2-chloroethylphosphonic Acid Research Articles

Comparisons of mineral and non-mineral prediction methods for bitter pit in ‘Honeycrisp’ apples

Bitter pit is a physiological disorder that can develop during storage and result in major economic losses of susceptible apple cultivars such as ‘Honeycrisp’. Prediction methods to determine the risk of disorder development have focused primarily on mineral composition of the fruit, but there has also been interest in non-mineral based methods. In this study, we have compared non-mineral methods with mineral analyses for bitter pit prediction. Fruit of ‘Honeycrisp’ were harvested three weeks before anticipated commercial harvest and at commercial harvest. Mineral contents in peel from the calyx-end were measured in fruit at both harvest times. In year 1, fruit were kept at 20 °C (passive method), dipped in 2000 mg L−1 2-chloroethylphosphonic acid (ethylene method) or 0.8 M MgCl2 (Mg method). Treated fruit were then kept at 20 °C for three weeks. At commercial harvest, fruit were stored at 0.5 or 3 °C with and without 1 week of conditioning at 10 °C. The Mg method showed toxicity on the fruit, which was hard to distinguish from bitter pit. Therefore, in year 2, only the passive and ethylene methods were used, and fruit from the commercial harvest were stored at 3 °C with or without conditioning. In year 3, only the passive method was used because of its simplicity and lack of registration of ethephon for this purpose. Fruit from the commercial harvest of 38 orchards in three growing regions were stored at 3 °C after conditioning. Fruit were stored for two months in year 1 and four months in years 2 and 3, and assessed after 4 d at 20 °C. Multivariate analysis shows that the passive and ethylene methods for fruit harvested three weeks before the anticipated harvest had higher or similar correlations with the actual bitter pit after cold storage than those from minerals. Although actual bitter pit incidence was higher than that predicted from the passive method, the method results in predictions that are similar to mineral-based predictions, and also is more straightforward for commercial application.

Use of 2,4-D in Mixture with Ethephon and Calcium Carbide in Pineapple Crop

ABSTRACT: The 2-Chloroethylphosphonic acid (ethephon) and calcium carbide are used to induce and synchronize the flowering of pineapple crop. Some farmers have used the 2,4-D herbicide in combination with these flowering inducers. This practice is based on the hypothesis that 2,4-D would act as a growth regulator, increasing fruit size and weight. The objectives of this work was to verify if the use of 2,4-D, associated to calcium carbide or ethephon, influences the productivity and quality of the pineapple fruits and, also if the use of this herbicide leaves residues in the fruits. For this, two field experiments were carried out in two different farms. The treatments consisted of the application of ethephon and calcium carbide, alone, and in a mixture with two, four and six drops of 2,4-D in the center of the leaflet of the pineapple cv. “Pérola” at 10 months after planting. The use of 2,4-D mixed with calcium carbide or ethephon, regardless of the dose and culture environment, did not influence the size, weight, total soluble solids content, density and pH of the pineapple fruits. However, depending on the growing environment, ethephon + 2,4-D mixtures did not influence or reduce flowering and crop yield. No 2,4-D residues were found in the fruit pulp of pineapple. It was concluded that the use of 2,4-D as a growth regulator of pineapple under the conditions evaluated does not incorporate qualitative or quantitative benefits to the productive system of this crop. In addition, no 2,4-D residues were found in the fruit pulp of pineapple.

PdII Immobilized on Ferromagnetic Multi-Walled Carbon Nanotubes Functionalized by Aminated 2-Chloroethylphosphonic Acid with S-Methylisothiourea (FMMWCNTs@CPA@SMTU@PdII NPs) Applied as a Highly Efficient and Recyclable Nanostructured Catalyst for Suzuki–Miyaura and Mizoroki–Heck Cross-Coupling Reactions in Solvent-Free Conditions

The new ferromagnetic nanostructured FMMWCNTs@CPA@SMTU@PdII NPs (IV) as an eco-friendly heterogeneous nanocatalyst with a particle size of ~20–30nm reported earlier by our group has been found to be very effective for Suzuki–Miyaura and Mizoroki–Heck cross-coupling reactions at ambient temperature. The procedure has been applied for a wide range of aryl halides, arylboronic acids, and alkenes. The magnetic separation by an external magnetic field, mild reaction conditions, and catalyst reusability up to four times without significant decrease in catalytic activity (reduced catalytic activity from 11 to 18% in the fifth, sixth, and seventh cycles) made the present method sustainable and economically viable for C–C cross-coupling reactions.

Effects of CEPA and 1-MCP on Flower Bud Differentiation of Apple cv. ‘Nagafu No.2’ Grafted on Different Rootstocks

The apple (Malus domestica Borkh.) has a relatively long sapling stage which prevents fruit breeding. The understanding of the flowering system is important to improve breeding efficiency in apple. In this context, 2-year-old “Fuji” apple cv. “Nagafu No.2” trees were grafted onto dwarf self-rooted rootstock M.26, vigorous rootstock M. sieversii and interstock M.26/M. sieversii, respectively. Trees were sprayed with clean water (as controls), 800 mg·L−1 2-chloroethylphosphonic acid (CEPA), and 2 µL·L−1 1-methylcyclopropene (1-MCP). The results showed that CEPA significantly repressed the vegetative growth attributed to the increase of ABA and ZT synthesis, and the decrease of IAA synthesis in leaves and buds. However, there was no significant difference or significant inverse effect between 1-MCP and control. Furthermore, CEPA promoted flower formation, increased the flowering rate, and advanced the blossom period for 2 days compared with the control, which was accompanied by the accumulation of soluble sugar, glucose, and sucrose; and the increase of α-amylase and sucrose phosphate synthase activities; and the decrease of starch contents and sucrose synthase activities in leaves and buds. However, the blossom period was delayed for 2 days after spraying with 1-MCP. Finally, the expression of TFL1 was significantly repressed, whereas AP1 was significantly promoted in buds from M.26 and M.26/M. sieversii after spraying with CEPA, whereas the effect was not significant from M. sieversii. However, the expression levels of TFL1 and AP1 were not significantly different from the control after the application of 1-MCP. In spite of this, CEPA was more susceptible to easy-flowering M.26, followed by M.26/M. sieversii, and still less susceptible to difficult-flowering rootstock M. sieversii.

Ethephon Foliar Sprays Are Influenced by Carrier Water Alkalinity and Ambient Air Temperature at Application

The plant growth regulator (PGR) ethephon [(2-chloroethyl) phosphonic acid; ETH] can be sprayed on floriculture crops to inhibit internode elongation, hinder apical dominance, increase lateral branching, and abort flower buds and flowers. However, the efficacy of ETH can be reduced as the pH of the carrier water used to mix the spray solution or temperature increase. Therefore, our objective was to quantify how the efficacy of ethephon sprays is influenced by carrier water alkalinity (CaCO3; ALK) and the air temperature at application (TEMP). Young plants of verbena (Verbena peruviana) ‘Aztec Blue Velvet’, ivy geranium (Pelargonium ×peltatum) ‘Precision Pink’, and petunia (Petunia ×hybrida) ‘Easy Wave Neon Rose’ were transplanted into 11-cm-diameter containers and grown in a greenhouse with an average daily air temperature (ADT) set point of 21 °C. Before the ETH spray application(s), the ADT in each greenhouse compartment was changed from a set point of 21 °C to 14, 17, 20, 23, or 26 °C for ≈24 hours. Plants were sprayed with 0, 250, 500, or 750 mg·L−1 ETH mixed with carrier water containing ≈50, 150, or 300 mg·L−1 CaCO3 2 and 3 weeks (Expt. 1) or 1 or 2 weeks (Expt. 2) after transplant. Generally, high ALK had a negative effect on spray efficacy. For example, an increase in ALK from 50 to 300 mg·L−1 CaCO3 resulted in one and five fewer ivy geranium and verbena branches, respectively. In addition, as application TEMP increased above 23 °C, chemical efficacy generally decreased in all species. For instance, as ETH increased from 0 to 750 mg·L−1 across ALKs, inflorescence number of ivy geraniums increased from 7 to 18 at a TEMP of 23 °C, but was unaffected at 26 °C. Based on our results, we can conclude that both ALK and TEMP influence ETH efficacy and are additional factors for greenhouse growers to consider when making applications.

Effects of ethylene and 1-MCP on quality maintenance of fresh cut celery

Ethylene is accepted to be a key player in the regulation of climacteric fruit ripening and senescence of leafy vegetables. In contrast, there is still disparity in the literature on the role it may have on quality deterioration of edible petioles. In this work, we evaluated the influence of the ethylene generator 2-chloroethylphosphonic acid (Ethephon) and the ethylene action inhibitor 1-methylcyclopropene (1-MCP) on quality maintenance of fresh cut celery. Commercially mature stalks from self-blanching celery cv. Golden Clause were cut into 2 cm-long slices. Samples from the apical and basal petiole zones were segregated and treated with 2000 mg L−1 2-chloroethylphosphonic acid or with 1 μL L−1 1-MCP. Corresponding slices without any treatment were used as control. Samples were packed and stored for 0, 6, 13 and 20 d at 4 °C and during this period celery visual deterioration (VD), respiration, weight loss and aerobic mesophilic bacteria, yeasts and molds counts were determined. Carotenoids, chlorophylls, phenolics, ascorbic acid, polyphenol oxidase (PPO), sugars, acidity, cell wall content and consumer acceptability were also evaluated. Ethylene had no major effects on weight loss, PPO, phenolic, sugars, acidity, and ascorbic acid. Instead, it increased respiration and accelerated chlorophyll degradation and surface yellowing. These changes were delayed in 1-MCP treated celery, which also maintained lower mesophilic bacteria and yeast counts, showed lower incidence of soft rots. 1-MCP treated celery received higher consumer acceptability scores. The effects were more marked on the samples obtained from the apical region of the petioles. Overall, results reassess the role of ethylene on celery petiole metabolism and indicate that 1-MCP treatments may be useful to supplement the benefits of refrigeration and extend the shelf life of fresh cut self-blanching celery.

Optimizing the performance of a commercial electrochemical ethylene sensor via controlled ethylene generation in situ

Ethylene, which regulates fruit ripening processes in some species, is a molecule of central interest to postharvest researchers and technologists. There is a need for a portable, inexpensive, accurate, and repeatable sensor for infield or storeroom measurements. To help ensure repeatable results, we developed a field calibration protocol for a portable electrochemical gas sensor that combines ethephon (2-chloroethylphosphonic acid) with a buffering agent to release a controlled amount of ethylene gas (1–4 μL/L). The ethephon reaction provides an economical source of standard gas for device calibration. This work addresses device selectivity issues through the use of an inline aqueous trap to remove polar volatile organics (50% reduction, as reported by an electrochemical sensor), interfering with the ethylene detection. A complementary gas chromatographic (GC) assay provided an independent validation of these results. A post-harvest study of ethylene production of apples as detected by the electrochemical sensor illustrates significant improvements in the accuracy and precision of these measurements.

Ameliorative effects of Saussurea lappa root aqueous extract against Ethephon-induced reproductive toxicity in male rats.

This study was designed to evaluate protective effect of Saussurea lappa root aqueous extract against Ethephon (2-chloroethylphosphonic acid)-induced reproductive toxicity in rats. Control group received distilled water. Second group was given S. lappa extract at a dose 50 mg/kg bw. Third group was given Ethephon at a dose 200 mg/kg bw. Fourth, fifth, and sixth groups were given S. lappa extract before, with or after Ethephon administration, respectively. Ethephon intoxication significantly decreased serum levels of follicle stimulating hormone, luteinizing hormone, testosterone, and prolactin. Also, it significantly decreased sperms count, vitality, morphology index, total motility, progressive motility, and proliferating cell nuclear antigen protein expressions in spermatogonia. However, it significantly increased sperms abnormalities, testicular tissue and DNA damages, P53 protein expressions, noprogressive motility, and immotile sperms. In contrast, S. lappa extract ameliorated these alterations. These results indicated that S. lappa had potential preventive and curative effects against Ethephon-induced reproductive toxicity in rats.

Ethylene Supplementation Increases PSII Efficiency and Alleviates Chromium-Inhibited Photosynthesis Through Increased Nitrogen and Sulfur Assimilation in Mustard

The effect of chromium (Cr) toxicity on four cultivars of mustard (Brassica juncea), Varuna, Pusa Bold, Rohini and SS2, was studied to select the cultivar with the highest tolerance potential based on higher photosynthesis and growth and lower oxidative stress. Plants receiving Cr showed enhanced superoxide production, accumulation of H2O2 and lipid peroxidation and reductions in photosynthesis and growth. We also studied the potential of ethephon (ethylene source; 2-chloroethyl phosphonic acid) in the amelioration of Cr-induced oxidative stress in the Varuna cultivar which had the highest tolerance potential. Supplementation of plants with ethylene resulted in the alleviation of Cr-induced stress by enhancing proline accumulation and the activity of proline metabolism enzymes and glutamyl kinase, and reduction in proline oxidase activity. Ethylene also increased the activity of enzymes of sulfur assimilation, ATP-sulfurylase and serine acetyl transferase and the content of reduced glutathione (GSH). Furthermore, application of ethylene to plants under Cr stress resulted in ethylene levels in the optimal range and increased the activity of anti-oxidant enzymes such as glutathione reductase and ascorbate peroxidase, reduced oxidative stress and increased photosynthesis and growth. The key role of ethylene in the reversal of Cr-induced photosynthetic inhibition was clearly seen with the application of the ethylene action inhibitor, silver nitrate (AgNO3). The supplementation of AgNO3 resulted in decreased GSH and proline content and lowered ethylene production and photosynthetic and growth compared to ethylene-treated plants. This suggests that ethylene is involved in -reversal of Cr inhibited photosynthesis and growth in mustard.

Ethephon Seed Treatment Impacts on Drought Tolerance of Kentucky Bluegrass Seedlings

Ethephon [ETH (2-chloroethylphosphonic acid, an ethylene-releasing compound)] has been used as a plant growth regulator in turfgrass management. The aim of the study was to assess the effects of ETH seed treatment on drought tolerance of kentucky bluegrass (Poa pratensis) seedlings. Seeds of two kentucky bluegrass cultivars, Midnight and Nuglade, were exposed to ETH treatment or untreated as controls. Seedlings were then exposed to two water regimes: well-watered conditions and polyethylene glycol (PEG)–induced drought conditions. ETH-treated plants exhibited better turf performance relative to the untreated control under PEG-stressed conditions illustrated by higher relative water content (RWC) and lower lipid peroxidation and lower electrolyte leakage (EL). In both cultivars, ETH treatment increased enzyme activity of ascorbate peroxidase (APX), peroxidase (POD), and catalase (CAT); proline content; and soluble protein content under PEG-induced drought conditions. The results suggest that ETH seed treatment can improve drought tolerance in kentucky bluegrass seedlings.

Promotion of shoot regeneration of Swertia chirata by biosynthesized silver nanoparticles and their involvement in ethylene interceptions and activation of antioxidant activity

Chemically synthesized silver nanoparticles (AgNP) have been assessed on plant tissue cultures but the impact of biologically synthesized AgNP fabricated by different phytoconstituents has not been sufficiently investigated. In this study biogenic AgNP prepared from leaf extract of Swertia chirata was utilized to address the problems associated with conservation of endangered medicinal plant through plant tissue culture. Endangered as well as economically important medicinal plant considered for this analysis was the same plant S. chirata itself. Excessive deforestation and exploration of this plant had led to complete eradication of the natural reservoir. Thus in vitro plant tissue propagation had attained much importance for maintaining the plant species. Nano-sized particles of diameter 20 nm encapped by different phytochemicals applied on regenerating shoot cultures showed enhanced shoot induction and proliferation. Other forms of silver like AgNO3 (SN) and Ag2S2O3 (STS) showed improved regeneration in comparison to control samples. Ethylene precursors like 1-aminocyclopropane-1-carboxylic acid (ACC) and 2-chloroethylphosphonic acid (CEPA) downregulated the regeneration process considerably. Reactive oxygen species (ROS) status of the treated cultures were evaluated considering hydrogen peroxide and malondialdehyde (MDA) content in treated cells as wells as their antioxidant enzyme activity. Combined manipulation and coordination of ethylene evolution, maintenance of ROS balance and better bio-acceptance of AgNP were responsible for improvement in shoot regeneration of the plant. Phytoencapsulated and nano-dimensioned Ag was capable of changing the chemical reactions of different regulating players of plant regeneration. These findings will facilitate the understanding and future utilization of biofabricated AgNP in agriculture and plant sciences.

