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Do plants explore habitats before exploiting them? An explicit test using two stoloniferous herbs

Chinese Science Bulletin 2012年第19期57卷 2425-2432页

作者： PENG YouHong NIKLAS KarlJ SUN ShuCun Ecological Restoration and Biodiversity Conservation Key Laboratory of Sichuan Province Chengdu Institute of BiologyChinese Academy of SciencesChengdu 610041China department of plantbiology Cornefl UniversityIthacaNY14850USA department of Biology Nanjing UniversityNanjing 210093China

We tested whether the processes of exploration and exploitation can be explicitly distinguished as plants grow and develop within a habitat using two stoloniferous clonal herbs,Hydrocotyle sibthorpioides(Umbelliferae) and Potentilla anserina(Rosaceae).Ramets were planted in four circular trays differing in *** replicate from each diameter-group was sampled at intervals corresponding to plant coverage of the trays,and plant biomass allocation to leaves,stolons,and roots and internode length were *** both species,at early sampling times(when the smallest trays were full),total plant biomass and ramet number were larger in the smaller trays than in the larger ***,this trend was reversed for plants collected at later *** ***,leaf mass ratios(leaf mass to total plant mass) were significantly greater,but stolon mass ratios(stolon mass to total plant mass) were less in the small trays than in the larger ones,particularly during the early stages of the ***,for ***,leaf mass ratios decreased in the smaller trays but increased in the larger ones as the experiment *** mass ratios showed contrasting pattern to leaf mass ratios for both species;stolon mass ratios were significantly smaller in the smaller trays than in the larger ones,although there were no obvious patterns during the course of the *** addition,for both species,internode length was shorter but the number of ramets was greater in the smaller trays at early sampling *** conclude that plants invest greater biomass in resource-exploring organs(stolons) than in resource-exploiting organs(leaves or roots) as they initially establish in a *** relatively lower plant productivity in the largest trays at early sampling times presumably reflects the cost of exploration prior to resource exploitation and utilization.

关键词：草本植物匍匐茎栖息地测试采样时间早期阶段物探实验过程

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The 2012 Flash Drought Threatened US Midwest Agroecosystems

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Chinese Geographical Science 2019年第5期29卷 768-783页

作者： JIN Cui LUO Xue XIAO Xiangming DONG Jinwei LI Xueming YANG Jun ZHAO Deyu College of Urban and Environment Liaoning Normal UniversityDalian116029China department of Microbiology and plantbiology Center for Spatial AnalysisUniversity of OklahomaNormanOK73019USA Ministry of Education Key Laboratory ofBiodiversity Science and Ecological Engineering Institute of Biodiversity ScienceFudan UniversityShanghai200433China KeyLaboratory of Land Surface Pattern and Simulation Institute of Geographic Sciences and Natural Resources ResearchChinese Academyof SciencesBeijing100101China

In the summer of 2012, the US Midwest, the most productive agricultural region in the world, experienced the most intense and widespread drought on record for the past hundred years. The 2012 drought, characterized as ‘flash drought’, developed in May with a rapid intensification afterwards, and peaked in mid-July. ~76% of crop region and 60% of grassland and pasture regions have been under moderate to severe dry conditions. This study used multiple lines of evidences, i.e., in-situ AmeriFlux measurements, spatial satellite observations, and scaled ecosystem modeling, to provide independent and complementary analysis on the impact of 2012 flash drought on the US Midwest vegetation greenness and photosynthesis carbon uptake. Three datasets consistently showed that 1) phenological activities of all biomes advanced 1–2 weeks earlier in 2012 compared to the other years of 2010–2014;2) the drought had a more severe impact on agroecosystems(crop and grassland) than on forests;3) the growth of crop and grassland was suppressed from June with significant reduction of vegetation index, sun-induced fluorescence(SIF) and gross primary production(GPP), and did not recover until the end of growing season. The modeling results showed that regional total GPP in 2012 was the lowest(1.76 Pg C/yr) during 2010–2014, and decreased by 63 Tg C compared with the other-year mean. Agroecosystems, accounting for 84% of regional GPP assimilation, were the most impacted by 2012 drought with total GPP reduction of 9%, 7%, 6%, and 29% for maize, soybean, cropland, and grassland, respectively. The frequency and severity of droughts have been predicted to increase in future. The results imply the importance to investigate the influences of flash droughts on vegetation productivity and terrestrial carbon cycling.

关键词： food security terrestrial carbon cycling eddy covariance Vegetation Photosynthesis Model sun-induced fluorescence(SIF)

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Estimating the spatial distribution of organic carbon density for the soils of Ohio, USA

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Journal of Geographical Sciences 2013年第2期23卷 280-296页

作者： Sandeep KUMAR Rattan LAL Desheng LIU Rashid RAFIQ departmentofPlantScience.Room248CNPB BOX2140C1110RotundaLaneNorthSouthDakotaStateUniversityBrookingsSD57007USA CarbonManagementandSequestrationCenter SchoolofEnvironmentandNaturalResourcesTheOhioStateUniversity2021CoffeyRoad414AKo~manHallColumbusOH43210-1085USA departmentofGeographyanddepartmentofStatistics TheOhioStateUniversityColumbusOH43210USA departmentofMicrobiology&plantbiology.UniversityofOklahoma NormanOK73019USA

Historical database of National Soil Survey Center containing 1424 geo-referenced soil profiles was used in this study for estimating the organic carbon （SOC） for the soils of Ohio, USA. Specific objective of the study was to estimate the spatial distribution of SOC density （C stock per unit area） to 1.0-m depth for soils of Ohio using geographically weighted regression （GWR）, and compare the results with that obtained from multiple linear regression （MLR）. About 80% of the analytical data were used for calibration and 20% for validation. A total of 20 variables including terrain attributes, climate data, bedrock geology, and land use data were used for mapping the SOC density. Results showed that the GWR provided better estimations with the lowest （3.81 kg m-2） root mean square error （RMSE） than MLR approach Total estimated SOC pool for soils in Ohio ranged from 727 to 742 Tg. This study demon strates that, the local spatial statistical technique, the GWR can perform better in capturing the spatial distribution of SOC across the study region as compared to other global spatial statistical techniques such as MLR. Thus, GWR enhances the accuracy for mapping SOC density.

关键词： geographically weighted regression multiple linear regression major land resource areas root meansquare error soil organic carbon

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