Influence of Humic Acids on Plant Growth

Kock, P. C. De

doi:10.1126/science.121.3144.473-a

Cited by 51 publications

(11 citation statements)

References 5 publications

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“…At 1280 mg/L HA, roots were highly branched and this may have resulted in an increase in surface area, which could have facilitated more efficient nutrient absorption, or HA could also be acting as a chelating agent, as previously reported (DeKock, 1955;Linehan, 1978;Stevenson, 1972). Also, the significant correlation found between HA and electrolyte leakage which was used as an indication of membrane permeabilty suggest that HA maybe influencing plant growth at the cellular level by influencing cell permeability.…”

Section: Discussionmentioning

confidence: 63%

A humic acid improves growth of tomato seedling in solution culture

David

Nelson

Sanders

1994

Journal of Plant Nutrition

140

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The effects of humic acid (HA) on nutrient accumulation and growth of tomato seedlings were evaluated in a solution of limited nutrient availability in a greenhouse. HA additions were made to the nutrient solution at rates of 0, 640, 1280, or 2560 mg/L. The addition of 1280 mg/L HA produced significant increases in shoot accumulation of P, K, Ca, Mg, Fe, Mn, and Zn as well as increased accumulation of N, Ca, Fe, Zn, and Cu in roots. Fresh and dry weights of roots were also increased, However, on comparing nutrient accumulation in plants treated with 1280 mg/L HA and those given an additional supply of nutrients equivalent to those supplied by HA at the 1280 mg/L rate, shoots accumulated more N, P, K, Fe, and Cu, while roots accumulated more K and Ca. Therefore these increases do not appear to be associated with nutrients contained in HA. Eectrolyte leakage, as an indication of membrane permeability, did not differ as a consequence of HA additions. However, electrolyte leakage correlated positively with HA rate. A shift in solution pH from 5.8 to 7.0 had no effect upon on nutrient accumulation or growth of tomato seedlings. The interaction of pH and addition of HA was not significant 1. Partial funding for this research is from U.S.D.A.

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Section: Discussionmentioning

confidence: 63%

A humic acid improves growth of tomato seedling in solution culture

David

Nelson

Sanders

1994

Journal of Plant Nutrition

140

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“…As de Kock (1955) and many others have noted, plants grow very much better when they are supplied with a mobile form of iron in the form of a soluble complex or chelate. Pringsheim (1946) suggests that the role of the soil in his soil-water cultures is of this nature, and it may be of significance that of the three algae used here, only those two normally requiring soil extract were stimulated by the yellow subst,ances.…”

Section: Discussionmentioning

confidence: 99%

Chemical and Biological Studies on the Yellow Organic Acids of Lake Water1

Shapiro

1957

Limnology & Oceanography

182

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The yellow coloring matter of natural waters has been studied with particular emphasis on Lower Linsley Pond, Connecticut.The best method of isolation was by ethyl acetate extraction of acidified evaporation residues of filtered water.The material thus obtained was a mixture of colorless and colored carboxylic acids, the colored ones fluorescing under ultra-violet light. Numerous yellow fractions were distinguished through paper chromatography, none of which showed maxima in either their visible or ultra-violet absorption spectra. Chemical tests indicated a phenolic or enolic character with probable unsaturation.Elemental analyses showed 1.4% ash, no halogens or sulfur, and resulted in an empirical formula of (ChOH62027N)n. The nitrogen was believed to be an impurity, resulting in an empirical formula of CzlHzsOll on the basis of the determined mean molecular weight of 456. The mean equivalent weight of the mixture was 228. The salts of the acids were dialysable and the acids were amorphous as shown by x-ray diffraction.Infra-red spectroscopy of various derivatives indicated a mixture of hydroxy carboxylic acids and admitted the possibility of unsaturation and aromaticity, although the indications are that if aromaticity exists it is relatively inconsequential. The materials were very resistant to chemical oxidation.Lower Linsley Pond surface water contained between 4.5 and 9.0 milligrams of acids per liter, of which about 40% was estimated to be yellow. Raising the pH from 3 to 11 increased the color by 50%. Solutions of the salts obeyed Beer's law in the range studied from 5 to 70 mg/L. The materials may affect organisms through alteration of light and by their buffering action. They were reasonably stable to biological decomposition over a period of 4% months. Concentrations of up to 50 mg/L had no effect on pure cultures of Chlamydomonas Reinhardi, but Hematococcus pluvialis and Scenedesmus quadricauda were stimulated in their growth by concentrations of between 5 and 50 mg/L. The materials were able to retain iron in a filterable state at pH values up to 13.2.Eleven lakes showed very similar Chromatographic patterns on the same date and on different dates. Evidence is presented for the hypothesis that some of the numerous colored fractions are different salts of a small number of acids. It is concluded that the materials originate as a result of decomposition in soil and possibly in sediments as well. The name 'humolimnic acids' is suggested for the materials to indicate their probable relation but improbable equivalence with so-called 'humic' acids.

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“…De Kock (1955), hümik asitin topraktaki Fe'nin immobilizasyonunu önledi ğ ini, hümik asitlerin Fe ile dü ş ük molekül a ğırl ı kl ı bileş ikler olu şturarak ta şı y ı cı görev üstlendi ğ ini belirtmi ştir.…”

Section: Giri şunclassified

Hümik Asit ve Fosfor Uygulamalarının Mısır Bitkisinin (Zea mays L») Fe, Zn, Mn ve Cu içeriği Üzerine Etkisi

İbrahim;BOZKURT¹

2000

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Influence of Humic Acids on Plant Growth

Cited by 51 publications

References 5 publications

A humic acid improves growth of tomato seedling in solution culture

A humic acid improves growth of tomato seedling in solution culture

Chemical and Biological Studies on the Yellow Organic Acids of Lake Water1

Hümik Asit ve Fosfor Uygulamalarının Mısır Bitkisinin (Zea mays L») Fe, Zn, Mn ve Cu içeriği Üzerine Etkisi

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