2-chloroethane Phosphonic Acid Research Articles

Effect of GA3 plus Ethephon™ on glochid removal and cactus pear fruit quality

The market for cactus pear requires prior glochid removal; however, this process causes injury and damage to the fruit. The effect of growth regulators for pre-harvest removal of these small spines has been evaluated experimentally with promising results, to induce pre-harvest fall of glochids without damaging the fruit. In this study, the effectiveness of gibberellic acid (GA3; 50 ppm) plus 2-chloroethane phosphonic acid (Ethephon™; 700 or 900 ppm) on glochid removal and the effects of the treatment on fruit quality in cactus pear cultivars ‘Roja San Martin’, ‘Villanueva’, and ‘Roja Sangre de Cristo’ were determined in a commercial plantation of cactus pear in the producing region of Puebla, Mexico. After anthesis, consecutive weekly applications of GA3 in combination with Ethephon™ were made. The number and fall of glochids were evaluated, and fruit quality parameters were also assessed; weight loss of fruits stored at 25°C for 14 days was also evaluated. Both treatments induced an elongation of around 65% in glochids; in general, 62-80% fall of glochids was also observed in harvested control fruits. The treatments, in general, caused a significant pre-harvest fall (PHF) of glochids. Besides, it was also observed that the glochids that remained on the treated fruits were easier to remove mechanically. Treated fruits of ‘Roja San Martin’ responded with the greatest total fall of glochids (97.8%), without significant differences between the two treatments. Fruit quality was slightly affected, positively or negatively, depending on the cultivar and treatment.

Pre-harvest ethylene control affects vase life of cut rose ‘Carola’ by regulating energy metabolism and antioxidant enzyme activity

We studied the role of ethylene control in regulating energy metabolism, antioxidant enzyme activity, and vase life of cut rose Rosa hybrida ‘Carola’. Rose flowers at stage II were sprayed with one of the following solutions: water (control), 10 μL L−1 1-methylcyclopropene (1-MCP), or 0.5 g L−1 2-chloroethanephosphonic acid (ethephon). After harvest, ethylene production rate, respiration intensity, energy charge (EC), activities of energy metabolism-related and antioxidant enzymes, and malondialdehyde (MDA) content were measured. Results showed that 1-MCP enhanced the activities of superoxide dismutase, H+-adenosine triphosphatase, Ca2+-adenosine triphosphatase, succinic dehydrogenase, and cytochrome c oxidase, increased adenosine triphosphate (ATP) content, maintained high EC levels, inhibited respiration intensity, reduced peroxidase (POD) and polyphenol oxidase (PPO) activity and MDA accumulation, and prolonged vase life. Ethephon promoted ethylene production and respiration intensity, increased POD and PPO activity, reduced ATP content and EC levels, and accelerated senescence. Our results support a novel role for ethylene control in regulating senescence of ‘Carola’.

Porównanie wpływu opryskiwania roztmorem NAA i Ethrelu na wzrost i kwitnienie ogórka (Cucumis sativus L.) odm. 'Monastyrski' [Comparison of the influence of sprays with NAA and Enthrel solution on the growth and flowering of cucumber (Cucumis sativus L.) Monastyrski variety

The effects of NAA and Ethrel (2-chloroethanephosphonic acid) spray on the growth and flowering of cucumber plants were compared. The influence of NAA spray on the appearance of the pistillate flowers and on male sterility was considerably lower and less successful than that of Ethrel.

Ethylene is involved in stress responses induced by fusicoccin in sycamore cultured cells

The phytohormone ethylene is involved in many physiological and developmental processes of plants, as well as in stress responses and in the development of disease resistance. Fusicoccin (FC) is a well-known phytotoxin, that in sycamore ( Acer pseudoplatanus L.) cultured cells, induces a set of stress responses, including synthesis of ethylene. In this study, we investigated the possible involvement of ethylene in the FC-induced stress responses of sycamore cells by means of Co 2+, a well-known specific inhibitor of ethylene biosynthesis. Co 2+ inhibited the accumulation of dead cells in the culture, the production of nitric oxide (NO) and of the molecular chaperone Binding Protein (BiP) in the endoplasmic reticulum induced by FC. By contrast, Co 2+ was ineffective on the FC-induced accumulation of cells with fragmented DNA, production of H 2O 2 and release of cytochrome c from the mitochondrion, and only partially reduced the accumulation of regulative 14-3-3 proteins in the cytosol. In addition, we compared the effect of FC on the above parameters with that of the ethylene-releasing compound ethephon (2-chloroethane phosphonic acid). The results suggest that ethylene is involved in several stress responses induced by FC in sycamore cells, including a form of cell death that does not show apoptotic features and possibly involves NO as a signaling molecule.

Effects of gibbereline and 2-Chloroethanephosphonic acid on the sprouting and growth of lateral buds in mulberry plants

Effects of gibbereline and 2-Chloroethanephosphonic acid on the sprouting and growth of lateral buds in mulberry plants

Molecular cloning and characterization of two cDNAs encoding 1-deoxy- d-xylulose 5-phosphate reductoisomerase from Hevea brasiliensis

1-Deoxy-d-xylulose 5-phosphate reductoisomerase (DXR, EC: 1.1.1.267) is the second enzyme in the 2C-methyl-d-erythritol 4-phosphate (MEP) pathway, one of the two pathways in plants that can produce isoprenoids. The MEP pathway is the source of isoprene emitted from leaves, but rubber production is believed to result primarily from the mevalonic acid (MVA) pathway. Two cDNAs for DXR designated HbDXR1 and HbDXR2 were isolated from leaves and latex of rubber tree using RT-PCR based methods. Both cDNAs contain an open reading frame (ORF) of 1416bp encoding 471 amino acids with a molecular mass of about 51kDa. The deduced HbDXRs show extensive sequence similarities to that of other plant DXRs (73-87% identity). Molecular modeling revealed that the two HbDXRs contain all typical characteristics of DXR and share spatial structures, which are very similar to that of Escherichia coli DXR. Phylogenetic and DNA gel blot analyses suggested that a duplication of the DXR gene has occurred in the rubber tree. Semi-quantitative RT-PCR analysis showed that the HbDXR genes are differentially regulated in various tissues of the rubber tree. The HbDXR2 was more highly expressed in clone RRIM 600 than in the wild type, and this is consistent with higher rubber content of this clone. While 2-chloroethane phosphonic acid (ethephon) significantly increased latex yield, it only transiently induced the HbDXR2 gene. The expression of HbDXR2 in the latex suggests its important role in isoprenoid biosynthesis by substrate molecules, indicating that the MEP pathway may have some indirect roles in the biosynthesis of rubber.

Role of Ethylene and 1-MCP in Flower Development and Petal Abscission in Zonal Geraniums

Geraniums are sensitive to ethylene during shipping and respond by abscising their petals. Treatment of stock plants with ethylene (ethephon) in order to increase cutting yield resulted in earlier flowering in Pelargonium × hortorum `Kim' and `Veronica', but did not result in increased susceptibility to petal abscission following exposure to 1.0 μL·L-1 ethylene. Treatment of `Kim', `Veronica', `Fox', and `Cotton Candy' with 1.0 μL·L-1 ethylene resulted in increased petal abscission within one hour, with `Fox' being the most sensitive and `Kim' the least. Pretreatment of florets with 1-MCP for 3, 6, 12, or 24 hours at concentrations of 0.1 or 1.0 μL·L-1 decreased petal abscission in all cultivars following exposure to 1.0 μL·L-1 ethylene. Treatment with 0.1 μL·L-1 1-MCP for 1 hour reduced petal abscission rates in ethylene treated florets to that of non-ethylene treated controls in all cultivars except Fox. `Fox' florets, which are more sensitive to ethylene, required 12 to 24 hours of exposure to 1-MCP to reduce petal abscission rates to that of control flowers. Pretreatment of geranium plants with 1-MCP can be used to reduce petal shattering during shipping. Chemical names used: 2-chloroethanephosphonic acid (ethephon); 1-methylcyclopropene (1-MCP).

