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Clonal integration affects growth and sediment properties of the first ramet generation,but not later ramet generations under severe light stress

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Journal of Plant Ecology 2022年第5期15卷 1080-1090页

作者： Xiaowen Ma Yang Li Weicheng Yu Junnan Wang Chunhua Liu The National Field Station of Liangzi Lake Ecosystem Department of EcologyCollegeof Life SciencesWuhan UniversityWuhan 430072China

Clonal integration benefits clonal plants by buffering environmental stress and increasing resource extraction ***,the number of connected ramet generations that benefit from clonal integration in a clonal system has received relatively little attention.A pot experiment was conducted to evaluate the extent of physiological integration within the clonal system of Vallisneria natans consisting of a mother ramet and three sequentially connected offspring *** ramets were grown in full sunlight,and offspring ramets were heavily shaded with limited light *** between mother ramets and offspring ramets were severed or connected,but connection among the three offspring ramets *** photosynthetic ability of unshaded mother ramets of *** was significantly enhanced,but their biomass accumulation was greatly reduced when connected to shaded offspring *** integration significantly increased biomass accumulation,C and N availabilities,extracellular enzyme activities and microbial biomass of the first ramet generation(adjacent ramet),but not later ramet *** results indicate that support from the mother ramet of *** may be limited to the adjacent offspring ramet in a clonal system under severe light stress,implying an effect of ramet *** results contribute to a better understanding of the hierarchy and segmentation of clonal *** findings suggest that the extent of clonal integration plays a vital role in ecological interactions of the ramet population.

关键词： clonal integration ramet generation clonal system sediment properties Vallisneria natans

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Influence of cohesion on California bearing ratio of clay-gravel mixtures

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International Journal of sediment Research 2023年第3期38卷 374-386页

作者： Rajesh Jain Ketan Timani Manish Pandey Civil Engineering Department L.D.College of Engineering 2. Vishwakarma Government Engineering College Department of Civil Engineering National Institute of Technology

An understanding of the behavior of cohesive sediment is required to solve various engineering problems such as scour around bridge elements, mitigation of soil erosion, pavement design, river bed degradation,stable channel design. Pavement foundation designers principally use the California bearing ratio(CBR)to describe the subgrade and subbase materials and their strength. Several laboratory experiments were done to study the variation in the CBR of cohesive mixtures comprised of clay-gravel mixtures. Nine different clay-gravel mixtures were used in which the clay content varies from 10% to 50% by *** variation of the CBR with clay percentage, moisture content, and undrained shear strength parameters was studied. The CBR value reduces with the increase in the moisture content and clay fraction in the mixtures and increases with an increase in the dry density of the mixture under unsoaked conditions. The CBR also increases with the increase of the angle of internal friction of clay-gravel mixtures.A functional relation has been identified to estimate the CBR of clay-gravel mixtures. Using multiple linear regression analysis(MLRA), a relation is proposed to estimate the CBR of clay-gravel mixtures under unsoaked conditions. A statistical analysis was done to judge the behavior of the pertinent variables on the CBR. The proposed relation predicts the CBR of clay-gravel mixtures very well. Artificial neural network(ANN) analysis using R programming was also done to determine the effects of the pertinent variables on the CBR. ANN methodology was applied to predict the contribution of each variable. Three different methods: Garson algorithm, Olden algorithm, and Lek’s profile model are used to assess the influence of variable parameters. The Olden algorithm and Lek’s profile both show positive association of cohesion with CBR in an unsoaked condition. The role of moisture content was found to be marginally negative in the Olden algorithm and Lek’s profile results

关键词： Clay–gravel mixture Cohesive sediment California bearing ratio Clay percentage sediment properties

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Phosphorus Sorption-desorption Characteristics of Ditch sediments from Different Land Uses in a Small Headwater Catchment in the Central Sichuan Basin of China

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Journal of Mountain Science 2012年第3期9卷 441-450页

作者： WANG Zhenhua HE Min WANG Tao ZHU BO Key Laboratory of Mountain Environment Evolvement and Regulation Chinese Academy of SciencesChengdu 610041China Institute of Mountain Hazards and Environment Chinese Academy of SciencesChengdu 610041China Department of Water Environment Research Changjiang River Scientific Research InstituteWuhan 430010China Faculty of Forestry Sichuan Agriculture UniversityYa'an 625014China

Investigation of phosphorus (P) sorption-desorption characteristics of drainage ditch sediments is important for better understanding on sediment P transport behaviors in ditches. Surface ditch sediment samples were collected from headwater sub-catchment of forestland, sloping cropland, paddy field, and residential area in a representative catchment in the central Sichuan Basin. These sediment samples were used for determination of P sorption-desorption characteristics by a batch equilibrium technique. Results showed that the maximum P sorption capacities (Qm) in the sediments ranged from 159.7 to 263.7 mg/kg, while higher Qm were observed in the ditch sediments from the paddy fields. The Qm was significantly and positively correlated with oxalate-extractable Fe and Al oxides (r=0.97 and 0.98, p sediment pH, clay and organic matter influenced the P sorption through amorphous Fe and Al oxides. CaCO3 content was negatively correlated with the Qm (r = -0.83, p 50 g/kg) would not increase P sorption capacity in the ditch sediments. The ditch sediments featured a linear desorption curve, suggesting that P release risk would be enhanced with the increase of the P adsorption. The P desorption rate was positively correlated with Olsen P (r = 0.94, p sediments from residential area had a higher P release risk than that from the other ditches of forestland, sloping cropland and paddy field. The P sorption index (PSI) derived from single-point measurement was significantly correlated with the P sorption capacity (r = 0.99, p sediments

关键词： Ditch sediment Phosphorus sorption-desorption sediment properties Land use

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