Germination in Photosensitive Seeds: Does Phytochrome Stimulate Metabolism of GA19 and GA20 to GA1?

The effect of light on gibberellic acid (GA) metabolism was investigated in Asteraceae seeds. White light (80 mmol m-2 s-1 PAR) increased seed germination in Craspedia sp., Erymophyllum ramosum and Rhodanthe chlorocephala subsp. splendida compared with darkness. In these taxa, red light (R, 640 nm, 8 mmol m-2 s-1) stimulated and far red light (FR, 720 nm, 4 mmol m-2 s-1) inhibited germination, indicating the involvement of phytochrome. Paclobutrazol, a GA biosynthesis inhibitor, reduced light-stimulated germination and this was overcome by exogenous GA3. GA3 and GA1 promoted germination in the dark, but GA19 and GA20, which are precursors to GA1, generally did not. GAs were applied to paclobutrazol-treated seeds which were incubated under either R or FR. Very few paclobutrazol-treated seeds germinated without GAs under FR, and exposure to R only marginally improved germination. Application of GA19 or GA20 to paclobutrazol-treated seeds increased germination in Rhodanthe chlorocephala subsp. splendida under R, with no germination under FR. This trend was observed in Craspedia sp., but not in Erymophyllum ramosum or Rhodanthe floribunda. CGA 163′935, a 3b-hydroxylation inhibitor, and R and FR were used to investigate phytochrome-stimulated conversion of GA19 and GA20 to GA1. It could not be shown that R was required for 3b-hydroxylation in light stimulated germination of these species.

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Effect of light and temperature on seed germination in Tibouchina mutabilis (Vell.) Cogn. (Melastomataceae)

Biota Neotropica ◽

10.1590/s1676-06032008000200006 ◽

2008 ◽

Vol 8 (2) ◽

pp. 63-68 ◽

Cited By ~ 5

Author(s):

Edson Simão ◽

Massanori Takaki

Keyword(s):

Seed Germination ◽

White Light ◽

Light Sensitivity ◽

Pioneer Species ◽

Continuous Darkness ◽

Effect Of Light

The effect of light and temperature on Tibouchina mutabilis seed germination was analyzed by isothermic incubations in the range of 10 to 40 °C, with 5 °C intervals under both continuous white light (32.85 µmolm-2s-1) and darkness and alternating temperatures (15-20; 15-25; 15-30; 15-35; 20-25; 20-30; 20-35; 25-30; 25-35 and 30-35 °C) under both photoperiod of 12 hours and continuous darkness. The seeds of T. mutabilis need light to trigger the germination and no germination was observed in darkness. The range of optimum temperatures for germination was between 25 to 30 °C and the 20-25 °C alternating temperatures. These results indicate that T. mutabilis behaves as a pioneer species and daily alternating temperatures did not change the light sensitivity of seeds.

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Effect of NaCl on seed germination in some Centaurium Hill. Species (Gentianaceae)

Archives of Biological Sciences ◽

10.2298/abs0703227z ◽

2007 ◽

Vol 59 (3) ◽

pp. 227-231 ◽

Cited By ~ 3

Author(s):

S. Zivkovic ◽

M. Devic ◽

B. Filipovic ◽

Z. Giba ◽

D. Grubisic

Keyword(s):

Life History ◽

Salt Tolerance ◽

Seed Germination ◽

Gibberellic Acid ◽

White Light ◽

The Other ◽

Distilled Water ◽

Nacl Concentration ◽

History Of ◽

Species Specific

The influence of high NaCl concentrations on seed germination in both light and darkness was examined in the species Centaurium pulchellum, C. erythraea, C. littorale, C. spicatum, and C. tenuiflorum. Salt tolerance was found to depend on the life history of the seeds. To be specific, seeds of all five species failed to complete germination when exposed to continuous white light if kept all the time in the presence of 100-200 mM and greater NaCl concentrations. However, when after two weeks NaCl was rinsed from the seeds and the seeds were left in distilled water under white light for an additional two weeks, all species completed germination to a certain extent. The percent of germination not only depended on NaCl concentration in the prior medium, but was also species specific. Thus, seeds of C. pulchellum, C. erythraea, and C. littorale completed germination well almost irrespective of the salt concentration previously experienced. On the other hand, seeds of C. tenuiflorum completed germination poorly if NaCl concentrations in the prior media were greater than 200 mM. When seeds after washing were transferred to darkness for an additional 14 days, they failed to complete germination if previously imbibed on media containing NaCl concentrations greater than 400 mM. However, the seeds of all species, even if previously imbibed at 800 mM NaCl, could be induced to complete germination in darkness by 1 mM gibberellic acid. .

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The effect of sodium hypochlorite, gibberellic acid, and light on seed dormancy and germination of wild buckwheat (Polygonum convolvulus) and cow cockle (Saponaria vaccaria)

Canadian Journal of Botany ◽

10.1139/b79-213 ◽

1979 ◽

Vol 57 (16) ◽

pp. 1735-1739 ◽

Cited By ~ 17

Author(s):

A. I. Hsiao

Keyword(s):

Seed Germination ◽

Gibberellic Acid ◽

Sodium Hypochlorite ◽

Seed Coat ◽

Inhibitory Effect ◽

Promoting Effect ◽

Wild Buckwheat ◽

Polygonum Convolvulus ◽

Effect Of Light ◽

Main Factor

Seed germination of wild buckwheat (Polygonum convolvulus L.) and cow cockle (Saponaria vaccaria L.) increased with increasing time of immersion in 6% sodium hypochlorite (NaOCl). Maximum germination was obtained at 6 to 8 h for wild buckwheat and at 2 h for cow cockle. The effect of NaOCl treatment of wild buckwheat seeds mimics the effect of acid scarification. Wild buckwheat germination was not influenced by light and (or) gibberellic acid (GA3). To induce 50% germination (t½) of cow cockle NaOCl treatments of 0.5 and 1 h were required for seeds incubating in the dark and light, respectively. Once the seed coat was made more permeable by NaOCl, both the promoting effect of GA3 and the inhibitory effect of light were increased. When the optimum effect of NaOCl occurred, all the seeds germinated. However, prolonged NaOCl treatment resulted in either poor germination or seed disintegration.The hard coat seems to be the main factor in regulating wild buckwheat seed germination. Cow cockle, however, is regulated by at least two other factors, light and hormones, in addition to seed coat.

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Photosensitivity of anthocyanin production in dark-grown and light-pretreated Zea mays seedlings

Canadian Journal of Botany ◽

10.1139/b88-147 ◽

1988 ◽

Vol 66 (6) ◽

pp. 1021-1027 ◽

Cited By ~ 3

Author(s):

Zdenko Rengel ◽

Herbert A. Kordan

Keyword(s):

Zea Mays ◽

Blue Light ◽

White Light ◽

Zea Mays L ◽

Red Light ◽

Anthocyanin Formation ◽

Anthocyanin Production ◽

Effect Of Light

Anthocyanin production in roots and shoots of Zea mays L. seedlings was higher in blue than in red light and was very low in far red light. Under dichromatic irradiation, a phytochrome mediation of a blue-dependent photoreaction was evident. Pretreatments with both white and blue light allowed increased anthocyanin production under subsequent inductive conditions, as did occurs in treatments with continuous blue, red, far red, or white light. It is suggested that the effect of light pretreatments on phytochrome-controlled anthocyanin formation may differ from that controlled by the combination of cryptochrome and phytochrome.

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Germination and seed conservation of a pioneer species, Tecoma stans (Bignoniaceae), from tropical dry forest of Colombia

Revista de Biología Tropical ◽

10.15517/rbt.v66i2.33423 ◽

2018 ◽

Vol 66 (2) ◽

pp. 918

Author(s):

Jhon Alexander Vargas-Figueroa ◽

Alba Marina Torres-González

Keyword(s):

Seed Germination ◽

White Light ◽

Germination Rate ◽

Red Light ◽

Tropical Dry Forest ◽

Seed Storage ◽

Dry Forest ◽

Storage Behavior ◽

Mean Germination Time ◽

Seed Storage Behavior

Seed germination and seed longevity under different environmental conditions are fundamental to understand the ecological dynamics of a species, since they are decisive for its success within the ecosystem. Taking this into account, seed germination and seed storage behavior of a pioneer species of tropical dry forest (Tecoma stans) were studied in the laboratory, to establish the effect of different environmental conditions on a local tree population. Two seed lots collected in July 2011, from Cali (Colombia), were evaluated under three alternating temperatures (20/30, 20/25, 25/30 ºC; 16/8 h) and four light qualities (12-hour white light photoperiod, darkness, and 15 minutes of red light -R and far red light -FR). Final germination was recorded for all treatments; for white light treatment the daily germination was recorded to calculate mean germination rate, mean germination time, and two synchronization indices. To assess the effect of light quality on physiological variables, a destructive germination test was carried out. For this test, another seed lot was evaluated under the same light conditions using an alternating temperature of 20/30 °C - 16/8 h, recording germination during six days for every treatment. In addition, seeds were stored at two different moisture contents (7.7, 4.1 %) and three storage temperatures (20, 5, -20 ºC), during two time periods (one and three months); a seed germination test was conducted for each treatment. Four replicates of 35 seeds per treatment were used for all experiments. Germination was high (GP > 90 %) with all alternating temperatures under white light, whereas under R, FR, and darkness germination was evenly successful at low temperatures, but at higher temperature, half of the seeds entered into secondary dormancy (GP= 45-65 %). However, mean germination rate and synchronization under R and FR decreased significantly in comparison to white light treatment and, consequently, mean germination time increased. Seed storage behavior of this species is orthodox due to the high germination (GP > 90 %) obtained under all treatments. In conclusion, T. stans seeds have a negative germination response at high incubation temperatures in the absence of white light, entering into a secondary dormancy. In contrast, an environment with a lower temperature and without white light delays the germination, but at the end seeds are able to reach the same germination values. This seed dependence on incident light in limiting conditions suggests a physiological mechanism on the seed tissues of this species, probably mediated by phytochromes. Finally, the orthodox seed storage behavior of T. stans is a reason to include this species in ex situ seed conservation programs for restoration and recovery of the tropical dry forest; however, long-term studies should be conducted in order to evaluate the maintenance of this characteristic throughout longer periods of time. Rev. Biol. Trop. 66(2): 918-936. Epub 2018 June 01.

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Germination responses of seeds of Desmodium triflorum

International Journal of Scientific Reports ◽

10.18203/issn.2454-2156.intjscirep20180392 ◽

2018 ◽

Vol 4 (2) ◽

pp. 19 ◽

Cited By ~ 1

Author(s):

Niroj Paudel ◽

Prakash Deep Rai

Keyword(s):

Seed Germination ◽

Blue Light ◽

White Light ◽

Red Light ◽

Light Condition ◽

Dark Condition ◽

Percentage Germination ◽

Negative Effect

Background: Germination of Desmodium triflorum is used for the scarification using the acid is valuable for the different light condition.Methods: The sample was collected as four month of interval of time and the seed is treated with acids with different time. Results: seeds scarified with sulfuric acids for 10 min before sowing had better germination than those scarified for 5 and 15 min. Among them light qualities, red and white light had slightly promoted effect whereas blue light and dark condition had slightly negative effect on seed germination.Conclusions: In comparison to blue light and dark condition, red light and white light were promoted to percentage germination indicating the role of phytochrome in seed germination of Desmodium triflorum.

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Effects of a butenolide present in smoke on light-mediated germination of Australian Asteraceae

Seed Science Research ◽

10.1079/ssr2005232 ◽

2006 ◽

Vol 16 (1) ◽

pp. 29-35 ◽

Cited By ~ 55

Author(s):

D.J. Merritt ◽

M. Kristiansen ◽

G.R. Flematti ◽

S.R. Turner ◽

E.L. Ghisalberti ◽

...

Keyword(s):

Seed Germination ◽

Gibberellic Acid ◽

White Light ◽

Light Regime ◽

Ecological Significance ◽

Light Regimes ◽

Smoke Water

This study investigated the effects of 3-methyl-2H-furo[2,3-c]pyran-2-one, a germination active butenolide present in plant-derived smoke, gibberellic acid and smoke water on seeds of AustralianAsteraceaeexposed to different light regimes. Seeds of all species required light, with maximum germination occurring under white light, or light dominated by 640 nm. Compared to untreated seeds, butenolide increased germination ofAngianthus tomentosus,Gnephosis tenuissima,Myriocephalus guerinae,Podolepis canescensandRhodanthe citrinaat suboptimal light wavelengths and in the dark to a level equal to, or greater than, smoke water. Germination ofErymophyllum glossanthusandGnephosis aciculariswas not promoted by butenolide or smoke water under any light regime. The action of gibberellic acid was compared to that of butenolide for three species (Angianthus tomentosus,Myriocephalus guerinaeandPodolepis canescens), and both compounds were found to stimulate germination. This study provides evidence that butenolide can act in a similar fashion as gibberellic acid in promoting seed germination of light-sensitive seeds. The ecological significance of these findings is discussed.

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Ecophysiology of seed germination in Mediterranean geophytes. 1. Muscari spp

Seed Science Research ◽

10.1079/ssr2002111 ◽

2002 ◽

Vol 12 (3) ◽

pp. 193-201 ◽

Cited By ~ 49

Author(s):

Maria A. Doussi ◽

Costas A. Thanos

Keyword(s):

Seed Germination ◽

White Light ◽

Mediterranean Climate ◽

Germination Rate ◽

Red Light ◽

Rainfall Regime ◽

Light Conditions ◽

Rainy Period ◽

Germination Characteristics ◽

The Mediterranean

Ecophysiological aspects of seed germination were investigated in four Mediterranean geophytes of the genus Muscari (Liliaceae): M. comosum (tassel hyacinth), M. neglectum (common grape hyacinth), M. commutatum and M. weissii. Experiments were performed at constant temperatures in the dark and under temperature and light conditions simulating those prevailing in nature during November–January, i.e. well into the rainy season of the Mediterranean climate. In all species, no primary dormancy was revealed, and germination occurred in a rather narrow range of cool temperatures (optimum at 10 or 15°C) and at a remarkably slow rate; both germination characteristics seem to be associated with autumn/winter seed germination and seedling establishment. Such a postulated strategy is ecologically advantageous within an unpredictable rainfall regime, known to prevail during the start of the rainy period of the Mediterranean climate. This strategy may also explain the spread of germination of M. comosum seeds over two consecutive years, observed by Theophrastus. Far-red light, simulating light conditions under a dense canopy, resulted in only a slight delay of germination compared to dark controls. Diurnal white light, qualitatively simulating natural daylight, caused a significant decrease of the germination rate in all four species studied. Moreover, white light was found to suppress considerably final seed germination (photoinhibition) in M. weissii and M. neglectum; in the latter species, prolonged imbibition under white light also led to the induction of secondary dormancy.

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The effect of light and heat on 4CH and 200CH potencies of gibberellic acid as a promoter of germination in barley seed (Hordeum vulgare), measured by a germination index

10.51415/10321/2691 ◽

2002 ◽

Author(s):

◽

Hayley Pieterse

Keyword(s):

Hordeum Vulgare ◽

Seed Germination ◽

Gibberellic Acid ◽

Germination Index ◽

Barley Seed ◽

Effect Of Light

The purpose of this investigation was to evaluate the effects of light and heat on homoeopathic dilutions of gibberellic acid (cHGA3) as measured on Hordeum vulgare (barley) seed germination.

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Germinación de Chiranthodendron pentadactylon Larr. (Sterculiaceae), en respuesta a la escarificación, temperatura y luz

Botanical Sciences ◽

10.17129/botsci.1515 ◽

2017 ◽

pp. 5

Author(s):

Reyna Osuna-Fernández ◽

Guillermo Laguna-Hernández ◽

Alicia Brechú-Franco ◽

Alma Orozco-Segovia

Keyword(s):

Seed Germination ◽

Seed Coat ◽

White Light ◽

Maternal Effect ◽

Seed Quality ◽

Variable Temperature ◽

Red Light ◽

Seed Viability ◽

Weather Conditions ◽

Two Populations

Seed quality and seed germination with scarification and non scarification and variable temperature and light were determined in Ch. pentadactylon seeds form two places of Guerrero and Oaxaca. Also seed viability was determined in seeds from Guerrero stored 6 months at 5º C. Seeds showed to be orthodox and dormant due to an impervious seed coat. The seeds from Guerrero had higher weight, length and water content than those from Oaxaca, however the scarified seeds from Oaxaca reached a higher germination percentages. Germination of scarified seeds of the two populations was enhanced by alternated temperatures and inhibited by far red light. Germination under darkness, red light and white light did not differ significantly. In soil some seeds could be dormant under a low ratio red:far red light transmitted by litter. The differences between the two populations might be due to a maternal effect induced by weather conditions in their geographic localities.

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