摘要:

A substantial acreage of soils in northwestern Canada is acidic and P‐deficient. In this study wheat (Triticum aestivumL.) genotypes with different tolerance to acid soils were evaluated for their response to P fertility levels in greenhouse experiments. In Experiment 1, six wheat genotypes were grown on an acid soil (pH 4.8) with toxic level of Al. The Al‐tolerant genotypes included the Brazilian BH1146 and three experimental lines developed in Alberta. The soil was amended with CaCO3to three pH levels (4.8 (untreated), 6.3, and 7.1) and with 0, 1, or 2 mmoles P/kg soil. Liming to pH 7.1 increased dry matter yields and P uptake but not liming to pH 6.3, most probably because of decreased P solubility at the lower lime rate. Consequently, yields were not correlated with soil pH. Phosphate addition increased both dry matter yield and P uptake. Shoot and root dry matter yields were positively correlated with the interaction factor P x pH but not with P alone. Differential response in this regard appeared to be related to acid‐soil tolerance. Some Al‐tolerant genotypes, such as the Alberta lines, were P efficient as measured by P uptake per g of root biomass, whereas BH1146 appeared to have a low internal P requirement combined with a relatively low shoot/root ratio.

ISSN:0190-4167    

DOI:10.1080/01904169209364338

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

Aluminum tolerant soybean cultivars are needed for deeper rooting and increased drought tolerance in acid subsoils. Fifteen cultivars or plant introductions were screened for Al tolerance by growing them for 33 days in pots of unlimed (pH 4.3) and limed (pH 5.6) Taturn subsoil. Tolerance was based upon plant symptoms on unlimed soil (leaf cupping, chlorosis or necrosis, and petiole collapse), absolute dry‐weights of shoots and roots on unlimed soil and relative (unlimed/limed%)shoot and root weights. On unlimed soil, absolute dry weights ranged 4‐fold for shoots and 7‐fold for roots. Relative weights (unlimed/limed %) ranged 2.7‐fold for shoots and 6‐fold for roots. Based on these criteria, entries PI248511 (Japan), Perry (USA), PI381674 (Uganda), Amcor (Ohio USA) and Hernon 147 (Zimbabwe, Africa) were judged most tolerant to the acid soil. Most sensitive entries included Sable, Oribi and Duiker, all from Zimbabwe, Africa, and Chief (USA). Santa Rosa (Brazil) was only moderately tolerant. Entries from Zimbabwe, Africa showed a range of acid soil tolerance. Hernon 147 was most tolerant, Oribi and Sable least tolerant and Buffalo and Impala intermediate. None of the introduced gerrnplasm was superior to Perry in acid soil tolerance. Amcor (Ohio, USA), reportedly tolerant to low soil fertility and drought, was more tolerant to acid Tatum soil than Beeson (Indiana USA). Results suggest that Amcor soybean, like some Ohio cultivars of wheat and barley, may have been exposed to Al during its breeding history. Entries producing highest shoot and root dry weights on unlimed soil were also generally more vigorous on limed soil. Thus, overall vigor may contribute to Al tolerance. Similar observations have been made for selections of Ky 31 tall fescue. Our results suggested that shoot growth alone was an adequate index of acid soil tolerance among the soybean entries tested. Mineral element concentrations in plant shoots were not useful in understanding differential acid soil tolerance.

ISSN:0190-4167    

DOI:10.1080/01904169209364339

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

Water culture experiments are described which provide conclusive evidence that Mo uptake by tomato plants is markedly enhanced by P deficiency. In a longterm experiment, which ran for 11 days, in marked contrast to the uptake of other nutrients, a three fold higher Mo uptake rate was observed after only four days of withdrawal of P from the nutrient medium. In contrast to the gradual increase in pH of the nutrient medium of the plants supplied with P, the pH in the medium of the ‐P plants fell. Throughout the growth of these plants net H+efflux could be accounted for by excess cation over anion uptake, indicating that organic acid extrusion plays no major role in the observed fall in pH.

ISSN:0190-4167    

DOI:10.1080/01904169209364340

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

Plants ofTagetes patulaL. ‘Honeycomb’ andImpatiens wallerana’Novette Red’ were grown in 4‐cell plastic containers (pack) using two different soilless media, Metro‐Mix 350 or peat:perlite (1:1 by volume), or a soil‐based medium, soil:peat:perlite (3:5:3 by volume). Both formulated media were amended with P and K and limed to desired pH. Although differences between media occurred, both species exhibited maximum growth and shelf‐life when fertilized with 100 mg N/L from NO3‐, as compared to those fertilized with 0, 200, or 300 mg N/L. Leaf tissue from the 100 mg N treatments contained lower N levels, but had comparable chlorophyll levels. As N concentrations increased beyond 200 mg N/L, shelf‐life was reduced. Plants receiving 0 mg N exhibited low visual quality and growth parameters; plants grown at 400 mg N/L had high mortality rates and were not marketable.

ISSN:0190-4167    

DOI:10.1080/01904169209364341

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

Two strainsof Rhizobium phaseoli(CP Mex. 46 and CP Mex. 3) and five ofPseudomonas fluorescens(A3, A5, A9, A10, and A12) were compared for their ability to inhibit the growth of six phytopathogenic bacterial strains on iron‐rich and iron‐deficient media. The strains CP Mex. 46 and CP Mex. 3 inhibited five and two of the phytopathogenic strains respectively, but only on the iron‐deficient medium. Each displayed their highest inhibitory activity againstXanthomonas campestrisCBP 123. Similarly,Agrobacterium tumefacienswas inhibited by the strains A3, A5, A9, and X.campestrisby A10 and A12. In all these cases it was inferred that the bacterial interference was mediated by competition for iron through excretion of siderophores. In additionCorynebactererium fscianswas inhibited by A3;X. campestrispvphaseoliCBP 123 by A5 and A10; CBP 140 by A5, A9, and A10; and CBP 147 by A3 and A10; however, in these particular cases other mechanisms other than competition for iron may have been involved, since the inhibition was also clearly detected on the iron‐rich medium as well. Addition of spent media from cultures ofP. fluorescensto low‐iron cultures ofPhaseolus vulgarisplantlets regeneratedin vitroinduced the on set of chlorosis 10 days earlier than exhibited by control plants.

ISSN:0190-4167    

DOI:10.1080/01904169209364342

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

The effect of the nitrogen form (NH4+or NO3‐) added to the nutrient solution and salinity levels (NaCl) was studied in peanut and cotton plants grown in hydroponics. Salinity levels particularly affected the growth of NH4+‐fed plants. Salinity and nitrogen form had different effects in the levels of K+and Na+in the shoots of these two species. Salinity only reduced photosynthesis in severely stressed cotton plants. A high correlation was observed between the level of K+and stomatal conductance. Ammonium resulted in a less efficient use of nitrogen under saline conditions for both species.

ISSN:0190-4167    

DOI:10.1080/01904169209364343

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

Leaf mineral composition of cvs. ‘Red Delicious’ (strain ‘Clear Red') and ‘Golden Delicious’ (strain B) apple(Malus domestica,Borkh) on M 27, M 9 and MM 106 rootstocks was determined six times at 15‐day intervals, beginning 50 days after full bloom from 1986 to 1990. ‘Clear Red’ had significantly higher foliar concentrations of N, P, Mg, Fe and Cu and lower levels of K and Ca. The M 27 dwarfing rootstock increased leaf N, Ca, Mg and Zn but depressed K concentration. Decreasing concentrations of N, Ca and Mg were associated with an increase of cultivar vigour, suggesting a dilution effect of these elements in larger canopy. Because of its preferential capacity to accumulate K in the scion, MM 106 could be useful in reducing K deficiency. Except for Fe, Cu and Zn, mineral content of leaves varied according to sampling date. Generally, concentrations of N, P and K, expressed as dry weight, decreased and those of Ca, Mg, Mn and B increased from the first to the last sampling. Expressing data as dry weight and leaf area led to comparable results for all nutrients except N. For this element, the leaf area method appears more reliable for comparing concentrations sampled over the growing season.

ISSN:0190-4167    

DOI:10.1080/01904169209364344

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

Plant growth parameters, nitrogen content, root and stem nodulation, and acetylene reduction activity of nodules after root and shoot inoculation of hydroponically grown plants ofSesbania rostratawere studied. Stem nodulation reduced the number of root nodules whether stem inoculation was done simultaneously before or after root inoculation. Stem inoculation seven days after root inoculation gave best plant growth. Acetylene reduction was greatest in the root nodules. No significant difference in nitrogen % was observed with the different types of inoculation.

ISSN:0190-4167    

DOI:10.1080/01904169209364345

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

The effects of aluminum on biomass, nutrients and kinases were studied in two durum wheat cultivare(Triticum durumDesf. cvs Sapfo, Capeiti 82) grown in nutrient solutions (pH 4.5) at seven Al levels (0, 9.3, 18.5, 37.1, 74.1, 148, and 297 μM). The most evident Al toxicity symptom was a reduction in root growth. Sapfo showed greater Al tolerance than Capeiti 82. However, both cultivare must be characterized as Al‐sensitives. Aluminum in the nutrient solution above 74.1 μM significantly (P<0.05) reduced root growth of both durum wheat cultivare. The concentration of 74.1 μM Al can be suggested for screening of durum wheats on the basis of tolerance to Al.

ISSN:0190-4167    

DOI:10.1080/01904169209364346

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

Soybean production is increasing in savanna regions of West Africa. However, only limited information exists concerning nutrient requirements of soybean in the region. Trials were conducted at five locations in the Southern Guinea Savanna of Nigeria to determine the response of soybean [Glycine max(L.) Merr.] to P, K, and to a combination of secondary elements and micronutrients. Responses to P varied with P status of the soil and with the application of supplemental secondary elements and micronutrients. Fertilization with K had no effect on yield. Fertilization with secondary elements and micronutrients increased grain yield at all sites after severe P deficiencies were eliminated. Mineral analyses of leaf tissue suggested deficiencies in several secondary elements and micronutrients as well as the possibility of Mn toxicity.

ISSN:0190-4167    

DOI:10.1080/01904169209364347

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor