Characterizing the Phytotoxic Effects of Hydrogen Peroxide on Common Microgreen Species and Lettuce Cultivars

Hydrogen peroxide (H2O2) is an oxidizing agent used to disinfect recirculated irrigation water during the production of organic crops under controlled environmental systems (e.g., greenhouses). To characterize the phytotoxic effects and define a concentration threshold for H2O2, three microgreen species [arugula (Brassica eruca ssp. sativa), radish (Raphanus sativus), and sunflower (Helianthus annuus ‘Black Oil’)], and three lettuce (Lactuca sativa) cultivars, Othilie, Xandra, and Rouxai, were foliar sprayed once daily with water containing 0, 25, 50, 75, 100, 125, 150, or 200 mg·L−1 of H2O2 from seed to harvest under greenhouse conditions. Leaf damage was assessed at harvest using two distinct methods: 1) the percentage of damaged leaves per tray and 2) a damage index (DI). Applied H2O2 concentrations, starting from 25 mg·L−1, increased the percentage of damaged leaves in every species except ‘Black Oil’ sunflower, which remained unaffected by any applied concentration. Symptoms of leaf damage manifested in similar patterns on the surface of microgreen cotyledons and lettuce leaves, while mean DI values and extent of damage were unique to each crop. Fresh weight, dry weight, and leaf area of all crops were not significantly affected by daily H2O2 spray. Identifying how foliar H2O2 damage manifests throughout the crop, as well at individual cotyledon or leaf surfaces, is necessary to establish an upper concentration threshold for H2O2 use. On the basis of the aforementioned metrics, maximum recommended concentrations were 150 mg·L−1 (radish), 100 mg·L−1 (arugula) for microgreens and 125 mg·L−1 (‘Othilie’), 75 mg·L−1 (‘Rouxai’), and 125 mg·L−1 (‘Xandra’) lettuce.

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Characterizing the Phytotoxic Effects of Hydrogen Peroxide Root Dips on Hybrid Phalaenopsis Orchid Plants

HortTechnology ◽

10.21273/horttech04923-21 ◽

2021 ◽

pp. 1-7

Author(s):

Renata Goossen ◽

Kimberly A. Williams

Keyword(s):

Hydrogen Peroxide ◽

Root Zone ◽

Root Systems ◽

Plant Health ◽

Flower Bud ◽

Phytotoxic Effects ◽

Concentration Threshold ◽

Root Health ◽

Health Rating ◽

Over Time

Hydrogen peroxide (H2O2) is a well-known oxidizing agent often used as a remedy by consumers to treat algae and root decay from presumed root disease on interior plants, as well as to encourage root growth and health. To characterize the phytotoxic effects and define the safe concentration threshold for H2O2 use on ‘Vivaldi’ hybrid phalaenopsis orchid (hybrid Phalaenopsis), root systems were dipped for 3 minutes in 0%, 3%, 6%, or 12% H2O2 one time and observed in greenhouse conditions for the following 27 days. Root systems of each plant were assessed over time for percent visible root damage; ratings of root health on a scale of 1 to 5 points, with 5 points indicating “very healthy”; and final fresh and dry weights. To determine when symptoms manifested above the root zone, foliage and flower damage was evaluated over time by assessing percent visible foliage damage, ratings of foliage health, percent foliar wilt, flower/bud count, and final foliage and flower fresh and dry weights. Over the evaluation period, the root health rating of the ‘Vivaldi’ hybrid phalaenopsis orchids treated with 12% H2O2 decreased from 5 to 1.13, whereas those treated with 3% H2O2 only decreased from 5 to 4.13. H2O2 concentrations of 6% and 12% damaged root health permanently, whereas the 3% H2O2 concentration only caused minor damage to overall root health. However, algae were not killed at the 3% rate. Neither foliage nor flowers were seriously affected during the 3 weeks after application, but foliage wilt did result in the 6% and 12% treatments by week 4. As H2O2 concentration increased, fresh weights decreased in roots and leaves. Although a single 3% H2O2 root dip did not result in severe symptoms of phytotoxicity, the treatment’s long-term plant health effects are unknown. Because the 3% H2O2 root dip caused minor plant health setbacks and failed to subdue algae populations in the root zone, consumers should be wary of using H2O2 to improve orchid (Orchidaceae) root health and should instead focus on altering care and watering practices.

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Phytotoxic effects of Cerbera manghas L. leaf extracts on seedling elongation of four monocot and four dicot test species

Acta Agrobotanica ◽

10.5586/aa.1720 ◽

2017 ◽

Vol 70 (3) ◽

Cited By ~ 3

Author(s):

Ichsan Nurul Bari ◽

Hisashi Kato-Noguchi

Keyword(s):

Weed Management ◽

Dry Weight ◽

Phleum Pratense ◽

Italian Ryegrass ◽

Lepidium Sativum ◽

Leaf Extracts ◽

Isolation And Identification ◽

Test Species ◽

Phytotoxic Effects ◽

Cerbera Manghas

Exploration of allelochemicals with phytotoxic effects is intended to minimize a current dependency on synthetic herbicides in weed management. Several allelochemicals from the tropical tree Cerbera manghas (sea mango) have been reported as termiticides and bactericides. The present study investigated possible phytotoxic effects of C. manghas leaf extracts under laboratory conditions. Four monocots: barnyard grass (Echinochloa crus-galli), foxtail fescue (Vulpia myuros), Italian ryegrass (Lolium multiflorum), and timothy (Phleum pratense) and four dicots: alfalfa (Medicago sativa), garden cress (Lepidium sativum), lettuce (Lactuca sativa), and rapeseed (Brassica napus) were used as test species. Elongation of both shoots and roots of seedlings was measured to assess any phytotoxic effects. The results showed that the sensitivities of shoots and roots were different between the test species, and the inhibition of seedling elongation significantly increased with increasing concentration of leaf extracts of C. manghas for all the test species. The IC50 (50% inhibitory concentration) values showed that 8.50–32.30 and 4.26–34.67 mg dry weight equivalent extract mL−1 of C. manghas inhibited seedling elongation by 50%, for shoots and roots respectively. Isolation and identification of the phytotoxic substances from C. manghas are suggested for future investigation.

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Timing and Rates of Two Products Using Hydrogen Peroxide (H2O2) to Control Algae in Ebb and Flow Hydroponic Systems

HortScience ◽

10.21273/hortsci16193-21 ◽

2022 ◽

Vol 57 (1) ◽

pp. 32-39

Author(s):

Dharti Thakulla ◽

Bruce L. Dunn ◽

Carla Goad ◽

Bizhen Hu

Keyword(s):

Hydrogen Peroxide ◽

Plant Height ◽

Growth Parameters ◽

Dry Weight ◽

Pepper Plant ◽

Flower Number ◽

Cell Counts ◽

Hydroponic Systems ◽

Weekly Application ◽

Ebb And Flow

Algae is not desirable in hydroponics and creates problems such as reduced yield and decreased dissolved oxygen, and affects the physiology of plants and, thus, needs to be controlled. An experiment was conducted in Ebb and Flow hydroponic systems to investigate the application timing and rates of two hydrogen peroxide products (Zerotol and PERpose Plus). Treatments included 35 mL weekly, 35 mL biweekly, 70 mL weekly, 70 mL biweekly, and a control with no application of hydrogen peroxide using a 40-gallon reservoir of water. Pepper ‘Early Jalapeno’ and ‘Lunchbox Red’ and tomato ‘Geronimo’ and ‘Little Sicily’ were used. The study was conducted in a split-plot design with two replications over time. Plant growth parameters, including plant height, flower number, net CO2 assimilation, fresh weight, and dry weight were recorded. Algae data, including dry weight, algae cell counts, and chl a were also measured. Results indicated that with increasing rate and timing of either product decreased algae counts, dry weight, and chl a values. However, weekly and biweekly application of 70 mL of both products were not different for algae quantification. In pepper, plant height, shoot fresh and dry weight, and root fresh and dry weight were found to be significantly greater with Zerotol 35 mL biweekly, Zerotol 70 mL weekly, PERpose Plus 35 mL biweekly, and PERpose Plus 70 mL weekly compared with the control. ‘Lunchbox Red’ was significantly greater than ‘Early Jalapeno’ in all growth parameters, except soil plant analysis development (SPAD). ‘Lunchbox Red’ had the greatest flower number, with weekly application of 70 mL PERpose Plus. In tomato, greatest flower number and SPAD were observed in ‘Geronimo’ with a weekly application of 70 mL PERpose Plus and 70 mL Zerotol, respectively. Greater shoot and root fresh and dry weight for both tomato cultivars were recorded with 35 mL biweekly or 70 mL weekly application with either product. The results from both plants as well as algae analysis suggest that weekly application of 70 mL of either Zerotol or PERpose Plus produced the best results in terms of controlling algae and improving the growth of pepper and tomato plants.

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Sources of resistance to the erineum strain of Colomerus vitis (Acari: Eriophyidae) in grapevine cultivars

Systematic and Applied Acarology ◽

10.11158/saa.23.3.1 ◽

2018 ◽

Vol 23 (3) ◽

pp. 405 ◽

Cited By ~ 4

Author(s):

Saeid Javadi Khederi ◽

Mohammad Khanjani ◽

Mansur Gholami ◽

Enrico De Lillo

Keyword(s):

Damage Index ◽

Leaf Damage ◽

Plant Responses ◽

Sources Of Resistance ◽

Western Iran ◽

Potted Plants ◽

Mite Density ◽

Bud Breaking ◽

Almost All ◽

The Impact

The erineum strain of Colomerus vitis (GEM) is the most destructive pest of vineyards in western Iran and sometimes causes considerable damages to the grapevine. Little information is available on the susceptibility of the grapevine to this pest and its knowledge can be useful for a sustainable management of GEM. The present study was aimed at evaluating the responses of the plants to the infestation of GEM in order to compare the resistance/susceptibility of some native cultivars to this pest. Also, the profiling of JA, SA and IAA in leaves of infested plants of Sezdang was studied. The experiment was carried out on eighteen native cultivars and the non-native Muscat Gordo which were selected amongst the most common in southern and western Iran. Potted plants were cultivated under greenhouse conditions at a temperature of 32 ± 3.8°C, 75 ± 5% R.H. and a photoperiod of L16: D8 h. The impact of GEM was evaluated on the basis of the leaf area and weight, number and size of the erinea, and percentage of leaves with erinea three months after the infestation. The cane length was measured, too. Mite density on galled leaves (three months after the infestation) and in buds (at the bud breaking) was assessed. Cluster analysis based on the leaf damage index induced by GEM allowed to distinguish highly affected (Sezdang, Khalili, Ghalati and Rishbaba), moderately affected (Neyshaboori, Gazne, Muscat, Lale, Shahani Sefid, Ahmad, Monagha and Sia) and scarcely affected (Yaghuti, Rotabi, White Thompson, Atabaki, Koladari and Sahebi and Shahani Gerd) cultivars. The mite density into the buds and on the galled leaves was higher in the medium-late (Rishbaba and Khalili) and late ripening (Sezdang and Ghalati) cultivars rather than in the early (Sahebi and Shahani Gerd) and early-medium (Atabaki) ripening ones. The leaf damaged area, the leaf weight, the shoot length and the erineum development were correlated to the mite density and were the highest on Sezdang, Khalili, Ghalati and Rishbaba and the lowest on Atabaki, Koladari, Sahebi and Shahani Gerd. The highest density of the overwintering population was detected in proximal buds of all treated cultivars. The plant responses and the mite density were investigated also in the second and third year after the first mite infestation on highly affected (Sezdang, Khalili, Ghalati, Rishbaba), a few of the moderately affected (Neyshaboori, Gazne, Muscat) and the scarcely affected cultivars (White Thompson, Atabaki, Koladari, Sahebi, Shahani Gerd). The leaf damaged area, the percentage of galled leaves, the percentage of cane length reduction and the mite density strongly decreased during all three years of observations on the highly affected Sezdang, Khalili and Gazne. On the contrary, Ghalati and Rishbaba displayed an increase of the leaf damaged area, leaf damaged index and mite density on galled leaves during the same period in comparison to the first year of observation. The percentage of the leaves with erinea, the leaf damaged area and the mite density of Sezdang were highly and positively correlated with IAA while a negative correlation was found between the leaf damaged area and the mite density with SA and JA in the assayed years. Almost all data currently collected allowed a recognition of White Thompson, Atabaki, Koladari, Sahebi and Shahani Gerd as the least affected cultivars.

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Influence of BAS-145138 on the Activity of Sulfonylurea and Imidazolinone Herbicides

Zeitschrift für Naturforschung C ◽

10.1515/znc-1991-11-1202 ◽

1991 ◽

Vol 46 (11-12) ◽

pp. 939-944

Author(s):

Robert M. Devlin ◽

Irena I. Zbiec

Keyword(s):

Root Growth ◽

Dry Weight ◽

Sulfonylurea Herbicides ◽

Fresh Weight ◽

Phytotoxic Activity ◽

Phytotoxic Effects ◽

Shoot And Root Growth ◽

Imidazolinone Herbicides

This study demonstrates that corn can be partially safened by BAS-145138 against sulfonylurea and imidazolinone herbicides. The corn seeds were impregnated with BAS-145138 by soaking the seeds for 6 h in solutions of the safener. BAS-145138 had no effect on corn growth. However, corn shoot and root growth in length, fresh weight, and dry weight was partially protected by BAS-145138 from the phytotoxic effects of the sulfonylurea herbicides thiameturon and CGA -136872. Similar protection was given to corn against the phytotoxic activity of the imidazolinone herbicides imazapyr, imazaquin, and imazethapyr. This study suggests that corn could be safened with BAS-145138 against the phytotoxic effects of residual amounts of sulfonylurea and imidazolinone herbicides found in fields where wheat/corn or soybean/corn rotations take place.

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The influence of the lucerne bud mite (Eriophyes medicaginis Keifer) on the growth of lucerne

Australian Journal of Agricultural Research ◽

10.1071/ar9810773 ◽

1981 ◽

Vol 32 (5) ◽

pp. 773 ◽

Cited By ~ 2

Author(s):

PM Ridland ◽

GM Halloran

Keyword(s):

Medicago Sativa ◽

Dry Weight ◽

Stem Length ◽

Infestation Level ◽

Axillary Shoots ◽

Two Temperatures ◽

Medicago Sativa L ◽

Extent Of Damage ◽

Initial Infestation ◽

Damage Symptoms

The influence of Eriophyes medicaginis on the growth of lucerne (Medicago sativa L.) was studied at four temperatures (15, 20, 25 and 29�C) at an initial infestation level of 10 mites per seedling, and at two temperatures (20 and 29�C) with four initial levels of infestation (2, 5, 10 and 20 mites per seedling). At 25� and 29�C, infestation with 10 mites per seedling significantly reduced dry weight of tops, stem length and the development of axillary shoots within 22 days of infestation. In this period, the numbers of mites increased 16-fold at 29OC, ninefold at 25�C and sixfold at 20�C, but there was no increase at 15�C. The extent of damage caused by mites at 20�C appeared to vary with the differences in growth of the plants under different photoperiods. Under a short photoperiod (10.3 h) where no axillary shoots developed on either infested or control plants, the extent of damage due to mite infestation was much higher than under a longer photoperiod (13.2 h) where axillary shoots developed on all seedlings. Damage symptoms on leaves of infested plants included chlorotic patches (mainly at 20� and 25�C), agate-like banding (29�C) and a waxy mottle (15�C).

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A Simple HPLC Method for the Determination of Chlorpyrifos in Black Oil Sunflower Seeds

Journal of Liquid Chromatography &amp Related Technologies ◽

10.1080/10826070500451863 ◽

2006 ◽

Vol 29 (3) ◽

pp. 339-348 ◽

Cited By ~ 16

Author(s):

Richard E. Mauldin ◽

Thomas M. Primus ◽

Theresa A. Buettgenbach ◽

John J. Johnston ◽

George M. Linz

Keyword(s):

Hplc Method ◽

Sunflower Seeds ◽

Black Oil ◽

Oil Sunflower

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Simulated frosting of tropical grasses

Australian Journal of Agricultural Research ◽

10.1071/ar9740045 ◽

1974 ◽

Vol 25 (1) ◽

pp. 45 ◽

Cited By ~ 14

Author(s):

JB Hacker ◽

BJ Forde ◽

JM Gow

Keyword(s):

Vapour Pressure Deficit ◽

Frost Tolerance ◽

Leaf Damage ◽

Soluble Carbohydrates ◽

Leaf Surfaces ◽

Ranking Order ◽

Simulated Field ◽

Frost Period ◽

Relationship Of ◽

Tropical Grass

Ranking order for leaf damage was determined in six varieties of the tropical grass setaria after frosting in a controlled environment and was found to be similar to known field response. A frost temperature of –2.5°C provided good discrimination between populations subjected to three successive frost cycles of 4 hr under programmed conditions which closely simulated field conditions. Further experiments were carried out to investigate: (a) The relative frost tolerance of a range of varieties in the genera Setaria, Digitaria, Paspalum, and Lolium; (b) the effect of vapour pressure deficit (VPD) during frosting and rate of temperature change into the frost period on leaf damage; (c) the effect of temperatures preceding frosting and duration of frost on leaf damage; (d) the relationship of concentration of alcohol-soluble carbohydrates to susceptibility to frost. The most tolerant tropical grass tested was Paspalum dilatatum. Significant variation in frost tolerance in Setaria was related to altitude of origin, whereas in Paspalum plicatulum latitude of origin appeared to be the controlling factor. Frost tolerance was slightly increased by pre-hardening for 3 days or by growing at a lower night temperature. Frosting at a VPD of –3 mb resulted in less damage than frosting at a VPD of zero, when visible frost formed on leaf surfaces. Extending the duration of the frost resulted in an increase in leaf damage. Ranking order for frost tolerance was not attributable to differences in concentration of alcohol soluble carbohydrates and was not affected by environmental conditions either preceding or during the frost period.

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Frequency and length of stomata of 21 Populus clones

Canadian Journal of Botany ◽

10.1139/b79-298 ◽

1979 ◽

Vol 57 (22) ◽

pp. 2519-2523 ◽

Cited By ~ 22

Author(s):

S. G. Pallardy ◽

T. T. Kozlowski

Keyword(s):

Dry Weight ◽

Relative Distribution ◽

Stomatal Frequency ◽

Abaxial Surface ◽

Stomatal Characteristics ◽

Independent Variables ◽

Shoot Dry Weight ◽

Leaf Surfaces ◽

Surface Variation ◽

Weight Data

Frequency and length of stomata of field-grown plants of 21 Populus clones were studied. All clones except one were amphistomatous, and all clones had the greatest number of stomata per unit of leaf area on the abaxial surface. Variation in stomatal frequency, length, and relative distribution of stomata between abaxial and adaxial leaf surfaces among clones was found. Although differences in stomatal frequency and length were observed in some cases between early and late leaves of a clone, pore area differences were small because of the tendency for leaves with fewer stomata to have larger stomata. Cluster analysis utilizing abaxial and adaxial stomatal frequency and length as independent variables indicated that stomatal characteristics were related to parentage. Relationships between clonal stomatal characteristics and preliminary shoot dry weight data were not significant.

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Role of Dipicolinic Acid in Resistance and Stability of Spores of Bacillus subtilis with or without DNA-Protective α/β-Type Small Acid-Soluble Proteins

Journal of Bacteriology ◽

10.1128/jb.00212-06 ◽

2006 ◽

Vol 188 (11) ◽

pp. 3740-3747 ◽

Cited By ~ 114

Author(s):

Barbara Setlow ◽

Swaroopa Atluri ◽

Ryan Kitchel ◽

Kasia Koziol-Dube ◽

Peter Setlow

Keyword(s):

Hydrogen Peroxide ◽

Dna Damage ◽

Bacillus Subtilis ◽

Dipicolinic Acid ◽

Dry Weight ◽

Definitive Evidence ◽

Dry Heat ◽

Spore Resistance ◽

Wet Heat

ABSTRACT Dipicolinic acid (DPA) comprises ∼10% of the dry weight of spores of Bacillus species. Although DPA has long been implicated in spore resistance to wet heat and spore stability, definitive evidence on the role of this abundant molecule in spore properties has generally been lacking. Bacillus subtilis strain FB122 (sleB spoVF) produced very stable spores that lacked DPA, and sporulation of this strain with DPA yielded spores with nearly normal DPA levels. DPA-replete and DPA-less FB122 spores had similar levels of the DNA protective α/β-type small acid-soluble spore proteins (SASP), but the DPA-less spores lacked SASP-γ. The DPA-less FB122 spores exhibited similar UV resistance to the DPA-replete spores but had lower resistance to wet heat, dry heat, hydrogen peroxide, and desiccation. Neither wet heat nor hydrogen peroxide killed the DPA-less spores by DNA damage, but desiccation did. The inability to synthesize both DPA and most α/β-type SASP in strain PS3664 (sspA sspB sleB spoVF) resulted in spores that lost viability during sporulation, at least in part due to DNA damage. DPA-less PS3664 spores were more sensitive to wet heat than either DPA-less FB122 spores or DPA-replete PS3664 spores, and the latter also retained viability during sporulation. These and previous results indicate that, in addition to α/β-type SASP, DPA also is extremely important in spore resistance and stability and, further, that DPA has some specific role(s) in protecting spore DNA from damage. Specific roles for DPA in protecting spore DNA against damage may well have been a major driving force for the spore's accumulation of the high levels of this small molecule.

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