摘要:

The uptake of cyanamide by plants results in an increase of basic free amino acids, especially arginine. The enhanced increase in arginine content by additional doses of ornithine to cyanamide nutrition suggests that the usual synthesis of arginine (along the course: ornithine ‐‐>citrulline ‐‐> arginino succinate) is shortened to ornithine ‐‐> arginine. Additionally, there is a reduced activity of arginase as a consequence of cyanamide application. Cyanamide is obviously metabolized by plants to lysine and histidine, and after supply of ornithine via the nutrient solution incorporated into arginine.

ISSN:0190-4167    

DOI:10.1080/01904168909363932

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

1.Net NO3‐uptake rates and internal root NO3‐contents were studied in 9 barley (Hordeum vulgareL.) varieties and 5 genetically pure lines of wild oats (Avena fatuaL.). Significant differences in net NO3‐uptake rates and [NO3‐]ewere found among barley cultivars while the NO3‐uptake rates were only significantly different amoung wild oat lines. No correlation existed between net NO3‐flux and [NO3‐]iin barley cultivars.2.Net NO3‐uptake isotherms were determined for 3 barley varieties, Compana, Fergus, and Betzes, and 3 wild oat lines, CS40, AN51, and SH319. Kinetic constants Vmaxand Km, calculated for uptake rates of selected cultivars, indicate that net NO3‐flux was generally higher for Compana than Fergus and Betzes. Although the wild oat lines had similar NO3‐flux rates at higher [NO3‐]elevels, CS40 had a higher net flux at lower nutrient levels.3.Variations in growth characteristics were seen between 9 barley varieties and 5 wild oat lines at 4 different [NO3‐]elevels (25, 50, 100, and 200 μM [NO3‐]e). Variations were more apparent with the biomasses of the cultivars compared with the nutrient contents, suggesting that the intervarietal differences were not so much due to internal total nitrogen but the biomass of the plant.4.Significant differences were seen among barley cultivars and among wild oat lines in seed N, F, and K levels. There was no correlation between the rankings of the seed N content and the growth at 25, 50, 100, or 200 μM [NO3‐]ebetween barley cultivars or wild oat lines in our hydroponic system.

ISSN:0190-4167    

DOI:10.1080/01904168909363933

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

Calcium is known to be passively absorbed by developing peanut pods directly from the soil solution. However, the factors influencing the distribution of Ca in the hull and seed have not been thoroughly studied. In this study of two peanut cultivars (Florunner and Tifton‐8) differing in hull and seed size, pod zones containing differing solution concentrations of Ca (0.025, 0.625, 1.875 and 3.75 mM) were separated from the rooting medium. The increased pod surface area, and hull thickness of Tifton‐8 resulted in greater uptake of Ca (mg pod‐1) and higher hull Ca concentrations when compared to Florunner. However, the thin hull of Florunner (0.59 nun, compared to 1.04 mm for Tifton‐8) resulted in a mean seed Ca contribution to total pod Ca uptake of 62.5% compared to 46.5% for Tifton‐8. Increasing the calcium level in the pod zone increased pod dry weight in both Florunner and Tifton‐8. Pods grown in 3.75 mM Ca for the first 30 days after initial pegging, followed by no Ca in the pod zone until 30 days after initial pegging, had significantly lower seed and hull Ca when compared to pods grown in a continuous supply of Ca. Electron microprobe analysis of pod sections revealed high Ca levels in the exocarp, mesocarp and the outer and inner surfaces of the testa. Both the highly lignified endocarp and the seed were significantly lower in Ca concentration than other pod layers. These results were confirmed by direct analysis of the tissue.

ISSN:0190-4167    

DOI:10.1080/01904168909363934

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

Field experiments were conducted in Prince Edward Island, Canada to determine the effect of Cu applied in the form of copper sulfate as a foliar spray and to the soil; and the effect of chelated Cu as a foliar spray on Cu concentration and yields of wheat (Triticum aestivumL.), oats (Avena sativaL.), alfalfa (Medicago sativaL.), and timothy (Phleum pratenseL.). Copper treatments had no significant effect on the yield of cereals or forages (data not reported). The Cu concentration in the check treatments ranged from 3.4 to 6.6 μg g‐1and 4.4 to 12.1 μg g‐1in the cereals (boot stage tissue and grain) and forage plant tissues, respectively. The cereal grain Cu concentration was not affected but the boot stage tissue and first cut forage tissue Cu concentration increased with Cu applications with highest values occurring in the foliar spray treatments. The first cut of forages from the soil and foliar applied Cu treatments generally had more Cu than the second cut. The Cu values as high as 54 to 55 μg g‐1in timothy and wheat were not related to Cu toxicity.

