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1. chinaXiv:201801.00128 [pdf]

Habitat, occurrence and conservation status of the Saharo-Macaronesian and Southern-Mediterranean element Fagonia cretica L. (Zygophyllaceae) in Italy

分类: 生物学 >> 植物学

Fagonia cretica L. is an important component of Mediterranean dry grasslands and a rare and isolated species of Italian flora. In this study, an assessment is presented on the distribution, habitat, and conservation status of F. cretica in Italy. The results of field investigation and herbarium analysis show that this species grows in a small area within the southern Calabria region characterized by a warmest and driest Mediterranean climate on the Italian peninsula. F. cretica is a semi-desert plant species growing in Italy in only one peripheral and isolated population at the northern limit of its distribution. Plant community analysis, using the phytosociological method, shows that F. cretica grows in wintergreen perennial dry grasslands dominated by Lygeum spartum and Hyparrhenia hirta. F. cretica plant communities are located in thermo-xeric habits such as south-, southeast- and east-facing slopes on clays and sandy clays in southern Calabria. The population of F. cretica is fragmented in six neighbouring localities, with two of which belonging to a Site of Community Importance (SCI). The conservation status of F. cretica population is not very good, and is defined as “Critically Endangered” in accordance with IUCN criteria. There are many threats affecting the F. cretica population in Italy, primarily the changes in land uses due to urban expansion and reforestation with exotic plants. The southern end of the Italian peninsula hosts other plants from thermo-xeric habits that do not adapt to the current local climate. This territory can be considered as a microrefugia for plants currently distributed in the arid territory of the southern Mediterranean. These results contribute to the discussion of some conservation measures, and the possibility of establishing a micro-reserve. For all these reasons, we propose to include F. cretica in the lists of protected plant species at regional (Calabria) and country (Italy) scales in Italy.

提交时间: 2018-01-10 来自合作期刊:《Journal of Arid Land》 点击量190下载量75 评论 0

2. chinaXiv:201801.00129 [pdf]

Utilizing a new soil effective temperature scheme and archived satellite microwave brightness temperature data to estimate surface soil moisture in the Nagqu region, Tibetan Plateau of China

TIAN Hui; Mudassar IQBAL
分类: 农、林、牧、渔 >> 土壤学

Since the early 2000s, many satellite passive microwave brightness temperature (BT) archives, such as the Advanced Microwave Scanning Radiometer for the Earth Observing System (AMSR-E) BTs, have become the useful resources for assessing the changes in the surface and deep soil moistures over both arid and semi-arid regions. In this study, we used a new soil effective temperature (Teff) scheme and the archived AMSR-E BTs to estimate surface soil moisture (SM) over the Nagqu region in the central Tibetan Plateau, China. The surface and deep soil temperatures required for the calculation of regional-scale Teff were obtained from outputs of the Community Land Model version 4.5 (CLM4.5). In situ SM measurements at the CEOP-CAMP/Tibet (Coordinated Enhanced Observing Period Asia-Australia Monsoon Project on the Tibetan Plateau) experimental sites were used to validate the AMSR-E-based SM estimations at regional and single-site scales. Furthermore, the spatial distribution of monthly mean surface SM over the Nagqu region was obtained from 16 daytime AMSR-E BT observations in July 2004 over the Nagqu region. Results revealed that the AMSR-E-based surface SM estimations agreed well with the in situ-based surface SM measurements, with the root mean square error (RMSE) ranging from 0.042 to 0.066 m3/m3 and the coefficient of determination (R2) ranging from 0.71 to 0.92 during the nighttime and daytime. The regional surface soil water state map showed a clear spatial pattern related to the terrain. It indicated that the lower surface SM values occurred in the mountainous areas of the northern, mid-western and southeastern parts of Nagqu region, while the higher surface SM values appeared in the low elevation areas such as the Tongtian River Basin, Namco Lake and bog meadows in the central part of Nagqu region. Our analysis also showed that the new Teff scheme does not require special fitting parameters or additional assumptions, which simplifies the data requirements for regional-scale applications. This scheme combined with the archived satellite passive microwave BT observations can be used to estimate the historical surface SM for hydrological process studies over the Tibetan Plateau regions.

提交时间: 2018-01-10 来自合作期刊:《Journal of Arid Land》 点击量329下载量160 评论 0

3. chinaXiv:201801.00130 [pdf]

Influences of calcium silicate on chemical forms and subcellular distribution of cadmium in Amaranthus hypochondriacus L.

