Effect of hydrogen cyanamide on the endogenous hormonal content of pea seedlings (Pisum sativum L.)

Abstract

Hydrogen cyanamide (HC) has been used to break bud and seed dormancy and to improve rooting in several species, responses usually associated with the action of plant hormones. However, very few studies have measured endogenous hormones after HC treatment. Therefore, pea (Pisum sativum L.) seedlings with two fully developed internodes above the first leaf were sprayed with 0, 0.1 and 0.3% (v/v) HC. Endogenous concentration of indole-3-acetic acid (IAA), abscisic acid (ABA), zeatin/zeatin riboside and N 6 (∆ 2 -isopentenyl) adenine/ N 6 (∆ 2 -isopentenyl) adenosine were measured by radioimmunoassay 31 and 80 h after HC treatment. A significant increase in ABA and cytokinin (CK) levels was observed 31 h after treating the plants with 0.3% HC. Small necrotic spots were also noticed in this treatment, thus revealing a toxic effect of this treatment. Additionally, at 80 h, a significant increase in IAA was found for both HC concentrations applied. The action of HC upon ABA, CKs and IAA endogenous levels is discussed. Key words: abscisic acid, cytokinins, indole-3-acetic acid Efeito da cianamida hidrogenada sobre o conteúdo de hormônios endógenos em plântulas de ervilha (Pisum sativum L.): A cianamida hidrogenada (CH) tem sido usada para quebrar a dormência de sementes e estimular o enraizamento em várias espécies, respostas estas usualmente associadas com a ação de hormônios de plantas. Todavia, em muito poucos estudos se tem avaliado os níveis endógenos de hormônios após a aplicação de CH. Portanto, plântulas de ervilha (Pisum sativum L.), com dois internódios completamente desenvolvidos acima da primeira folha, foram pulverizadas com soluções de CH a 0; 0,1; e 0,3% (v/v). Concentrações endógenas de ácido indol-3-acético (AIA), ácido abscísico (AAB), zeatina/ribosídeo de zeatina e N 6 (∆ 2 -isopentenil) adenina/ N 6 (∆ 2 -isopentenil) adenosina foram medidas por radioimunoensaio após 31 e 80 h da aplicação de CH. Observaram-se aumentos significativos nas concentrações de AAB e citocininas 31 h após o tratamento das plantas com 0,3% de CH. Verificaram-se pequenas manchas necróticas nas plantas desse tratamento, que se revelou, pois, tóxico. Adicionalmente, observou-se um incremento na concentração de AIA após 80 h da aplicação de CH, tanto a 0,1 como a 0,3%. Discute-se a ação da CH sobre as concentrações endógenas de AAB, AIA e citocininas. Palavras-chave: ácido abscísico, ácido indol-3-acético, citocininas

Resistance Inducers and Plant Growth Regulators Show Only Limited and Transient Effects on Infection Rates, Growth Rates and Symptom Expression of Apple Trees Infected With ‘candidatus Phytoplasma mali’

“…apple) in areas with warm winters and insufficient chill hours. Hydrogen cyanamide, the active ingredient of Dormex, increases IAA and cytokinin (CK) levels (Guevara et al 2008) and inhibits catalases (Amberger 1961). Catalases degrade hydrogen peroxide, a crucial anti-microbial compound produced by infected plants to attack plant pathogens.…”

Comparative Study on Reagents Involved in Grape Bud Break and Their Effects on Different Metabolites and Related Gene Expression during Winter

“…A crosstalk between grape bud dormancy and plant hormones along with the bud break is a critical dilemma for grape production. Previously, Guevara et al (2008) , Mornya and Cheng (2011) , Okay et al (2011) examined the endogenous hormonal change during bud dormancy release process and demonstrated that regulation and control, occurrence and termination of dormancy were regulated by hormones. Different levels of endogenous abscisic acid (ABA) are linked with development and release of apical buds dormancy in plants ( Powell, 1987 ).…”

Impact of Chilling Requirement on Budburst, Floral Development and Hormonal Level in Buds of Early and Late Apple Varieties (<i>Malus</i> <i>sylvestris, </i>Mill) under Natural Conditions

“…The relation of plant hormones and bud dormancy in additionally as bud break was a major down aspect for every theories and production practices. Seasonal changes in endogenous hormone during and after bud dormancy release was studied by many researchers (Guevara et al, 2008, Dong et al, 2009, Mornya and Cheng, 2011, Okay et al, 2011, Seif El-Yazal and Rady, 2014, Seif El-Yazal et al, 2014, 2018a, b, c &d). They found that the incidence, termination, regulation and management of dormancy were regulated by hormones throughout sufficiently winter chilling requirement.…”