivotal to agricultural practice management. In the specific case studied, the spatio-temporal variability of water quality parameters and the need for monitoring were evident, as low irrigation water quality was encountered throughout the study area.  相似文献   

Root distribution of three co-occurring desert shrubs and their physiological response to precipitation   总被引：1，自引：0，他引：1  

GuiQing Xu  Yan Li 《寒旱区科学》2009,1(2):0120-0127

Root distribution of three desert shrubs,Tamarix ramosissima Ledeb.,Haloxylon ammodendron(C.A.Mey.) Bunge and Reaumuria soongorica(Pall.) Maxim.was investigated under co-occurring conditions using a method for excavating the whole root system.Assimilation shoot water potential and transpiration rates were monitored during the wet-dry cycle.Leaf-specific apparent hydraulic conductance and the index of water stress impact for the three species were calculated from shoot water potential and transpiration rate.The results showed that,along the soil profile,the root system of T.ramosissima mainly distributed at 50 to 310 cm interval,with an average total absorbing root-surface area of 30,249.2 cm2 per plant;the root system of H.ammodendraom distributed at 0 to 250 cm interval with an average total absorbing root-surface area of 12,847.3 cm2 per plant;the root system of R.soongorica distributed at 0-80 cm interval,with an average total absorbing root-surface area of 361.8 cm2.The root distribution shows the following:T.ramosissima uses groundwater as its main water source;H.ammodendraom uses both groundwater and rainwater;and R.soongorica uses rainwater only.During the wet-dry cycle,the hydraulic parameters of T.ramosissima showed no responses to precipitation.R.soongorica responded most significantly,and the responses of H.ammodendraom were intermediate.In conclusion,the plant response to rain events is closely related to their root distribution and plant water-use strategy.  相似文献   

Evapotranspiration and canopy characteristics of two lodgepole pine stands following mountain pine beetle attack   总被引：1，自引：0，他引：1       下载免费PDF全文

Mathew G. Brown  T. Andrew Black  Zoran Nesic  Vanessa N. Foord  David L. Spittlehouse  Arthur L. Fredeen  Rebecca Bowler  Nicholas J. Grant  Philip J. Burton  J. A. Trofymow  Dominic Lessard  Gesa Meyer 《水文研究》2014,28(8):3326-3340

Over the past decade, British Columbia (BC), has experienced the largest mountain pine beetle (MPB) outbreak on record. This study used the eddy‐covariance (EC) technique to examine the impact of the MPB attack on evapotranspiration (E) and associated canopy characteristics of two lodgepole pine stands with secondary structure (trees, saplings and seedlings surviving the attack) located in central BC. MPB‐06, an 85‐year‐old almost pure stand of pine trees, was first attacked in 2006, and by 2010, ~80% of the trees had been killed. MPB‐03, a 110‐year‐old stand with an overstory consisting of over 90% pine and a developed sub‐canopy, was first attacked in 2003 and by 2007 had > 95% pine canopy mortality. EC measurements began in August 2006 at MPB‐06 and in March 2007 at MPB‐03, and continued for four years. Annual total E ranged from 226 mm to 237 mm at MPB‐06, and from 280 to 297 mm at MPB‐03, showing relatively little year‐to‐year change at both sites over the four years. Increased E from the accelerated growth of the surviving vegetation (secondary structure, shrubs and herbs) compensated for reduction in E due to the death of the overstory. Monthly average daytime canopy conductance, the Priestley–Taylor (α), and the canopy–atmosphere decoupling coefficient (Ω) steadily increased during the growing season reaching approximate maximum values of 5 mm s^?1, 0.75 and 0.12, respectively. Potential evapotranspiration was approximated using a vapour pressure deficit‐dependent α obtained at high soil water content. Calculated water deficits indicated some water‐supply limitation to the surviving trees and understory at both sites. Rates of root zone drainage during the growing season were low relative to precipitation. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   

高山植物稳定碳同位素沿海拔梯度响应机制的研究进展   总被引：1，自引：0，他引：1  

刘小宁  马剑英  孙伟  崔永琴  段争虎 《山地学报》2010,28(1)

简要介绍了国内外关于植物δ~(13)C对海拔梯度响应规律的研究情况,叙述了植物叶片δ~(13)C对海拔梯度响应的内在机理.重点介绍了随海拔变化的气压、温度、降水(湿度)、光照等环境因子和植物的叶片厚度、比叶重(LMA)、氮含量、气孔密度、气孔导度等生物因子对高山植物δ~(13)C的影响作用.由于各因子的多变性以及之间的相互作用,任何单一因子都不足以决定植物δ~(13)C的最终变化,也不能解释植物δ~(13)C随海拔的变化趋势,这种趋势可能是众多因子综合作用的结果.最后对本领域取得的一些认识和结论进行了总结,并对存在的一些问题以及今后的研究方向提出了一些见解.  相似文献   

MAPGIS在内蒙古1: 50万数字地质图中的应用     

孙政平  张梅 《内蒙古地质》1999,(3)

ＭＡＰＧＩＳ是具有国际先进水平的完整地理信息系统。利用这套系统完成的内蒙古１∶５０ 万数字地质图是新一代的地质图件,具有传统地质图件无法比拟的先进功能。它可随时进行地质、地理内容的更新与修改;可按用户要求做图面分幅与投影转换;可进行各种地质、地理信息的分层检索与输出;对图中重要的地质内容,如地层、岩体、区域性大断裂、同位素年龄等建立了数据库,使其具有可视化功能;可与其他计算机图件进行迭置分析  相似文献   

Variation in canopy conductance of Cunninghamia lanceolata forest and its response to environmental factors after an extreme rainfall event     

Wanqiu Xing  You Cheng  Lilin Yang  Weiguang Wang 《水文研究》2024,38(3):e15121

Canopy conductance (g_c) is a crucial parameter in simulating evapotranspiration and modulating water exchange, but its variation mechanism has regional uncertainties and complex environmental co-controls. In addition, the effect of extreme rainfall on g_c cannot be ignored under the changing climate. Here, we investigated the variation and environmental controls on g_c and the effect of extreme rainfall events in a Cunninghamia lanceolata forest across the subtropical area of Southern China. In July 2020, an extreme rainstorm hit the source area of the Xin'an River, with the cumulative rainfall on July 7 and 8 reaching 216.6 mm. The thermal diffusion probe method was used to measure the density of sap flow, and the environmental factors such as air temperature (T_a), net solar radiation (R_n) and soil water content (SWC) were monitored during the growing seasons of 2020 and 2021. Ultimately, g_c obtained by the Penman-Monteith equation was adopted since the result from the Köstner equation was overestimated. g_c showed a unimodal curve on the diurnal scale, and this characteristic was more obvious after the extreme rainfall. Daily g_c appeared a fluctuating pattern with a maximum in summer. g_c was simultaneously affected by T_a, R_n, water vapour pressure difference (VPD), SWC, among which T_a was the most significant driving factor at both the diurnal and daily timescales. The regulation of T_a, VPD and SWC on g_c had obvious thresholds, and the most definite response mode was VPD (2020: 1.25 kPa; 2021: 0.95 kPa). SWC and T_a were the dominant factors after the rainfall period, and the promotion effect of VPD on post-rainy days turned to inhibition effect on typical sunny days. These findings will further reveal the water exchange mechanism between atmosphere and vegetation and impacts of environmental factors in subtropical coniferous forests, especially after the extreme rainfall events.  相似文献   

Simulations of water movement and solute transport through different soil texture configurations under negative‐pressure irrigation          下载免费PDF全文

Jiajia Wang  Yuanfang Huang  Huaiyu Long  Sen Hou  An Xing  Zhongxiang Sun 《水文研究》2017,31(14):2599-2612

This study examined the effects of different soil texture configurations on water movement and solute transport to provide a reliable scientific basis for the application of negative‐pressure irrigation (NPI) technology. HYDRUS‐2D was used to analyse water movement and solute transport under NPI. The main results are as follows: (a) HYDRUS‐2D can be used to simulate water movement and solute transport under NPI, as there was good agreement between the simulated and measured values for water contents, NaCl concentrations, cumulative water infiltration, and wetting distances in the horizontal and vertical directions; the Nash–Sutcliffe efficiency coefficients were in the range of 0.94–0.97. (b) Layered soils have obvious effects on water movement under NPI. With the emitter position in the loam layer, when a coarse texture of loamy sand was present below the loam layer (namely, L‐LS), irrigation water accumulated in the topsoil, and this led to an increase in evaporation compared with the homogeneous loam profile. However, fine texture silty loam or silty clay loam layers beneath the loam layer (namely, L‐SiL or L‐SiCL, respectively) was more conducive to water infiltration into the lower layer, and this increased the amount of water infiltration and simultaneously reduced the surface evaporation effectively. (c) Layered soils have obvious effects on solute transport under NPI, and salt accumulation will readily occur in the clay‐rich soil layer at the interface. The maximum soil salt accumulation of L‐LS occurred above the soil interface between the two soil layers with a value of 21.80 g/kg; however, for L‐SiCL and L‐SiL, the maximum salt accumulation occurred below the soil interface between the two soil layers, with values of 23.80 g/kg and 20.08 g/kg, respectively. (d) Interlayered soils showed remarkable changes in the water infiltration characteristics and salt‐leaching intensities under NPI, and the properties for the soil profile with a silty loam interlayer were better than those for the soil profile with a silty clay loam interlayer. The soil profile with a loamy sand interlayer had the lowest amount of water infiltration, which resulted in reductions of the salt‐leaching intensities. Thus, NPI is clearly not suitable for loamy sand soil. Overall, the results demonstrated that soil texture configurations affected water movement and solute transport under NPI. Therefore, careful consideration should be given to the use of NPI to achieve target soil water and solution conditions and reduce water loss.  相似文献   

Development of pan coefficients for estimating evapotranspiration from riparian woody vegetation          下载免费PDF全文

Tanya M. Doody  Richard G. Benyon  S. Theiveyanathan  Vijay Koul  Leroy Stewart 《水文研究》2014,28(4):2129-2149

The long‐term ‘Millennium Drought’ has put significant pressure on water resources across Australia. In southeastern Australia and in particular the Murray‐Darling Basin, removal of exotic, high‐water‐use Salix trees may provide a means to return water to the environment. This paper describes a simple model to estimate evapotranspiration of two introduced Salix species under non‐water‐limited conditions across seven biogeoclimatic zones in Australia. In this study, Salix evapotranspiration was calculated using the Penman–Monteith model. Field measurements of leaf area index and stomatal conductance for Salix babylonica and Salix fragilis were used to parameterize the models. Each model was validated using extensive field estimates of evapotranspiration from a semi‐arid (S. babylonica, r² = 0.88) and cool temperate (S. fragilis, r² = 0.99) region. Modelled mean annual evapotranspiration showed strong agreement with field measurements, being within 32 and 2 mm year^?1 for S. babylonica and S. fragilis, respectively. Monthly pan coefficients (the ratio of mean evapotranspiration to mean pan evaporation) were developed from 30 years of meteorological data, for 30 key reference sites across Australia for both species using the validated Penman–Monteith models. Open‐water evaporation was estimated from field measurements and was used to develop a simple linear regression model for open‐water evaporation across the 30 reference sites. Differences between modelled evapotranspiration and open‐water evaporation at each site provide an indication of the amount of water that might be returned to the environment from removal of in‐stream Salix species. The monthly pan coefficient method reported has application across riparian environments worldwide where measured evapotranspiration is available for model validation. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献