H2O2 is involved in the dormancy-breaking effect of hydrogen cyanamide in grapevine buds

Abstract Peach trees initiate flowering and then dense budding when the temperatures in winter are steadily low. When temperatures during the winter are high or when the chilling accumulation needs of the cultivar are not met, it is necessary to apply chemicals that stimulate flowering and budding in a uniform manner. This study aimed to evaluate alternative products for breaking the dormancy of ‘Kampai’ peach trees in a subtropical region. The experiment was conducted with ‘Kampai’ peach trees in the 2018, 2019 and 2020 production with the following treatments: (1) negative control composed only of water (control); (2) positive control composed of hydrogen cyanamide at a dose of 1.5% (commercial product Dormex®) plus 4.5% mineral oil; (3) Erger G® organomineral fertilizer supplemented with calcium nitrate at a dose of 3%; (4) potassium nitrate at a dose of 5%; and (5) copper sulphate at a dose of 0.3%. We evaluated affected budding capacity, flowering, the production cycle, peach production, the quality of peach trees and the enzymatic activities of catalase and guaiacol peroxidase. Hydrogen cyanamide and the organomineral fertilizer Erger G® promoted earlier flowering and an earlier production cycle. On the other hand, hydrogen cyanamide and copper sulphate stimulated flower opening and peach production. The chemicals used decreased catalase activity (24 h after application) and increased guaiacol peroxidase activity (6 h after application). The application of copper sulphate may be an option to break the dormancy of peach trees in the subtropics.

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An alternative dormancy-breaking agent to hydrogen cyanamide for sweet cherry (Prunus aviumL.) under low chilling accumulation conditions in the Central Valley of Chile

Acta Horticulturae ◽

10.17660/actahortic.2017.1161.68 ◽

2017 ◽

pp. 423-430

Author(s):

M. Ardiles ◽

M. Ayala

Keyword(s):

Sweet Cherry ◽

Central Valley ◽

Dormancy Breaking ◽

Hydrogen Cyanamide

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Budbreak patterns and phytohormone dynamics reveal different modes of action between hydrogen cyanamide- and defoliant-induced flower budbreak in blueberry under inadequate chilling conditions

PLoS ONE ◽

10.1371/journal.pone.0256942 ◽

2021 ◽

Vol 16 (8) ◽

pp. e0256942

Author(s):

Syuan-You Lin ◽

Shinsuke Agehara

Keyword(s):

Model Fitting ◽

Vaccinium Corymbosum ◽

Steady Increase ◽

Dormancy Breaking ◽

Water Control ◽

Acetic Acid Production ◽

Rapid Phase ◽

Hydrogen Cyanamide ◽

Yield Increase ◽

Modes Of Action

Under inadequate chilling conditions, hydrogen cyanamide (HC) is often used to promote budbreak and improve earliness of Southern highbush blueberry (Vaccinium corymbosum L. interspecific hybrids). However, HC is strictly regulated or even banned in some countries because of its high hazardous properties. Development of safer and effective alternatives to HC is critical to sustainable subtropical blueberry production. In this study, we examined the efficacy of HC and defoliants as bud dormancy-breaking agents for ‘Emerald’ blueberry. First, we compared water control, 1.0% HC (9.35 L ha–1), and three defoliants [potassium thiosulfate (KTS), urea, and zinc sulfate (ZS)] applied at 6.0% (28 kg ha–1). Model fitting analysis revealed that only HC and ZS advanced both defoliation and budbreak compared with the water control. HC-induced budbreak showed an exponential plateau function with a rapid phase occurring from 0 to 22 days after treatment (DAT), whereas ZS-induced budbreak showed a sigmoidal function with a rapid phase occurring from 15 to 44 DAT. The final budbreak percentage was similar in all treatments (71.7%–83.7%). Compared with the water control, HC and ZS increased yield by up to 171% and 41%, respectively, but the yield increase was statistically significant only for HC. Phytohormone profiling was performed for water-, HC- and ZS-treated flower buds. Both chemicals did not increase gibberellin 4 and indole-3-acetic acid production, but they caused a steady increase in jasmonic acid (JA) during budbreak. Compared with ZS, HC increased JA production to a greater extent and was the only chemical that reduced abscisic acid (ABA) concentrations during budbreak. A follow-up experiment tested ZS at six different rates (0–187 kg ha–1) but detected no significant dose-response on budbreak. These results collectively suggest that defoliants are not effective alternatives to HC, and that HC and ZS have different modes of action in budbreak induction. The high efficacy of HC as a dormancy-breaking agent could be due to its ability to reduce ABA concentrations in buds. Our results also suggest that JA accumulation is involved in budbreak induction in blueberry.

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Transcriptomic Study of Early Responses to the Bud Dormancy-breaking Agent Hydrogen Cyanamide in ‘TropicBeauty’ Peach

Journal of the American Society for Horticultural Science ◽

10.21273/jashs04686-19 ◽

2019 ◽

Vol 144 (4) ◽

pp. 244-256 ◽

Cited By ~ 3

Author(s):

Lisa Tang ◽

Shweta Chhajed ◽

Tripti Vashisth ◽

Mercy A. Olmstead ◽

James W. Olmstead ◽

...

Keyword(s):

Oxidative Stress ◽

Cell Wall ◽

Prunus Persica ◽

Cell Activity ◽

Pentose Phosphate ◽

Bud Dormancy ◽

Sequencing Analysis ◽

Dormancy Breaking ◽

Ros Scavenging ◽

Hydrogen Cyanamide

To determine how the dormancy-breaking agent hydrogen cyanamide (HC) advances budbreak in peach (Prunus persica), this study compared the transcriptome of buds of low-chill ‘TropicBeauty’ peach trees treated with 1% (v/v) HC and that of nontreated trees at 3 and 7 days after treatment (DAT), respectively, using an RNA sequencing analysis. The peak of total budbreak occurred 6 weeks earlier in the HC-treated trees (at 32 DAT) than the nontreated trees (at 74 DAT). There were 1312 and 1095 differentially expressed genes (DEGs) at 3 and 7 DAT, respectively. At 3 DAT, DEGs related to oxidative stress, including the response to hypoxia, lipid oxidation, and reactive oxygen species (ROS) metabolic process, were upregulated in HC-treated buds. Additionally, DEGs encoding enzymes for ROS scavenging and the pentose phosphate pathway were upregulated at 3 DAT but they were not differently expressed at 7 DAT, indicating a temporary demand for defense mechanisms against HC-triggered oxidative stress. Upregulation of DEGs for cell division and development at 7 DAT, which were downregulated at 3 DAT, suggests that cell activity was initially suppressed but was enhanced within 7 DAT. At 7 DAT, DEGs related to cell wall degradation and modification were upregulated, which was possibly responsible for the burst of buds. The results of this study strongly suggest that HC induces transient oxidative stress shortly after application, leading to the release of bud dormancy and, subsequently, causing an increase in cell activity and cell wall loosening, thereby accelerating budbreak in peach.

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757 PB 155 LABORATORY RESPONSE TO DORMANCY-BREAKING TREATMENTS DIFFERS BY BUD AND CUTTING TYPE IN PEACH

HortScience ◽

10.21273/hortsci.29.5.541e ◽

1994 ◽

Vol 29 (5) ◽

pp. 541e-541

Author(s):

Gil Nir ◽

Greg Lang

Keyword(s):

Gibberellic Acid ◽

Methyl Jasmonate ◽

Sodium Azide ◽

Differential Regulation ◽

Hot Water ◽

Model Systems ◽

Aminooxyacetic Acid ◽

Dormancy Breaking ◽

Hydrogen Cyanamide ◽

Early Autumn

Endodormant `Hawthorne' peach shoots were collected in early autumn and sectioned into long (30-40 cm), short terminal (10-15 cm), or short sub-terminal (IO-15 cm) cuttings. Dormancy-breaking treatments included application of hydrogen cyanamide H2C N2), thiourea (TU), sodium azide (NaN3) or gibberellic acid (GA3) solutions; atmospheric methyl jasmonate (MJ); hot water (50C for 1-2 h); or chilling (3.5C for 1-4 weeks). During forcing at 24C, & budbreak of all bud types on long cuttings was very low. On short cuttings, % apical budbreak was greater than % lateral vegetative budbreak, with almost no floral budbreak. Relative to H2CN2-induced lateral vegetative budbreak, budbreak induced by MJ, TIJ, GA,, and NaN3 was 17, 34, 50, and 92%, respectively. Relative apical budbreak was 0, 95, 53, and 63%, respectively. Addition of aminooxyacetic acid (AOA) to the beaker solution (in which cuttings were forced) induced apical, but not lateral, budbreak by itself; AOA synergistically improved H2CN2-induced budbreak by 23%. Latetal budbreak on short sub-terminal cuttings treated with hot water (1 h) was similar to that of H2CN2 treatment. Chilling increased apical budbreak to 100% as duration increased to 3 weeks, lateral vegetative budbreak only reached 43% after 4 weeks of treatment. The use of different bud and cutting types as model systems to study the differential regulation of dormancy by various treatments will be discussed.

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Hot Water Treatment Released Endodormancy but Reduced Number of Flowers in Potted Red Raspberry Plants

HortScience ◽

10.21273/hortsci.45.6.894 ◽

2010 ◽

Vol 45 (6) ◽

pp. 894-898 ◽

Cited By ~ 3

Author(s):

Marja Rantanen ◽

Pauliina Palonen

Keyword(s):

Water Treatment ◽

Dry Weight ◽

Rubus Idaeus ◽

Hot Water ◽

Bud Break ◽

Hot Water Treatment ◽

Dormancy Breaking ◽

Red Raspberry ◽

Hydrogen Cyanamide ◽

Sublethal Stress

Partially released dormancy causes poor and uneven bud break in temperate plant species like red raspberry (Rubus idaeus L.). Insufficient chilling may be a problem when raspberries are grown at southern latitudes and in year-round production. Dormancy may be released by sublethal stress in many species. We studied the effect of sublethal stress on endodormancy in red raspberry ‘Glen Ample’ and ‘Ottawa’. Canes growing in pots were treated with either hot water (45 °C, 1 h) or the dormancy-breaking chemical, hydrogen cyanamide (1.04%), after accumulation of 0, 240, 480, 720, 960, or 1200 h of chilling at 1 °C. Bud break, vegetative growth, and number of flowers were recorded during 12 weeks of greenhouse forcing after the treatments. Chilling increased bud break, growth, and dry weight of lateral shoots and number of flowers in both cultivars. During deepest endodormancy (0 and 240 h of chilling), treatment with either hot water or hydrogen cyanamide enhanced bud break and lateral shoot growth but could not completely replace chilling. In ‘Ottawa’, hydrogen cyanamide was more effective than hot water during deepest endodormancy, but hot water treatment broke dormancy effectively when 720 h of chilling had accumulated. For ‘Glen Ample’, hot water was as effective as hydrogen cyanamide in breaking endodormancy. Hot water treatment reduced the number of flowers in ‘Glen Ample’ during late endodormancy (720, 960, and 1200 h of chilling). The chilling requirement for ‘Ottawa’ was fulfilled between 720 and 960 h of chilling. However, in ‘Glen Ample’, 1200 h of chilling was not enough to fully release bud dormancy; bud break remained low and it was increased by dormancy-breaking treatments. Hot water treatment can be used to release endodormancy in raspberries, but treatment conditions need to be optimized to preserve crop potential. Chemical name used: hydrogen cyanamide (Dormex, Hi-Cane, Morgrapes).

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