Search Results

You are looking at 1 - 10 of 333 items for :

  • "hydrogen peroxide" x
  • Refine by Access: All x
Clear All
Full access

Christopher J. D’Angelo and Irwin L. Goldman

inhibitor, which is a key enzyme that removes reactive oxygen species from plant cells. When administered to endodormant grapevine buds, hydrogen cyanamide was shown to increase levels of hydrogen peroxide in cells before breaking dormancy ( Mazzitelli et al

Open access

Michael Stein, Corina Serban, and Per McCord

are the reactive oxygen species (ROS) and reactive nitrogen species (RNS). These reactive species have been found to reduce seed sensitivity to ABA ( Gniazdowska et al., 2010a ). Hydrogen peroxide, a ROS and well-known molecular signaling agent, may

Open access

Renata Goossen and Kimberly A. Williams

recorded every 15 min from 1 to 27 d after treatment (DAT) of orchids with hydrogen peroxide. Temperature set point was 20 °C day and night. (1.8 × °C) + 32 = °F. E xperimental setup Four H 2 O 2 rates of 0 ppm, 30,000 ppm (3%), 60,000 ppm (6

Open access

Mitchell Eicher-Sodo, Robert Gordon, and Youbin Zheng

Reusing nutrient solution provides a unique, but challenging prospect within organic greenhouse production due to the restricted number of available pathogen control products. Oxidizing agents, such as ozone, peracetic acid, or hydrogen peroxide

Free access

Charles F. Forney, Roger E. Rij, Ricardo Denis-Arrue, and Joseph L. Smilanick

The potential use of vapor phase hydrogen peroxide (VPHP) to prevent decay caused by Botrytis cinerea Pers. ex Fr. in table grapes (Vitis vinifera L.) was investigated. `Thompson Seedless' and `Red Globe' grapes, inoculated with Botrytis cinerea spores, were placed in polyethylene bags and flushed for 10 minutes with VPHP generated from a 30% to 35% solution of liquid hydrogen peroxide at 40C. Immediately after treatment, bags were sealed and held at 10C. Vapor phase hydrogen peroxide significantly reduced the number of terminable Botrytis spores on grapes. The number of terminable spores on `Thompson Seedless' and `Red Globe' grapes had been reduced 81% and 62%, respectively, 24 hours following treatment. The incidence of decay on inoculated `Thompson Seedless' and `Red Globe' grapes was reduced 33% and 16%, respectively, after 8 days of storage at 10C compared with control fruit. Vapor phase hydrogen peroxide reduced the decay of noninoculated `Thompson Seedless' and `Red Globe' grapes 73% and 28%, respectively, after 12 days of storage at 10C. Treatment with VPHP did not affect grape color or soluble solids content.

Free access

Kwang-Hyun Baek and C.B. Rajashekar

Effects of hypoxia on germinating bean seeds (Phaseolus vulgaris cv. Tendergreen) were examined by imbibing them in water for various lengths of time. Hypocotyl elongation under hypoxic conditions and recovery from hypoxia in bean seeds were determined. Oxygen concentration in the water began to decrease sharply after 12 h of seed imbibition and had declined by more than 63% after 3 days of seed imbibition. When seeds were germinated on 0.8% agar after 24 h of imbibition, the hypocotyl elongation was reduced by about 70% compared to the seeds with no hypoxia, and longer imbibition resulted in poor or no germination. Exogenous hydrogen peroxide (20 mm) in water increased the oxygen concentration from 250 to 350 mm in the presence of seeds and was considerably higher after 3 days of seed imbibition than that in the control. Hypocotyl elongation occurred in seeds submerged in water containing hydrogen peroxide up to 72 h while none was observed in water. This was comparable to hypocotyl elongation under non-hypoxic conditions. Hypoxia in imbibing seeds was overcome by the high oxygen levels in the medium resulting from reaction of hydrogen peroxide with seed catalase and catalytic metal ions. Considerable catalase activity was detected in germinating seeds and the use of a catalase inhibitor, aminotriazole, suggests that the enzyme plays an important role in the release of oxygen into the medium. Of the catalytic metals, the seed content of iron was dominant and was about 6 folds higher than that of either copper or manganese.

Open access

Dharti Thakulla, Bruce L. Dunn, Carla Goad, and Bizhen Hu

peroxide (H 2 O 2 ), which decomposes rapidly into harmless products water and oxygen ( Randhawa et al., 2012 ). Hydrogen peroxide is generated via superoxide, presumably in a noncontrolled manner, during electron transport processes such as photosynthesis

Free access

Patrick J. Conner

in polyethylene bags and stored at 4 °C before treatment initiation. Expt. 1: Effects of 0.5 M hydrogen peroxide and 1 g·L −1 gibberellic acid pretreatment and cold-stratification period on germination rate. Seed received one of the following

Free access

Gilbert F. Simmons, Joseph L. Smilanick, Shama John, and Dennis A. Margosan

Moisture is raised in dehydrated prunes to improve palatability before packaging and potassium sorbate is added to inhibit microbial growth. Vapor phase hydrogen peroxide (VPHP) technology uses hydrogen peroxide pulses to disinfect dried prunes. Dried prunes were obtained from dehydrators. The number of colony-forming units per 10 prunes (cfu/p) was compared between untreated and VPHP treated. Three culture media—dichloran rose bengal chloramphenicol agar base (DRBC, Oxoid), aerobic plate count agar (PCA), and potato dextrose agar (PDA)—were used to evaluate cfu/p. Similar mean microbe populations were observed on DRBC (67) and PDA (70); PCA had higher cfu/p (99). Microbes washed from untreated prunes obtained from dehydrators were 58 to 112 cfu/p, depending on the culture medium used. The number of cfu/p assessed on all media on VPHP-treated prunes was near 0 after 100 min exposure. Unlike potassium sorbate, hydrogen peroxide is a microbiocide rather than a microbiostat.

Free access

Gilbert F. Simmons, Joseph L. Smilanick, Nuria Denis-Arrue, Dennis A Margosan, and Shama John

A new vapor phase hydrogen peroxide (VPHP) technology that uses relatively dry hydrogen peroxide pulses is a promising method for the disinfection of surface-borne bacteria, yeasts, and molds on walnut nutmeats. The number of colony forming units per gram (cfu/g) on untreated nutmeats was compared to those VPHP treated. Three culture media; dichloran rose bengal chloramphenicol agar base (DRBC, Oxoid), aerobic plate count agar (APC, Oxoid), and potato dextrose agar (PDA, Sigma), were utilized to evaluate cfu/g. Similar numbers of cfu/g of product were observed on APC and PDA. The more selective DRBC had lower cfu/g. Microorganisms washed from untreated walnut nutmeats purchased at retail outlets ranged between 17,000-29,000 cfu/g depending upon the culture medium used. The number of cfu/lg on nutmeats after VPHP treatments was reduced to 500-1400, a 95% reduction. VPHP may offer an alternative to propylene oxide fumigation. The moisture content of nutmeats was not significantly altered by VPHP. The Food and Drug Administration lists hydrogen peroxide as a “generally recognized as safe substance” (GRAS). Hydrogen peroxide is already produced in a food grade for aseptic packaging.