scholarly journals The Role of Abscisic Acid in Heat Stress-induced Secondary Dormancy in Apple Seeds

HortScience ◽  
1991 ◽  
Vol 26 (2) ◽  
pp. 175-177 ◽  
Author(s):  
Jocelyn A. Ozga ◽  
F.G. Dennis
Keyword(s):  
Abscisic Acid ◽  
Heat Stress ◽  
Germination Capacity ◽  
Embryonic Axes ◽  
Secondary Dormancy ◽  
Golden Delicious ◽  
Aba Content ◽  
Seed Coats ◽  
Apple Seeds

Exposure of stratified apple (Malus domestics Borkh. cv. Golden Delicious) seeds to 30C induces secondary dormancy. To determine if an increase in abscisic acid (ABA) content was associated with the loss in germination capacity, stratified seeds (3,- 6, or 9 weeks at 5C) were held at 30C for 0, 3, or 6 days. Stratification at 5C either had no effect or increased ABA content in embryonic axes, cotyledons, and seed coats. Exposure to 30C after stratification either did not affect or decreased ABA content of embryonic axes and seed coats; in contrast, cotyledonary ABA was increased. Seed coats, cotyledons, and embryonic axes stratified for 3, 6, or 9 weeks at 20C contained the same or higher levels of ABA in comparison with nonstratified seeds or seeds stratified at SC. Changes in ABA levels were not consistently correlated with changes in germination capacity during stratification or after exposure to 30C. These data suggest that changes in ABA are not related to changes in dormancy. Chemical names used: abscisic acid (ABA); butylated hydroxy-toluene (BHT); n-(trichloromethyl) thio-4-cyclohexene-1,2-dicarboximide(Captan).

scholarly journals Transcriptome Reveals Roles of Lignin-Modifying Enzymes and Abscisic Acid in the Symbiosis of Mycena and Gastrodia elata

2021 ◽  
Vol 22 (12) ◽  
pp. 6557
Author(s):  
Li-Ying Ren ◽  
Heng Zhao ◽  
Xiao-Ling Liu ◽  
Tong-Kai Zong ◽  
Min Qiao ◽  
...  
Keyword(s):  
Biological Activity ◽  
Abscisic Acid ◽  
Lignin Degradation ◽  
Molecular Mechanisms ◽  
Receptor Protein ◽  
Gastrodia Elata ◽  
Upregulated Genes ◽  
Aba Biosynthesis ◽  
Seed Coats

Gastrodia elata is a well-known medicinal and heterotrophic orchid. Its germination, limited by the impermeability of seed coat lignin and inhibition by abscisic acid (ABA), is triggered by symbiosis with fungi such as Mycena spp. However, the molecular mechanisms of lignin degradation by Mycena and ABA biosynthesis and signaling in G. elata remain unclear. In order to gain insights into these two processes, this study analyzed the transcriptomes of these organisms during their dynamic symbiosis. Among the 25 lignin-modifying enzyme genes in Mycena, two ligninolytic class II peroxidases and two laccases were significantly upregulated, most likely enabling Mycena hyphae to break through the lignin seed coats of G. elata. Genes related to reduced virulence and loss of pathogenicity in Mycena accounted for more than half of annotated genes, presumably contributing to symbiosis. After coculture, upregulated genes outnumbered downregulated genes in G. elata seeds, suggesting slightly increased biological activity, while Mycena hyphae had fewer upregulated than downregulated genes, indicating decreased biological activity. ABA biosynthesis in G. elata was reduced by the downregulated expression of 9-cis-epoxycarotenoid dioxygenase (NCED-2), and ABA signaling was blocked by the downregulated expression of a receptor protein (PYL12-like). This is the first report to describe the role of NCED-2 and PYL12-like in breaking G. elata seed dormancy by reducing the synthesis and blocking the signaling of the germination inhibitor ABA. This study provides a theoretical basis for screening germination fungi to identify effective symbionts and for reducing ABA inhibition of G. elata seed germination.

scholarly journals   Role of abscisic acid and drought stress on the activities of antioxidant enzymes in wheat

2012 ◽  
Vol 58 (No. 4) ◽  
pp. 181-185 ◽  
Author(s):  
A. Bano ◽  
F. Ullah ◽  
A. Nosheen
Keyword(s):  
Abscisic Acid ◽  
Drought Stress ◽  
Seed Treatment ◽  
Oxygen Species ◽  
Wheat Cultivars ◽  
Drought Tolerant ◽  
Relative Water ◽  
Aba Content ◽  
Endogenous Aba

The effect of drought stress and abscisic acid (ABA) applied at tillering stage (55 days after sowing) was compared in 2 wheat cultivars differing in drought tolerance. The activities of superoxide dismutase (SOD) and peroxidase (POD) and contents of endogenous ABA in plants were measured at 3 days of drought stress in cv. Chakwal-97 (drought tolerant) and cv. Punjab-96 (drought susceptible). ABA was applied at 10<sup>&ndash;6</sup> mol/L as presowing seed treatment for 18 h. Drought tolerant cultivar has a more efficient mechanism to scavenge reactive oxygen species as shown by a significant increase in the activity of antioxidant enzyme SOD. Under drought stress, ABA significantly increased the activities of SOD and POD, showing a significant decline on rewatering. The relative water content was significantly increased by ABA priming under drought stress in both wheat cultivars. The sensitive cultivar exhibiting lower endogenous ABA content was more responsive to ABA priming. On rewatering, the magnitude of recovery from drought stress was greater in tolerant cultivar. ABA was highly effective in improving grain weight of tolerant cultivar under drought stress. &nbsp;

Dormancy-break and germination in seeds of Prunus campanulata (Rosaceae): role of covering layers and changes in concentration of abscisic acid and gibberellins

2007 ◽  
Vol 17 (1) ◽  
pp. 21-32 ◽  
Author(s):  
Shun-Ying Chen ◽  
Ching-Te Chien ◽  
Jeng-Der Chung ◽  
Yuh-Shyong Yang ◽  
Shing-Rong Kuo
Keyword(s):  
Abscisic Acid ◽  
Seed Coat ◽  
Carotenoid Biosynthesis ◽  
Inhibitory Effect ◽  
Germination Percentage ◽  
Biosynthesis Inhibitor ◽  
Breaking Dormancy ◽  
Aba Content ◽  
Ga Biosynthesis

AbstractIntact seeds (seed+endocarp) from freshly harvested fruits of Prunus campanulata were dormant, and required 4–6 weeks of warm followed by 8 weeks of cold stratification for maximum germination percentage. Removing both endocarp and seed coat, however, promoted germination in a high percentage of non-stratified seeds. Treatment of intact, non-stratified seeds with gibberellic acid (GA3) was only partially effective in breaking dormancy. However, GA3 promoted germination of non-stratified seeds in which the endocarp (but not the seed coat) had been removed. The order of abscisic acid (ABA) concentration in fresh seeds was endocarp > seed coat > embryo, and its concentration in endocarp plus seed coat was about 6.2-fold higher than that in the embryo. Total ABA contents of seeds subjected to warm and/or cold moist stratification were reduced 6- to 12-fold. A higher concentration of GA4 was detected in embryos of non-dormant than in those of dormant seeds. Fluridone, a carotenoid biosynthesis inhibitor, was efficient in breaking dormancy of Prunus seeds. Paclobutrazol, a GA biosynthesis inhibitor, completely inhibited seed germination, and the inhibitory effect could be partially reversed by GA4, but not by GA3. Thus, dormancy in P. campanulata seeds is imposed by the covering layers. Dormancy break is accompanied by a decrease in ABA content of the covering layers and germination by an increase of embryonic GA4 content.

A critical update on seed dormancy. I. Primary dormancy

1995 ◽  
Vol 5 (2) ◽  
pp. 61-73 ◽  
Author(s):  
Henk W. M. Hilhorst
Keyword(s):  
Cell Wall ◽  
Abscisic Acid ◽  
Seed Dormancy ◽  
Decisive Role ◽  
Morphological Development ◽  
Primary Dormancy ◽  
Whole Seed ◽  
Aba Content ◽  
Cell Wall Properties

AbstractThe emphasis of modern dormancy research is almost entirely on the form of dormancy that is acquired during seed development, primary dormancy. Abscisic acid (ABA) appears to be intimately involved in its regulation. The action of abscisic acid has also been implied in many other developmental processes. The coincidence of developmental events, such as dehydration and completion of maturation, with the acquisition of primary dormancy suggests that dormancy is influenced by these processes. Germinability, both during development and after maturation, is sometimes directly correlated with ABA content. The lack of such a correlation may be explained by assuming a decisive role for the responsiveness to ABA or other overriding factors. ABA has been detected in all seed components. The different seed tissues may all contribute, to various extents, to the degree of whole seed dormancy. It is concluded that ABA action in dormancy regulation is not restricted to the embryo but is also located in endospermic tissue. In addition, a role of ABA in the morphological development of germination modifying seed tissues is proposed. The mechanism for ABA action appears to be associated with cell wall properties.

CHANGES IN ABSCISIC ACID AND GIBBERELLIN LEVELS IN APPLE SEEDS DURING STRATIFICATION AND THEIR RELATIONSHIP TO GENETIC COMPACTION

1978 ◽  
Vol 58 (3) ◽  
pp. 761-767 ◽  
Author(s):  
J. M. LEE ◽  
N. E. LOONEY
Keyword(s):  
Abscisic Acid ◽  
Seed Coat ◽  
Acid Content ◽  
Controlled Crosses ◽  
Aba Content ◽  
Abscisic Acid Content ◽  
Apple Seeds

The levels of abscisic acid (ABA) and gibberellin-like (GA-like) substances were examined in apple seeds from controlled crosses known to produce 0 or 50% compact seedlings. All seed lots exhibited similar changes in ABA and GA-like substances during an 80-day stratification period. The seeds were divided into two fractions, seed coat plus integuments (SC + I) and the embryo plus cotyledons (E + C). The ABA content of the E + C fraction was low relative to that in the SC +I fraction and gradually decreased during stratification. Abscisic acid content of the SC + I fraction increased markedly early in the stratification period and then gradually decreased. The GA-like activity, found primarily in the SC + I fraction, gradually increased (up to 40 days) and then decreased.

scholarly journals Abscisic Acid—Enemy or Savior in the Response of Cereals to Abiotic and Biotic Stresses?

