Exactly 35 years after the first Colloquium was held, the Eleventh International Plant Nutrition Colloquium took place from 30 July to 4 August 1989 in Wageningen, The Netherlands. Although impressive progress has been made during the past decades in our understanding of the mechanisms of uptake, distribution and assimilation of nutrients in relation to crop yield and quality, there are still significant gaps in our insight into many fundamental aspects of plant mineral nutrition and related metabolic processes. In spite of improved knowledge of nutrient requirements of crops and improved fertilizer application strategies, the world population remains to be burdened with an enormous shortage of plant products for food, timber, fuel, shelter, and other purposes. The main challenge facing the plant nutrition research community is to at least alleviate the increasing world-wide need for applying scientific knowledge to practical problems in agriculture, horticulture, and forestry. It is therefore felt by many scientists that the Plant Nutrition Colloquia, which are intended to bring together scientists and to integrate knowledge and approaches acquired in plant physiology, biochemis try, soil science, agronomy and related disciplines, have indeed made a significant contribution to the advancement of our knowledge and understanding in this vital and interdisciplinary field of agrobiology. About 260 scientists from 40 nations attended the Colloquium in Wageningen.

Proceedings of the XI International Plant Nutrition Colloquium 1989, Wageningen, The Netherlands, July 30 - August 4, 1989

Inhalt
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…