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Spatial and Temporal Quantitative Analysis of Cell Division and Elongation Rate in Growing Wheat Leaves under Saline Conditions

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Journal of Integrative plant Biology 2008年第1期50卷 76-83页

作者： Urs Schmidhalter chair of plant nutrition Technical University of MunichFreising D-85350Germany

Leaf growth in grasses is determined by the cell division and elongation rates, with the duration of cell elongation being one of the processes that is the most sensitive to salinity. Our objective was to investigate the distribution profiles of cell production, cell length and the duration of cell elongation in the growing zone of the wheat leaf during the steady growth phase. plants were grown in loamy soil with or without 120 mmollL NaCI in a growth chamber, and harvested at day 3 after leaf 4 emerged. Results show that the elongation rate of leaf 4 was reduced by t20 mmollL NaCI during the steady growth phase. The distribution profile of the lengths of abaxial epidermal cells of leaf 4 during the steady growth stage shows a sigmoidal pattern along the leaf axis for both treatments. Although salinity did not affect or even increased the length of the epidermal cells in some locations in the growth zone compared to the control treatment, the final length of the epidermal cells was reduced by 14% at 120 mmollL NaCI. Thus, we concluded that the observed reduction in the leaf elongation rate derived in part from the reduced cell division rate and either the shortened cell elongation zone or shortened duration of cell elongation. This suggests that more attention should be paid to the effects of salinity on those properties of cell production and the period of cell maturation that are related to the properties of cell wall.

关键词： cell production epidermal cell length growth zone relative elemental growth rate salinity wheat.

Effectiveness of 3,4-Dimethylpyrazole Phosphate as Nitrification Inhibitor in Soil as Influenced by Inhibitor Concentration,Application Form, and Soil Matric Potential

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Pedosphere 2008年第3期18卷 378-385页

作者： G.BARTH S.VON TUCHER U.SCHMIDHALTER chair of plant nutrition Technical University MunichD-85350 Freising-Weihenstephan(Germany)

The efficacy of nitrification inhibitors depends on soil properties and environmental conditions. The nitrification inhibitor 3.4-dimethylpyrazole phosphate （DMPP） was investigated in a sandy loam and a loamy soil to study its effectiveness as influenced by inhibitor concentration, application form, and soil matric potential. DMPP was applied with concentrations up to 34.6 mg DMPP kg^-1 soil as solution or as ammonium-sulfate/ammonium-nitrate granules formulated with DMPP. DMPP inhibited the oxidation of ammonium in both soils, but this effect was more pronounced in the sandy loam than in the loamy soil. When applied as solution, increasing DMPP concentrations up to 7 mg DMPP kg^-1 soil had no influence on the inhibition. The effectiveness of DMPP formulated as fertilizer granules was superior to the liquid application of DMPP and NH4^＋, particularly in the loamy soil. Without DMPP, a decline in soil matric potential down to -600 kPa decreased nitrification in both soils, but this effect was more pronounced in the sandy loam than in the loamy soil. DMPP was most effective in the sandy loam particularly under conditions of higher soil moisture, i.e., under conditions favorable for nitrate leaching.

关键词： 3,4-dimethylpyrazole phosphate DMPP fertilizer granules nitrification inhibitor

Influence of Soil Organic Carbon on Greenhouse Gas Emission Potential After Application of Biogas Residues or Cattle Slurry:Results from a Pot Experiment

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Pedosphere 2017年第5期27卷 807-821页

作者： gawan heintze tim eickenscheidt urs schmidhalter matthias drsler university of applied sciences weihenstephan-triesdorf Chair of Vegetation Ecology 85354Freising(Germany) technical university of munich Chair of Plant Nutrition85354 Freising(Germany)

A change in the European Union energy policy has markedly promoted the expansion of biogas production. Consequently, large amounts of nutrient-rich residues are being used as organic fertilizers. In this study, a pot experiment was conducted to simulate the high-risk situation of enhanced greenhouse gas （GHG） emissions following organic fertilizer application in energy maize cultivation. We hypothesized that cattle slurry application enhanced CO2 and N20 fluxes compared to biogas digestate because of the overall higher carbon （C） and nitrogen （N） input, and that higher levels of CO2 and N20 emissions could be expected by increasing soil organic C （SOC） and N contents. Biogas digestate and cattle slurry, at a rate of 150 kg NH＋-N ha-1, were incorporated into 3 soil types with low, medium, and high SOC contents （Cambisol, Mollic Gleysol, and Sapric Histosol, termed Clow, Cmedium, and Chigh, respectively）. The GHG exchange （CO2, CH4, and N20） was measured on 5 replicates over a period of 22 d using the closed chamber technique. The application of cattle slurry resulted in significantly higher CO2 and N20 fluxes compared to the application of biogas digestate. No differences were observed in CH4 exchange, which was close to zero for all treatments. Significantly higher CO2 emissions were observed in Chigh compared to the other two soil types, whereas the highest N20 emissions were observed in Cmedium. Thus, the results demonstrate the importance of soil type-adapted fertilization with respect to changing soil physical and environmental conditions.

关键词： C mineralization energy maize mineral soil N mineralization organic fertilization peatland

Current Soil Nutrient Status of Intensively Managed Greenhouses

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Pedosphere 2012年第6期22卷 825-833页

作者： HU Yun-Cai SONG Zhi-Wen LU Wen-Long C. POSCHENRIEDER U. SCHMIDHALTER chair of plant nutrition Technische Universitat Miinchen D-85350 Freising (Germany) Institute of Information Tianjin Academy of Agricultural Sciences Tianjin (China)

Nine districts covering the main greenhouse vegetable areas in Tianjin Municipality of the North China Plain were selected for the soil investigation in 2010 to survey the current soil nutrient status (soil available N, P and K), acidification and salinization due to excessive input of fertilizers in greenhouses in Tianjin. The study showed that, in particular, soil available P content increased with the age of greenhouses. In contrast, our results did not reveal higher K accumulation and lowered pH in the greenhouse soils compared with cultivation in open fields. Over-fertilization, causing high NO 3 accumulation, most likely resulted in salinity problems in the greenhouses. Ninety percent of the investigated greenhouse soils had electrical conductivity values of saturated paste extracts of 2-10 d S m-1 , which might affect the yields of vegetable crops like green bean, pepper, cabbage, carrot, eggplant, lettuce, spinach, celery, cucumber and tomato. The findings of our survey of the current fertility and salinity problems in greenhouse soils suggest that there is an urgent need to improve the farmers' practices and strategies in fertilization management in greenhouses of China. Because education and the agricultural technical extension services may play a more important role in avoiding overuse of fertilizers, we suggest that current nutrient management practices should be improved in the near future through training of local farmers in farmers' schools and through strengthening the agricultural extension services with practical techniques.

关键词： electrical conductivity greenhouse vegetables over-fertilization soil pH soil survey

Assessing the Suitability of Various Physiological Traits to Screen Wheat Genotypes for Salt Tolerance

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Journal of Integrative plant Biology 2007年第9期49卷 1352-1360页

作者： Salah E. EI-Hendawy Yuncai Hu Urs Schmidhalter chair of plant nutrition Technical University Munich D-85350 Freising-Weihenstephan Germany Agronomy Department Faculty of Agriculture Suez Canal University Ismalia Egypt

Success of improving the salt tolerance of genotypes requires effective and reliable screening traits in breeding programs. The objective was to assess the suitability of various physiological traits to screen wheat genotypes for salt tolerance. Thirteen wheat genotypes from Egypt, Germany, Australia and India were grown in soil with two salinity levels （control and 150 mmol/L NaCI） in a greenhouse. The physiological traits （ion contents in leaves and stems, i.e. Na^＋, Cl^-, K^＋, Ca^2＋）, the ratios of K^＋/Na^＋ and Ca^＋/Na^＋ in the leaves and stems, net photosynthesis rate, stomatal conductance, transpiration rate, chlorophyll content （SPAD value）, and leaf water relations, were measured at different growth stages. The physiological traits except for Na^＋ and Cl^- in stems and the leaf transpiration rate at 150 mmol/L NaCI showed a significant genotypic variation, indicating that the traits that have a significant genotypic variation may be possibly used as screening criteria. According to the analysis of linear regression of the scores of the physiological traits against those of grain yield, however, the physiological traits of Ca^2＋ and Ca2^＋/Na^＋ at 45 d and final harvest with the greatest genotypic variation were ranked at the top. From a practical and economic point of view, SPAD value should be considered to be used as screening criteria and/or there is a need to develop a quick and practical approach to determine Ca^2＋ in plant tissues.

关键词： physiological traits salinity screening wheat genotypes.

Shoot Apex Demand Determines Assimilate and Nutrients Partitioning and Nutrient-uptake Rate in Tobacco plants

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Journal of Integrative plant Biology 2007年第11期49卷 1654-1661页

作者： Huai-Yu Yang Chun-Jian Li Fu-Suo Zhang The Key Laboratory of plant nutrition Ministry of Agriculture Key Laboratory of Plant-Soil Interactions Ministry of Education Department of Plant Nutrition China Agricultural University Beijing 100094 China

Our previous experiment revealed that apex-removed plants have larger root systems but a lower K＋-uptake rates than intact tobacco plants. Since the apex is not only a center of growth and metabolism, but also an important place of auxin synthesis and export, the aims of this study were to distinguish whether the apex demand or auxin synthesized in the apex regulates assimilate and nutrients partitioning within plant, and to explain the reason for the lower K＋-uptake rate of the apex-removed plant. In comparison with the control plant, covering the shoot apex with a black transparent plastic bag reduced net increases in dry matter and nutrients; however, the distribution of the dry matter and nutrients between shoot and roots and nutrient-uptake rates were not changed. Removal of the shoot apex shifted the dry mass and nutrients distributions to roots, and reduced the rate of nutrient uptake. Application of 1-naphthylacetic acid （NAA） could partly replace the role of the removed apex, stimulated assimilate and nutrient deposition into the treated tissue, and enhanced the reduced plasma membrane ATPase activity of roots to the control level. However, treatment of the apex-removed plants with NAA could not rescue the reduced nutrient uptake rate and the shifted assimilates and nutrients partitioning caused by excision of the apex. Higher nutrient uptake rate of the intact plants could not be explained by root growth parameters, such as total root surface area and number of root tips. The results from the present study indicate that strong apex demand determined assimilates and nutrients partitioning and nutrient-uptake rate in tobacco （Nicotiana tabacum） plants.

关键词： assimilate and nutrient partitioning auxin nutrient uptake removal of the shoot apex shoot apex demand tobacco (Nicotiana tabacum).

Effect of long-term fertilization on soil nitrate distribution

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Journal of Environmental Sciences 2001年第1期13卷 58-63页

作者： GUO Li ping ZHANG Fu suo WANG Xing ren MAO Da ru CHEN Xin ping Department of plant nutrition China Agricultural UniversityBeijing 100094China.

A thirteen years long-term field fertilizer experiment was conducted to monitor the effect of different fertilization on soil nitrate distribution. The results showed: (1) Applying relative excessive N fertilizer could result large quantities of NO3- residue and NO3- movement downward in soil profiles; amending phosphate fertilizer or organic manure with nitrogen fertilizer together could significantly improve the status of NO3- leaching downward due to the balanced uptake of nutrients by crops. ( 2) Appropriate amounts of nitrogen fertilizer which was equal or smaller than the optimal fertilization rate could not result in more NO3- leaching in Northern China. (3) Precipitation influenced the amounts and depth of soil NO3- leaching: NO3- could move to 80 cm depth or below at autumn or at the next spring when rainfall was higher during the rainy season through July to September in North China.

关键词： fertilization soil nitrate nitrate leaching long-term experiment nitrogen apparent recovery

Ammonium improves iron nutrition by decreasing leaf apoplastic pH of sunflower plants(Helianthus annuus ***)

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Chinese Science Bulletin 2003年第20期48卷 2215-2220页

作者： ZOU Chunqin & ZHANG Fusuo Key Laboratory of plant-Soil Interactions, Ministry of Education Key Laboratory of plant nutrition, Ministry of Agriculture of China Department of plant nutrition, China Agricultural University, Beijing 100094, China Correspondence should be addressed to Zhang Fusuo (e-mail: zhangfs@ ***) Key Laboratory of plant-Soil Interaction Ministry of Education Key Laboratory of Plant Nutrition Ministry of Agriculture of China Department of Plant Nutrition China Agricultural University Beijing China

The effect of nitrogen form on pH and concentration of soluble iron (Fe) in leaf apoplast was investigated in hydrophonically grown sunflower plants (Helianthus annuus L. cv. Frankasol), and the mechanism underlying the improved Fe nutrition by ammonium (NH4) supply was also elucidated. Ammonium supply ameliorated Fe nutrition of plants grown without Fe through decreasing apoplastic pH and increasing soluble Fe concentration in apoplastic fluid of young leaves. The soluble Fe concentration in apoplastic fluid and cell sap of young leaves, and xylem exudates of NH4 fed-plants was higher than that of nitrate (NO3) fed-plants, and no typical Fe-deficiency chlorosis in young leaves was observed in NH4 fed plant without Fe supply. The apoplastic pH was 6.15 and 5.94 in young leaves of Fe-deficient plants fed respectively with NO3 and NH4, while in Fe-sufficient plants, the apoplastic pH was 6.43 with NO3, and 5.50 with NH4 supply. In primary leaves, the apoplastic pH was around 6.25 irrespective of nitrogen form and Fe supply. The pH of xylem exudate was 5.72 in Fe-deficient plants fed with NO3 and 5.49 with NH4. Iron nutrition increased the pH of xylem exudate by 0.27 and 0.16 unit under NO3 and NH4 supply respectively.

关键词：向日葵铁营养学非原质体 pH值氮铵赋存形态植物生理学

Modulation of Soil Particle Size and Nutrient Availability in the Maize Rhizosheath

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Pedosphere 2011年第4期21卷 483-490页

作者： MA Wei LI Xue-Xian LI Chun-Jian Department of plant nutrition China Agricultural University Beijing 100193 (China)

Root exudates,microorganism colonization and soil aggregates together form the rhizosheath,a special cylinder of micro-ecosystem adhering to the root *** study how the rhizosheath affects soil structure and nutrient distribution,we analyzed the impact of maize rhizosheath on soil particle size and nutrient availability in pot and field *** results showed that there was a significant size decrease of soil particles in the ***,the soil mineral nitrogen in the rhizosheath was significantly higher than that in the rhizosphere or bulk soil at tasseling and maturity stages of *** contents of Fe and Mn were also differentially altered in the *** development,indicated by a dry weight ratio of rhizosheath soil to the root,was relatively independent of root development during the whole experimental *** formation of maize rhizosheath contributed to the modulation of soil particle size and nutrient *** subtle local changes of soil physical and chemical properties may have profound influence on soil formation,rhizospheric ecosystem initiation,and mineral nutrient mobilization over the long history of plant evolution and domestication.

关键词： micronutrient mineral nitrogen mucilage rhizosphere root exudates