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1. chinaXiv:202006.00139 [pdf]

干旱区盐湖沿岸土壤呼吸特征及其影响因素

李典鹏; 姚美思; 孙 涛
Subjects: Agriculture, Forestry,Livestock & Aquatic Products Science >> Soil Science

明确不同生态系统土壤碳排放规律及其影响因素对准确评估全球碳循环具有重要意义。为揭示干旱区典型盐湖沿岸土壤呼吸(Rs)、土壤呼吸温度敏感系数(Q10)变化特征及其影响因素,以新疆干旱区达坂城盐湖和巴里坤湖沿岸土壤为研究对象,在2015—2016年5~10月利用LI–8100土壤碳通量自动测量系统对盐湖沿岸土壤呼吸速率进行测定,分析了土壤呼吸季节性变化特征及其影响因子。结果表明,干旱区盐湖土壤呼吸变幅较大(0.07~11.59 μmol?m-2?s-1),平均值为2.45 μmol?m-2?s-1,7月土壤呼吸速率最高为4.69 μmol?m-2?s-1,10月最低(1.01 μmol?m-2?s-1);土壤CO2累积排放量为9.30 g?m-2?d-1,7月累积排放量最大为17.82 g?m-2?d-1。Q10呈“降低—增加—降低”趋势,6月最低(2.25)9月最高(3.52),平均值为2.79。干旱区盐湖沿岸土壤呼吸受土壤有机碳(SOC)、5 cm土壤温度(ST5)、土壤含水量(SM)和土壤盐分(Salt)的共同影响,单因素模型模拟可解释土壤呼吸速率变化的41.7%~75.7%(R2=0.417~0.757,P<0.05),多因子综合模型拟合结果最佳Rs=0.001×SOC+0.039 ×SM-0.534×Salt-0.116×ST5+5.06(R2=0.804,P=0.05),且均表明盐分是影响干旱区盐湖沿岸土壤呼吸速率的主要因子。因此,在考虑陆地生态系统碳收支和碳循环时不能忽略干旱区盐湖沿岸土壤碳过程,以及盐分对盐湖生态系统碳排放的影响。

submitted time 2020-06-12 From cooperative journals:《干旱区地理》 Hits141Downloads66 Comment 0

2. chinaXiv:202002.00074 [pdf]

Molecular karyotypes of loquat (Eriobotrya japonica) aneuploids can be detected by using SSR markers combined with quantitative PCR irrespective of heterozygosity

Wen, Guo; Dang, Jiangbo; Xie, Zhongyi; Wang, Jinying; Jiang, Pengfei; Guo, Qigao; Liang, Guolu
Comment:This article has been published online in Plant Methods (https://plantmethods.biomedcentral.com/articles/10.1186/s13007-020-00568-7)
Subjects: Biology >> Botany
Subjects: Agriculture, Forestry,Livestock & Aquatic Products Science >> Horticulture

Background: Aneuploidy, a condition caused by an imbalance between the relative dosages of chromosomes, generally produces a novel phenotype specific to the molecular karyotype. Few techniques are currently available for detecting the molecular karyotypes of aneuploids in plants. Methods: By PCR amplification of 209 pairs of SSR primers, 17 pairs of SSR primers with no polymorphism and stable amplification in 23 different ploidy loquat were screened out. Seventeen SSR markers combined with qPCR for detection of aneuploid loquat H39 (2n=2x+5=39) karyotype variation. To verify the method for detection of aneuploid karyotype variation, 9 hybrid offspring of Q24 × ‘Huabai No. 1’ and 16 open-pollination progeny of the triploid loquat A313 and A322 were obtained, and we detected their chromosome numbers using conventional cytological methods. The SSR-qPCR method was used to detect the molecular karyotypes of aneuploids in the 9 hybrid offspring of Q24 × ‘Huabai No. 1’ and 16 open-pollination progeny of the triploid loquat A313 and A322. Results: Based on this imbalance in chromosome dosage, a new approach (referred to as ‘SSR-qPCR’) combining simple sequence repeat (SSR) markers and quantitative real-time PCR (qPCR) has been developed and utilized to detect some common aneuploids irrespective of heterozygosity. We screened 17 specific SSR markers covering all loquat linkage groups and redesigned 6 pairs of primers for SSR markers that can detect loquat chromosome aneuploidies. The SSR-qPCR detection results obtained for hybrid progeny and open-pollination progeny of triploid loquat showed diagnostic accuracies of 88.9% and 62.5%, respectively, compared with the chromosome preparation results. Limitations: Loquat genome sequences have not been published, available SSR markers are currently limited. Conclusion: SSR-qPCR can detect loquat aneuploids and be used to construct the entire molecular karyotypes of aneuploid individuals. Therefore, this method offers a novel alternative for the detection of chromosome aneuploidies.

submitted time 2020-03-03 Hits11039Downloads621 Comment 0

3. chinaXiv:202001.00083 [pdf]

现代林产化学加工工程学科发展研究

左宋林; 宫新栋; 王飞; 魏玲玲
Subjects: Agriculture, Forestry,Livestock & Aquatic Products Science >> Forestry

本文从学科科学的基本观点,分析了过去100多年来化学、化工、生物化学等基础学科对森林植物资源化学利用理论和技术发展的影响,阐述了林产化学加工学科的起源、形成和发展历程。在此基础上,提出现代林产化学加工工程学科是以森林植物资源为研究对象,以化学和生物化学为学科基础,合成和制备生物质新能源、化学品和功能材料的理论知识、方法和技术体系。最后,论文讨论了现代林产化学加工工程学科在理论知识和技术上面临的主要挑战。

submitted time 2020-01-13 Hits6149Downloads582 Comment 0

4. chinaXiv:201906.00046 [pdf]

Multi-scale spatial relationships between soil total nitrogen and influencing factors in a basin landscape based on multivariate empirical mode decomposition

ZHU Hongfen
Subjects: Agriculture, Forestry,Livestock & Aquatic Products Science >> Soil Science

The relationships between soil total nitrogen (STN) and influencing factors are scale-dependent. The objective of this study was to identify the multi-scale spatial relationships of STN with selected environmental factors (elevation, slope and topographic wetness index), intrinsic soil factors (soil bulk density, sand content, silt content, and clay content) and combined environmental factors (including the first two principal components (PC1 and PC2) of the Vis-NIR soil spectra) along three sampling transects located at the upstream, midstream and downstream of Taiyuan Basin on the Chinese Loess Plateau. We separated the multivariate data series of STN and influencing factors at each transect into six intrinsic mode functions (IMFs) and one residue by multivariate empirical mode decomposition (MEMD). Meanwhile, we obtained the predicted equations of STN based on MEMD by stepwise multiple linear regression (SMLR). The results indicated that the dominant scales of explained variance in STN were at scale 995 m for transect 1, at scales 956 and 8852 m for transect 2, and at scales 972, 5716 and 12,317 m for transect 3. Multi-scale correlation coefficients between STN and influencing factors were less significant in transect 3 than in transects 1 and 2. The goodness of fit root mean square error (RMSE), normalized root mean square error (NRMSE), and coefficient of determination (R2) indicated that the prediction of STN at the sampling scale by summing all of the predicted IMFs and residue was more accurate than that by SMLR directly. Therefore, the multi-scale method of MEMD has a good potential in characterizing the multi-scale spatial relationships between STN and influencing factors at the basin landscape scale.

submitted time 2019-06-20 From cooperative journals:《Journal of Arid Land》 Hits8974Downloads634 Comment 0

5. chinaXiv:201903.00234 [pdf]

Effects of spring fire and slope on the aboveground biomass, and organic C and N dynamics in a semi-arid grassland of northern China

ZHAO Xiang; HU Shuya
Subjects: Agriculture, Forestry,Livestock & Aquatic Products Science >> Soil Science

The aboveground primary production is a major source of carbon (C) and nitrogen (N) pool and plays an important role in regulating the response of ecosystem and nutrient cycling to natural and anthropogenic disturbances. To explore the mechanisms underlying the effect of spring fire and topography on the aboveground biomass (AGB) and the soil C and N pool, we conducted a field experiment between April 2014 and August 2016 in a semi-arid grassland of northern China to examine the effects of slope and spring fire, and their potential interactions on the AGB and organic C and total N contents in different plant functional groups (C3 grasses, C4 grasses, forbs, Artemisia frigida plants, total grasses and total plants). The dynamics of AGB and the contents of organic C and N in the plants were examined in the burned and unburned plots on different slope positions (upper and lower). There were differences in the total AGB of all plants between the two slope positions. The AGB of grasses was higher on the lower slope than on the upper slope in July. On the lower slope, spring fire marginally or significantly increased the AGB of C3 grasses, forbs, total grasses and total plants in June and August, but decreased the AGB of C4 grasses and A. frigida plants from June to August. On the upper slope, however, spring fire significantly increased the AGB of forbs in June, the AGB of C3 grasses and total grasses in July, and the AGB of forbs and C4 grasses in August. Spring fire exhibited no significant effect on the total AGB of all plants on the lower and upper slopes in 2014 and 2015. In 2016, the total AGB in the burned plots showed a decreasing trend after fire burning compared with the unburned plots. The different plant functional groups had different responses to slope positions in terms of organic C and N contents in the plants. The lower and upper slopes differed with respect to the organic C and N contents of C3 grasses, C4 grasses, total grasses, forbs, A. frigida plants and total plants in different growing months. Slope position and spring fire significantly interacted to affect the AGB and organic C and N contents of C4 grasses and A. frigida plants. We observed the AGB and organic C and N contents in the plants in a temporal synchronized pattern. Spring fire affected the functional AGB on different slope positions, likely by altering the organic C and N contents and, therefore, it is an important process for C and N cycling in the semi-arid natural grasslands. The findings of this study would facilitate the simulation of ecosystem C and N cycling in the semi-arid grasslands in northern China.

