Northeast Institute of Geography and Agroecology, Chinese Academy Of Sciences
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基于地形因子的吉林西部地区土地利用变化研究
No full text选取吉林省西部地区为研究对象,基于DEM及三期遥感影像,通过目视解译获取研究区土地利用数据,并从高程、坡度、坡向、坡形4个地形因子的角度对土地利用结构的变化特征进行了全面分析.结果表明:(1)1975-2013年间,吉林西部地区土地利用结构的变化主要表现为耕地、盐碱地面积的显著增加和草地面积的显著减少.(2)高程和坡度因子对吉林西部地区土地利用变化有着重要的影响,而坡向和坡形因子对土地利用变化影响不明显.(3)各土地利用类型多分布在100~200 m海拔范围和0°~6°坡度范围内,但200~250 m范围内土地利用变化量最大,主要表现为耕地、林地的增加和草地的减少.(4)1975-2000年间坡度在0°~6°范围内的土地表现为耕地、盐碱地面积的大幅增加和草地面积的大幅减少;2000-2013年间表现为耕地面积的小幅增加和草地、盐碱地面积的小幅减少
能将甲烷转化为乙醇的甲烷氧化菌群的筛选及其菌群组成分析
No full text本研究中,我们从污水、土壤等不同来源的样品中筛选出4种能将甲烷转化为乙醇的甲烷氧化菌群。用液相色谱法和核磁质谱法对乙醇进行了测定和鉴定,结果发现L菌群发酵液中乙醇最高含量约为0.09 g/L。用高通量测序对L菌群在一个生长周期内的变化进行了测定,结果发现该菌群中甲烷氧化菌含量由37.4%增至42.9%。高通量测序的结果表明,尽管细菌种类数增多,但也有菌种在此过程中消失。研究结果还显示,甲基单胞菌属与鞘氨醇单胞菌属和棒状菌属有相关关系。因此,我们推测这与产乙醇的代谢路径十分相关,并且有待进一步验证
辽河水体光学吸收特性的季节变化
No full text吸收特性是水体重要的光学特性,也是建立生物光学模型的基本参数。利用2013年5月和9月辽河流域水体实测数据对总悬浮颗粒物、浮游植物、非藻类颗粒物以及有色溶解有机物(CDOM)的吸收特性、季节变化进行了研究。研究表明,总颗粒物的吸收光谱曲线与非藻类颗粒物的吸收光谱基本保持一致并且与非藻类颗粒物的吸收[a_d(λ)]以及浮游植物的吸收[a_(ph)(λ)]都呈现显著相关。两个季节,a_d(440)均是总吸收的主要组成部分,CDOM的吸收[a_(CDOM)(440)]则大于a_(ph)(440)的贡献率,但9月a_d(440)的吸收所占比例较5月高。辽河水体非藻类颗粒物中矿物颗粒物的含量较其他一般水体要高。通过分析5月及9月的a_(ph)(440)/a_(ph)(675)发现浮游植物中辅助色素与叶绿素a浓度(Chla)的组成季节性变化不大,但其空间特征表现较为明显。另外,CDOM的吸收特性与非藻类颗粒物的吸收相似,呈现出较大的空间差异性;辽河S_(CDOM)基本小于其它河流、湖泊、河口等水体,其CDOM主要由大分子物质组成
青藏高原苔原自然带谱及复式三维地带模式
No full text首次依空间结构将青藏高原划分为外围高山、 外缘高山、 高原面高山、 高原面及高原盆地等五种地貌体; 厘清了高原不存在纬度地带性的误判, 并结合作者前期高原苔原的论证,创建了高原苔原带谱体系及其三维仿真地带模型, 分别为顶锥型(外围离散高山及高原面高山)、 带型(外缘带状高山)和平面型(高原面). 既具有一般高山苔原(alpine tundra)垂直带谱, 又呈现高原山原苔原所特有的"复式三维地带性模式", 在全球具有唯一性. 首次编制了表征北极苔原与高原苔原关系的北半球苔原带模式图, 指出长白山为东北亚高山苔原南界的论点不能成立, 青藏高原苔原才是中国及东北亚苔原的南界. 目前高原是第三极称谓皆无顶极生物带苔原带景观为前提,仅是高度上的寓意, 从地理概念上明确了其与南北极并列的世界第三极定位
中国区域创新绩效时空演变特征及其影响因素研究
No full text通过构建创新投入、产出指标体系,运用创新产出和创新效率两个因素表征区域创新绩效,并对区域创新绩效的时空演变特征进行分析,结果显示:创新绩效高值区域分布在东部沿海和长江沿岸地区,这种分布格局和T字形国土开发结构存在着高度的吻合,区域创新绩效的极化现象越来越明显;创新产出的区域差异最大,创新效率的区域差异最小;创新投入和创新产出的区域差异呈增大趋势,创新绩效和创新效率的区域差异呈现出先减小后缓慢增大的趋势。通过回归建模分析,探讨了区域创新基础、产业集群环境、产学研联系质量、政府支持、技术溢出效应等因子对于区域创新绩效的影响,发现区域创新绩效受创新基础和政府支撑的影响最大,受产学研联系质量的影响次之,而产业集群环境和技术溢出效应对区域创新绩效的影响较小
基于ASTER GDEM和均值变点分析的中国东北地形起伏度研究
No full text地形起伏度是指某一确定区域内最高点和最低点之间的高差,是宏观尺度上比较适宜的地形分析指标,而确定最佳统计单元的大小是提取地形起伏度的关键。本文以中国东北地区为研究区域,以ASTER GDEMv2为数据源,基于Python模块编程,利用窗口分析方法依次提取n × n(n = 2,3,4,……,198,199,200网格下的地形起伏度,然后采用均值变点分析方法计算平均地形起伏度的最佳统计单元大小,最后将东北地区的地形起伏度进行分级。研究结果表明: 1)通过Python模块编程可以实现提取地形起伏度的自动化运行; 2)均值变点分析方法能够有效得检测出平均地形起伏度与网格面积拟合曲线上由陡变缓的拐点,利用该方法得到基于ASTER GDEM提取中国东北地区地形起伏度的最佳统计单元面积为2. 62km~2; 3)东北地区整体起伏不大,以小起伏和微起伏为主,山地多为中小起伏
放牧对天山北坡山地草原生态系统土壤δ~(15) N的影响
