Eleventh International Plant Nutrition Colloquium.- International Council on Plant Nutrition.- Preface.- A: Uptake, assimilation, and distribution of macronutrients: Mechanisms and concepts.- The soil to plant-transfer of nutrients: Combining plant and soil characteristics.- Simulation of nutrient uptake by a growing root system considering increasing root density and inter-root competition.- Nitrate accumulation by wheat (Triticum aestivum) in relation to growth and tissue N concentrations.- Effect of varied shoot/root ratio on growth of maize (Zea mays) under nitrogenlimited conditions: Growth experiment and model calculations.- Influence of nitrate placement on morphology and physiology of maize (Zea mays) root systems.- Influence of nitrogen form and concentration on growth and ionic balance of tomato (Lycopersicon esculentum) and potato (Solanum tuberosum).- Growth responses of Plantago to ammonium nutrition with and without pH control: Comparison of plants precultivated on nitrate or ammonium.- Rhizosphere pH along different root zones of Douglas-fir (Pseudotsuga menziesii), as affected by source of nitrogen.- Effects of variation in nitrogen nutrition on growth of poplar (Populus trichocarpa) clones.- Adaptation of growth rate of Populus euramericana to light and nitrate proceeds via the vascular system.- Optimal nutrition in two forest stands exposed to acid atmospheric deposition.- Steady state nutrition by transpiration controlled nutrient supply.- A culture system for steady state nutrition in optimum and suboptimum treatments.- Interaction between nitrate assimilation in shoots and nitrate uptake by roots of soybean (Glycine max) plants: Role of carboxylate.- Diurnal changes of nitrate content and nitrate reductase activity in different organs of Atriplex hortensis (C3 plant) and Amaranthus retroflexus (C4 plant).- Nitrate assimilation and nitrate content in different organs of ash trees (Fraxinus excelsior).- The effect of cadmium on nitrate reductase activity in sugar beet (Beta vulgaris).- Transport of glutamine into the xylem of sunflower (Helianthus annuus).- Influence of fusicoccin and xylem wall adsorption on cation transport into maturing wheat (Triticum aestivum) ears.- Effect on phloem interruption on leaf senescence and nutrient redistribution in wheat (Triticum aestivum).- Efficiency of Azospirillum inocula in peat formulations: Maize (Zea mays) root colonization and effects on initial plant growth.- Cellular organization of symbiotic nitrogen fixation and nitrogen assimilation in leguminous plants.- Influence of phosphate status on phosphate uptake kinetics of maize (Zea mays) and soybean (Glycine max).- Using a mechanistic model to evaluate the effect of soil pH on phosphorus uptake.- Phosphorus diffusion to barley (Hordeum vulgare) roots as influenced by moisture and phosphorus content of soils.- Effects of Glomus fasciculatum and isolated rhizosphere microorganisms on growth and phosphate uptake of Plantago major ssp. pleiosperma.- Soluble carbohydrates in roots of leek (Allium porrum) plants in relation to phosphorus supply and VA mycorrhizas.- Benefit and cost analysis and phosphorus efficiency of VA mycorrhizal fungi colonizations with sorghum (Sorghum bicolor) genotypes grown at varied phosphorus levels.- Phosphorus absorption by chickpea (Cicer arietinum) as affected by VA mycorrhiza and carboxylic acids in root exudates.- Origin of organic acids exuded by roots of phosphorus stressed rape (Brassica napus) plants.- Grain development in wheat (Triticum aestivum) ears cultured in media with different concentrations of phosphorus and sucrose.- Nodule activity and nodule phosphorus in white clover (Trifolium repens) in the presence of mineral nitrogen.- Properties of ecto Ca-ATPase isolated from barley (Hordeum vulgare) roots.- B: Micronutrients and toxic elements in plant and crop nutrition.- Responses of chickpea (Cicer arietinum) to iron stress measured using a computer-controlled continuous-flow hydroponic system.- Responses of pepper (Capsium annum) plants to iron deficiency: Solution pH and riboflavin.- Iron requirement of cereals and legumes in solution culture.- A transport mutant of pea (Pisum sativum) for the study of iron absorption in higher plant roots.- The significance of the magnesium to manganese ratio in plant tissues for growth and alleviation of manganese toxicity in tomato (Lycopersicon esculentum) and wheat (Triticum aestivum) plants.- Effects of rhizosphere processes on the solubilization of manganese as revealed with radioisotope techniques.- Effect of manganese supply on development of wheat (Triticum aestivum) roots.- Growth enhancement by silicon in cucumber (Cucumis sativus) plants depends on imbalance in phosphorus and zinc supply.- The effect of zinc and magnesium application on ear density, grain development and grain yield of winter and spring barley (Hordeum vulgare) crops on some Irish soils.- Control of zinc deficiency in apple orchards in southern Brazil.- Zinc deficiency and pollen fertility in maize (Zea mays).- Micronutrients foliar intake by different crop plants, as affected by accompanying urea.- Internal boron requirements of green gram (Vigna radiata).- Effects of seed and soil boron on early seedling growth of black and green gram (Vigna mungo and K radiata).- The effects of short-term deficiency of boron on potassium, calcium, and magnesium distribution in leaves and roots of tomato (Lycopersicon esculentum) plants.- Effect of excess grain boron concentrations on early seedling development and growth of several wheat (Triticum aestivum) genotypes with different susceptibilities to boron toxicity.- Genetic differences in the copper efficiency of cereals.- Effect of arsenic and molybdenum on plant response of cauliflower (Brassica oleracea) grown in sand culture.- Correlation between extract able chromium, chromium uptake and productivity of beans (Phaseolus vulgaris) grown on tannery sludgeamended soil.- Plant uptake of cadmium as affected by variation in sorption parameters.- Interactive effects of cadmium, copper, manganese, nickel, and zinc on root growth of wheat (Triticum aestivum) in solution culture.- Long-term effects of fertilization and diffuse deposition of heavy metals on soil and crop quality.- C: Plant responses to acidity, salinity and other stress factors in the root environment.- Effects of low activities of aluminium on soybean (Glycine max). I. Early growth and nodulation.- Effects of low activities of aluminium on soybean (Glycine max). II. Root cell structure and root hair development.- Role of root cell walls in iron deficiency of soybean (Glycine max) and aluminium toxicity of wheat (Triticum aestivum).- Mechanical impedance increases aluminium tolerance of soybean (Glycine max) roots.- Aluminium toxicity tolerance in rice (Oryza sativa) seedlings.- Aluminium tolerance of the velvet beans Mucuna pruriens var. utilis and Mucuna deeringiana. I. Effects of aluminium on growth and mineral composition.- Effects of aluminium on tap-root elongation of soybean (Glycine max), cowpea (Vigna unguiculata) and green gram (Vigna radiata) grown in the presence of organic acids.- Organic acids related to differential aluminium tolerance in wheat (Triticum aestivum) cultivars.- Mineral element concentrations and grain yield of sorghum (,Sorghum bicolor) and pearl (Pennisetum glaucum) grown on acid soil.- Effects of aluminium on growth, nutrient uptake, proton efflux and phosphorus assimilation of aluminium-tolerant and -sensitive sorghum (Sorghum bicolor) genotypes.- Similarities and differences between aluminium toxicity and phosphorus deficiency in sorghum (Sorghum bicolor) plants.- Calcium protection against aluminium toxicity.- Temperature and magnesium effects on aluminium toxicity in annual ryegrass (Lolium multiflorum).- Bioassay technique to assess acid soil constraints for growth of wheat (Triticum aestivum) roots.- Level of acid soil field stress for sorghum (Sorghum bicolor) tolerance development: Comparison among locations.- Sequential growth stage adjustment to acid soil stress in sorghum (Sorghum bicolor).- Exchangeable aluminium and root growth of wheat (Triticum aestivum) as criteria of lime requirement in acid soils of northeast Portugal.- Effect of low pH of the root medium on proton release, growth, and nutrient uptake of field beans (Vicia faba).- Nitrogen fixation of lucerne (Medicago sativa) in an acid soil: The use of rhizotrons as a model system to simulate field conditions.- Role of plant aerenchyma in wet tolerance of and methane emission from plants.- Growth and chemical composition of barley (Hordeum vulgare) cultivars on saline substrate as compared with a salt tolerant variety of wheat (Triticum aestivum).- Effect of salinity on calcium transport in tomato (Lycopersicon esculentum).- Effect of salinity on the distribution of calcium in tomato (Lycopersicon esculentum) fruit and leaves.- Sodium, chloride and potassium allocation in an annual sweetclover (Melilotus segetalis) from the Guadalquivir salt marsh in southwest Spain.- The effect of magnesium sulphate and calcium sulphate on yield and nutrient composition of flax (Linum usitatissimum) grown on chernozemic soils.- Gas exchange of Fiscus carica in response to salinity.- Ionic balance and osmotic status in carrot (Daucus carota) cell suspensions grown under sodium chloride, osmotic and water stress.- D: Fertilizer application in relation to yield formation and quality characteristics.- Response of grass swards to fertilizer nitrogen under cutting and grazing.- Response of tomatoes (Lycopersicon esculentum) to an unequal distribution of nutrients in the root environment.- Effect of increasing nutrient concentration on growth and nitrogen uptake of container-grown peach and olive.- Nutrient uptake, production and quality of Rosa hybrida in rockwool as affected by electrical conductivity of the nutrient solution.- Synchronisation of supply and demand is necessary to increase efficiency of nutrient use in soilless horticulture.- Cultivation of cut flowers with ammonium as nitrogen source.- Conceptual evaluation of intensive production systems for tomatoes.- The effects of continuity of early nitrogen nutrition on growth and development of Lactuca sativa.- Influence of nitrogen nutrition on powdery mildew (Sphaerotheca fuliginea) infection and metabolism of cucumber (Cucumis sativus).- Fertilizer nitrogen budgets of 15N-labelled sugarbeet (Beta vulgaris) tops and Na15NO3 dressings split-applied to winter wheat (Triticum aestivum) in microplots on a loam soil.- Nitrate reductase activity, grain yield and grain protein in wheat (Triticum aestivum) as affected by nitrogen fertilization under semi-arid conditions.- Effects of nitrogen and herbicide on grain yield and protein content of a tall and a semi-dwarf wheat (Triticum aestivum) cultivar in semi-arid conditions.- Seed characters in oilseed rape (Brassica napus) in relation to nitrogen nutrition.- Effect of nitrogen on thiocyanate content of Brassica oleracea var. acephala leaves.- Influence of nitrogen fertilization on sugarbeet (Beta vulgaris) quality in an area of southern Spain.- Effect of preceding crops and nitrogen application on safflower (Carthamus tinctorius) yield and nutrient uptake, and on soil nitrogen.- Nitrogen, phosphorus and potassium uptake of two sorghum (.Sorghum bicolor) cultivars in an acid soil of Venezuela.- Genotypic diversity in pearl millet (Pennisetum glaucum) for nitrogen, phosphorus and potassium use efficiencies.- Nitrogen and potassium dynamics, rooting intensity, and infection with VA mycorrhiza in a haplic podzol at intensive and organic farming.- Nutritional stress of maize (Zea mays) growing on a gleysol of east Croatia.- Studies on potassium-magnesium interaction in coconut (Cocos nucifera).- Fruit calcium, quality and disorders of apples (Malus domestica) and pears (Pyrus communis) influenced by fertilizers.- Energy flow in an apple plant-aphid (Aphis pomi De Geer) (Homoptera: Aphididae) ecosystem, with respect to nitrogen fertilization. I. Life table analyses.- Influence of potassium on concentrations of water soluble carbohydrates, potassium, calcium, and magnesium and the osmotic potential in sap extracted from wheat (Triticum aestivum) ears during preanthesis development.- Source: sink relationships in potato (Solanum tuberosum) as influenced by potassium chloride or potassium sulphate nutrition.- Starch synthesis in potato (Solanum tuberosum) tubers: Activity of selected enzymes in dependence of potassium content in storage tissue.- The nutrient requirements of Ornithogalum and Lachenalia, two indigenous South African flowering bulbs.- Growth and mineral composition of grape-vine rootstock cultered in vitro with different levels of ammonium nitrate.- Phosphorus uptake characteristics of a world collection white clover (Trifolium repens) cultivars.- The effects of phosphorus and bio-fertilizers on physiological parameters, yield and quality of cowpea (Vigna sinensis).- Bowen, Effect of successive cutting on nodulation and nitrogen fixation of Leucaena leucocephala using 15N dilution and the difference methods.- Inorganic N x Bradyrhizobium strain interaction on cowpea (Vigna unguiculata) varietal performance in the field, using the 15N isotope dilution technique.- E: Methods and techniques aiming at optimization of crop nutrition and growth.- Prospects for improvement of nitrogen fertilizer recommendations for cereals: A simulation study.- Weather, nitrogen-supply and growth rate of field vegetables.- Modelling the response of crops to fertilizers.- Modelling potassium uptake by wheat (Triticum aestivum) crops.- Simulation of fertilizer influence on yield and quality of potato (Solanum tuberosum) tubers by nonlinear optimization method.- Determination of fruiting capacity of apple trees (Malus domestica) by DRIS.- Criteria for fertilization of vining peas in Portugal.- Problems of potassium nutrition in citrus (Citrus sinensis) orchards in Egypt.- Some criteria for the assessment of genetic specificity for nitrogen concentration in wheat (Triticum aestivum).- Yield and nitrogen concentrations in wheat (Triticum aestivum) as affected by split nitrogen application and growth stage.- The influence of available nitrate nitrogen in the soil profile on the nitrate contents of blanching celery.- Control of nitrogen supply of cucumber (Cucumis sativus) grown in soilless culture.- A double-pot technique as a tool in plant nutrition studies.- In situ nitrate reductase activity in winter wheat (Triticum aestivum) as an indicator of nitrogen availability.- Tissue test of rice plant (Oryza sativa) nitrogen using near infrared reflectance.- Pattern of nitrate assimilation and grain nitrogen yield in field-grown wheat (Triticum aestivum).- Inorganic leaf phosphorus as an indicator of phosphorus nutrition in cereals.- Potassium deficiency in sunflower (Helianthus annuus) is associated with changes in protein profiles: An approach to diagnosis of mineral status.- Diagnosis of sulfur deficiency in peanut (Arachis hypogaea) by plant analysis.- The diagnosis of manganese deficiency in barley (Hordeum vulgare).- Iron(II) determination in leaves of strawberry (Fragaria vesca).- An expert system for diagnosing Brussels sprout (Brassica oleracea) disorders in the UK.- Author index.- Proceedings previous Plant Nutrition Colloquia.