Effect of gibberellic acid and (2-chloroethane) phosphonic acid on glochid abscission in cactus pear fruit (Opuntia amyclaea Tenore)

Glochids (small spines) of cactus pear negatively affect harvest operations, and the quality and acceptance of this fruit. Different treatments for pre-harvest removal of glochids were evaluated. Gibberellic acid (GA 3 , 100 ppm) was sprayed over flower buds in six consecutive applications (every 7 days) during their development. Also, solutions of (2-chloroethane) phosphonic acid or ethephon (‘Ethrel’ ® ) at 500, 600, 700, 800, and 900 ppm a.i. were sprayed over the buds immediately after fruit set, alone or in combination with GA 3 applications. At harvest, it was concluded that GA 3 +ethephon treatments generally increased the length as well as the number of glochids compared with glochids on control fruit. Ethephon applications only caused slight abscission of glochids prior to harvest. However, after the mechanical effect of harvest, GA 3 +ethephon treatments caused significant abscission of glochids (>90% in the best case) compared with the controls (37%), while ethephon (alone) treatments caused 79% of glochids to abscise in the best case (700 ppm). None of the treatments negatively affected the quality of the fruit in terms of soluble solids concentration, acidity, color, weight of pulp and weight of peel.

Induced plant defense responses against chewing insects. Ethylene signaling reduces resistance of Arabidopsis against Egyptian cotton worm but not diamondback moth.

The induction of plant defenses by insect feeding is regulated via multiple signaling cascades. One of them, ethylene signaling, increases susceptibility of Arabidopsis to the generalist herbivore Egyptian cotton worm (Spodoptera littoralis; Lepidoptera: Noctuidae). The hookless1 mutation, which affects a downstream component of ethylene signaling, conferred resistance to Egyptian cotton worm as compared with wild-type plants. Likewise, ein2, a mutant in a central component of the ethylene signaling pathway, caused enhanced resistance to Egyptian cotton worm that was similar in magnitude to hookless1. Moreover, pretreatment of plants with ethephon (2-chloroethanephosphonic acid), a chemical that releases ethylene, elevated plant susceptibility to Egyptian cotton worm. By contrast, these mutations in the ethylene-signaling pathway had no detectable effects on diamondback moth (Plutella xylostella) feeding. It is surprising that this is not due to nonactivation of defense signaling, because diamondback moth does induce genes that relate to wound-response pathways. Of these wound-related genes, jasmonic acid regulates a novel beta-glucosidase 1 (BGL1), whereas ethylene controls a putative calcium-binding elongation factor hand protein. These results suggest that a specialist insect herbivore triggers general wound-response pathways in Arabidopsis but, unlike a generalist herbivore, does not react to ethylene-mediated physiological changes.

Electroluminescence: enhanced injection using ITO electrodes coated with a self assembled monolayer

In a typical organic bilayer electroluminescent device the hole injecting electrode is almost invariably ITO glass, but a number of electron injecting metal electrodes are possible. Unfortunately the low work function materials used readily oxidise and restrict the lifetime of the device. It is known that appropriate monolayers can change the work function of a solid and also that phosphonic acids can form self assembled monolayers on ITO glass. Using an ITO glass electrode coated with a self assembled monolayer of an electron accepting phosphonic acid (2-chloroethanephosphonic acid) and aluminium as the electron injecting electrode, it was found that the threshold voltage was significantly reduced to the same value as achieved with the less stable Mg:Ag electrode. The use of such modified ITO electrodes would obviate the use of highly reactive metal electrodes and help to overcome one of the factors which limit device lifetime.

