Involvement of ethylene signalling in a non-climacteric fruit: new elements regarding the regulation of ADH expression in grapevine

Although grape berries have been classified as non climacteric fruits, ongoing studies on grape ethylene signalling lead to challenge the role of ethylene in their ripening. One of the significant molecular changes in berries is the up regulation of ADH (alcohol dehydrogenase, EC. 1.1.1.1) enzyme activity at the inception of fruit ripening and of VvADH2 transcript levels. This paper shows that the ethylene signal transduction pathway could be involved in the control of VvADH2 expression in grapevine berries and in cell suspensions. The induction of VvADH2 transcription, either in berries at the inception of ripening or in cell suspensions, was found to be partly inhibited by 1 methylcyclopropene (1 MCP), an inhibitor of ethylene receptors. Treatment of cell suspensions with 2 chloroethylphosphonic acid (2-CEPA), an ethylene releasing compound, also resulted in a significant increase of ADH activity and VvADH2 transcription under anaerobiosis, showing that concomitant ethylene and anaerobic treatments in cell suspensions could result in changes of VvADH2 expression. All these results, associated with the presence in the VvADH2 promoter of regulatory elements for ethylene and anaerobic response, suggest that ethylene transduction pathway and anaerobic stress could be in part involved in the regulation of VvADH2 expression in ripening berries and cell suspensions. These data open new aspects of the expression control of a ripening-related gene in a non climacteric fruit

Hormonal regulation of wheat growth during hydroponic culture

Hormonal control of root growth has been explored as one means to alleviate the crowding of plant root systems experienced in prototype hydroponic biomass production chambers being developed by the CELSS Breadboard Project. Four plant hormones, or their chemical analogs, which have been reported to selectively inhibit root growth, were tested by adding them to the nutrient solutions on day 10 of a 25 day growth test using spring wheat in hydroponic cultures. Growth and morphological changes is both shoot and root systems were evaluated. In no case was it possible to inhibit root growth without a comparable inhibition of shoot growth. It was concluded that this approach is unlikely to prove useful for wheat

Induction of male sterility in wheat and barley by 2-chloroethylphosphonic acid (ethephon)

Emphasis has been directed towards the potential use of ethephon (2-chloroethylphosphonic acid) as a possible gametocide for induction of male sterility. Currently ethephon has been used experimentally as a male gametocide on both wheat and barley. The purpose of this research was to induce male sterility in winter wheat (Triticum aestivum L. em Thell), and winter barley (Hordeum vulgare L.) with foliar applications of ethephon. The field study was conducted at the Plant Science Field Laboratory, Knoxville, Tennessee. Ethephon was foliarly sprayed on Arthur wheat and Volbar barley, at 0.00, 0.10, 0.20, and 0.40 percent active ingredient when the plants were in early, mid-, and late boot stages. The most effective level was 0.40 percent ethephon in early, mid-, and late boot for Arthur wheat, and early, and late boot for Volbar barley. Concentration, stage, and concentration*stage interaction were significant for all variables except for seed weight. No concentration, stage or concentration*stage interaction occurred for seed weight. However there were significant differences among concentrations and stages which directly influenced male sterility. All ethephon treatments resulted in reduced plant heights and lodging. There was no apparent reduction in female fertility as a result of the treatments. The results of this research indicated that ethephon might have possibilities as a rapid and easy means of hybridization in wheat and barley

Effects of 2-chloroethylphosphonic acid formulations as yield stimulants on Hevea brasiliensis

Stimulation of Hevea brasiliensis is a common practice in rubber estates. The chemicals commonly used are formulations of 2-chloroethylphosphonic acid (ethephon). Low frequency of tapping must be accompanied by use of yield stimulants in order to enjoy the economics of low tapping frequency. It is thus necessary to evaluate the effects of the available yield stimulants on Hevea in order to betterformulate exploitation systems. Two formulations of  2-chloroethylphosphonic acid, under the tradename Hevetex 5% PA and Ehtrel® were used to stimulate two clones. Hevetex 5% PA was investigated using agronomic parameters, and latex diagnosis technique to determine its efficiency as a yieldstimulant, its ability to induce tree dryness, activation of tree metabolism and ability to sustain rubber yields. Hevetex 5% PA is a good yield stimulant and has good sustaining properties demonstrated by the level of its physiological properties (such as sugar and thiols) which are comparable to those of Ethrel®. The use of these stimulants led to an increase in rubber yield. The physiological parametersand yield varied with season

SEX EXPRESSION AND LEVEL OF PHYTOHORMONES IN MONOECIOUS CUCUMBER AS AFFECTED BY PLANT GROWTH REGULATORS

ABSTRACT The hormone levels of auxin and gibberellin were studied in monoecious cucumber plants treated with growth regulators e.g. 2-chloroethylphosphonic acid (ethrel

Óleos essenciais, estimulação química de resina e ocorrência de galhas de três espécies amazônicas de Protium

Protium is the most frequent genus of Burseraceae in the Adolpho Ducke Forest Reserve (Manaus, Amazonas), which is where its species were previously identified and mapped and this has favored various studies of this central Amazon forest. A number of P. divaricatum Engl., P. opacum Swart and P. strumosum Daly trees were selected with the objective of providing information about their chemical and biological aspects. Resin exudation was stimulated with the use of ethephon and the essential oils from the aerial parts and the resin were evaluated using GC. The occurrence of galls was also registered. The hydrocarbon sesquiterpene ß-caryophyllene was detected in high percentages in the essential oils of leaves and twigs of P. divaricatum (52.75% and 14.74%) and P. opacum (39.55% and 17.86%), respectively. The predominant oxygenated sesquiterpenes were spathulenol in the leaves (19.52%) and twigs (31.29%) of P. divaricatum, in addition to khusimone (32.36%) in the twigs of P. opacum. Monoterpenes were identified in the essential oils of the P. strumosum resin, with p-cymene (58.97%) predominating in the naturally exuded resin, limonene (61.45%) and p-cimen-8-ol (53.92%) in the resin of the first and second extraction with ethephon, respectively. On the trees, galls were identified that will help in the identification of the three species.Protium é o gênero mais frequente de Burseraceae da Reserva Florestal Adolpho Ducke (Manaus, Amazonas), onde as suas espécies foram previamente identificadas e mapeadas favorecendo os vários estudos dessa floresta da Amazônia Central. Selecionamos algumas árvores de P. divaricatum, P. opacum e P. strumosum como o objetivo de fornecer informações sobre seus aspectos químicos e biológicos. Estimulamos à exsudação de resina com o uso de ethephon e avaliamos por CG os seus óleos essenciais das partes aéreas e resina. Registramos também a ocorrência de galhas. O sesquiterpeno hidrocarboneto ß-caryophyllene foi detectado em altos percentuais nos óleos essenciais de folhas e galhos de P. divaricatum (52.75% e14.74%) e P. opacum (39.55% e 17.86 %), respectivamente. Os sesquiterpenos oxigenados predominantes foram o espatulenol de folhas (19.52%) e galhos (31.29%) of P. divaricatum além da khusimona (32.36%) dos galhos de P. opacum. Nos óleos essenciais da resina de P. strumosum foram identificados monoterpenos, predominando o p-cymene (58.97%) na resina exsudada naturalmente, limonemo (61.45%) e p-cimen-8-ol (53.92%) na resina da primeira e segunda extração com ethephon, respectivamente. Nas árvores, foram identificadas galhas que auxiliarão na identificação das três espécies

The Effects of 2-Chloroethylphosphonic Acid on Bud The Effects of 2-Chloroethylphosphonic Acid on Bud Vascularization in Sorghum Halapense, L.ascularization in Sorghum Halapense, L.

An assumption can be postulated that the auxin produced in the stem apex may inhibit bud development by preventing differentiation of vascular connections between the cauline bundle and the bud primordia. This would deprive the primordia of nutrients and growth substances being translocated in the mainstream vascular elements. The assumption is that prior to decapitation, vascularization is incomplete to the laterals in johnsongrass and that after decapitation, vascularization becomes complete. Dr. C. A. Beasley has found that plants treated with ethrel will react the same as decapitated plants. This study was designed to examine ethrel treated plants and examine anatomically the vascularization of lateral bud procambial strands, to determine if ethrel will increase differentiation of vascular tissue, thus making the bud physiologically receptive to herbicides