摘要:

Bud formation and flowering of Chrysanthemum morifolium grown at different levels of Cu, Fe and Mn in a peat/sand substrate have been studied in relation to the micronutrient status of the plants and to the phenolase, peroxidase and IAA oxidase activities in the leaves. When iron levels were inadequate, bud formation was inhibited by the omission of copper but there was no effect of omitting copper when iron was fully adequate. Very few buds opened fully, however, wherever copper was omitted. The copper content of the plants grown without added copper (2.4 ppm) was well below the published ‘critical’ level and was unaffected by the other treatments, Phenolase activity in the leaves was markedly reduced by copper deficiency irrespective of the level of iron applied. When the level of copper was adequate, however, phenolase activity increased with the level of iron. Similar but less marked effects were observed with peroxidase and IAA oxidase. The significance of the results in relation to the mechanism of flowering in the chrysanthemum is discussed.

ISSN:0010-3624    

DOI:10.1080/00103627809366806

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

Analysis of data obtained from samples collected in the Delta area of Mississippi showed that the potassium concentration of young mature and old mature cotton leaf‐blades correlated better with soil test potassium than did that of the apical immature leaf‐blades.

ISSN:0010-3624    

DOI:10.1080/00103627809366807

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

The distribution of some nutrient elements in parts ofDesmodium intortumcv. Greenleaf plants of different age was studied in order to determine the most appropriate sampling technique for chemical analysis of nutrient status. When expressed on a dry weight basis, concentrations of N, P, K, S, Ca, Mg, Al, B and Mn in plant parts of similar physiological age declined with plant age, thus necessitating a standardized plant age for sampling. Only Zn concentrations remained stable with plant age. When expressed relative to tissue water, concentrations of P, S, Mg, Al, B and Mn changed little with plant age because percentage dry matter in all plant parts increased with plant age. On a tissue water basis, K concentrations still decreased with plant age. Concentrations of N and Ca were most stable with plant age when expressed relative to tissue fresh weight.

ISSN:0010-3624    

DOI:10.1080/00103627809366808

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

Extractable li with ammonium acetate was determined by flamephotometry, in normal soils, alkaline soils and saline soils in the Province of La Pampa (Argentina).

ISSN:0010-3624    

DOI:10.1080/00103627809366809

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

The patterns of Zn absorption and transport from different concentrations of ZnSo4were examined in young peanut (Arachis hypogaeaL. cv. T.G. 1) seedlings. It was found that the absorption from low concentrations of ZnSO4followed a typical biphasic pattern suggestive of an active process. The transport to the leaves was very much less than the amount absorbed by roots. It is concluded that Zn is not freely mobile in peanut seedlings.

ISSN:0010-3624    

DOI:10.1080/00103627809366810

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

Four extractants for soil Mn were compared for their sensitivity to changes in Mn availability caused by rates and sources of added soil Mn and soil pH variations. Their ability to extract amounts of Mn correlated with plant Mn concentrations was also determined. Two field experiments were conducted on a sandy, high water table soil (Ultic Haplaquod‐Arenic Plinthaquic Paleudult) which included 5 Mn rates, 4 Mn sources and 3 soil pH levels. Soybeans [Glycine max(L.) Merr. cultivar Ransom] were grown and leaf tissue and soils sampled at the late pod‐fill stage. All four extractants separated the high‐ Mn rates, but the small exchange method did not separate the low Mn rates. Few differences were observed among extractants due to Ma sources. The DTPA method was the only procedure to correctly distinguish soil pH levels by showing decreasing extractable Ma with increasing soil pH. Including pH in multiple regressions significantly increased the plant Mn‐soil Mn correlation coefficients. The DTPA method and the 0.1NH3PO4method had the highest correlation coefficients and the double acid method the lowest. The small exchange method was intermediate. Considering all the results, the DTPA was the most promising method for extracting Mn from this sandy, southern Coastal Plain soil.

ISSN:0010-3624    

DOI:10.1080/00103627809366811

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

Nutrient ratios in plant tissue have often been used as diagnostic tools with varying degrees of success depending on whether or not they have been misunderstood or misinterpreted. The meaning of a nutrient ratio is explored so that the relationship between yield and a given ratio can be clearly defined and understood. When a nutrient ratio has an optimal value, any yield is possible, the actual level being determined by the factors contributing to yield. When a ratio is too low, a response to the element in the numerator will be obtained if, indeed, it is limiting. If the element in the denominator is in fact excessive, a yield response may or may not be recorded depending on the level of other yield factors. When the ratio is too high, the reverse is true. Thus consideration of a nutrient ratio in isolation does not permit one to identify which of the two nutrients being considered is limiting yield. However, as the number of nutrient ratios considered simultaneously increases, identification of the nutrient(s) limiting yield becomes easier and more reliable.

ISSN:0010-3624    

DOI:10.1080/00103627809366812

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

ISSN:0010-3624    

DOI:10.1080/00103627809366805

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor