摘要:

Aluminum (Al) activity was determined in nutrient solutions and in acid soil solutions. Aluminum concentrations in the solutions ranged from 7.4 μM to 370.3 μM giving values of ionic strength of nutrient solutions higher than the values of acid soil solutions. The increase of ionic strength values was due to the increase of Al concentrations. The values of Al activities of 20 uM in the acid soil solutions were noticed when Al concentrations were lower than 70 μM. On the other hand, these values of Al activities in nutrient solutions were noticed only when the Al concentrations were higher than 70 μM. This study demonstrates why it is important to use higher Al concentrations in nutrient solutions to obtain Al toxic effects.

ISSN:0190-4167    

DOI:10.1080/01904169909365706

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

The values of determined and calculated ionic strength and ion activity coefficient of simple solutions were studied in solutions consisting of monovalent, divalent, and trivalent salts. The nominal salt concentrations ranged from 100 to 1,000 μM. The pH of the solutions was adjusted to 4.0. The increase of salt concentrations resulted in an increase of electrical conductivity and the ionic strength values, and a good correlation was noticed between these parameters. The determined values of ion activity coefficients were very close to the calculated ones. The best relationship between the availability and/or toxicity of an element and plant physiological response has been verified when the ion activity was considered. The importance of the use of thermodynamic concepts in mineral nutrition is that avoid making incorrect interpretations of the results.

ISSN:0190-4167    

DOI:10.1080/01904169909365707

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

Two greenhouse trials were performed to assess the effect of applying various levels of inorganic nitrogen (N) fertilization in yield biomass and nodulation response of clover(Trifolium alexandrinumL.). A 2x2x4 complete factorial resulted in 16 treatments that were tested in a completely randomized design with four replications. Factor A consisted in two levels of inoculum (inoculated with a commercial strain ofRhizobiumand no inoculation), Factor B consisted in two times of harvesting (six and nine weeks after seeding), and Factor C consisted in four N fertilization rates applied as urea [CO(NH2)2] (45%N). The first experiment tested the application of 0, 30, 60, and 90 kg N ha−1, and according to the results, a second experiment evaluated the application of 5, 10, 15, and 20 kg N ha−1. The soil used as a growing medium was a sandy loam with a pH of 6.2 without salt problems nor sodium (Na) hazard. After handclipping top biomass, roots were carefully washed, obtained and a count of nodules was made. Dry matter for both top biomass as well as root biomass was determined. Crude protein (CP) content, calcium (Ca), and phosphorous (P) were estimated in laboratory for top biomass. Treatments in the six week harvest periods and treatments without inoculation did not present nodules. Inoculated treatments after nine weeks showed that the amount of nodules (29, 25, 16, and 12 nodules) decreased when increasing N fertilization. However, herbage weight increased (2.600, 3.8437, 4.3187, and 4.3206 g) in an evident linear trend. Number of nodules was stabilized in treatments of the second trial (30, 27, 27, and 25 nodules) as well as herbage yield (2.710, 2.850, 2.905, and 3.0105 g). Crude protein content showed a linear trend in the first experiment, but no differences were noted in the second experiment. Calcium and P concentrations were not affected by treatments. These results showed that application of 10 to 15 kg N ha−1permitted a maximum of both nodule formation as well as herbage and root weight in Alexandria clover.

ISSN:0190-4167    

DOI:10.1080/01904169909365708

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

Eight organic and either inorganic magnesium (Mg) compounds (sulphate, acetate, caproate, laurate, glycine salt, L‐valine salt, L‐phenylalanine salt, and ethylene‐diaminetetraacetic acid magnesium disodium salt) were tested for Mg resorption from the leaf surface of oats(Avena sativaL. cv. Zlat'ák) and for biological availability. The plants were grown on Mg‐deficient Hoagland nutrient solution. Significant differences among the alternatives studied were found through one‐way ANOVA in all parameters of plants (top and root dry weight, Mg content in tops and roots, chlorophyll a and b content and top height). A very significant decrease of Mg content in plants and aggravation of the plant health status with increasing molar weight value (Mr) of anhydrous compound used in corresponding experimental alternative was observed. The best results were obtained in the case of magnesium sulphate (MgSO4.7H2O) (the lowest Mr value) while the worst were observed in the case of Mg laurate. A different diameter of the biggest particle necessary to be absorbed with Mg (Mg complex molecule/anion, salt anion) resulting in different mobility of this particle in water solution was proposed to be the main reason of this effect. This diameter is closely related to the Mr value of the particular compound in this case. Surprisingly, no effect of fertilizer polarity on Mg penetration was observed. The effect of complex stability of some Mg compounds on Mg penetration was also investigated. The biological availability significantly decreased with the increase of the complex strength.