No full text测定了天山北坡山地草原优势植物种针茅(Stipa capillata)、羊茅(Festuca ovina)、短柱苔草(Carex turkestanica)、博乐绢蒿(Seriphidium borotalense)根际0 - 10 cm土壤和非根际10 - 20、20 - 30 cm土层土壤稳定性N同位素和全氮含量,通过对比放牧和围封草地优势植物根际土壤δ~(15)N的变化,分析不同利用方式对不同植物根际土壤和不同土层深度土壤δ~(15)N的影响。结果表明,天山北坡山地草原生态系统土壤δ~(15)N值在2. 25‰ ~ 16. 03‰变化,放牧显著降低了表层0 - 10 cm土壤δ~(15)N值; 放牧草地0 - 30 cm土壤δ~(15)N值(7. 14‰ ± 0. 67‰)整体上比围封(6. 95‰ ± 0. 34‰)增加了2. 8%,但差异不显著(P > 0. 05)。放牧和围封条件下天山北坡山地草原土壤δ~(15)N值均随着土层深度的加深而显著增加(P < 0. 05),且土壤δ~(15)N值与土壤全氮含量呈显著的负相关(P < 0. 05)。放牧对天山北坡山地草原不同植物种根际土壤δ~(15)N的影响程度不同,放牧草地的针茅和羊茅0 - 30 cm土壤δ~(15)N分别比围封草地的高17%和53%,但放牧降低了短柱苔草和博乐绢蒿0 - 30 cm土壤δ~(15)N,且对短柱苔草的降低作用显著
Analyzing the Effects of Climate Factors on Soybean Protein, Oil Contents, and Composition by Extensive and High-Density Sampling in China
No full textFrom 2010 to 2013, 763 soybean samples were collected from an extensive area of China. The correlations between seed compositions and climate data were analyzed. The contents of crude protein and water-soluble protein, total amount of protein plus oil, and most of the amino acids were positively correlated with an accumulated temperature >= 15 degrees C (AT(15)) and the mean daily temperature (MDT) but were negatively correlated with hours of sunshine (HS) and diurnal temperature range (DTR). The correlations of crude oil and most fatty acids with climate factors were opposite to those of crude protein. Crude oil content had a quadratic regression relationship with MDT, and a positive correlation between oil content and MDT was found when the daily temperature was <19.7 degrees C. A path analysis indicated that DTR was the main factor that directly affected soybean protein and oil contents. The study illustrated the effects of climate factors on soybean protein and oil contents and proposed agronomic practices for improving soybean quality in different regions of China. The results provide a foundation for the regionalization of high-quality soybean production in China and similar regions in the world
Carbon dioxide and methane supersaturation in lakes of semi-humid/semi-arid region, Northeastern China
No full textUnderstanding concentrations of carbon dioxide (CO2) and methane (CH4) in lakes is an important part of a comprehensive global carbon budget. We estimated data on the partial pressure of CO2 (pCO(2)) and CH4 (pCH(4)) from sampling with 95 lakes in semi-humid/semi-arid region of Northeastern China during ice free period. Both pCO(2) and pCH(4) varied greatly among the study sites. p(CO2) values in these lakes ranged from 21.9 to 30,152.3 mu atm (n = 403), and 91% of lakes in this survey were supersaturated with CO2. p(CH4) values ranged from 12.6 to 139,630.7 atm with all sites in this study of CH4 sources to the atmosphere during the ice-free period. The collected urban lakes samples exhibited higher pCO(2) and pCH(4) than wild lakes samples. Either the mean value of p(CO2) or p(CH4) in saline waters is higher than in