ISSN:0010-3624    

DOI:10.1080/00103627909366875

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

ISSN:0010-3624    

DOI:10.1080/00103627909366874

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

A general discription of soil characteristics of Latin America is given with emphasis being put on the oxisols of the subtropical and tropical regions; the relationships among pH and degree of Al and Ca saturation is presented; special mention of the cerrado soils of Brazil is made. Calcium requirements of main crops are tabulated. A review is made of known cases of Ca deficiency under field or green house conditions with an attempt to differentiate between Ca responses and other effects of liming and/or fertilization on observed crop responses. Losses by leaching, erosion, and crop removal of Ca are estimated; a rough balance sheet of inputs and outputs is presented.

ISSN:0010-3624    

DOI:10.1080/00103627909366876

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

The appearance of the so‐called “bull‐whip”; in leaves of maize plants has been recognized as a calcium deficiency symptom. Another characteristic symptom, in which the leaf edges of maize plants become serrated and curl, is often observed when there is a low calcium supply, especially in solution cultures. The effects of several factors on this symptom were investigated using solution cultures.

ISSN:0010-3624    

DOI:10.1080/00103627909366877

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

An electron‐microprobe study of ‘Golden Delicious’ apples with and without bitter pit revealed a 1.7‐fold increase in calcium and a 5‐to 8‐fold increase in magnesium in pitted as compared to non‐pitted tissue. Potassium gradients were not evident in either pitted or non‐pitted tissues. The highest concentration of calcium and magnesium was in the approximate center of the pitted area. No significant gradients in calcium, magnesium and potassium appeared in the control tissue. A scanning electron microscope (SEM) study revealed spherical shaped'globules’ in the pitted tissue only. Electron microprobe analysis indicated these globules to be high in calcium and ultra‐high in magnesium as compared to the surrounding tissue. Golden Delicious apples were vacuum infiltrated with calcium or magnesium alone or in combination with ethylene or ethephon. Within 1 week after infiltration, the magnesium‐treated fruit exhibited bitter‐pit symptoms that were morphologically similar to those induced either by ethylene or ethephon treatment. The results indicate that magnesium can stimulate bitter‐pit symptoms, whereas, calcium treatment can totally prevent bitter‐pit development.

ISSN:0010-3624    

DOI:10.1080/00103627909366878

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

Calcium deficiency was induced in developing potato sprouts by growing them in a humid atmosphere.

ISSN:0010-3624    

DOI:10.1080/00103627909366879

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

In view of the possibility that senescence may be a consequence of the deterioration of cell walls and membrane compartments, calcium was studied as a possible agent which might defer senescence. Calcium treatment delayed leaf senescence in corn leaf discs. The effect of calcium on senescencse was additive to the cytokinin deferral of senescence. An increase in hydraulic permeability to [3H] water during senescence was demonstrataed and this increase was deferred by calcium; calcium plus benzyladenine was even more effective. Analysis of inorganic ions in the pericarp of nonripeningrinmutant tomajç fruits and isogenic Rutgers revealed higher levels of bound Ca inrinat advanced stages of maturity. In the normal fruits, bound Ca decreased about 3‐fold during maturity. Inrinfruits, no change in polygalacturonase (PG) activity was detected, whereas in Rutgers, an increase in PG activity was observed at advanced stages of maturity. Each of the measured changes associated with senescence (pigment changes, protein decrease, hydraulic permeability increase, and an increase in cell wall enzyme activity) was suppressed by calcium, and the interpretation is offered that the effects are a consequence of the calcium function in maintaining cell wall structure and membrane integrity.

ISSN:0010-3624    

DOI:10.1080/00103627909366880

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

This review paper examines the relative importance of the major factors which influence the uptake of Ca by crop plants. Sources of soil Ca and the significance of mass flow and diffusion in Ca uptake are discussed. The cation composition of the soil solution, the form and level of N‐nutrition, root extension, morphology and distribution in the soil, and the specific plant species and cultivar are all important in regulating Ca uptake at the soil/plant root level. The close relationship between Ca uptake and water uptake by plant roots is of further importance. The specific effects of Ca on membrane structure and function are also discussed in relation to the uptake process.

ISSN:0010-3624    

DOI:10.1080/00103627909366881

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

Uptake and transport of Ca by apple seedlings is affected by the nutrient balance in the solution. The order and magnitude of these effects depend upon the N source and concentration and the presence or absence of Al. Nitrogen concentration had a greater effect on Ca uptake than did the concentration of either K_or Mg. Apple seedlings did not grow in the presence of Al when NO3, alone was the N source and a large number of Ca‐containing crystals were precipitated in Jhe phloem of these seedlings. Few crystals were observed when NH4+was present in the nutrient solution. When 1/5 of the total N was present as NH, growth of seedlings in the presence of Al was similar to that of those receiving only NH4+Calcium uptake was affected differently by NH4+: NO3‐ratio in the absence or presence of Al.

ISSN:0010-3624    

DOI:10.1080/00103627909366882

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

Effects on nutrient uptake and incidence of corking on Yorking/M106 of various Ca and N sources applied prior to orchard planting are reported. After 3 years, no treatment consistently reduced cork spots/fruit. Calcitic, calcitic with 3% Mg, hydrated, and dolomitic lime at 11.2 MT/ha increased leaf Ca, calcitic by 15%, dolomitic by 6%. All but hydrated decreased leaf K. Hydrated gave highest leaf P. All types increased leaf Mg, dolomitic by 24%, calcitic by 20%. All types decreased leaf Mn. Increasing lime up to 33.6 MT/ha further increased leaf Ca, soil injection at 40 cm depth giving highest leaf and peel, but not highest flesh Ca. Of triple superphosphate, gypsum, or calcium chloride added to lime, calcium chloride, though toxic to some trees, had the greatest effect, incresing leaf P,K, and Ca, and lowering N and Mg. Calcium chloride did not raise leaf Ca above that from the deep‐lime treatment. When sodium nitrate, calcium nitrate, or ammonium sulfate were applied at 18 g N/year of tree age, calcium nitrate increased leaf, peel, and flesh Ca as compared to ammonium sulfate. Ammonium sulfate depressed B in flesh and peel. Results showed nutritional status can be substantially changed with little effect on corking.

ISSN:0010-3624    

DOI:10.1080/00103627909366883

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor