摘要:

Interaction between uptake of calcium and phosphate has been found. A reduction in growth rate and nutrient uptake rates caused by mixing ground barley straw into a soil could be restored by three different treatments:1.by adding phosphate fertilizers2.by adding gypsum solution, or3.by simply not incorporating straw into the soil. The application of gypsum solution without the incorporation of straw or phosphate fertilizers had a negative effect.

ISSN:0010-3624    

DOI:10.1080/00103627909366884

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

ISSN:0010-3624    

DOI:10.1080/00103627909366885

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

ISSN:0010-3624    

DOI:10.1080/00103627909366886

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

Calcium movement in plants is unidirectional, moving up from the roots and generally routed to meristematic zones and young tissue. Once deposited in leaf tissue it is not recycled, even under calcium stress conditions.

ISSN:0010-3624    

DOI:10.1080/00103627909366887

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

In a pot experiment with two year old Golden Delicious apple trees on Merton 793 rootstock it has been shown that calcium was actively absorbed during the shoot extension period as well as during summer and autumn. At dormancy, the bark of the trees contributed about 59% to the total calcium content although it contributed only 12% to the total tree mass. During the period of rapid shoot extension the calcium reserves from the permanent structure of the trees made a very important contribution (22.8%) to the total calcium content of the new growth (shoots, leaves, and fruit), suggesting that at least a portion of calcium present in the trees at dormancy was in an exchangeable form.

ISSN:0010-3624    

DOI:10.1080/00103627909366888

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

In multicellular tissues such as the cortex of roots and the mesophyll cells of leaves, where there are no specialized vascular elements, the pathways for the movement of ions are the symplast and apoplast. Observation of calcium transport in regions where these pathways are physically or physiologically blocked can provide information on the pathways of calcium movement. In roots, calcium movement to the central xylem is heavily reduced in regions where suberization and cellulose thickening of the endodernis constitutes a barrier to apoplastic movement. The implication that calcium moves with difficulty in symplastic pathways in general is supported by the relative immobility of calcium in the phloem, its slow rates of diffusion across layers of cells such as in fruit cortical tissue, and lack of redistribution from aging leaves to other parts of the plant. It is suggested that suberization of bundle sheath cells in many monocotyledons may have a restrictive effect on the transfer of calcium between leaf vascular tissue and surrounding cells.

ISSN:0010-3624    

DOI:10.1080/00103627909366889

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

The transport processes of divalent cations in the xylem have been studied using semiconductor radiation detectors, operated at room temperature. Cut shoots of a papyrus plant (Cyperus papyrus spec.) have been used as a model system. Using a sequential supply of labelled and unlabelled solutions (45Ca,115Cd) in the presence or absence of a chelating agent (EDTA), the CEC of the transport system has been determined. Results have been verified in perfusion experiments, using isolated stem segments. Values obtained for CEC, expressed in moles calcium or cadmium per unit of vessel wall surface, range from 3 to 5 x 10∼2. Such a high density (1.8 to 3 ions A0–2) is not realistic, and shows that the exchange sites are located in an extended volume rather than only at the surface of the vessel wall. Different possible consequences regarding the cation exchange processes and calcium transport are discussed.

ISSN:0010-3624    

DOI:10.1080/00103627909366890

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

The objective of the investigation was to localize in short‐term experiments the pathway of Ca along its acropetal long distance transport, especially to the fruit. An easy lateral transfer from the conducting vessels to the adjacent tissues was demonstrated. After root uptake by strawberries, and even after pulse labeling by injection of45ca into the fruit stalk, a substantial amount of the radioactivity was always present in the phloem. Nevertheless, appropriate histoautoradiographs as well as auxiliary experiments indicated that the ascending of Ca primarily occurs in the xylem.

ISSN:0010-3624    

DOI:10.1080/00103627909366891

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

Tipburn of cabbage has been prevented in growth‐chamber studies by enclosing plants at night in plastic bags to encourage root pressure flow. Short‐period (4 hour) uptake studies of45Ca from nutrient solutions have shown a large accumulation of45Ca in the inner leaves when the entire plant was enclosed, so that root pressure flow occurred. However, there was essentially no accumulation of45Ca in inner leaves when only the inner leaves were enclosed and the outer leaves were exposed to an atmosphere that encouraged transpiration from these leaves. The small amount of45Ca present in these leaves accumulated in the center one‐half of the leaves and none was found in the marginal areas of the leaves. A tipburn of developing leaves of young ‘Red Core Chantenay’ carrot plants also has been prevented by enclosing the plants in plastic bags at night to encourage root‐pressure flow. This disorder of carrot leaves occurs with rapid growth in controlled‐environment chambers. Daily sprays of CaCl2solutions greatly reduced the severity of this injury.

ISSN:0010-3624    

DOI:10.1080/00103627909366892

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

An attempt will be made to elucidate how the basic phenomena governing Ca uptake and distribution in the plant respond to manipulation.

ISSN:0010-3624    

DOI:10.1080/00103627909366893

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor