Some accessory factors in plant growth and nutrition

Abstract

Recent research has demonstrated the importance of the presence of minute amounts of certain substances as accessory factors in normal dietaries of man and animals. The most striking examples of the influence of these substances are seen in their curative effect on the diseases of beri-beri and scurvy, and their stimulative effect on the growth of young animals.Beri-beri is caused by the deficiency in a diet of polished rice of a nitrogenous substance, small amounts of which are essential for the metabolism of the nervous system. The curative substance is found in rice husks, barley, wheat, lentils, yeast, egg-yolk, milk, etc., and is pre cipitated from an aqueous solution of an alcoholic extract of these bodies by phosphotungstic acid. It is effective in very minute amounts, an addition to the diet of 0'02 grm. of the active fraction of the extract curing polyneuritis (beri-beri) in pigeons.Scurvy also is caused by a diet adequate as regards proteins, carbohydrates and fats, but deficient in some constituent, small amounts of which are essential. This anti-scorbutic substance is found in lime-juice, fresh vegetables and fruits, and, like the curative substance of beri-beri, is precipitated by phosphotungstic acid.The special importance of small amounts of substances of unknown com position in the metabolism of growing animals has been demonstrated by the recent researches of Osborne and Mendel* and Hopkins.f These investiga tions have shown that young rats, fed on a diet consisting of a mixture of pure proteins, carbohydrates, fats, and inorganic salts, failed to grow, but on the addition of a very small amount of certain substances obtained from milk growth was normal. Hopkins found that the fraction obtained from a phosphotungstic acid precipitation of proteid-free milk contained the active substance and gave excellent growth results. As a result of his experiments he states that " the presence of minute traces of certain

Plant biostimulants: physiological responses induced by protein hydrolyzed-based products and humic substances in plant metabolism

“…Several authors have found evidence of HS improving plant growth and physiology (Bottomley, 1914a(Bottomley, , 1914b(Bottomley, , 1917O'Donnell, 1973;Cacco and Dell'Agnola, 1984;Dell'Agnola and Nardi, 1987;Nardi et al, 1988;Schiavon et al, 2008;Pizzeghello et al, 2013). These positive effects on plants could be ascribed, in the main, to hormone-like activity, as a number of hormones enclosed in the humus structure have been identified (Muscolo et al, 1998;Nardi et al, 2000b;Pizzeghello et al, 2001).…”

Biological Activities of Humic Substances

“…Lawes and Gilbert (1905) fi rst demonstrated that soil fertility could be preserved for many years by applying only mineral fertilizers. Meanwhile, Bottomley (1914aBottomley ( ,b, 1917Bottomley ( , 1920 asserted that small quantities of humic substances favored plant growth. However, Clark and Roller (1924) , although working closely with Bottomley, found that humic substances were not essential for plant growth.…”

The USDA Bureau of Soils and Its Influence

“…13 There are several isomeric forms, and assumedly the form found was 9,10-dihydroxyoctadecanoic acid, a compound produced by various soil fungi; this is the compound illustrated here. sick soil that led ultimately to the isolation and identification of dihydroxystearic Schreiner and his associates subsequently identified many more organic compounds in soils (Schreiner 1912, Shorey 1913, including terpenes, sterols (Schreiner and Shorey 1909a, 1909b, 1909c, hydrocarbons Shorey 1909a, 1911c), fatty acids Shorey 1910d, 1911c), phenolic acids and aldehydes 14 (Schreiner and Skinner 1914a, 1914b, 1914cShorey 1914;Skinner 1914Skinner , 1918aSkinner , 1918bSkinner , 1918cSkinner , 1918dSkinner and Noll 1916;Walters 1917) and nitrogenous compounds (Schreiner and Lathrop 1911c;Schreiner and Reed 1908b;Schreiner and Shorey 1907, 1910b, 1910cSchreiner and Skinner 1912a) (see Table 1). A useful summary of Schreiner's methods for extracting different groups of organic constituents from the soil was given by Thomas (1914).…”