Smoke exposure alters endogenous gibberellin and abscisic acid pools and gibberellin sensitivity while eliciting germination in the post-fire annual, Nicotiana attenuata

2004 ◽  
Vol 14 (1) ◽  
pp. 51-60 ◽  
Author(s):  
Jens Schwachtje ◽  
Ian T. Baldwin
Keyword(s):  
Abscisic Acid ◽  
Great Basin ◽  
De Novo ◽  
Light Exposure ◽  
Natural Habitat ◽  
Smoke Exposure ◽  
Nicotiana Attenuata ◽  
Control Water ◽  
Ga Biosynthesis ◽  
Endogenous Aba

Exposure to smoke is required for the germination of seeds from dormant genotypes ofNicotiana attenuata, a post-fire annual of the Great Basin Desert. Germination can be elicited by GA1,3,4,7treatments and inhibited by the GA biosynthesis inhibitor, paclobutrazol (PAC), abscisic acid (ABA) and terpenes leached from unburned litter of the plant’s natural habitat. We analysed the endogenous GA and ABA dynamics during the 22 h after imbibition, when smoke-treated dormant seeds commit to germination. Extractable GA1+3pools decreased in all seeds, but the decrease was more dramatic within 2 h of smoke exposure, which was followed by an increase between hours 2 and 4. Extractable ABA pools increased shortly after imbibition and remained stable in control, water-treated seeds, but decreased sharply in smoke-treated seeds. PAC completely inhibited smoke-induced germination when seeds were treated for 12 h after smoke exposure, consistent with the requirement ofde novoGA synthesis for germination. Smoke treatment in the dark did not result in germination, whereas GA3treatment did, a result consistent with phytochrome-mediated GA biosynthesis. Smoke exposure dramatically increased the sensitivity of seeds to exogenous GA3treatments in both the light and dark, and light exposure increased this sensitivity an additional tenfold. Taken together, these results suggest that while germination requires endogenous GA synthesis, the effects of smoke treatment increase GA sensitivity, which is correlated with a decrease in endogenous ABA pools.

Vegetation-derived abscisic acid and four terpenes enforce dormancy in seeds of the post-fire annual,Nicotiana attenuata

2002 ◽  
Vol 12 (4) ◽  
pp. 239-252 ◽  
Author(s):  
Bernd Krock ◽  
Sybille Schmidt ◽  
Christian Hertweck ◽  
Ian T. Baldwin
Keyword(s):  
Abscisic Acid ◽  
Environmental Control ◽  
Wood Smoke ◽  
Nicotiana Attenuata ◽  
Germination Inhibitors ◽  
Physiological Basis ◽  
Fire Environment ◽  
Aba Content ◽  
Aba Biosynthesis ◽  
Endogenous Aba

AbstractThe native tobacco,Nicotiana attenuata, synchronizes its germination with the immediate post-fire environment with a combination of germination stimulants found in wood smoke and inhibitors from the unburned litter of the dominant vegetation. The inhibitors override the stimulants and prevent seeds from germinating maladaptively in unburned habitats adjacent to burns. To understand the physiological basis of this environmental control of germination, we tested several previously isolated signals, phytohormones and their respective biosynthesis inhibitors. The germination inhibitors methyl jasmonate (MeJA, a constituent of sagebrush litter), bornane-2,5-dione (BD, a constituent of juniper litter extract, JLE) and JLE did not alter abscisic acid (ABA) content of imbibed seeds. Treatment with the ABA biosynthesis inhibitor, fluridone, inhibited the dormancy-inducing effects of BD, JLE and MeJA, but surprisingly did not affect endogenous ABA levels in treated seeds. However, ABA leached from litter of the species, which dominate the plant community before fires, plays an important role in germination control. We conclude thatN. attenuataseeds, which can lie dormant in the soil for 150 years between fires, time their germination with the post-fire environment by responding to smoke, ABA and four terpenes (BD, 1,8-cineole, β-thujaplicin and camphor) leaching from the litter of the dominant vegetation.

Inhibition of cambial activity in Abies balsamea by internal water stress: role of abscisic acid

1975 ◽  
Vol 53 (24) ◽  
pp. 3041-3050 ◽  
Author(s):  
C. H. A. Little
Keyword(s):  
Abscisic Acid ◽  
Water Stress ◽  
Indoleacetic Acid ◽  
Stomatal Closure ◽  
Abies Balsamea ◽  
Cambial Activity ◽  
Inhibitory Effect ◽  
Internal Water ◽  
Endogenous Aba

In experiments with attached and detached shoots of balsam fir, Abies balsamea L., synthetic (±)abscisic acid (ABA) (1) reduced photosynthesis and transpiration by inducing stomatal closure, (2) inhibited indoleacetic acid (IAA) - induced cambial activity in photosynthesizing and non-photosynthesizing shoots, and (3) inhibited the basipetal movement of [14C]IAA. Neither gibberellic acid nor kinetin counteracted the inhibitory effect of (±)ABA on IAA-induced cambial activity. In addition it was demonstrated that increasing the internal water stress increased the level of endogenous ABA in the phloem–cambial region of bark peelings and decreased the basipetal movement of [14C]IAA through branch sections. On the basis of these findings it is proposed that internal water stress inhibits cambial activity, partly through increasing the level of ABA; the ABA acts to decrease the provision of carbohydrates and auxin that are required for cambial growth.