Lu, Huanping; Li, Zhian; Wu, Jingtao; Shen, Yongd; Li, Yingwen; Zou, Bi; Tang, Yetao; Zhuang, Ping
分类: 生物学 >> 植物学

A pot experiment was conducted to investigate the effects of calcium silicate (CS) on the subcellular distribution and chemical forms of cadmium (Cd) in grain amaranths (Amaranthus hypochondriacus L. Cv. 'K112') grown in a Cd contaminated soil. Results showed that the dry weight and the photosynthetic pigments contents in grain amaranths increased significantly with the increasing doses of CS treatments, with the highest value found for the treatment of CS3 (1.65 g/kg). Compared with the control, application of CS4 (3.31 g/kg) significantly reduced Cd concentrations in the roots, stems and leaves of grain amaranths by 68%, 87% and 89%, respectively. At subcellular level, CS treatment resulted in redistribution of Cd, higher percentages of Cd in the chloroplast and soluble fractions in leaves of grain amaranths were found, while lower proportions of Cd were located at the cell wall of the leaves. The application of CS enhanced the proportions of pectate and protein integrated forms of Cd and decreased the percentages of water soluble Cd potentially associated with toxicity in grain amaranths. Changes of free Cd ions into inactive forms sequestered in subcellular compartments may indicate an important mechanism of CS for alleviating Cd toxicity and accumulation in plants.

提交时间: 2018-01-10 点击量126下载量89 评论 0

4. chinaXiv:201801.00131 [pdf]

Assessment of influences of cooking on cadmium and arsenic bioaccessibility in rice using in vitro physiologically based extraction test

Zhuang, Ping; Zhang, Chaosheng; Li, Yingwen; Zou, Bi; Mo, Hui; Wu, Kejun; Wu, Jingtao; Li, Zhian
分类: 生物学 >> 生态学

The health risks associated with the consumption of rice may decrease if consumers use cooking practices which can reduce the concentrations of metal(loid)s and their bioaccessibility. The effects of cooking on the bioaccessibility of Cd and As in three contamination levels of rice were studied. The results indicated that cooking reduced bioaccessibility of Cd and As in rice. Cooking resulted in a significant increase in Cd and As concentrations in the residual fraction. Low volume cooking rice to dryness remove total Cd by about 10% for rice A and B, while middle or high volume water had no effect on Cd bioaccessibility in all rice types. In contrast, low volume cooking did not remove As, but a significant decrease was observed when cooking with middle or high volume water. This study provides information for a better understanding of more realistic estimation of metal(loid)s exposure from rice and the possible health risks.

提交时间: 2018-01-10 点击量63下载量44 评论 0

5. chinaXiv:201801.00145 [pdf]


分类: 生物学 >> 生态学

以开心形、Y字形、双层分层形和自然圆头形的龙安柚为试验材料,比较不同树形的冠层特性、叶片结构和生理特征,以期为龙安柚果园小环境的调控提供理论基础。结果表明:(1)开心形间隙分数阈值最高,是自然圆头形的4.33倍。开心形与Y字形的冠层光合辐射与透射系数均显著高于其他树形,但二者无显著差异,表明开心形和Y字形的冠层通风透光特性较好。(2)开心形与Y字形叶片厚度增加,叶面积和气孔密度较大,栅栏/海绵组织厚度和组织紧密度较高,叶片组织疏密度较低,且二者无显著差异,表明开心形与Y字形利于提高叶片的光合作用,降低蒸腾作用。(3)Y字形和开心形净光合速率、水分利用率、最大表观电子传递速率、初始斜率和半饱和光强较高,而蒸腾速率较低,二者对强光的耐受能力较强;其中开心形蒸腾速率最低为2.43 mmol m-2 s-1,且其结果枝光抑制参数最小,为0.629。说明开心形为最佳的高光效树形。(4)冠层微环境因子、叶片结构及光合生理指标之间多呈极显著相关关系,但开心形叶片结构和生理的大部分指标与冠层环境因子之间相关性较低,说明开心形树形不同部位的营养枝和结果枝的叶片性状差异较小,其光渗透性好,整个冠层的光截获能力和有效光辐射的分布差异较小,笔者认为开心形是龙安柚栽培中的适宜高光效树形。

提交时间: 2018-01-10 来自合作期刊:《生态学报》 点击量9下载量4 评论 0

6. chinaXiv:201801.00156 [pdf]


分类: 生物学 >> 生态学

分析了塔里木河上游荒漠区灌木植物叶片和土壤碳(C)、氮(N)、磷(P)含量及其化学计量特征以及二者之间的相关性,旨在阐明荒漠植被在极端环境下养分循环及限制状况,为塔里木河上游荒漠生态系统的恢复与保护提供理论依据。以塔里木河上游多枝柽柳(Tamarix ramosissma)、盐穗木(Halostachys caspica)、黑果枸杞(Lycium ruthenicum)、铃铛刺(Halimodendron halodendron)4种荒漠灌木植物叶片和土壤为研究对象,分析植物叶片和土壤C、N、P生态化学计量特征及其相关性。结果表明:在4种不同荒漠灌木植物叶片中柽柳叶片的C含量为(484.77±59.74)mg/g,显著高于其他灌木植物(P < 0.05);铃铛刺的N含量是(14.20±1.58)mg/g,显著高于其他灌木植物(P < 0.05);柽柳叶片的P含量为(0.54±0.16)mg/g,显著低于其他灌木植物(P < 0.05)。4种灌木植物叶片C/N比值大小为黑果枸杞 > 柽柳 > 铃铛刺 > 盐穗木,且黑果枸杞的C/N比值显著最高为(37.83±7.74)(P < 0.05);C/P为柽柳 > 铃铛刺 > 盐穗木 > 黑果枸杞,盐穗木和黑果枸杞的C/P显著低于其他灌木(P < 0.05),其比值分别为(379.76±158.63)和(383.47±128.95);N/P为柽柳 > 铃铛刺 > 盐穗木 > 黑果枸杞,柽柳的N/P比值显著最高为(22.34±4.60)(P < 0.05)。4种不同荒漠灌木土壤的有机碳(SOC)、全氮(TN)、全磷(TP)含量及其化学计量比特征均未表现出显著的差异。由相关性分析可知柽柳叶片仅P含量与土壤TP含量呈现出显著正相关(P < 0.05);铃铛刺叶片C含量与土壤TN、叶片P含量与土壤TN/TP均呈显著负相关(P < 0.05),而叶片C含量与土壤TN/TP呈极显著负相关(P < 0.01);盐穗木和黑果枸杞叶片化学计量特征与土壤的化学计量特征均未表现出显著相关性(P > 0.05)。说明植物叶片化学计量特征并非是由土壤养分含量特征直接决定的,更多受植物自身遗传特性的影响,体现了荒漠灌木植物对极端生境的适应性。

提交时间: 2018-01-10 来自合作期刊:《生态学报》 点击量42下载量23 评论 0

7. chinaXiv:201801.00160 [pdf]


分类: 生物学 >> 生态学

在木论国家级自然保护区内喀斯特常绿落叶阔叶混交林内建立500 m×500 m长期监测样地,采用经典统计学和地统计学方法研究喀斯特森林土壤磷钾养分含量及其空间变异特征。结果表明:研究区土壤全磷(TP)、全钾(TK)、速效磷(AP)、速效钾(AK)含量分别为(1.60±0.76)g/kg、(5.42±2.74)g/kg、(5.74±3.63)mg/kg、(5.20±2.96)mg/kg;磷钾养分含量均为中等变异,变异强度为AP > AK > TK > TP。研究区土壤TP、TK、AP、AK变异函数值的最佳拟合模型均为指数模型,决定系数均很高(0.671-0.995),TP、AP呈中等强度空间自相关,TK、AK呈弱空间自相关。TP、AP的变程较长,分别为336.00 m和373.50 m,空间连续性较好,TK、AK变程较短(33.30 m、64.50 m),空间依赖性较强。土壤TP表现为坡下(含洼地)含量高,坡上含量较低;AK表现为坡中含量高于洼地含量;AP、TK呈斑块破碎化分布。海拔、坡度和地面凹凸度是土壤磷钾养分空间异质性的主要影响因素。喀斯特常绿落叶阔叶混交林土壤磷钾养分存在不同空间异质性和空间关联性,这为小流域尺度上土壤养分管理、可持续利用策略、喀斯特退化生态系统生态恢复提供理论依据。

提交时间: 2018-01-10 来自合作期刊:《生态学报》 点击量25下载量13 评论 0

8. chinaXiv:201801.00105 [pdf]

Springer Nature SciGraph关联开放数据分析

白林林; 祝忠明
分类: 图书馆学、情报学 >> 图书馆学

[目的/意义]Springer Nature SciGraph平台提供的关联开放数据的分析,为国内出版商在学术交流和语义出版中使用关联数据促进科研的关联开放实践提供参考,可推动我国开放科研运动的进一步向前发展。[方法/过程] 对Springer Nature SciGraph平台发布的实体对象、采用的词表、数据模型进行详细分析。[结果/结论] Springer Nature SciGraph通过构建自己的本体,采用一种用于RDF的更简单的序列化N-Triples格式的三元组对数据进行表示,作为世界上最大的出版商之一,Springer Nature关联数据在今后必将为其他出版商要实现科研关联开放提供一定的借鉴。

提交时间: 2018-01-10 来自合作期刊:《知识管理论坛》 点击量406下载量255 评论 0

9. chinaXiv:201801.00106 [pdf]


武丽娜; 左阳; 窦天芳
分类: 图书馆学、情报学 >> 图书馆学

[目的/意义]调研了解大学出版社学术资源在发现系统中的开放现状和发展趋势。[方法/过程] 以两个主流发现系统PRIMO和SUMMON覆盖的15所大学出版社学术资源为对象,对这些学术资源在发现系统中的索引深度进行测试。统计发现系统中大学出版社学术资源的索引深度和索引规模,以及发现系统覆盖的大学出版社及其资源数量的变化趋势。以清华大学出版社为例,对国内大学出版社学术资源应加快开放共享进行探讨。[结果/结论] 发现系统中国外大学出版社的数量和学术资源数量呈现上升趋势,但订购刊和OA的索引深度未全部达到全文级别。中文资源的开放共享应受到关注。

提交时间: 2018-01-10 来自合作期刊:《知识管理论坛》 点击量306下载量190 评论 0

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