fresh waters. Correlation analysis implied that the partial pressure of the GHGs (CO2 and CH4) showed statistically correlations with water environment indicators like pH, dissolved organic carbon (DOC), total nitrogen (TN), total phosphorus (TP), and chlorophyll a (Chla). However, the most of the relationships showed a high degree of scatter, only pH might be used as the predictor of the gas partial pressure based on the result of this study (r(pCO2) = -0.437, p < 0.01, n = 382; r(pCH4) = -0265, p < 0.01, n = 400). Furthermore, salinity could be a good predictor for p(CO2) and p(CH4) in 83 freshwater lakes in our study (r(pCO2) = 0.365, r(pCH4) = 0.323, p < 0.01, n = 348). The mean CO2 flux increased with the decreasing lake area size. The calculated annual areal carbon emission rate is 560.2 g C m(-2) from 95 lakes in Northeastern China. We could not extrapolate carbon emission from these lakes to the boreal region or a wider scale because of the change of environmental conditions. (C) 2016 Elsevier Ltd. All rights reserved
The dehydration- induced ERECTA gene, MsSIK1, from alfalfa improved water use efficiency in transgenic Arabidopsis
No full textUnder global climate change, alfalfa (Medicago sativa L.) development is facing a large challenge of drought, which made it crucial and necessary to improve its drought tolerance through biotechnological approaches. In alfalfa, the MsSIK1 gene was identified to be one of the water use efficiency (WUE)-related genes due to its strong expression in response to dehydration. In this study, after the 26-day-long drought treatment, transgenic Arabidopsis seedlings over-expressing the MsSIK1 gene were measured to be taller than the wild-type (WT) and mutants of er-105/MsSIK1 and loss-of-function er-105 which has reduced drought tolerance capacity and serves as a WUE negative control. The length of inflorescence for the Ox MsSIK1 plants was measured to range from 192 to 213 mm, which was different among different transgenic lines; meanwhile that for the WT plants and those in er-105/MsSIK1 lines were measured to be 100 mm and the mutant line averaged 60 mm. Compared to WT and er-105/MsSIK1 and er-105 mutant lines, transgenic Arabidopsis had higher rate of long-term CO2 assimilation but lower rate of transpiration, therefore had higher instantaneous WUE, long-term WUE, and endogenous GA content. In conclusion, the MsSIK1 gene isolated from alfalfa confers an improved WUE in transgenic Arabidopsis. These results fully illustrated that the alfalfa MsSIK1 gene could improve WUE in transgenic Arabidopsis. Also they would supply genetic evidence for improving biotechnological approach for alfalfa to adapt drought stress driven by probably future climate change