scholarly journals Induction of Dormancy in Nondormant Seeds

1994 ◽  
Vol 119 (3) ◽  
pp. 408-413 ◽  
Author(s):  
Anwar A. Khan
Keyword(s):  
Abscisic Acid ◽  
Lycopersicon Esculentum ◽  
Gibberellic Acid ◽  
Lactuca Sativa ◽  
Daucus Carota ◽  
Apium Graveolens ◽  
Lettuce Seeds ◽  
Moist Chilling ◽  
Dormancy Induction ◽  
Ga Biosynthesis

A gibberellic acid (GA) biosynthesis inhibitor, tetcyclacis, induced dormancy in nondormant seeds of lettuce (Lactuca sativa L.), tomato (Lycopersicon esculentum Mill.), pepper (Capsicum annuum L.), carrot [Daucus carota var. sativus (Hoffn.)], onion (Allium cepa L.), celery (Apium graveolens L.), and impatiens (Impatiens novette), as most of the seeds failed to germinate after washing under conditions that permitted germination before dormancy induction. In lettuce seeds, tetcyclacis and paclobutrazol were more effective in inhibiting germination in light than in darkness. A 16- to 24-h soak treatment with tetcyclacis was sufficient to induce dormancy in nearly all seeds. Tetcyclacis failed to induce dormancy if applied after 6 h presoak in water. Dormancy induced by tetcyclacis was released by GA4+7 (a mixture of gibberellin A4 and A7), light, and moist-chilling treatments. When GA4+7 was applied with tetcyclacis, dormancy induction was prevented under both favorable, e.g., 25C, and unfavorable, e.g., 5C, or low water potential (Ψ), germination conditions. Unlike tetcyclacis, abscisic acid (ABA) failed to induce dormancy in lettuce seeds. Thermodormancy induction in lettuce seeds at 35C was prevented by fluridone. However, neither ABA nor tetcyclacis countered its effect. Dormancy was also induced in lettuce seeds by ancymidol, flurprimidol, or paclobutrazol. Dormancy induced by tetcyclacis in pepper, tomato, carrot, and onion seeds was released by GA4+7, but not by irradiation or moist-chilling. Chemical names used: 5-(4-chlorophenyl)-3, 4, 5, 9, 10-pentaazatetracyclo [5.4.102,6.08,11]-dodeca-3, 9-diene (tetcyclacis); 1-(4-chlorophenyl)-4, 4-dimethyl-2-(1H-1, 2, 4-triazole-1-yl)-3-pentanol (paclobutrazol); α-cyclopropyl-α-(4-methoxyphenyl)-5-pyrimidine methanol (ancymidol); α-(1-methyl)-α-[4-(trifluoromethoxy) phenyl]-5-pyrimidine-methanol (flurprimidol); 1-methyl-3-phenyl-5-[3-(trifluoromethyl)phenyl]-4 (1H)-pyridinone (fluridone).

scholarly journals Abscisic acid as a factor in regulation of photosynthetic carbon metabolism of pea seedlings

2014 ◽  
Vol 51 (2) ◽  
pp. 229-240 ◽  
Author(s):  
Maria Faltynowicz ◽  
Waldemar Lechowicz ◽  
Jerzy Poskuta
Keyword(s):  
Abscisic Acid ◽  
Carbon Metabolism ◽  
Rubp Carboxylase ◽  
Pep Carboxylase ◽  
Pea Seedlings ◽  
Photosynthetic Carbon ◽  
Photosynthetic Carbon Metabolism ◽  
Sugar Phosphates ◽  
Reduced Activity ◽  
Endogenous Aba

The influence of abscisic acid (ABA) on carbon metabolism and the activity of ribulosebisphosphate (RuBP) and phosphoenolpyruvate (PEP) carboxylases in 8-day-old pea seedlings was investigated. It was endeavoured to correlate the changes observed in metabolic processes with the endogenous ABA level. In plants treated with ABA incorporation of labeled carbon into sucrose, glucose, fructose and sugar phosphates was depressed, while <sup>14</sup>C incorporation into starch, ribulose and malic acid was enhanced. The activity of RuBP carboxylase was considerably lowered, whereas that of PEP carboxylase was slightly increased. It is considered that inhibition of photosynthesis due to the action of ABA is caused to a great extent by the obstruction of the C-3 pathway and reduced activity of RuBP carboxylase, whereas (β-carboxylation was not blocked.

scholarly journals De novo transcriptome provides insights into the growth behaviour and resveratrol and trans-stilbenes biosynthesis in Dactylorhiza hatagirea - An endangered alpine terrestrial orchid of western Himalaya

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Nisha Dhiman ◽  
Nitesh Kumar Sharma ◽  
Pooja Thapa ◽  
Isha Sharma ◽  
Mohit Kumar Swarnkar ◽  
...  
Keyword(s):  
Secondary Metabolite ◽  
De Novo ◽  
Natural Habitat ◽  
Sugar Metabolism ◽  
Western Himalaya ◽  
Metabolite Profile ◽  
Clonal Plants ◽  
Phenylpropanoid Pathway ◽  
Terrestrial Orchid ◽  
Metabolite Synthesis

Abstract This is the first report on de novo transcriptome of Dactylorhiza hatagirea, a critically-endangered, terrestrial orchid of alpine Himalayas. The plant is acclaimed for medicinal properties but little is known about its secondary-metabolites profile or cues regulating their biosynthesis. De novo transcriptome analysis was therefore, undertaken to gain basic understanding on these aspects, while circumventing the acute limitation of plant material availability. 65,384 transcripts and finally, 37,371 unigenes were assembled de novo from a total of 236 million reads obtained from shoot, tuber and leaves of the plant. Dominance of differentially-expressing-genes (DEGs) related to cold-stress-response and plant-hormone-signal-transduction; and those involved in photosynthesis, sugar-metabolism and secondary-metabolite-synthesis provided insights into carbohydrate-partitioning in the plant during its preparation for freezing winter at natural habitat. DEGs of glucomannan, ascorbic acid, carotenoids, phylloquinone/naphthoquinones, indole alkaloids, resveratrol and stilbene biosynthesis revealed the secondary-metabolite profile of D. hatagirea. UHPLC results confirmed appreciable amounts of resveratrol and trans-stilbene in D. hatagirea tubers, for the first time. Expression analysis of 15 selected genes including those of phenylpropanoid pathway confirmed the validity of RNA-seq data. Opportunistic growth, temperature- and tissue-specific-differential-expression of secondary metabolite biosynthesis and stress tolerant genes were confirmed using clonal plants growing at 8, 15 and 25 °C.

Molybdenum deficiency in wheat results in lower dormancy levels via reduced ABA

1994 ◽  
Vol 4 (3) ◽  
pp. 329-333 ◽  
Author(s):  
A. T. Modi ◽  
A. L. P. Cairns
Keyword(s):  
Abscisic Acid ◽  
Field Experiment ◽  
Nutrient Solution ◽  
Foliar Application ◽  
Flag Leaf ◽  
Foliar Spray ◽  
Leaf Stage ◽  
Enhanced Sensitivity ◽  
Aba Content ◽  
Endogenous Aba

AbstractWheat which was grown in acid-washed sand and irrigated with a molybdenum-free nutrient solution was treated with various concentrations of molybdenum (Mo) as a foliar spray at the flag leaf stage. At maturity, dormancy levels and abscisic acid (ABA) content of the seed were determined. Seed dormancy and ABA content increased with increasing rates of Mo application. In a field experiment, wheat (cv. SST 66) was treated with 100 ppm Mo by foliar application at the flag leaf stage. Embryos were tested for sensitivity to exogenously applied ABA. Embryos from Mo-treated plants showed enhanced sensitivity to ABA-induced inhibition of germination. The Mo application also resulted in significantly higher levels of endogenous ABA and Mo in the seeds. It is postulated that Mo deficiency leads to a lack of dormancy in wheat via reduced synthesis of ABA.

scholarly journals Transcriptome-wide analysis of auxin-induced carotenoid accumulation in Chlorella microalgae

2018 ◽  
Author(s):  
Faisal Alsenani ◽  
Taylor J. Wass ◽  
Ruijuan Ma ◽  
Eladl Eltanahy ◽  
Michael E. Netzel ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Abscisic Acid ◽  
De Novo ◽  
Higher Plants ◽  
Abiotic Stress Tolerance ◽  
Auxin Signaling ◽  
Rna Seq ◽  
Carotenoid Accumulation ◽  
Close Relationship ◽  
Indole 3 Acetic Acid

AbstractMicroalgae are a commercially viable route for the production of carotenoids, including β-carotene and astaxanthin. In the current study, the commercially relevant microalga, Chlorella sp. BR2 was treated with four plant hormones: indole-3-acetic acid, salicylic acid, abscisic acid and methyl jasmonate, over a range of dosages and screened for enhanced carotenoid production. Indole-3-acetic acid was the only hormone with an inductive effect on carotenoid accumulation. As such, the transcriptome under the condition with the highest carotenoid increase was profiled using RNA-Seq and expressed sequences reconstructed with de novo assembly. This allowed for the profiling of transcriptome-wide changes following auxin treatment, revealing the active pathway components of auxininduced carotenogenesis. Data analysis specified the differentially expressed genes involved in auxin biosynthesis and signal transduction, which suggest a close relationship to equivalent pathways in higher plants. However unlike in plants, the ancient ABP1/SCFSKP2A/IBR5-mediated pathways for auxin response likely acted as the primary signaling route in Chlorella. As carotenoids are precursors for abscisic acid, the findings suggest a causative link between auxin signaling and abiotic stress tolerance.HighlightTranscriptomics of plant hormone-treated Chlorella revealed the active pathway components of auxin-induced carotenogenesis and included the ancient ABP1/SCFSKP2A/IBR5-mediated pathways. The manuscript presents the first documented transcriptomic data of auxin-treated microalgae.

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