submitted time 2019-03-28 From cooperative journals:《Journal of Arid Land》 Hits8860Downloads692 Comment 0

6. chinaXiv:201903.00236 [pdf]

Distribution of soil aggregates and organic carbon in deep soil under long-term conservation tillage with residual retention in dryland

WANG Bisheng; GAO Lili; WEI Xueqin
Subjects: Agriculture, Forestry,Livestock & Aquatic Products Science >> Soil Science

To ascertain the effects of long-term conservation tillage and residue retention on soil organic carbon (SOC) content and aggregate distribution in a deep soil (>20-cm depth) in a dryland environment, this paper analyzed the SOC and aggregate distribution in soil, and the aggregate-associated organic carbon (OC) and SOC physical fractions. Conservation tillage (reduced tillage with residue incorporated (RT) and no-tillage with residue mulch (NT)) significantly increased SOC sequestration and soil aggregation in deep soil compared with conventional tillage with residue removal (CT). Compared with CT, RT significantly increased the proportion of small macroaggregates by 23%–81% in the 10–80 cm layer, and the OC content in small macroaggregates by 1%–58% in the 0–80 cm layer. RT significantly increased (by 24%–90%) the OC content in mineral-SOC within small macroaggregates in the 0–60 cm layer, while there was a 23%–80% increase in the 0–40 cm layer with NT. These results indicated that: (1) conservation tillage treatments are beneficial for soil aggregation and SOC sequestration in a deep soil in a dryland environment; and (2) the SOC in mineral-associated OC plays important roles in soil aggregation and SOC sequestration. In conclusion, RT with NT is recommended as an agricultural management tool in dryland soils because of its role in improving soil aggregation and SOC sequestration.

submitted time 2019-03-28 From cooperative journals:《Journal of Arid Land》 Hits9376Downloads746 Comment 0

7. chinaXiv:201811.00103 [pdf]

Changes in soil microbial community response to precipitation events in a semi-arid steppe of the Xilin River Basin, China

ZHANG Hui; LIU Wenjun; KANG Xiaoming; CUI Xiaoyong; WANG Yanfen; ZHAO Haitao; QIAN Xiaoqing; HAO Yanbin
Subjects: Agriculture, Forestry,Livestock & Aquatic Products Science >> Soil Science

In the context of climate change, precipitation is predicted to become more intense at the global scale. Such change may alter soil microbial communities and the microbially mediated carbon and nitrogen dynamics. In this study, we experimentally repackaged precipitation patterns during the growing season (from June to September) of 2012 in a semi-arid temperate steppe of the Xilin River Basin in Inner Mongolia of China, based on the 60-year growing season precipitation data. Specifically, we manipulated a total amount of 240 mm precipitation to experimental plots by taking the following treatments: (1) P6 (6 extreme precipitation events, near the 1st percentile); (2) P10 (10 extreme precipitation events, near the 5th percentile); (3) P16 (16 moderate precipitation events, near the 50th percentile); and (4) P24 (24 events, 60-year average precipitation, near the 50th percentile). At the end of the growing season, we analyzed soil microbial community structure and biomass, bacterial abundance, fungal abundance and bacterial composition, by using phospholipid fatty acid (PLFA), real-time quantitative polymerase chain reaction (RT-qPCR) and 16S rRNA gene clone library methods. The extreme precipitation events did not change soil microbial community structure (represented by the ratio of PLFA concentration in fungi to PLFA concentration in bacteria, and the ratio of PLFA concentration in gram-positive bacterial biomass to PLFA concentration in gram-negative bacterial biomass). However, the extreme precipitation events significantly increased soil microbial activity (represented by soil microbial biomass nitrogen and soil bacterial 16S rRNA gene copy numbers). Soil fungal community showed no significant response to precipitation events. According to the redundancy analysis, both soil microbial biomass nitrogen and soil ammonium nitrogen (NH4-N) were found to be significant in shaping soil microbial community. Acidobacteria, Actinobacteria and Proteobacteria were the dominant phyla in soil bacterial composition, and responded differently to the extreme precipitation events. Based on the results, we concluded that the extreme precipitation events altered the overall soil microbial activity, but did not impact how the processes would occur, since soil microbial community structure remained unchanged.

