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1.
Possible role of jasmonic acid in the regulation of floral induction, evocation and floral differentiation in Lemna minor L.
Božidar Krajnčič, Janja Kristl, Ignac Janžekovič, 2006, original scientific article

Abstract: Jasmonic acid (JA) is implicated in a wide variety of developmental and physiological processes in plants. Here, we studied the effects of JA and the combination of JA and ethylenediamine-dio-hydroxypheny-acetic acid (EDDHA) on flowering in Lemna minor in axenical cultures. JA (0.475-47.5 nmol l-1) enhanced floral induction in L. minor under long-day (LD) conditions. Under the same conditions, at the concentration of 237.5 nmol l-1, JA inhibited floral induction, and at the concentration of 475 nmol l-1 it prevented floral induction. Under LD conditions with LD preculture, a combination of EDDHA (20,500 nmol l-1) and JA (47.5 nmol l-1) had a synergistic effect on the promotion of floral induction. Floral induction was enhanced to the greatest extent in experiments with LD precultures. Microscopic examination of microphotographs of histological sections showed that JA and, to an even greater extent, JA+ EDDHA at optimal concentrations promote apical floral induction (evocation). Furthermore, and to an even greater extent JA in combination with EDDHA in an optimal concentration, also promote flower differentiation, especially the development of stamens, as is evident from themicrophotographs. The experimental results show that JA promotes floral induction in other species of Lemnaceae from various groups according to their photoperiodic response. The results support our hypothesis that, in addition to previosly ascribed functions, JA may regulate floral induction, evocation and floral differentiation. Our hypothesis is supported also by the results obtained by quantitative determination of endogenous JA levels in L. minor at three growth stages. The levels of endogenous JA decreased from 389 ng JA g-1 (fresh weight) of L. minor during the vegetative stage to 217 ng JA g-1 during the evocation stage, and to 37.5 ng JA g-1 during the flowering stage, which proves that JA is used for flowering.
Keywords: chelating agent EDDHA, flowering, jasmonic acid (JA), Lemna minor L., endogenous JA levels
Published: 10.07.2015; Views: 668; Downloads: 59
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2.
Morpho-agronomic characteristics of the interspecific hybrid Cucurbita ficifolia x C. maxima
Anton Ivančič, Metka Šiško, Borut Bohanec, Simona Šiftar, 2004, original scientific article

Abstract: The aim of the investigation was to describe some of the main morpho-agronomiccharacteristics of the interspecific hybrid Cucurbita ficifolia x C. maxima, and to define the traits which can be used for distinguishing this hybrid from the parental species. The hybrid was obtained using emryo-rescue technique. The plants were extremely vigorous and were growing and flowering until the first frost. The ratio male versus was rangingbetween 1:40 and 1:80. Most of the male and female were sterile or partly sterile. The majority of the analysed traits were intermediate regarding the parental species. The most appropriate traits for the determination of the interspecific nature were the leaf margin, the shape and colour of ripe fruits and the shape of fruit stalks. The fruit exterior was extremely hard (similarly to the one of C. ficifolia) and cracked in several places.
Keywords: interspecific hybridisation, Cucurbita ficifolia, Cucurbita maxima, flowering, morphology
Published: 10.07.2015; Views: 542; Downloads: 13
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3.
The effects of jasmonic acid and ethylenediamine-di-o-hydroxyphenyl-acetic acid on floral induction and induction of turions in Spirodela polyrhiza (L.) Schleiden
Virgilija Marinc Hrženjak, Janja Kristl, Božidar Krajnčič, 2008, original scientific article

Abstract: We investigated the effects of jasmonic acid (JA) and ethylenediamine-di-o-hydroxyphenyl-acetic acid (EDDHA) on floral induction and induction of turions in the photoperiodically neutral clone Djelekovec of the species Spirodela polyrhiza in axenical cultures. JA (0.475-47.5 nmol.L-1) promoted floral induction under long-day (LD) and short day (SD) conditions, while it had no effect on turion induction. The inhibitory effect of JA on flowering and turion induction was observed at a JA concentration of 237.5 nmol.L-1 and 475 nmpl.L-1. Under the same conditions, flowering and induction of turions were enhanced by EDDHA (20.5 nmol..L-1(. The combination od EDDHA and JA had an additive effect on promotion of floral induction, which was promoted significantly in experiments with LD preculture. The results obtained by quantitative determination of endogenous JA levels in Spirodela polyrhiza at two growth stages support our previous findings that JA may regulate floral induction. The levels of endogenous JA decreased from 226±12 ng·g–1 fresh weight during the vegetative stage in LD to 38.1±3.5 ng·g–1 in the flowering plants. In SD the levels of endogenous JA decreased from 62±9ng·g–1 fresh weight during vegetative stage to 29.2±3.1 ng·g–1 in the flowering plants.
Keywords: Spirodela polyrhiza (L.) Schleiden, chelating agent EDDHA, flowering, induction of turions, jasmonic acid
Published: 28.03.2017; Views: 445; Downloads: 50
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