Articles
ENDOGENOUS PHYTOHORMONE LEVELS IN DWARF AND NORMAL HOP (HUMULUS LUPULUS L.) PLANTS
Article number
1010_16
Pages
141 – 148
Language
English
Abstract
The cultivated hop (Humulus lupulus L.) is normally grown in 5-8 m tall wirework to produce commercial yields of inflorescences known as cones.
Relatively recently, dwarf hops have been developed in the United Kingdom, which have shorter internode lengths and are cultivated in low trellis systems.
Phytohormones are associated with plant growth and developmental processes including vegetative growth, internode elongation, flower induction, shoot formation, leaf senescence, chlorophyll production, etc.
The aim of our study was to reveal possible differences in endogenous phytohormone contents between normal and dwarf hop genotypes during development in field conditions.
Growth hormones (auxins, gibberellins, cytokinins) and stress hormones (abscisic acid, jasmonic acid, salicylic acid) were measured by LC-electrospray tandem-mass spectrometry in female plants of three normal (Saazer, Sladek, Admiral) and three dwarf (First Gold, Herald, 5021) cultivars.
Various tested plant tissues (apex buds, young leaves, old leaves, inflorescences) markedly differed in the phytohormone levels, independently on hop genotypes.
Enhanced levels of auxins and gibberellins (GA19, GA20, GA29) were detected in inflorescences suggesting these classes of hormones might be involved in flowering, maturating and generative growth of plants.
As for cytokinins, cis-zeatin types were found to occur in considerably higher amounts in dwarf cultivars compared to normal ones.
The statistically significant difference between dwarf and normal hop plants was revealed for cis-zeatin-9-riboside-O-glucoside exhibiting enhanced levels in all tested tissues of dwarf cultivars.
Similarly, concentrations of another cytokinin storage form, cis-zeatin-O-glucoside, exceeded in all tissues of dwarf genotypes (except for young leaves) those in normal hop plants.
Slightly higher levels of abscisic acid were detected in apex buds of normal cultivars while considerably enhanced levels of salicylic acid occurred in apex buds and young leaves of dwarf cultivars.
Our results indicate an involvement of both growth and stress hormones in the dwarfism as well as their relationships during vegetative and reproductive development of hop plants.
Relatively recently, dwarf hops have been developed in the United Kingdom, which have shorter internode lengths and are cultivated in low trellis systems.
Phytohormones are associated with plant growth and developmental processes including vegetative growth, internode elongation, flower induction, shoot formation, leaf senescence, chlorophyll production, etc.
The aim of our study was to reveal possible differences in endogenous phytohormone contents between normal and dwarf hop genotypes during development in field conditions.
Growth hormones (auxins, gibberellins, cytokinins) and stress hormones (abscisic acid, jasmonic acid, salicylic acid) were measured by LC-electrospray tandem-mass spectrometry in female plants of three normal (Saazer, Sladek, Admiral) and three dwarf (First Gold, Herald, 5021) cultivars.
Various tested plant tissues (apex buds, young leaves, old leaves, inflorescences) markedly differed in the phytohormone levels, independently on hop genotypes.
Enhanced levels of auxins and gibberellins (GA19, GA20, GA29) were detected in inflorescences suggesting these classes of hormones might be involved in flowering, maturating and generative growth of plants.
As for cytokinins, cis-zeatin types were found to occur in considerably higher amounts in dwarf cultivars compared to normal ones.
The statistically significant difference between dwarf and normal hop plants was revealed for cis-zeatin-9-riboside-O-glucoside exhibiting enhanced levels in all tested tissues of dwarf cultivars.
Similarly, concentrations of another cytokinin storage form, cis-zeatin-O-glucoside, exceeded in all tissues of dwarf genotypes (except for young leaves) those in normal hop plants.
Slightly higher levels of abscisic acid were detected in apex buds of normal cultivars while considerably enhanced levels of salicylic acid occurred in apex buds and young leaves of dwarf cultivars.
Our results indicate an involvement of both growth and stress hormones in the dwarfism as well as their relationships during vegetative and reproductive development of hop plants.
Publication
Authors
J. Patzak, P.I. Dobrev , V. Motyka
Keywords
abscisic acid, auxin, cytokinin, gibberellin, jasmonic acid, salicylic acid
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