Effect of methyl jasmonate on gummosis in petioles of culinary rhubarb (Rheum rhabarbarum L.) and the determination of sugar composition of the gum

This study aimed to know the key chemical compound influencing gummosis in petioles of intact growing culinary rhubarb (Rheum rhabarbarum L.) with special emphasis on its sugar composition. The application of methyl jasmonate (JA-Me, 0.5 and 1% in lanolin, w/w) in the middle of intact petiole of growing rhubarb substantially induced gummosis in the entire petioles, below and above the treatment, within several days. JA-Me at 0.5% in lanolin greatly stimulated ethylene production in intact petiole of growing rhubarb, on the 3rd day after JA-Me treatment, ethylene level being increased five times or more. However, an ethylene-releasing compound, ethephon (2-chloroethylphosphonic acid, 1 and 2% in lanolin, w/w) alone had no effect on gummosis. Analysis of gum polysaccharides by a gel permeation chromatography with a Tosho TSK-gel G5000PW gel permeation column revealed that almost all of rhubarb gum polysaccharides were eluted near the void in this gel chromatography system, suggesting that molecular mass of rhubarb gum polysaccharides are more than 500 kDa, while precise mass has not been decided in this study. Analysis of gum sugar composition after hydrolysis revealed that rhubarb gums is rich in galactose (ca. 30%), arabinose (ca. 20%), and galacturonic acid (15–20%), although other sugars also existed in small quantities. These results suggest that the key chemical compound of gummosis in petioles of rhubarb is jasmonates rather than ethylene, and gum polysaccharides consist of not only pectic arabinogalactans but also homogalacturonans.

Ethephon, an organophosphorous, a Fruit and Vegetable Ripener: Has potential hepatotoxic effects?

Introduction:In the recent years, ethephon, 2-chloroethylphosphonic acid, is one of the most commonly used plant growth regulators. At present, it is being used on fruits, vegetables, and cereals for promoting pre- and post-harvest ripening. The effect of artificial ripening has become questionable because of various health-related issues. This study was conducted to note the morphology of liver after ethephon administration as it is the site where chemicals undergo first pass metabolism and probably will be affected by ethephon. Materials andMethods:Adult Wistar albino rats were divided into experimental and control groups (10 each). Ethephon was administered at a dose of 200 mg/kg/day by a gavage tube in the experimental rats for 14 days. The animals were sacrificed within 24 h of the last dose; liver was dissected and processed for light microscopy. Hematoxylin and eosin-stained sections were studied using an image-pro express analyzer. The data obtained from control and experimental groups were statistically analyzed.Results:In the experimental rats, the body weight was found to be significantly decreased. The orderly arrangement of hepatocytes was disrupted and was replaced by blood-filled sinusoids. At sites, hepatocytes appeared to be degenerated. Councilman bodies with pyknotic nuclei and inflammatory infiltrations were seen. The population per unit area of the hepatocytes and Kupffer cells was 29.53 ± 10.65 versus 44.18 ± 10.31 and 25.12 ± 4.41versus 13.05 ± 6.5 in experimental and control groups, respectively. The decrease of hepatocytes and increase of Kupffer cells were found to be statistically significant.Conclusions:The observations in the liver are probably indicative of degenerative changes associated with ethephon. Hence, we can conclude that this plant growth regulator, Fruit and Vegetable Ripener, has hepatotoxic potential. General awareness and regarding the use of such plant growth regulators is must to reduce the intake.

Plant Growth Regulator Effects on Germination and Root Traits of ‘Lambada’ and ‘Don Victor’ Onion Cultivars

Onions (Allium cepa L.) are easily outcompeted by weeds because of slow germination and relative growth rates. Therefore, high percentage of seed germination and root vigor are important traits to improve field performance. The effects of exogenous plant growth regulators (PGRs), 2-chloroethylphosphonic acid (ethephon, Eth), indole-3-acetic acid (IAA), trans-zeatin (tZ), and 1-aminocyclopropane-1-carboxylic acid (ACC) were evaluated on the germination and root growth of ‘Don Victor’ (yellow) and ‘Lambada’ (red) onion seedlings. Seeds were soaked for 10 hours in hormonal solutions and water (hydro-priming). Seed germination improved with Eth (30 and 100 μm), Eth (100 μm) + IAA (10 μm), and IAA (3 μm) treatments. Root surface area (RSA) increased in response to Eth at 30 and 100 μm, Eth + IAA, and 3 μm IAA. Root length (RL) and root diameter (RD) were enhanced by 1 μm tZ and 100 μm ACC. Eth reduced RL and RD, whereas IAA showed no effects. A subsequent experiment evaluated synergistic effects of different PGRs. Treatment of seeds with ACC (250 μm) + tZ (0.5 μm) and ACC (250 μm) + tZ (0.5 μm) + Eth (20 μm) enhanced RL and RD. RSA was unaffected by ACC + tZ + Eth. The results suggest that exogenous PGRs could be useful to enhance germination, RL, and RSA of onion seedlings.

Synchronous fruit splitting in nutmeg using plant growth regulators

In this study, a simple technique with hormone treatment was developed for synchronous splitting (ripening) of nutmeg fruits. The methodology involves harvesting physiologically mature fruits, dipping the harvested fruits in 500 ppm ethrel (2-chloroethylphosphonic acid) solution for 10 minutes, and then storing them in shade. By this method, 90 to 100 per cent fruits split in 18 to 20 hours. Width of the split which helps in easy separation of nut from fruit pericarp was on par with that of naturally split fruits. The dry recovery, nut to mace ratio and fresh and dry weight of the nut and mace of the treated fruits were comparable with naturally split fruits. The intrinsic quality i.e. , oil, oleoresin and moisture content of nut and mace of treated fruits were on par with that of naturally split fruits. This indicates that nut and mace of treated fruits had similar physical and intrinsic quality parameters as that of naturally split fruits. The advantage of the method is that it is very effective in preventing aflatoxin (mycotoxin) contamination of nut and mace due to soil contact of naturally split fruits that fall on the ground. The method for synchronous fruit splitting in nutmeg is very simple and can be easily practiced by farmers. It also saves time, labour and money both for harvesting and processing of nutmeg. The cost of ethrel treatment would be around ` 800 per ton of fruit. This is the first report on the induction of synchronous and uniform fruit splitting (ripening) of pre-split harvested fruits in nutmeg.

Histological and Biochemical Traits of Chilling-injured Pulp Tissues as Affected by Cold Storage of Mango Fruit

Green mango (Mangifera indica L.) ‘Nam Doc Mai See Thong’ fruit were dipped in 2-chloroethylphosphonic acid solution (50 ppm) for 5 minutes, kept at 25 °C for 3 days, cold stored at 5 °C for 35 days and then transferred to 25 °C for 7 days. The skin color of the cold-stored fruit partly changed to dark-brown with surface depression. In addition, desiccated white-corky pulp tissues developed mainly along to the dark-brownish skin. Histological and biochemical analyses revealed that the formation of white-corky pulp tissues was correlated with starch accumulation in the hypodermal cells. Cell wall polymers of the white-corky pulp tissues were characterized by both a lower amount of solubilized pectins and higher amount of hemicelluloses than those of normally ripened (NR) tissues. The highest fatty acid unsaturation was observed in the NR pulps under chilling conditions followed by the white-corky pulp tissues under chilling conditions and the NR tissues without chilling. These results suggested that the disordered membrane caused by chilling inhibited the subsequent cascade of secondary reactions, such as the cell wall degradation. The skin damage derived from chilling injury (CI) is a direct factor inducing abnormal desiccation in the adjacent pulp, resulting in the formation of white-corky pulp tissues.

Effect of ethrel spray on the ripening behaviour of mango (Mangifera indica L.) variety 'Dashehari'

An experiment was carried out to investigate the effect of post harvest spray of different concentrations (100, 200, 400, 600 and 800 ppm) of ethrel (2-chloroethyl phosphonic acid) on ripening and colour development in ‘Dashehari’ mango fruits harvested in second week of June, 2015. The treated fruits were assessed for physico-chemical parameters such as physiological loss in weight (%), firmness (Kg/cm2), TSS (°Brix), titrable acidity (%), total carotenoids (mg/100g) and peel chlorophyll (mg/100g) and observations were recorded at 2 days interval during 8 days storage at ambient temperature. Changes in total soluble solids (8.5 to 23.23° Brix), total carotenoids (0.807 to 7.12 mg/100g) and PLW (14.58%) showed increasing trends up to 8 days during storage whereas fruit firmness (8.5 to 0.68 Kg/cm2), titrable acidity (1.26 to 0.08%) and total peel chlorophyll (5.2 to 0.14 mg/100g) showed decreasing trends. At the end of the storage period for 8 days, Ethrel spray at 600 ppm induced uniform ripening with attractive yellow colour within 4 days while untreated control fruits failed to ripen uniformly and remain light green even after 8 days of storage. Ripening advances by 4 days in fruits sprayed with 600 ppm ethrel com-pared to unsprayed control fruits.

Expressional characterization of two class I trehalose-6-phosphate synthase genes in Hevea brasiliensis (para rubber tree) suggests a role in rubber production

In plants, trehalose-6-phosphate (Tre6P) synthesized by the Tre6P synthase (TPS) acts as a signal metabolite in regulating sucrose metabolism in relation to plant growth and development. The Hevea genome predicts a total of 14 TPS genes, and two class I TPS members, HbTPS1 and 2, were explored here for their expressions under various hormone and abiotic stress treatments. HbTPS1 and 2 expressions in latex, cytoplasm of rubber-producing laticifers, were markedly affected by the treatments of ethephon (2-chloroethylphosphonic acid, an ethylene releaser), 2,4-dichlorophenoxyacetic acid, jasmonic acid and salicylic acid although in a distinct manner. HbTPS1 and 2 expressions were significantly up-regulated in a similar manner by cold (5 °C) and heat (40 °C) as examined in Hevea seedling leaves and roots, and by wounding in latex. In comparison, the drought treatment (20% PEG) posed a different effect on HbTPS1 and 2 expressions in Hevea seedlings. For example, in roots, HbTPS1 transcripts accumulated with the treatment, whereas those of HbTPS2 decreased for the first 24 h. Various hormone- and stress-responsive elements could be in silico predicted in HbTPS1 and 2 promoters, and a universal expression was observed for the HbTPS1::GUS activity in all growth stages of transgenic Arabidopsis. These results, coupled with the fact of rubber biosynthesis as a defense response using sucrose as the precursor molecule, propose a potential role of TPS genes in regulating rubber production.

Utilizing the Ethylene-releasing Compound, 2-Chloroethylphosphonic Acid, as a Tool to Study Ethylene Response in Bacteria.

Ethylene (C2H4) is a gaseous phytohormone that is involved in numerous aspects of plant development, playing a dominant role in senescence and fruit ripening. Exogenous ethylene applied during early plant development triggers the triple response phenotype; a shorter and thicker hypocotyl with an exaggerated apical hook. Despite the intimate relationship between plants and bacteria, the effect of exogenous ethylene on bacteria has been greatly overlooked. This is partly due to the difficulty of controlling gaseous ethylene within the laboratory without specialized equipment. 2-Chloroethylphosphonic acid (CEPA) is a compound that decomposes into ethylene, chlorine, and phosphate in a 1:1:1:1 molar ratio when dissolved in an aqueous medium of pH 3.5 or greater. Here we describe the use of CEPA to produce in situ ethylene for the investigation of ethylene response in bacteria using the fruit-associated, cellulose-producing bacterium Komagataeibacter xylinus as a model organism. The protocols described herein include both the verification of ethylene production from CEPA via the Arabidopsis thaliana triple response assay and the effects of exogenous ethylene on K. xylinus cellulose production, pellicle properties and colonial morphology. These protocols can be adapted to examine the effect of ethylene on other microbes using appropriate growth media and phenotype analyses. The use of CEPA provides researchers with a simple and efficient alternative to pure ethylene gas for the routine determination of bacterial ethylene response.

Utilizing the Ethylene-releasing Compound, 2-Chloroethylphosphonic Acid, as a Tool to Study Ethylene Response in Bacteria

Utilizing the Ethylene-releasing Compound, 2-Chloroethylphosphonic Acid, as a Tool to Study Ethylene Response in Bacteria