摘要:

Four tomato(Lycopersicon esculentumMill.) strains (203, 474, 546, and 576) that are equally efficient in potassium (K) absorption, but different in efficiency of K use were studied using a continuously flowing solution culture to determine the importance of K‐transport rate from root to shoot in relation to K‐use efficiency. Strains 203 and 546 are inefficient in K use, ratios of K in shoots to roots were found to be three times higher than those of the two K‐use efficient strains 474 and 576 when grown under low‐K stress (0.1 mM). In addition, both the K concentrations and rates of K flow in xylem exudates of decapitated strains 203 and 546 were significantly higher than those of strains 474 and 576. These results suggest that high rates of K transport from roots to shoots are unrelated to K‐use efficiency in the tomato strains grown under low‐K stress. Further studies of K distributions in leaves and stems found that K concentrations in matured leaves and stems of the two efficient strains 474 and 576 were markedly lower than those of the two inefficient strains 203 and 546, while K in young and expanding leaves of the efficient strains were significantly higher than those of the inefficient strains, indicating that the ability to mobilize K from matured leaves to young and expanding leaves is an important factor that contributes to K‐use efficiency in tomato plants grown under low‐K stress.

ISSN:0190-4167    

DOI:10.1080/01904169909365658

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

To examine the role of organic manure on boron (B) availability, a greenhouse experiment was conducted to study the effect of B and farmyard manure (FYM) levels on growth, yields, and B accumulation of sunflower(Helianthus annuusL.). Application of B or FYM individually increased the plant height, capitulum diameter, dry matter yields of seed and stalk and their B concentration and accumulation. The interaction of B and FYM levels had a significant influence only on B concentration of stalk and total B accumulation of sunflower. In the absence of B application, use of highest level of FYM (10 g kg‐1soil) significantly increased B concentration of stalk and total B accumulation by the crop while with B application, use of FYM at lower rates was effective. Application of B or FYM, especially at higher rates of the latter (5 and 10 g FYM kg‐1soil) increased the content of hot‐water soluble soil B in the soil after crop harvest. The interaction of B and FYM levels had no significant effect on the content of hot‐water soluble soil B. Application of FYM increased apparent availability of native and added B from soil to sunflower crops.

ISSN:0190-4167    

DOI:10.1080/01904169909365659

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

Crop and native plants can be characterized as high and low nutrient‐adapted based on their expected response to native and applied nutrients. Our objective was to compare the plasticity of biomass allocation and tissue nutrient concentrations to added sulfur (S) and nitrogen (N) across a continuum of high and low nutrient‐adapted grasses, represented by barley(Hordeum vulgare),smooth brome(Bromus inermis),bluebunch wheatgrass(Pseudoroegneria spicata),and Idaho fescue(Festuca idahoensis).In our greenhouse study, treatments included two S sources (pyrite and gypsum), at 150 and 300 kg S ha‐1, N at 50 kg ha‐1, and a check. Shoot biomass of barley, smooth brome, and bluebunch wheatgrass was enhanced by S plus N. Shoot biomass of barley and smooth brome was greater with pyrite than with gypsum. Root biomass of smooth brome and bluebunch wheatgrass was greater with pyrite than with gypsum. Plant S concentrations of barley and Idaho fescue were enhanced by added S. Plant S concentrations in barley and smooth brome were greater with gypsum than with pyrite. Except for barley, plant S pools (shoot biomass x shoot S concentration) were enhanced with S plus N compared with no added nutrients. Nitrogen pools of barley, smooth brome, and bluebunch wheatgrass were higher with pyrite than with gypsum. Soil sulfate (SO4) was greater when S or S plus N was added than without any added nutrients. For barley and smooth brome, soil sulfate tended to be lower with pyrite than with gypsum. For all soils, pH was lower with added S or added S plus N compared with unamended soils. While pyrite lowered soil pH, gypsum tended to increase soil pH. Overall, barley and smooth brome were highly plastic in responding to enhanced nutrient levels, bluebunch wheatgrass was relatively responsive, and Idaho fescue was least responsive.

ISSN:0190-4167    

DOI:10.1080/01904169909365660

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

The 3–4 year monitoring study showed that fluctuations in durian(Durio zibethinttsMurray) leaf and soil nutrient element levels were closely related to seasonal changes in the crop phenology. The leaf sampling method was standardized taking the 5th and 6th mature green leaf from the shoot tip. The best sampling time was determined to be in November where the coefficient of variability for most nutrient elements were the lowest at or lower than 20%. Tentative standards for durian leaf nutrient elements were set up taking the 95% confidence interval of the means at this sampling stage. All the leaf macro elements, nitrogen (N), phosphorus (P), potassium (K), sulfur (S), and the micro elements, zinc (Zn), manganese (Mn), copper (Cu), and iron (Fe) declined or were lower during fruit set and development from September to end of fruit harvest in January. Leaf N was also the lowest in July and leaf P at the tail end of harvest. Soil N, P, and the bases K, Ca, and Mg also exhibited similar trends, lower during fruit development especially in October‐November and were lower during active leaf flushing from March to May.

ISSN:0190-4167    

DOI:10.1080/01904169909365661

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

Tomato(Lycopersicon esculentumMill. cv. Sunny) was grown with the full‐bed polyethylene mulch‐seepage (modified furrow) irrigation system for three seasons to evaluate the effects of potassium (K) sources and K rates on fruit yields and leaf K concentrations. Soil in the experimental area was an Eau Gallie fine sand (sandy, siliceous, hyperthermic Alfic Haplaquods) that varied from 12 mg kg‐1(very low) to 56 mg kg‐1(medium) K by Mehlich I extraction prior to planting. Potassium sources, potassium chloride (KC1), potassium nitrate (KNO3), and potassium sulfate (K2SO4) were evaluated at 0, 90, 180, 270, and 360 kg kg‐1K rates. Nitrogen (N) was applied at 270 kg kg‐1and P at 43 kg kg‐1with all K rates. Yields of extra‐large and marketable total yields in one season were higher (P<0.05) with potassium nitrate (KNO3) than with KC1. Maximum yields were produced from 270 to 360 kg K kg‐1, regardless of pre‐plant soil K concentrations. In the shoots, K concentrations increased with increasing K rates. At 90 and 180 kg K kg‐1application rates, K concentrations in the shoots were <2% and the plants and fruits had K‐deficiency symptoms.

ISSN:0190-4167    

DOI:10.1080/01904169909365662

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

Two white clover (Trifolium repensL.) genotypes, identified by their differing ability to increase in biomass in response to added phosphorus (P) (high P responder, low P responder) were subjected to P deprivation and examined for differences in root growth, root surface acid phosphatase activity, and soluble and ionically‐bound root cell wall isoform profile. As leaf P levels declined, the high P responder showed a greater increase in biomass allocated to the roots, and highest root surface acid phosphatase activity. However, these differences were not statistically significant. The onset of P deprivation enhanced the intensity of several acid phosphatase isoforms in the P deprived root extracts from both genotypes. After 11 days, one basic isoform (resolved atpH4.5) was enhanced in the cell wall extract, an enhancement that was also observed after 26 days. However, for the soluble isoforms, a temporal separation of response was observed in both genotypes. After 11 days, there was no discernable enhancement of the major staining basic isoform or in the major staining acidic isoform (resolved at pH 8.8) in extracts from P‐deprived roots. After 26 days, these isoforms were enhanced in extracts from P‐derived root tissues. Further, a second acidic isoform could now be discerned as a major staining enzyme in P‐derived root extracts from both genotypes.

ISSN:0190-4167    

DOI:10.1080/01904169909365663

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

The effects of silicon (Si) on the toxicity of aluminum (Al) to mungbean(Phaseolus aureusRoxb.) seedlings were studied in a growth chamber. Mungbean seedlings were grown in a nutrient solution with combinations of three concentrations of Si (0,1, and 10 mM) and three concentrations of Al (0, 2, and 5 mM) in randomized completely block design experiments for 16 days. Silicon at 1 mM in the solution decreased root length, fresh and dry weights, and chlorophyll content, and showed no significant effect on epicotyl length and seedling height, and protein contents of shoots or roots in mungbean seedling under no Al stress. But, Si at 10 mM showed marked toxic effects on mungbean seedling growth and increased protein contents of the shoots or roots. In contrast, under 2 mM Al stress, Si addition at 1 mM had significant increasing effect on root length, fresh and dry weights, and chlorophyll content. It also had decreasing effect on protein contents of the shoots or roots, and had no effect on epicotyl length and seedling height. Silicon addition at 10 mM showed no effect on morphological and physiological measurements of mungbean seedling. However, Si at 1 mM added to solution only increased seedling height, epicotyl length, fresh weight, and chlorophyll content, but decreased dry weight and protein content of the roots under 5 mM Al stress, significantly. Silicon addition at 10 mM showed similar toxic effects on mungbean seedling growth under 5 mM Al stress to that under no Al stress.

ISSN:0190-4167    

DOI:10.1080/01904169909365664

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

Seedlings of elephantgrass (Pennisetumpurpureum,Schum.), cvs. Vruckwona and Napier, were grown in aerated nutrient solution and exposed to pH levels of 4.0, 5.0, 6.0, or 7.0. After 30 days under controlled conditions, the effects on growth were evaluated. Plants exposed to pH 5.0, as compared to those under pH 4.0, showed increases in total leaf area, plant height, number of leaves (NL), and leaf, root, and stem fresh weight. No significant differences were found in stubble fresh weight, maximum individual leaf area, leaf area ratio (LAR), leaf area:plant height ratio, and leaf, root, stem, and stubble dry weight and dry matter percentage. Seedlings exposed to pH 4.0, as compared to those under pH 5.0, exhibited higher leaf:stem ratio on a fresh weight basis (FWR) and a tendency for higher leaf :stem ratio on a dry matter basis (DWR). Cultivar Vruckwona yielded superior results than Napier for most studied parameters, except for NL, LAR, and DWR (in which there were no significant differences) and for stubble length and FWR (in which Napier performed better). The results suggest that reductions below 5.0 in the nutrient solution pH cause growth inhibition, affecting root, stem, and leaf FW to a greater extent. The magnitude of such effects varies among contrasting cultivars. In turn, pH increases above 5.0 induce no significant growth reduction or promotion.

ISSN:0190-4167    

DOI:10.1080/01904169909365665

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

Greenhouse and field experiments were conducted to determine the influence of nitrogen (N) fertilization and DTPA‐extractable soil zinc (Zn) on Zn concentration in wheat (Triticum aestivumL., cv. Pioneer 2375) grain. Application of zinc sulfate (ZnSO4) in the range of 0 to 8 mg Zn kg‐1increased linearly DTPA‐extractable Zn in an incubated calcareous soil from 0.3 to 5.0 mg kg‐1. Application of these rates of ZnSO4to the same soil under greenhouse conditions increased Zn concentration of wheat grain from 26 to 101 mg kg‐1. The influence of 134 kg urea‐N ha‐1on Zn concentration in wheat grain at eight field sites, with DTPA‐extractable soil Zn levels ranging from 0.3 to 4.9 mg kg‐1, was studied. Nitrogen fertilizer increased wheat‐grain yields in four of the eight experiments but had little effect on grain‐Zn concentration. Grain‐Zn concentration ranged from 31 to 45 mg kg‐1in N‐fertilized plots at the various sites and was related (r=0.74*) to DTPA‐extractable soil Zn.

ISSN:0190-4167    

DOI:10.1080/01904169909365666

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

Mineral nutrition of panicled gypsophila roots (Gypsophila paniculataL.) (Caryophyllaceae) cultivatedin vitroin two media with different mineral composition, a classical Gamborg's B5 medium and a modified MH3 medium, was studied over a growth cycle of 28 days, by continuous measurement of mineral element consumption, without opening the culture flasks. The comparison between the total mineral element quantities consumed from media and those absorbed by roots at harvesting showed a good correspondence, proving the validity of the technique used and the absence of insolubilized mineral forms in the in vitro culture media. The mineral element composition of the MH3 medium was found to be better suited toGypsophila paniculataroot culture since all mineral nutrient elements are supplied in adequate quantities which are non‐limiting and non‐excessive. Culture on B5 medium showed that phosphorus (P) and copper (Cu) are probably the factors limiting growth and revealed an ammonium (NH4+)/potassium (K+) ion antagonism. Thein vitroroots, although uncoupled from the aerial part, behave like the roots of whole plants in several ways: the evolution of the medium pH corresponds to the form of the mineral nitrogen (N) consumed by the roots; sodium (Na) and chloride (Cl) are barely consumed and may be considered as non‐essential elements. Lastly, thisin vitroroot culturemodel makes itpossible to explain that the absorption of Na and Cl by the roots of whole plants is probably dependent on the transpiratory flow of the aerial part.

ISSN:0190-4167    

DOI:10.1080/01904169909365667

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor