CID-340Portable photosynthetic system was employed to measure the net photosynthetic rate,intercellular carbon dioxide concentration,photosynthetically active radiation,stomatal conductance,atmospheric temperature around the leaves,leaf temperature,and transpiration rate of Hydrocotylev ulgaris to study the photosynthetic characteristics in ecological ditch.The objective was to provide theoretic bases for ditch wetland restoration.The results were as follows:(1) The net photosynthetic rate of Hydrocotylev ulgaris changed in a double-peak curve with its peaks occurring separately at 11:00(16.21 μ mol.m-2.s-1) and 15:00(19.32 μ mol.m-2.s-1),which indicated a photosynthetic midday depressions at noon.(2) The regression equation of the diurnal variation of Pnand its major physi-ecological factors attained by the method of stepwise multiple-regression was as follows:Pn=-5.45613+0.006797PAR+0.050099Gs(multiple correlated coefficient 0.868).The results indicated that stomatal conductance(Gs) and transpiration rate(Tr) were the important factors that affected Pn.The analysis of partial correlation and path on Pnand factors showed that the diurnal variation of Pnhad significan impact with photosynthetically active radiation(PAR) and stomatal conductance(Gs),were the important factors which affected Pnand he order of effecting ability was GsPAR.
Based on gray relational analysis,the phytoplankton abundance and environmental factors were investigated from April 2006 to January 2007 in Mudanjiang River.The results showed that temporal of phytoplankton abundance distribution was superior in spring,in autumn was inferior to the spring,in winter was the lowest.The spatial distribution of phytoplankton abundance was that the area of Jingpo lake was superior to the others,including 2# and 3# site,then was the 9# site,and the 1# was lower,and middle-low stream was the lowest,including 4#、5#、6#、7#.The phytoplankton quantity varied with the changes of environmental factors,and the factors which seriously influenced phytoplankton were different in seasonal variation,in spring,CODMn、BOD5 and pH were the main factors;in summer,BOD5、temperature and DO were the main factors;in autumn and winter,NH4-N,temperature and BOD5 were the main factors;BOD5 was the most influenced factor.Therefore,it is important to control the polluted water from the city and manufactory inputting to maintain ecosystem healthiness of Mudan River.
Pinus yunnanensis Franch . , P. kesiya var. Langbianensis and P. densata Masters have take n on an obvious geographical overlapped region and were difficult to be dis tinguished . In this study, w e discriminated these three species by Fourier transform near infrared (FT - NIR) spectroscop y . The discriminant analysis model incorrectly assessed the P. kesiya to P. yunnanensis species in cross areas , and optimized one was able to estimate the unknown samples exactly while the overlapped P. kesiya in dividuals have been abandoned , which highly matched the geographical distribution of P. yunnanensis , P. densata and P. kesiya . T he close relationship between P. yunnanensis and P. kesiya probably resulted from the gene flow among species in cross areas .
This paper describes the Around View Monitoring (AVM) system for hydraulic excavators that prevents the safety accidents caused by blind spots and increases the operational efficiency. To verify the developed system, experiments were conducted with its prototype. The experimental results demonstrate its applicability in the field with the following values: 7m of a visual range, 15fps of image refresh rate, 300ms of working information data reception rate, and 300ms of surface condition data reception rate.
본 연구는 평생교육을 위해 사이버대학에 진학한 학생들을 대상으로 지각된 수단성, 숙달접근목표지향성 및 자기조절학습능력과 학업성취도 간의 인과관계를 규명하는 것을 목적으로 W사이버대학의 2010년 2학기 재학생 317명을 대상으로 설문조사를 하여 그 결과를 구조방정식모형을 통해 검증하였다. 연구 결과 첫째, 내재적 수단성이 숙달접근목표지향성에 유의한 영향을 미쳤다. 둘째, 숙달접근목표지향성이 자기조절학습능력에 유의한 영향을 미쳤다. 셋째, 자기조절학습능력이 유일하게 학업성취도에 정적인 영향을 미쳤으며 외재적 수단성은 학업성취도에 부정적인 영향을 미쳤다. 또한, 내재적 수단성은 학업성취도에 직접적인 영향을 미치지는 못 했지만 간접효과를 보였으며 자기조절학습능력이 숙달접근목표지향성과 학업성취도 간을 매개하고 있음이 추가적으로 검증되었다.
Aims Grassland desertification is being accelerated because of adverse climate change effects and unsustainable land uses, resulting in several major environmental problems. However, there are few studies on the economics spectrum of different plant functional types in desert steppe. The objectives of the current study are to examine the relationships among leaf functional traits of native plant species, to compare the functional traits among different plant functional types, and to determine whether an economic spectrum exists for the majority of species in the desert steppe of Damao Banner, Nei Mongol, China. Methods Photosynthetic and chlorophyll fluorescence parameters, specific leaf area(SLA), and leaf nitrogen contents across 24 species of different functional types were measured in situ in the desert steppe ecosystem. Non-parametric tests were used to analyze leaf trait differences in plant species of different functional types. Linear regression analysis was used to determine the relationships among leaf traits in different plant species. Finally, a comprehensive analysis on these leaf traits in different plant species was conducted using the principal component analysis. All data analyses were performed using SPSS 16.0(SPSS, Chicago, USA). Important findings Significant differences among plant functional types were found in most of the leaf traits. SLA and mass-based nitrogen concentration(Nmass) in grasses were 2.39 and 1.20 folds, respectively, of that in shrubs; area-based photosynthetic capacity(Aarea), SLA, and photosynthetic nitrogen use efficiency(PNUE) in annual species were 1.93, 2.13, and 4.24 folds, respectively, of that in perennial species; and Aarea, SLA, and PNUE in C4 species were 2.25, 1.73, and 3.61 folds, respectively, of that in C3 species. Almost all relationships signifi-cantly differed(p 0.01) among the leaf traits, with exception of the relationships between Aarea and area-based nitrogen concentration(Narea) and between quantum yield of PSII electron transport(ΦPSII) and SLA, implying that an economic spectrum may exist in the desert steppe ecosystem. The relationships of Narea, mass-based photosynthetic capacity(Amass), and PNUE with SLA were most significantly strong(R2 = 0.54, 0.62, 0.60, respectively; p 0.01). Results in this study suggest that the annuals, grasses, and C4 species might be located at the end of the leaf economic spectrum with high area-based photosynthetic rate, high nitrogen concentration on mass basis, short leaf lifespan, and high SLA; whereas the perennials, shrubs, and C3 species could be located at the another end of the economic spectrum with contrasting traits.
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