Phytohormone pre-treatment for the enhancement of seed germination and protocorm formation by the terrestrial orchid, Calanthe discolor (Orchidaceae), in asymbiotic culture

Pre-soaking the seeds of Calanthe discolor Lindl. for 7 days in solutions containing α-naphthaleneacetic acid (NAA) at 1–100 mg l −1, 2-chloroethane phosphonic acid (Ethephon) at 1000 mg l −1 or 6-benzylaminopurine (BA) at 10, and 100 mg l −1 prior to germination in a growth-regulator-free medium resulted in overall 1.5–2.9 fold increases in protocorm formation compared with control cultures. Gibberellic acid (GA 3) exerted no stimulatory effect on seed germination and protocorm formation. The possible mechanisms of seed germination and protocorm formation of this species are discussed.

Reducing height and lodging in rapeseed with growth regulators

The plant growth regulators (PGRs) ethrel (20% a.i. 2-chloroethane phosphonic acid), PP 333 (25% w/v a.i. paclobutrazol), cycocel (50% w/v a.i. chlormequat chloride), pix (5% w/v a.i. mepiquat chloride) and EL 500 (50% w/w a.i. flurprimidol) were applied to bulky crops of Jumbuck, Marnoo and RU 14 rapeseed at Cowra and Woodstock in central-western New South Wales, in an effort to reduce their height and lodging. The most effective growth retardants under evaluation were PP 333 and EL 500, and this was achieved without apparent phytotoxicity. Height reductions were enhanced as rates were increased from 0 to 2 Lha, and the heights of Jumbuck, Mamoo and RU 14 were reduced on average by 22% (from 159 to 124 cm), 26% (from 136 to 100 cm) and 14% (from 150 to 129 cm), respectively. Significant reductions in lodging accompanied these changes. Ethrel resulted in some phytotoxicity, while pix and cycocel had little or no measured effect on any plant characters. Jumbuck was the tallest variety and the most severely lodged, and under these conditions, yield responses to PGR were large (900 kg/ha or 54%). Shorter, erect plants produced an even, compact pod canopy, and as a result, ripening was more uniform, pod shattering reduced and harvesting more efficient. In situations where seed yields were increased, these practical considerations, rather than physiological responses (e.g. pod and seed set), were largely responsible. These findings support further research and commercial development of PGRs for use in canola production in the more favoured areas and support the inclusion of reduced plant height and increased stem strength as integral components of the overall breeding objectives for canola in Australia.

Control of ribulose 1,5-bisphosphate carboxylase synthesis in the cotyledons of Citrullus lanatus

White light completely inhibits the germination of Citrullus lanatus (Thunb.) Matsumara & Nakai seeds. Under these conditions light does not induce ribulose bisphosphate carboxylase (Rubisco) synthesis in the cotyledons. Although the seeds apparently are capable of attaining sufficient levels of the far-red light absorbing form of phytochrome, Pfr, in the dark to permit germination this does not induce Rubisco synthesis. However, it appears that a substantial amount of synthesis of the small subunit (SSU) takes place in the dark. The synthesis of the two subunits is therefore not tightly coordinated in this tissue, and in none of the treatments were equimolar concentrations of the two subunits present in the cotyledons. However, if the seeds are allowed to start germination in the dark and are then transferred to continuous light, Rubisco synthesis is induced. This induction of Rubisco synthesis in the cotyledons is dependent on the presence of the elongating radicle. Kinetin induces synthesis of Rubisco in isolated cotyledons in both the light and the dark, while 2-chloroethanephosphonic acid (Ethrel) only restores the sensitivity towards light activation of Rubisco synthesis. Synthesis of Rubisco in isolated cotyledons in the presence of these two compounds differs from that of the intact tissue in that the synthesis of the SSU is stimulated more than the synthesis of the large subunit (LSU).

Desenvolvimento e produtividade do tomateiro cultivar santa cruz sob ação de retardadores de crescimento aplicados em plântulas

No presente trabalho, foi estudado, em condições de casa de vegetação, o efeito dos reguladores vegetais cloreto (2-cloroetil) trimetilamônio (CCC), ácido succínico - 2,2-dimetilhidrazida (SADH) e ácido (2-cloroetil) fosfônico (CEPA), aplicados em plintulas, na produtividade do tomateiro (Lycopersicon esoulentum cv. Santa Cruz). O ensaio constou de sete tratamentos com dez repetições , inteiramente casualizados. Os tratamentos utilizados foram CCC em aplicação única e dupla na concentração de 1000 ppm; SADH em aplicação única e dupla na dosagem de 3000 ppm; CEPA em aplicação única e dupla na concentração de 300 ppm, além do controle. A primeira aplicação dos reguladores vegetais foi realizada 12 dias após o transplante e a segunda 20 dias. Para efeito de avaliação, foram determinadas a altura e diâmetro da planta, peso total e médio dos frutos, número de frutos e classificação dos mesmos. Foram efetuadas determinações de altura em quatro épocas diferentes e diâmetro em três. As mensurações, para todos tratamentos, foram realizadas 12, 23, 27 e 32 dias após o transplante, sendo que na primeira data somente a altura foi avaliada. Para a observação do florescimento foram realizadas contagens diárias, num período de 34 a 47 dias após o transplante, do número de flores abertas. Para análise de produção foram efetuadas sete solheitas aos 75, 82, 85, 89, 92, 98 e 106 dias após o transplante. Pela análise estatística dos dados pode-se concluir, para as condições do ensaio, que a aplicação dos reguladores vegetais não afetou a produção média e total dos frutos e a classificação desses, sendo que o tratamento SADH, aplicado duas vezes, reduziu o número de frutos em relação ao controle. O tratamento CEPA dose única, tendeu elevar a produção média e total dos frutos em relação ao controle. Para as condições do experimento, pode-se observar que todos reguladores vegetais reduziram significativamente a altura em relação ao controle, a partir da segunda data de coleta de dados, uma vez que a primeira foi realizada no sentido de observar a uniformidade na altura dos tratamentos. Quanto ao diâmetro, observou-se que o tratamento CCC, em dose dupla, reduziu significativamente este parâmetro com relação ao controle, uma semana após a primeira aplicação dos reguladores, o mesmo ocorrendo para o tratamento CCC, em dose única, após vinte dias.

Efeitos de ethephon e uréia na morfologia e produtividade do milho (Zea mays L.)

Ethephon é um regulador vegetal capaz de liberar etileno, que por sua vez atua como um retardador de crescimento por inibir o transporte de auxinas. A uréia pode incrementar o efeito do ethephon ou exercer um efeito oposto como fonte de nitrogênio. Estes compostos foram utilizados em plantas de milho visando modificar a dominância apical e consequentemente a época de alongamento da inflorescência, a altura da planta e a posição da espiga superior. Ethephon (ácido 2-cloroetilfosfônico) foi pulverizado em Zea mays cv. Piranão VF-2 38 dias após a semeadura, nos tratamentos: ethephon 500 ppm, ethephon 500 ppm + uréia 2%, ethephon 1.000 ppm, ethephon 1.000 ppm + uréia 2%, ethephon 1.500 ppm e ethephon 1.500 ppm + uréia 2%, além do controle. O regulador vegetal promoveu precocidade no alongamento da inflorescência masculina da planta de milho. Ethephon causou redução na altura da planta de milho 'Piranão VF-2'. A altura da espiga superior foi diminuída com ethephon ou ethephon + uréia. A distancia da espiga superior ao ápice foi reduzida com ethephon por causar diminuição no comprimento dos meritalos apicais. As modificações na época de alongamento da inflorescência masculina revestem-se de importância para a produção de híbridos de linhagens, sendo que reduções na dominância apical poderiam aumentar a prolificidade e consequentemente a produção.

Effects of ethephon and urea on ripening of fruits and leaf abscission of coffee (Coffea arábica L.)

A field experiment was carried out to investigate the effects of ethephon and urea on ripening of fruits and leaf abscission of coffee plant. Ethephon (2-chloroethane phosphonic acid) sprays were applied to green Coffea arábica berries 26 days before counting date in concentrations of 0.5 and 0.25 ml/1 from Ethrel (240 a.i./l). The chemical accelerated the onset of fruit ripening at both concentrations. The efficacy of ethephon was increased adding urea. Ethephon 0.5 ml/1 promoted abscission of leaves and low concentration reduced shedding of leaves. The treatments did not affect the growth and production on the next harvest.

Synergistic Effects in the Abscission: 8-Hydroxyquinolinsulfate Act Synergistically with 2-Chloroethanephosphonic Acid in the Abscission Process

A synergistic effect was observed between 2-chloroethanephosphonic acid (CEPA) and 8-hydroxyquinolinesulfate (8-HQS) for inducing the abscission of plants. It is supposed that in this combination 8-HQS modifies the water-household of the cells by its antitranspiratory effects and besides provoking an enhanced sensitivity of the cells against ethylene, it also leads to a direct induction of the ethylene production. Most likely the last factor is of the greatest importance. As a result of the significant synergism observed between 2-CEPA and 8HQS, the concentration of 2-CEPA needed for stimulating abscission of plants may be reduced to one-tenth of the usually applied amount.

Transport of 86Rb+ in Corn Leaves as Influenced by Some Growth Substances

The transport of 86 Rb + supplied to the middle of young corn leaves was scanned by means of a modified chromatogram scanner and it was found that the movement towards the base was larger than to the apex of both intact and excised leaves. Application of 25 ppm of ABA (abscisic acid) or ethrel (2-chloroethane phosphonic acid) did not affect the pattern of transport. However, the growth substances tested, viz , ABA, ethrel, GA 3 and IAA generally enhanced the rate of 86 Rb + transport towards the base of the leaf.

Zum Rückstandsverhalten von Ethephon an Tomaten 1. Mitt. Gewächshaustomaten

The preparation Flordimex, which contains Ethephon (2-chloroethanephosphonic acid) as the active ingredient, is used for accelerating the ripening of tomatoes. During the years 1974--1977, tomato samples from 89 experiments were tested for Ethephon residues. The determination was performed gas chromatographically using alkali flame ionization detector as 2-chloroethanephosphonic acid dimethyl ester; the detection limit of the method was 0.01 mg/kg. The observed results must be evaluated on the basis of the permissible value (1 mg/kg) stipulated for vegetables by the Ministry of Health of the GDR. 1--2 days after the use of concentrations of 0.1%, 0.2%, 0.3% and 0.4%, respectively, the following mean residue values were found: 0.31, 0.50, 0.39 and 0.91 mg/kg, respectively, which decreased but slowly. This leads to the conclusion that formulation concentrations of more than 0.3% and applications of more than 6 1/ha should not be allowed by the Ministry. In case of repeated uses, 3-week intervals are imperative. Under the above-mentioned conditions of use, the mean residue values determined 4--5 days after application approximated 0.6 mg/kg. This period is to be regarded as a tentative waiting-period that must be respected after the treatment of glasshouse tomatoes with Flordimex.

Prospects of Selecting Genotypes ofCoffea ArabicaL. Which do not Require Tonic Sprays of Fungicide for Increased Leaf Retention And Yield

The initial effect of ‘tonic’ fungicide sprays on Coffea arabica in Kenya is a 2–3 month delay in leaf fall and this causes a marked increase in yield even when the trees are not noticeably diseased. Five field experiments were carried out to investigate leaf abscission responses to 2-chloroethane phosphonic acid (CEPA) of fungicide-sprayed and unsprayed genotypes. Fungicide-sprayed leaves showed a significantly lower abscission response. Fungicides appear to remove a factor, possibly the leaf surface microflora, which causes increased levels of endogenous ethylene. This induces the leaves to senesce and abscise prematurely under natural conditions, or makes them more responsive to exogenous ethylene. There were marked genotype differences in thresholds for leaf abscission, and the locally selected cv SL28 was among the most resistant to CEPA-induced abscission. It was concluded that tonic sprays of fungicide will continue to be effective in Kenya in increasing yields, even after the introduction of new d...