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Journal of Environmental Sciences 2010年第7期22卷 1080-1085页

作者： Ulrico J.López-Chuken Scott D.Young Division of Environmental Sciences School of ChemistryUniversidad Autónoma de Nuevo León Division of Agricultural & Environmental Sciences School of Biosciencesthe University of Nottingham

A controlled hydroponic experiment was undertaken to investigate Cd uptake in relation to the activity of Cd species in solution other than the free ion （Cd^2＋） by maintaining a constant Cd^2＋ activity under variable SO4^2- and Cl^- concentrations exposed to maize （Zea mays vat. Cameron） plants. The objectives of these experiments were：（1） to distinguish and quantify the different uptake rates of free and inorganic-complexed Cd from nutrient solution, and （2） to model the uptake of Cd by maize with a Biotic Ligand Model （BLM） in a system which facilitates the close examination of root characteristics. Results of the current experiments suggest that, in addition to the free ion, CdSO4^0 complexes are important factors in determining Cd uptake in nutrient solution by maize plants. Higher nominal SO4^2- concentrations in solution generally resulted in a greater Cd accumulation by maize plants than predicted by the Cd^2＋ activity. A better integration of the complete dataset for the 3 harvest times （6, 9 and 11 days after treatment） was achieved by including consideration of both the duration of Cd exposure and especially the root surface area to express Cd uptake. Similarly, the fit of the BLM was also improved when taking into account exposure time and expressing uptake in terms of root morphological parameters.

关键词： free ion activity model biotic ligand model root surface area Cd complexation metal exposure time hydroponics plant uptake

root Physiological and Morphological Characteristics of Two Rice Cultivars with Different Nitrogen-Use Efficiency

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Pedosphere 2010年第4期20卷 446-455页

作者： FAN Jian-Bo ZHANG Ya-Li D. TURNER DUAN Yin-Hua WANG Dong-Sheng SHEN Qi-Rong Jiangsu Provincial Key Laboratory for Solid Organic Waste Utilization Nanjing Agricultural University Nanjing 210095(China) College of Resources and Environmental Sciences Nanjing Agricultural University Nanjing 210095 (China) Institute of Soil Science Chinese Academy of Sciences Nanjing 210008 (China) School of Resource Management The University of MelbourneVictoria 3010 (Australia)

The variation in nitrogen （N） uptake by rice has been widely studied but differences in rice root morphology that may contribute to this variation are not completely understood. Field and greenhouse experiments were carried out to study N accumulation, root dry weights, total root lengths, root surface areas, and root bleeding rates of two rice cultivars, Elio with low N-use efficiency and Nanguang with high N-use efficiency. Low （1 mmol N L^-1） and high （5 mmol N L^-1） N applications were established in the greenhouse experiment, and the N rates were 0, 120, and 240 kg ha^-1 in the field experiments at Jiangning and Jiangpu farms, Nanjing, China. The results showed that the N accumulation, root dry weight, total root length, and root surface area increased with an increase in N application. At the heading stage, N accumulation in the shoots and roots of Nanguang was greater than that of Elio in the field experiments and that of Elio at 5 mmol N L^-1 in the greenhouse experiment. After the heading stage, N accumulation was higher for Nanguang at both 1 and 5 mmol N L^-1 in the greenhouse experiment. The total root length and root surface area were significantly different between the two cultivars. Over the range of the fertilizer application rates, the root lengths of Nanguang at Jiangning Farm were 49%-6170 greater at booting and 26%-39% greater at heading than those of Elio, and at Jiangpu Farm they were 22%-42% and 26%-38% greater, respectively. Nanguang had a greater root bleeding rate than Elio. It was concluded that the N-use efficiency of the two rice cultivars studied depended to a great extent on the root morphological parameters and root physiological characteristics at different growth stages.

关键词： N accumulation root bleeding rate root dry weight root surface area total root length

Intercropping of Sonchus asper and Vicia faba affects plant cadmium accumulation and root responses

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Pedosphere 2020年第4期30卷 457-465页

作者： Yanqun ZU Li QIN Fangdong ZHAN Jiong WU Yuan LI Jianjun CHEN Jixiu WANG Wenyou HU College of Resources and Environment Yunnan Agricultural UniversityKunming 650201(China) Institute of Soil Science Chinese Academy of SciencesNanjing 210008(China)

The cadmium(Cd)pollution of farmland soil is serious in the *** present study investigated the effects of intercropping Vicia faba and the hyperaccumulator Sonchus asper on the Cd accumulation and root responses(morphology and secreted organic acids)of plants grown on soil from a mining area in Yunnan Province,China,under different Cd stress levels(0,50,100,and 200 mg kg-1).Intercropping increased the biomass of both *** and ***,as well as the Cd accumulation and Cd transfer coefficient from roots to shoots of ***,but decreased those of *** in the 200 mg kg-1Cd *** Cd concentrations in roots,shoots,and grains from intercropped *** plants were positively correlated(Proot secretions of *** *** secreted more citric,oxalic,acetic,and malic acid compared with *** also increased root length and root surface area of both *** and *** 50 mg kg-1Cd,root length for *** was higher than that at 0 mg kg-1Cd,whereas *** roots had significantly decreased length and mean *** of *** and *** is suggested as an in situ phytoremediation strategy of Cd-contaminated soils and may improve the food quality of ***.

关键词： organic acid phytoremediation root length root surface area transfer coefficient

root Growth of the Annual Tillering Grass Panicum miliaceum in Heterogeneous Nutrient Environments

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Acta Botanica Sinica 2001年第8期43卷 846-851页

作者：何维明董鸣中国科学院植物研究所植被数量生态学开放研究实验室

To study growth responses of the roots of Panicum miliaceum L. to heterogeneous supply of nutrients. The authors analyzed the effects of the nutrient levels in both original patches (O) and destination patches (D) on the root growth of P. miliaceum when its roots were allowed to extend from original patch into destination patch. When the nutrient levels in the original patches were low, coarse root biomass ratio (coarse root biomass in the D/total coarse root biomass), coarse root length ratio (coarse root length in the D/total coarse root length), coarse root surface area ratio (coarse root surface area in the D/total coarse root surface area) and fine root length ratio (fine root length in the D/total fine root length) were greater in the destination patches with lower nutrient levels than in the destination patches with higher nutrient levels, while fine root length, fine root length density, fine root surface index, and fine root surface area density were smaller in the former than in the latter. When the nutrient levels in the original patches were high, fine root length, fine root length density, fine root surface area index and fine root surface density were greater in the destination patches with lower nutrient levels than in the destination patches with higher nutrient levels, coarse roots did not respond to the nutrient levels in the destination patches significantly. When the roots extended from the original patches with the same nutrient level into the destination patches with contrasting nutrient levels, fine root biomass and its percentage allocation did not respond to the nutrient levels in the destination patches significantly, whereas both root length and root surface area did. This indicates that the fine roots of P. miliaceum responded to difference in nutrient supply by plasticity in their length and surface area, rather than in their root biomass.

关键词： Panicum miliaceum nutrient patch root biomass root length root surface area root density