submitted time 2018-11-23 From cooperative journals:《Journal of Arid Land》 Hits9710Downloads884 Comment 0

8. chinaXiv:201807.00075 [pdf]

基于SCI文献计量分析的土壤电动修复研究.docx.docx

袁立竹; 盛宇平; 盛春蕾; 郭书海
Subjects: Agriculture, Forestry,Livestock & Aquatic Products Science >> Soil Science

土壤电动修复是一种新兴的土壤修复技术。本文以1972-2017土壤电动修复SCI文献为分析对象,通过定量统计和文本挖掘对过去45年土壤电动修复发展历程和研究态势进行了描述。根据对关键词的整理与分析,发现土壤电动修复研究主要围绕电动修复机理、联合修复技术和场地应用等3个方面,重点修复对象主要是重金属、有机污染物、盐和其他离子以及复合污染物等。开发便捷高效的电动修复场地应用技术将是今后的研究重点之一;电动修复技术与其他修复技术的有机结合,联合修复已成为电动修复研究的热点。

submitted time 2018-07-26 Hits7083Downloads1051 Comment 2

9. chinaXiv:201808.00151 [pdf]

宁夏枸杞(LyciumbarbarumL.)花器官形态多样性与品系间识别研究

张益芝; 戴国礼; 秦垦; 马海军
Subjects: Agriculture, Forestry,Livestock & Aquatic Products Science >> Plant Protection

本研究以宁夏枸杞( L y c i u m b a r b a r u mL.)种内 42 个品系为实验材料,在对其花器官的 16 项性状的形态学指标进行赋值,测量的基础上,利用组间单因素方差分析、主成分分析和聚类分析法对其形态学差异的多态性进行了研究。研究结果表明:同一品系宁夏枸杞花器官形态学指标在不同时间(具体观测时间为 2017 年 7 月、8 月、9 月)p<0.05,差异不显著;同时,主成分分析显示花瓣外缘色泽、花瓣正-背面脉络、花瓣形状、花瓣背部色泽、花喉色泽、雌雄蕊位置 6 个花部形态指标的累积贡献率达到 84.791%,为宁夏枸杞不同品系花器官差异的主成分;聚类分析以欧式距离 7.5 为阈值,将参加试的 42 个品系分成 6类。通过本项研究明确了,同一品系的宁夏枸杞花器官形态在不同时间表现出一定的稳定性,作为区分宁夏枸杞种内不同品系的鉴别指标之一;同时,筛选出了反映宁夏枸杞花器官形态差异的 6 个主成分并将 42份宁夏枸杞分为六类,初步建立了宁夏枸杞种内品系间的形态学鉴别方法,可为宁夏枸杞的形态学研究及品系鉴定等工作提供依据。

submitted time 2018-07-18 From cooperative journals:《广西植物》 Hits8637Downloads929 Comment 0

10. chinaXiv:201808.00150 [pdf]

基于 OTCs 模拟增温方式探讨气候变暖对青藏高原草地生态系统的影响

张相锋; 彭阿辉; 宋凤仙; 陈冬勤
Subjects: Agriculture, Forestry,Livestock & Aquatic Products Science >> Plant Protection

开顶式生长室(OTCs)增温实验是研究全球气候变化与陆地生态系统关系的主要方法之一,已广泛 应用于青藏高原地区。该文通过对近些年国内外研究文献的回顾,分别从植物物候、群落结构、生物量和 土壤方面综合分析青藏高原草地生态系统对 OTCs 模拟增温实验的响应。研究发现:增温使群落返青期提 前、枯黄期延迟,生长季延长;有利于禾本科植物的生长;高寒草甸地下生物量分配格局向深层转移;高寒草地生态系统对模拟增温的响应存在不确定性,受到地域、群落类型和实验时间的影响;在增温条件下,降雨和冻土融化引起的土壤水分变化通过调控生态系统的物候、生产力、土壤等途径控制着生态系统对气 候变暖的响应。在并在此基础上,提出了将来应着重研究的几个方面。

submitted time 2018-07-18 From cooperative journals:《广西植物》 Hits9074Downloads949 Comment 0

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