ISSN:0190-4167    

DOI:10.1080/01904169909365709

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

The effect of nitrate nutrition and long‐term waterlogging on the pattern of accumulation of inorganic nutrients in different plant organs was studied in corn(Zea maysL.) in glasshouse conditions. Continuous flooding of soils with NO3added for 21 days, caused a complete depletion of NO3, but in turn NH4‐N increased significantly in these soils. Potassium (K) and phosphorus (P) contents in the flooded soils also increased whereas calcium (Ca) and magnesium (Mg) contents remained unaffected. Iron (Fe) and manganese (Mn) contents increased manifold as a result of flooding. Long‐term flooding caused a marked reduction in dry weight of both shoots and roots, and supplementary NO3‐N exacerbated the inhibitory effect of waterlogging on plant growth. A considerable decrease in nitrogen (N), P, and K contents in leaves was observed as a result of flooding, whereas in roots the reverse was true. However, N and P contents under waterlogged conditions increased consistently with an increase in the applied NO3level. Flooding caused a marked reduction in Ca in both leaves and roots, and Mg only in leaves. Enhanced soil NO3‐N had no effect on the concentration of Ca and Mg in leaves or roots. Concentrations of Fe and Mn in leaves and roots increased significantly due to continuous flooding, but a marked increase in these two nutrients was observed in roots. Addition of NO3‐N to the waterlogged soils caused a slight increase in Fe in both leaves and roots but did not affect the Mn content in leaves or roots. Supplementary NO3‐N was inhibitory to corn growth under long‐term hypoxic conditions, particularly, the two higher concentrations (294 and 392 mg NO3‐N kg−1soil).

ISSN:0190-4167    

DOI:10.1080/01904169909365710

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

Alfalfa leaf (from second cutting), soil, and irrigation water samples were collected from a farm in the Eastern Province of Saudi Arabia. These samples were analyzed for 18 elements using an inductively coupled argon plasma analyzer (ICP). Among the major elements, sodium (Na) was the most abundant element in the leaf samples, followed by calcium (Ca), magnesium (Mg), potassium (K), and phosphorus (P) in descending order. In the micronutrient group, iron (Fe) was found in the highest concentrations in alfalfa leaves. Metal concentrations in alfalfa leaves varied significantly (p<0.01) from field to field. Vanadium (V) was the only element whose total concentrations in the soil samples significantly (p<0.01) affected its levels in alfalfa leave. The DTPA‐extracted copper (Cu), Fe, manganese (Mn), zinc (Zn), cadmium (Cd), cobalt (Co), nickel (Ni), and lead (Pb) in soil samples were not associated with their respective concentrations in the leaf samples (p<0.05). Concentrations of Fe and Zn in the irrigation water and alfalfa leaf samples were significantly (p<0.01) correlated.

ISSN:0190-4167    

DOI:10.1080/01904169909365711

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

In vivonitrate reductase activity and nitrate uptake in gibberellic acid (GA)‐and kinetin (KN)‐treated mustard (Brassica junceaCoss. cv. T‐59 Varuna) seedlings grown in the presence of light were investigated. An attempt was also made to determine the metabolic pool size andin vivoapparent Kmvalue of nitrate reductase (NR) for nitrate (NO3). Both NO3uptake andin vivoNR activity showed biphasic saturation kinetics, but causal relationship between them was not evident. Kinetin inhibited uptake and promotedin vivoNR activity, while although GA promoted uptake,in vivoNR activity was almost equal to distilled water (DW) control. The hormones affected the Kmvalue differently, GA showed lower Kmvalue while KN showed higher Kmvalue for NO3. Metabolic pool size (MPS) was also significantly affected by both the hormone treatments. The results are discussed in relation to the use ofin vivoNR activity for calculating the apparent Kmand MPS for NO3.

ISSN:0190-4167    

DOI:10.1080/01904169909365712

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

The effect of fruiting on mineral composition of leaves and flower buds in pistachio (Pistachia veraL., cv. Aegenes) was studied in two experimental years (1990 and 1992). Nutrient concentrations were measured in leaves and flower buds on fruiting and non‐fruiting pistachio trees at two week intervals from leaf emergence until the flower bud abscission of fruiting trees was completed. The results showed that the presence of fruit significantly increased the leaf concentrations of magnesium (Mg), calcium (Ca), manganese (Mn), and zinc (Zn) throughout the whole period of measurement and that of nitrogen (N) only until the commencement of seed growth (in June). In contrast, fruit decreased leaf concentrations of potassium (K) (throughout the whole period) and that of N (after the commencement of seed growth and high rates of bud abscission). Phosphorus (P) and iron (Fe) concentrations in leaves were not influenced by fruit. The results for flower buds were similar to those for leaves for the nutrients K, Mg, Mn, and Ca, while P, Zn, and Fe tended to be higher in buds of fruiting trees. Nitrogen concentrations were higher in buds of fruiting trees.

ISSN:0190-4167    

DOI:10.1080/01904169909365713

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

Expanding commercial interest in the use of inulin as a bulking agent for artificial sweeteners, dietary fiber health supplement, fat replacement for processed foods, feed stock for fructose syrups, and a wide range of potential industrial products, has stimulated research on inulin‐containing crops such as the Jerusalem artichoke. To better understand the developmental physiology of the crop and to identify potential breeding objectives, the temporal pattern of development of individual plant parts (shoots, branches, leaves, flowers, stolons, tubers, and roots) and the allocation of dry matter into the same plant parts were monitored in the cultivar ‘Sunchoke’ over the entire growing season and duringin situfield storage during the early winter, 32 weeks after planting. While number of shoots (∼9) peaked in week 10, the number of branches (42.8), stolons (49.4), and tubers (85.5) reached a maximum 24–28 weeks after planting. Number of leaves (∼525) peaked between weeks 20–24 after planting, as did number of flowers (∼55). The Jerusalem artichoke allocated the major portion of its dry matter (dm) into aboveground plant parts during the first half of the growing season. Approximately 16 weeks after planting, the pattern of allocation shifted dramatically with: a) near cessation in the acquisition of dry matter; and b) the reallocation of existing dry matter from the aboveground organs into the tubers. By the 16th week after planting, 85% of the total dm was in the aboveground plant parts, but declined to 28% by the 30th week. Of the total dm, 92% was accrued during the first 16 weeks and only 8% thereafter. The shift in dry matter resources coincided with a dramatic decrease in leaf number and in leaf and branch dry weight. By the end of the season, the harvest index reached 0.70 and the tuber yield 14.61 dm ha−1. Yield improvement could potentially be facilitated through lengthening the logarithmic period of carbon fixation and by earlier tuber induction and development.

ISSN:0190-4167    

DOI:10.1080/01904169909365714

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

Jerusalem artichokes store carbon (C) predominately in the form of inulin, a functional food of increasing interest due to its dietary health benefits for humans and calorie replacement potential in processed foods. To better understand the developmental and agronomic requirements of this crop, the allocation of C and nutrient elements into individual plant parts (stems, leaves, stolons, tubers, ‘seed’ tuber, and roots) was monitored at 2‐week intervals throughout the entire growth cycle of the cultivar ‘Sunchoke’ grown on a Cecil sandy clay loam. Accumulation patterns of C and nutrient elements in individual plant parts were generally in accordance to the pattern of dry matter accumulation, though concentration patterns differed. Overall, nutrient element levels in vegetative structures decreased with the onset of rapid tuber development. Leaves had the highest nutrient levels, except iron (Fe) and sodium (Na). The concentrations of nitrogen (N), phosphorus (P), potassium (K), sulfur (S), and copper (Cu) in tubers were greater than in stems. Total N, P, and K concentrations in the stolons were at lower levels and the total calcium (Ca), Fe, and manganese (Mn) at higher levels compared to the tubers. During rapid tuber growth, the concentration of individual phloem‐mobile nutrient elements (e.g., N, P, and K) in the leaves and stems decreased progressively due in part to reallocation. In contrast, the concentration of less mobile nutrient elements (e.g., Ca and Mn) in the leaves and stems generally increased due to losses of C and other mobile materials. In the tubers, the concentration of C and most nutrient elements remained fairly constant through the final harvest, indicating carbohydrates and nutrient elements were accumulating at the same rate. Knowledge of C and nutrient element allocation/ reallocation in the Jerusalem artichoke is of value for improving fertilization strategies and in identifying critical traits for the selection of new, high yielding cultivars.

ISSN:0190-4167    

DOI:10.1080/01904169909365715

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor