摘要:

Disorders of vegetable crops caused by deficiencies or toxicities of the elements essential for higher plants are described. The soil and environmental conditions affecting the availability of plant nutrients in soils are discussed in reference to the potential for occurrence of nutritional disorders.

ISSN:0190-4167    

DOI:10.1080/01904167909362696

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

ISSN:0190-4167    

DOI:10.1080/01904167909362695

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

The experiments reported here were designed to examine the influx kinetics of K, Rb and Cs into the intact plant root systems. Roots of intact corn, onion and wheat plants showed no kinetic discrimination in absorption of K and Rb so that K and Rb are suitable cations to use for studies of the mechanism of their absorption by plant roots growing in soil systems. Absorption of Cs by corn roots was slower in relation to K absorption than would be the case if both were taken up without discrimination. There was a linear relation between K/Cs uptake and K/Cs concentration in the solution indicating that K was absorbed approximately twice as rapidly as Cs. The K‐Cs pair of ions would not be suitable for studies of ion uptake mechanisms.

ISSN:0190-4167    

DOI:10.1080/01904167909362697

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

Moderate B deficiency in plants has been reported to enhance Cu deficiency by keeping these plants in the vegetative growth stage. In this study, ascorbate oxidase activity was used as an index of the effect of B stress on Cu activity. When T3238FER (B‐inefficient) and Rutgers (B‐efficient) tomatoes(Lycopersicon esculentumMill.) were grown in nutrient solutions at various B levels, B‐stressed plants had higher ascorbic acid oxidase activity than B‐sufficient plants. This activity was significantly higher in T3238FER than in Rutgers. Ascorbic acid oxidase activity may be directly or indirectly related to the role of B in plant growth and may be responsible for the more efficient use of B by Rutgers than by T3238FER tomato.

ISSN:0190-4167    

DOI:10.1080/01904167909362698

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

The effects of major nutrient elements supplied as (NH4)2SO4, urea, K2SO4and KH2PO4on the absorption and transport of Fe were studied in intact bean plants, and compared with the absorption patterns in excised bean roots. (NH4)2SO4and urea, which are sources of N, generally decreased the absorption by roots and enhanced the transport to the shoot, while in contrast, K2SO4and KH2PO4both increased the absorption and reduced the transport. The absorption of Fe by excised bean roots was increased significantly by urea and KH2PO4.

ISSN:0190-4167    

DOI:10.1080/01904167909362699

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

Foliage of each species was sampled at 26 paired locations in the San Francisco Bay area.Eucalyptus globulushad significantly higher concentrations of Mn, Ca and Na, but significantly lower concentrations of Cu, Fe, Zn, P, NO3‐N and Kjeldahl‐N than didQuercus agrifolia. Concentrations of K and Mg did not differ between species. The relative concentration series for the species were similar: N>Ca>K>Mg>Na>P>Mn>Fe forQ.agrifoliaand Ca>N>K> Mg>Na>Mn>P>Fe forE.globulus. Correlations between species were statistically significant for concentrations of Fe and Ca only. Thus, for these elements analysis of one species could be used as an indicator of the other.

ISSN:0190-4167    

DOI:10.1080/01904167909362700

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

Four Se accumulators and two non‐accumulator plants were examined for their Se content in wet and dry years. No significant change in Se quantity was noted in the non‐accumulators in relation to variations in annual precipitation. However, the concentration of Se found in accumulator plants is significantly higher in wet years than in dry ones. Furthermore, in wet years there is a higher percentage of water soluble Se in these plants than in dry ones. The soils supporting these plants were also examined for their Se content. In dry years these soils contain more water soluble Se than in wet ones but, in dry years, this form of Se is less available due to the lack of available moisture. High precipitation may tend to reduce absorption of Se by plants by diluting the water soluble Se present in the soil solution, but it is clear that it also promotes absorption of Se by encouraging vigorous growth of these accumulator plants.

ISSN:0190-4167    

DOI:10.1080/01904167909362701

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

Switchgrass (Panicum virgatumL.) and timothy (Phleum pratenseL.) shoots were harvested at 12 noon during three days at Madison, Wisconsin. Shoots were separated into the inflorescence, individual green leaf blades, green leaf sheaths, and internodes. Switchgrass shoots, inflorescences, and leaves were greater in dry weight than those of timothy. Switchgrass shoots had higher concentrations of all macro‐ and microelements measured than timothy, except for K. Most shoot parts of switchgrass were low in K percentage, indicating that switchgrass possibly may have a lower critical K level than timothy for maximum herbage production. Switchgrass shoots contained a concentration of Mg that was three times higher than timothy. This difference is worthy of note since one problem associated with grazing is hypomagnesemia. Fructosans were found only in timothy, but both grasses contained starch. Percentage of total nonstructural carbohydrates (TNC) was nearly three times higher in the shoot of timothy than switchgrass, indicating possibly a much higher energy value from timothy for the grazing animal and for making silage.

ISSN:0190-4167    

DOI:10.1080/01904167909362702

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

ISSN:0190-4167    

DOI:10.1080/01904167909362694

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor