摘要:

The influence of three potassium:rubidium (K:Rb) ratios (6:0, 5:1, and 4:2) on the xylematic transport of solutes in cucumber plants cv. Medusa supplied with both nitrate (NO3‐) (60%) and ammonium (NH4+) (40%) was studied in greenhouse conditions. In the xylem sap of plants grown with a K:Rb ratio of 4:2, there was an increase in the transport of NO3‐, phosphate (H2PO4‐), calcium (Ca2+), magnesium (Mg2+), sodium (Na+), manganese (Mn) and boron (B) while that of organic‐N, organic‐P, K+, zinc (Zn), organic acids, and carbohydrates decreased, if compared with the sap of the plants supplied with K alone. The translocation of NO3‐, H2PO4‐, Ca2+, Mg2+, and Mn was enhanced and that of K+and organic acids decreased when the plants were supplied with a K:Rb ratio of 5:1. The K:Rb ratio detected in the xylem sap was the same K:Rb ratio as in the solutions. However, in the cucumber plant substituting 33% of total K by Rb resulted in an alteration in the transport of solutes, probably due to a competition between Rb and K rather than between the latter two and NH4+.

ISSN:0190-4167    

DOI:10.1080/01904169609365136

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

The effect of phosphorus (P), copper (Cu), and zinc (Zn) addition on the P‐Cu and P‐Zn interaction in lettuce(Lactuca sativaL.) was analyzed following a factorial design. The experiment was conducted in a greenhouse. Two levels of P (62 and 224 ppm), three levels of Zn (0, 0.17, and 0.34 ppm), and three levels of Cu (0, 0.03, and 0.06 ppm) were applied in all combinations to lettuce grown in perlite. The influence of the different treatments on the leaf P concentration suggests that the P‐Cu interaction was positive, whereas P‐Zn was negative. An increase in root absorption and retention and a decrease in translocation to leaves were observed for Zn and Cu when the nutrient solution was supplied at a luxurious consumption level of P.

ISSN:0190-4167    

DOI:10.1080/01904169609365137

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

The dry weight accumulation per leaf as well as the concentration per gram of dry weight and the accumulation of nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), iron (Fe), manganese (Mn), zinc (Zn), and copper (Cu) were determined in walnut tree leaves(Juglans regiaL.) during a complete life cycle. Additionally, the dynamics of plant nutrient concentration in leaf petiole sap and carbohydrate accumulation in leaves were studied in relation to the main life cycle events of the walnut tree. Total N, P, K, Cu, and Zn concentrations decreased, whereas that of Ca, Mg, and Mn increased during the season. Iron concentration fluctuated around a mean value. Total N, P, K, Mg, and Cu concentrations detected in younger mature leaves were at the sufficient level, whereas Ca, Fe, Mn, and Zn concentrations were at higher levels as compared to those previously reported. All the detected nutrient accumulations increased abruptly during leaf ontogeny and leaf maturation until a maximum level was attained in the younger mature leaves. Similarly, sucrose, glucose, and fructose accumulation were observed at the same period. The rates of total N, P, Cu, and Zn accumulation were lower than the rates of the observed dry matter accumulation and nutrient concentration dilution. Potassium and Mn accumulation rates were almost equal, whereas those for Ca and Mg were higher as compared to the dry matter accumulation rate. The fast embryo growing phase resulted in a considerable decrease in dry weight, total N, P, K, Cu, Zn, and carbohydrate accumulation, and to a lesser degree in Ca, Mg, and Mn accumulation. Nutrient accumulation reduction in leaves by the influence of the growing fruits were estimated to be: total N 52%, K 48%, P 29.5%, Mg 16.3%, Ca 15%, Fe 51.2%, Cu 55.2%, Zn 37.3%, and Mn 5.4% of the maximum nutrient value of the younger mature leaves. Old leaves preserved nutrients before leaf fall as follows: total N 25.4%, P 45%, K 31%, Ca 74.8%, Mg 76.5%, Mn 89.2%, Fe and Zn 50%, and Cu 37%. Nutrient remobilization from the senescing old leaves before leaf fall were: total N 22.6%, P 25.5%, K 21%, Ca 10.2%, Mg 7%, Fe 3.2%, Mn 5.4%, Cu 8%, and Zn 13.3% of the maximum value in the younger mature leaves. In early spring, the absorption rates of N, P, and Ca were low while those of Mg, Fe, Mn, Cu, and Zn were high. During the fast growing pollen phase, the N, P, Fe, Mn, Cu, and Zn concentrations were reduced. Calcium concentration is supposed to be more affected by the rate of transpiration rather than during the growing of embryo. Calcium and Mg concentrations in the sap were negatively correlated. The detected K concentration level in the sap was as high as 33 to 50 times that of soluble N, 12 to 21 times to that of P, 5 times to that of Ca, and 10 to 20 times to that of Mg. The first maximum of starch accumulation in mature leaves was observed during the slow growing embryo phase and a second one after fruit ripening. Old senescing leaves showed an extensive carbohydrate depletion before leaf fall.

ISSN:0190-4167    

DOI:10.1080/01904169609365138

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

The seeds of forbs, grass, and woody halophytes were collected from a cool moist temperate habitat of North America and subtropical maritime desert conditions of Karachi, Pakistan. Sodium, potassium, calcium, magnesium, and chloride concentrations as well as total ash content were determined. Ion concentrations of seeds are expressed both as relative values and on a dry weight basis. Plants were found to vary in the total ash content of seeds and the relative distribution of ions. In general, temperate forbs and grasses had lower ion content of seeds and several tropical shrub species had the highest ionic content.

ISSN:0190-4167    

DOI:10.1080/01904169609365139

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

We characterized and quantified the chemical form of cadmium (Cd) in intercellular solutions of the apparent free space (AFS) of roots and leaves of bush bean plants. Plants were grown in sand and treated daily for five days with Hoagland nutrient solution containing, respectively, 0.5 and 1 mM Cd(NO3)2. The intercellular solution was collected by infiltration‐extraction procedure using successively distilled water, 5 mM CaCl2, and 5 mM EDTA in order to collect separately the water soluble, exchangeable, and complexed Cd. The ability of extradant solutions to remove Cd from the AFS of roots and leaves was: H2O < CaCl2≪ EDTA, confirming that most of Cd was bound at the cell wall. Voltarimetric technique showed that water‐soluble Cd in intercellular solutions of the root and leaf tissues was as the Cd2+ion, suggesting that Cd might be taken up by the roots and transported to leaves as the free ion.

ISSN:0190-4167    

DOI:10.1080/01904169609365140

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Manganese (Mn) toxicity can develop in peanuts grown on low pH soils. The objectives of this study were to quantify the impact of soil pH and magnesium (Mg) on the uptake of Mn and the development of Mn toxicity symptoms in peanut plants and to evaluate the use of the Mg:Mn ratio as a diagnostic tool for Mn toxicity in peanuts. Three greenhouse tests were utilized to meet these objectives: a study to determine dolomitic limestone effects, an experiment comparing rate effects of calcium (Ca), Mg, and potassium (K) on Mn toxicity, and a test to separate the effects of pH, Mn, and Mg on Mn toxicity. Soil, leaf, and stem samples were taken for analysis, and toxicity ratings were made. Increasing pH diminished the toxicity rating and leaf Mn concentration and increased the leaf Mg:Mn ratio. The toxicity rating was significantly correlated with both leaf Mn and Mg:Mn ratio, but leaf Mn generally had stronger correlations and was more useful in diagnosis. Magnesium application resulted in a marked reduction in the Mn toxicity rating and leaf and stem Mn concentrations in the second experiment; however, this result was not repeated in the final test. Using Mg to prevent Mn toxicity would require large Mg applications, which could have the serious detrimental effect of interfering with Ca uptake by the peanut fruit. Liming is the more practical method for avoidance of Mn toxicity in peanuts.

ISSN:0190-4167    

DOI:10.1080/01904169609365141

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

The effect of the zinc (Zn) nutritional status on the rate of phyto‐siderophore release was studied in three wild grass species (Hordeum murinum, Agropyron orientale,andSecale cereale)grown in nutrient solution under co‐trolled environmental conditions. These wild grasses are highly “Zn‐efficient”; and grow well on severely Zn‐deficient calcareous soils in Turkey (DTPA‐extractable Zn was 0.12 mg/kg soil and CaCO3was 37%). In all wild grasses studied, Zn deficiency reduced shoot growth but had no effect on root growth. Low amounts of phytosiderophores were released from roots of all wild grasses adequately supplied with Zn. In plants grown without Zn, release of phytosiderophores progressively increased with the onset of visual Zn deficiency symptoms, such as inhibition of shoot elongation and appearance of chlorotic and necrotic patches on leaves. Compared to Zn‐sufficient plants, phytosiderophore release increased 18–20‐fold in deficient plants. HPLC analysis of root exudates showed that the dominating phytosiderophore in Zn‐deficientAgropyronandHordeumwas 3‐epi‐hydro‐xymugineic acid (epi‐HMA) and was 3‐hydroxy‐mugineic acid (HMA) inSecale.Besides HMA,epi‐HMA and mugineic acid (MA) were also detected in exudates of Zn‐deficientSecale.The results indicate the importance of phytosiderophores in adaptation of wild grasses to Zn‐deficient calcareous soils. Phytosiderophores might enhance mobilization of Zn from sparingly soluble Zn pools and from adsorption sites, both in the rhizosphere and within the plants.

ISSN:0190-4167    

DOI:10.1080/01904169609365142

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

In a series of preliminary experiments, the effect of varying solution concentrations of several nutrients on yield in ryegrass (Lolium perenneL. cv Grasslands Nui) or white clover(Trifolium repenscv Grasslands Huia) were investigated using a still low ionic strength (2.7 x 10‐3M) nutrient solution culture technique. The concentration of the nutrients in the basal solution was (μM): 500 calcium (Ca); 100 magnesium (Mg); 300 potassium (K); 600 nitrogen (N) [150 ammonium (NH4), 450 nitrate (NO3)]; 2.5 phosphorus (P); 600 sulfur (S); 3 boron (B); 2.5 iron (Fe); 0.5 zinc (Zn); 0.5 manganese (Mn), and 0.1 copper (Cu) at pH 4.7. The solution concentrations required for 95% maximum yield in ryegrass (μM) were: < 240 for total N, 2 for P, < 240 for S, < 40 for Mg, < 200 for Ca, and < 100 for K. The < symbol indicates that yield did not decrease nor increase, suggesting that the lowest solution concentration used (shown after < symbol) was adequate for 95% maximum yield. In white clover, solution concentrations required for 95% maximum yield (μM) were: < 38 for NH4, 10 for P,< 150 for S, 150 for Mg, < 125 for Ca, and 300 for K. Yield also declined for white clover when additional trace nutrients [Mn, Zn, Cu, iron (Fe), and boron (B)] were added, although the trace nutrient that was toxic could not be determined.

ISSN:0190-4167    

DOI:10.1080/01904169609365143

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

A commercially blended 7–2–11 fertilizer containing 27 g • kg‐1soluble ammoniacal nitrogen (NH4‐N) was evaluated for ammonia (NH3) volatilization and injury to leatherleaf fern (Rumohra adiantiformis)and an indicator plant, tomato (Lycopersicon esculentum).Closed system laboratory incubation studies on pH‐buffered sand medium indicated a very highly significant response (p≤0.001) of NH3volatilization to sand pH. The greatest risk from NH3emissions at pH 8.6 and 32°C appeared to be in the 5 to 70 hour period after fertilizer application. Gypsum (CaSO4) did not affect NH3volatilization. Ammonium nitrate (NH4NO3) was identified as the main source of NH3volatilization from this fertilizer formulation, while on an equal mass basis, ammonium sulphate [(NH4)2SO4] was more important. Both tomato and immature leatherleaf fern fronds were highly sensitive to volatilized NH3from the fertilizer. A critical phytotoxic NH3(aq) concentration in sand solution of 0.14 mM was estimated for immature fern fronds. Mature fern fronds were significantly more tolerant of NH3emissions, which may explain their observed resistance to NH3injury in the field. Assessment of selected soil and irrigation water pH's from a leatherleaf fern growing area in Florida indicated a strong likelihood that volatilized NH3injury to foliage can occur under field conditions.

ISSN:0190-4167    

DOI:10.1080/01904169609365144

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

The partitioning of biomass between aboveground parts and roots, and between vegetative and reproductive plant parts plays a major role in determining the ability of cotton (Gossypium hirsutumL.) to produce a crop in a given environment. We evaluated the single and combined effects of water and N supply on the partitioning of biomass in cotton plants exposed to two N supply levels, 0 and 12 mM of N, and two water regimes, well irrigated and water‐stressed at an early reproductive stage. The N treatments began when the third true leaf was visible, while water deficit treatments were imposed over the N treatments when the plants were transferred into controlled‐environment chambers at a leaf area near 0.05 m2. Both water deficits and N deficits inhibited total biomass accumulation and its partitioning in cotton. Water deficit alone and N deficit alone inhibited the growth of leaves, petioles, and branches, but did not inhibit growth of the stem and enhanced the accumulation of biomass in squares. When water deficit was superimposed on N deficit, leaf growth was inhibited, although to a lesser extent than when it was the sole stress factor, and the accumulation of biomass in squares was also inhibited. Yet, the dry weight of squares in plants exposed to water and N deficits was greater than that of non‐stressed plants. Water and N deficits, either alone or in combination, did not inhibit the growth of the tap root. Growth of lateral roots was not inhibited either by water deficit alone or in combination with N deficit, but was enhanced when plants were exposed to N deficit alone. Exposure to water deficit alone or in combination with N deficit decreased the shoot:root ratio through the inhibition of shoot growth. Exposure to N deficit alone decreased the shoot:root ratio through the combination of shoot growth inhibition and root growth enhancement.

ISSN:0190-4167    

DOI:10.1080/01904169609365145

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor