Fruit hormones

The results of Urayama s work showed that each of the four fractionations induced primordia formation provided aqueous methanol (80%) and only young mushrooms were used. Extractsfrom older fruitbodies, especially that oi Agaricus brunnescens and Lentinus edodes, had no effect whatsoever. Urayama tried other solvents to isolate the mysterious fruiting hormone" and discovered that it was soluble in water and not soluble in absolute methanol, chloroform or petroleum benzine. He worked on his "Substance X", as he liked to call it, for many years until his death in 1980. 

Ethylene occurs naturally in small amounts as a plant hormone Hormones are substances that act as messengers to regulate biological processes Ethylene IS involved in the ripening of many fruits in which it IS formed in a complex series of steps from a com pound containing a cyclopropane ring... 

The modification and enhancement of biological activity of drugs and hormones by fluorination represent one of the most fruitful recent developments in medicinal chemistry. Its first successes and most interesting subsequent developments were in the steroid field. Almost every new technique of introducing fluorine into organic compounds has been applied in this area and, as a result of both the gross and subtle chemical differences which steroids display at different locations of the nucleus, has produced a wealth of new chemistry. 

An alkene, sometimes caJled an olefin, is a hydrocarbon that contains a carbon-carbon double bond. Alkenes occur abundantly in nature. Ethylene, for instance, is a plant hormone that induces ripening in fruit, and o-pinene is the major component of turpentine. Life itself would be impossible without such alkenes as /3-carotene, a compound that contains 11 double bonds. An orange pigment responsible for the color of carrots, /3-carotene is a valuable dietary source of vitamin A and is thought to offer some protection against certain types of cancer. 

Ethene is used to make a host of organic compounds it is also the starting material for the preparation of polyethylene (Chapter 23). Since it is a plant hormone, ethene finds application in agriculture. It is used to ripen fruit that has been picked green to avoid spoilage in shipping. Exposure to ethene at very low concentrations produces the colors we associate with ripe bananas and oranges. 

The phenomenon of leaf and fruit drop is known as abscission and has been suspected for some time to be under hormonal control. Dr. Addicott s description of the structure and properties of Abscisin II, the abscission hormone isolated from cotton, climaxes over 12 years of his own investigations on the subject and represents perhaps the greatest advance in plant hormone research in the past decade. It also provides an unusual and unsuspected structural model to guide... 

Abscisin II is a plant hormone which accelerates (in interaction with other factors) the abscission of young fruit of cotton. It can accelerate leaf senescence and abscission, inhibit flowering, and induce dormancy. It has no activity as an auxin or a gibberellin but counteracts the action of these hormones. Abscisin II was isolated from the acid fraction of an acetone extract by chromatographic procedures guided by an abscission bioassay. Its structure was determined from elemental analysis, mass spectrum, and infrared, ultraviolet, and nuclear magnetic resonance spectra. Comparisons of these with relevant spectra of isophorone and sorbic acid derivatives confirmed that abscisin II is 3-methyl-5-(1-hydroxy-4-oxo-2, 6, 6-trimethyl-2-cyclohexen-l-yl)-c s, trans-2, 4-pen-tadienoic acid. This carbon skeleton is shown to be unique among the known sesquiterpenes. 

Several alkenes occur naturally in living organisms. Some of these alkenes act as hormones and control biological functions. Plants produce ethene as a hormone to stimulate flower and seed production and to ripen fruits. Ethene stimulates enzymes in the plants to convert starch and acids of unripe fruit into sugars. The enzymes also soften fruit by breaking down pectin in cell walls. 

Ethene is produced naturally by fruits such as tomatoes and bananas as a plant hormone for the ripening process of these fruits. 

Alvim (1) in Costa Rica confirmed in part the studies of Pound (Al), Voelcker (50), and Humphries (22) and found that higher incidence of Cherelle wilt usually occurred after periods of intense growth of the leaf flushes and/or when the rate of growth in trunk diameter decreased or was checked. Spraying the fruits with p-chlorophenoxyacetic acid did not reduce the condition, as reported by Naundorf and Gardner (30). Alvim concluded that Cherelle wilt in Costa Rica is apparently caused by food strain (carbohydrates) or by depression in the mechanism of food translocation, and not by hormonal or mineral deficiencies. 

Despite the potent influence of ethylene on the whole plant development, most often it has been recognized as a fruit-ripening and senescence-associated hormone. With respect to the gaseous nature of this hormone, the knowledge about ethylene sensitivity of fruit and flower is necessary to predict the effects of their mixed storage and transport and the usefulness of anti-ethylene treatments. Such commercial implications of ethylene have made it a topic of investigation for decades. 

Schwarz, A., Felippe, E. C., Bernardi, M. M. and Spinosa, H. S. 2005. Impaired female sexual behavior of rat offspring exposed to Solanum lycocarpum unripe fruits during gestation and lactation Lack of hormonal and fertility alterations. Farmacology, Biochemistry, and Behavior, 81 928-934. 

---