ISSN:0190-4167    

DOI:10.1080/01904168909363935

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

Soil fertility with effective nodulation and favorable mycorrhizal colonization favor production of high quality, sound mature peanuts within the warm humid and tropical regions of the world. Total top growth of well nodulated and mycorrhizal infected Spanco peanuts, grown on Dougherty sand loam, was depressed with only soil K additions but increased linearly with increased K amendment when combined with P + Ca. Mature peanut yields plant‐1increased with K additions only when combined with P, Ca or P + Ca treatments. Highly significant linear increases of improved marketable, mycotoxin free, sound mature kernels (SMK) resulted with K additions when combined with P and Ca. Nodules plant‐1increased significantly with Ca, P and P + Ca. Nitro‐genase = 1.7 top growth + 3.69 nut yield + 1.12% SMK + 3.89 nodules, R2= 0.78 and C.V. = 13.2%. Plant nutrient content of nodule cytosol increased significantly with soil addition of the corresponding element. Na decreased significantly with increased K. Nitrogenase = 11.2 P + 10.5 Ca + 5.4 K + 1.1 Mg ‐ 0.9 Na, R2= 0.727 and C.V. = 10.7%. Nodule cytosol lipid components were almost equally composed of acylglycerides and phosphoglycerides with significant correlation for nitrogenase activity (r = 0.69). Fatty acid composition was directly related to nodule histology and histochemical cytoenzyme transformations. Brilliant, iridescent anisotropic “Maltese Cross”; birefringence within nonrhizoidal cytosol was related to highly unsaturated phosphoglycerides. This dicroism, within endothelial parenchyma, was highest at anthesis and decreased significantly with increased plant and seed maturity being virtually absent at mature seed harvest, 120 day age from germination. Mycorrizal rootlets, colonized withGlomus fasciculatumwere antibiosic toRhyzoctonia solani,Fusarium oxysporumandPythuim myriotylum.

ISSN:0190-4167    

DOI:10.1080/01904168909363936

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

When 14‐day old wheat plants were transferred from a medium containing nitrate as the sole N‐source to one containing ammonium, the root NH+4‐concentration increased rapidly. This was followed by increases in root phosphoenol pyruvate carboxilase (PEP‐carboxylase) activity, concentration of glutamine, and total free amino acids. Eventually the PEP‐carboxylase activity reached a plateau and free‐NH+4concentration increased thereafter. Similar plants transferred from NO3‐to a mixed N‐source (NH+4+ NO3‐) also showed an increase in root PEP‐carboxylase activity. The enhancement was slower but reached the same final value as for the plants transferred to NH4+‐only. The concentrations of glutamine and free amino acids increased, but to a smaller extent than in the plants transferred to all ammonium. In shoots the treatments produced no detectable changes in PEP‐carboxylase activity. It is concluded that high PEP‐carboxylase activity in roots helps to prevent accumulation of ammonium to toxic levels.

ISSN:0190-4167    

DOI:10.1080/01904168909363937

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

Tomato (Lvcopersicon esculentumMill.) was grown in soil culture in a greenhouse. Potassium nitrate, calcium nitrate, and urea as N sources were compared using biocides (nitrapymn, captan, treflan, and DDT) and an untreated control. The largest shoot growth and fruit yields were obtained with plants fertilized with potassium nitrate. Potassium deficiency, manifested by leaf and stem necrosis and low levels of K in these tissues, appeared to be a limiting factor for the plants receiving urea or calcium nitrate. The depression of leaf and stem K by NH4+or Ca++was associated with the antagonism of these ions on K+absorption. The biocides limited plant growth especially with urea and potassium nitrate. Depression of K, Ca, or Mg concentrations in the plants were effects associated with the biocides and their interactions with N sources.

ISSN:0190-4167    

DOI:10.1080/01904168909363938

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

Plant analysis has been used to evaluate the nutritional status of many crops for diagnostic and corrective purposes. This study was initiated to establish critical N plant tissue levels using midrib NO3‐N concentration for broccoli (Brassica oleraceaL., Botrytis group) during the growing season. Tissue samples for nitrate analysis were taken from broccoli plants over a period of three growing seasons beginning at the 4 to 6 leaf stage of growth and biweekly through pre‐harvest. The midrib from the most recently matured leaf was sampled for NO3‐N concentration determination.

ISSN:0190-4167    

DOI:10.1080/01904168909363939

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

ISSN:0190-4167    

DOI:10.1080/01904168909363931

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor