Molisch

Molisch s test A general test for carbohydrates. The carbohydrate is dissolved in water, alcoholic 1-naphthol added, and concentrated sulphuric acid poured down the side of the tube. A deep violet ring is formed at the junction of the liquids. A modification, the rapid furfural test , is used to distinguish between glucose and fructose. A mixture of the sugar, 1-naphthol, and concentrated hydrochloric acid is boiled. With fructose and saccharides containing fructose a violet colour is produced immediately the solution boils. With glucose the appearance of the colour is slower. 

Molisch s Test. Dissolve about 01 g. of the carbohydrate in z ml. of water (for starch use 2 ml. of starch solution ), add 2-3 drops of a 1 % alcoholic solution of i-naphthol (ignoring traces of the latter precipitated by the water) and then carefully pour 2 ml. of cone. H2SO4 down the side of the test-tube so that it forms a heavy layer at the bottom. A deep violet coloration is produced where the liquids meet. This coloration is due apparently to the formation of an unstable condensation product of i-naphthol with furfural (an aldehyde produced by the dehydration of the carbohydrate). 

All carbohydrates (mono-, di- and poly saccharides) give the Molisch colour test for details, see Section III,139,(i). ... 

Mix a few drops of a glucose solution with a few drops of an alcoholic solution of n-naphthol and poui slowly down the side of the test-tube a few drops of cone, sulphunc acid. A violet colouration is produced. (Molisch s reaction.) See AppendiXt p. 271. 

Molisch, H., Der Einfluss einer Pflanze auf die andere Allelo-pathie, Verlag G. Fischer, Jena, 1937. 

The term allelopathy was coined by Molisch in 1937 Q). Presently, the term generally refers to the detrimental effects of higher plants of one species (the donor) on the germination, growth, or development of plants of another species (the recipient). Allelopathy can be separated from other mechanisms of plant interference because the detrimental effect is exerted through release of chemical inhibitors (allelochemicals) by the donor species. Microbes associated with the higher plants may also play a role in production or release of the inhibitors (2). 

The term "Allelopathy" was coined by Molisch (2 ) to refer to both detrimental and beneficial biochemical interactions anong all classes of plants, including microorganisms. Because the root word "pathy," however, implies detrimental interactions, Rice (3) defines "allelopathy" as follows "Any direct or indirect harmful effects of one plant (including microorganisns) on another through the production of chemical compounds that escape into the envirorment." Perhaps, the term "allelopathy" should be extended to include the manifold mutual effects of metabolic products of both plants and animals. Now Rice includes beneficial interactions (18). 

The term allelopathy, when first proposed by Molisch (1 ), referred to either the beneficial or detrimental interaction between all types of plants and microorganisms. As presently used, this definition is generally accepted. Since 1970 a concerted effort has been made to understand the phenomenon of allelopathic interaction. The many interpretations resulting from these studies are well documented in the literature (2-4). An area currently receiving considerable attention is the allelopathic effect resulting from weed-crop and weed-weed interactions (2, 5-7). One study conducted by Wilson and Rice (7) showed that the common sunflower, Helianthus annuus L., possessed allelopathic properties. Realizing the inherent potential... 

Molisch, H. "Per Einfluss einer Pflanze and die andere—Allelo-pathic" 1937, Gustav Fisher Verlag, Jena. 

The term allelopathy was coined by Prof. Hans Molisch, a German plant physiologist in 1937. It is a new field of science and, till now there is no Book on Methodology of Allelopathy Research. Thus causing a lot of problems to researchers working in underdeveloped/Third World countries, in small... 

When heated with a strong acid, pentoses and hexoses are dehydrated to form furfural and hydroxymethylfurfural derivatives respectively (Figure 9.20), the aldehyde groups of which will then condense with a phenolic compound to form a coloured product. This reaction forms the basis of some of the oldest qualitative tests for the detection of carbohydrates, e.g. the Molisch test using concentrated sulphuric acid and a-naphthol. 

In spite of the early suggestions concerning apparent allelopathic effects, no solid scientific evidence was obtained to support the suggestions until the present century. The term allelopathy was coined by Molisch in 1937 to refer to biochemical interactions between all types of plants, including microorganisms traditionally placed in the plant kingdom (3). His discussion indicated that he meant the term to cover both inhibitory and stimulatory biochemical interactions. 

Molisch, H. "Der Einflus seiner Pflanzen auf die andere -- Allelopathie" G. Fischer Jena, 1937. 

We should encourage that the term allelopathy be used in its broadest sense (as intended by Hans Molisch). Allelopathy would logically include the chemicals produced by microbial plants (Actinomycetes, algae, fungi, etc.) and those that enhance growth as well as inhibit growth. 

Molecular extinction coefficients, 1135 Molecular weight, by Rast camphor method, 1037 Molisch test, 453 ... 

General Test for Carbohydrates.—To a small portion of the carbohydrate with about 5 c.cs. water, 2—3 drops of a saturated alcoholic solution of a-naphthol are added, and 2 c.cs. of cone, sulphuric acid. A violet colour is produced and is discharged by alkalis (Molisch). 

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