2020 ◽  
Vol 21 (13) ◽  
pp. 4607 ◽  
Author(s):  
Marta Gietler ◽  
Justyna Fidler ◽  
Mateusz Labudda ◽  
Małgorzata Nykiel
Keyword(s):  
Abscisic Acid ◽  
Stress Response ◽  
Environmental Factors ◽  
Triticum Aestivum L ◽  
Biotic And Abiotic Stress ◽  
Hordeum Vulgare L ◽  
Abiotic And Biotic Stresses ◽  
Biotic Stresses ◽  
Aba Content

Abscisic acid (ABA) is well-known phytohormone involved in the control of plant natural developmental processes, as well as the stress response. Although in wheat (Triticum aestivum L.) and barley (Hordeum vulgare L.) its role in mechanism of the tolerance to most common abiotic stresses, such as drought, salinity, or extreme temperatures seems to be fairly well recognized, not many authors considered that changes in ABA content may also influence the sensitivity of cereals to adverse environmental factors, e.g., by accelerating senescence, lowering pollen fertility, and inducing seed dormancy. Moreover, recently, ABA has also been regarded as an element of the biotic stress response; however, its role is still highly unclear. Many studies connect the susceptibility to various diseases with increased concentration of this phytohormone. Therefore, in contrast to the original assumptions, the role of ABA in response to biotic and abiotic stress does not always have to be associated with survival mechanisms; on the contrary, in some cases, abscisic acid can be one of the factors that increases the susceptibility of plants to adverse biotic and abiotic environmental factors.

Integrative hormone and transcriptome analysis underline the role of abscisic acid in seed shattering of weedy rice

2021 ◽  
Author(s):  
Hong Lang ◽  
Yuting He ◽  
Fengcheng Li ◽  
Dianrong Ma ◽  
Jian Sun
Keyword(s):  
Abscisic Acid ◽  
Critical Role ◽  
Weedy Rice ◽  
Seed Shattering ◽  
High Degree ◽  
Aba Content ◽  
Potential Signal ◽  
Aba Biosynthesis ◽  
Indole 3 Acetic Acid

AbstractWeedy rice is one of the most severe weeds in paddy fields, characterized by its high degree of seed shattering. Abscisic acid (ABA) serves as an abscission-accelerating signal and plays a critical role during abscission. However, mechanisms that link ABA and seed shattering remain elusive. In this study, WR04-6 (shattering) and SN9816 (non-shattering) were used to investigate the expression levels of genes involved in ABA biosynthesis and to determine the levels of ABA in tissues collected from the abscission zone (AZ) and the spikelet. ABA content in WR04-6, particularly in AZ, was significantly higher than in SN9816, significantly increasing prior to abscission. RNA-Sequencing and further expression analyses showed that the expression of OsNCED, the key gene involved in ABA biosynthesis, coincided with the increase of ABA content in the AZ and significantly increased during the seed shattering process. Additionally, the expression analysis of genes related to biosynthesis and metabolism of indole-3-acetic acid, gibberellin acid, and ethylene showed the greatest fold-change. Phytohormone levels associated with ABA co-expression-prediction revealed a potential signal transduction network among plant hormones involved in the regulation of seed abscission. Taken together, data presented in this study suggest that ABA contributes to seed shattering and transiently cooperates with other hormones, triggering a hormone imbalance that leads to the downstream activation of the AZ.

The role of abscisic acid in germination of light-sensitive and light-insensitive lettuce seeds

1999 ◽  
Vol 9 (2) ◽  
pp. 129-134 ◽  
Author(s):  
Nurit Roth-Bejerano ◽  
Norbert J.A. Sedee ◽  
Rene M. van der Meulen ◽  
Mei Wang
Keyword(s):  
Abscisic Acid ◽  
Seed Germination ◽  
Inhibitory Processes ◽  
Exogenous Aba ◽  
Lettuce Seeds ◽  
Endogenous Level ◽  
Aba Content ◽  
Aba Biosynthesis ◽  
Light Break

AbstractThe role of abscisic acid (ABA) in seed germination of two cultivars of lettuce (Lactuca sativa L.; light-sensitive Ritsa and light-insensitive Strada) was investigated. The inhibition of Ritsa seed germination by exogenous ABA was higher than that of Strada seeds, the extent of inhibition of both cultivars being reduced by a short light break. At 25°C the sensitivity of both cultivars to exogenous ABA was higher than at 15°C. The endogenous level of ABA was similar in dry seeds of both cultivars, increasing temporarily in Ritsa seeds during the first 4 h of imbibition in darkness but not in Strada seeds, nor in Ritsa seeds exposed to a short light break. The transitory increase of ABA content in Ritsa seeds imbibed in darkness was accompanied by increased expression of the gene responsive to ABA (Rab) under these conditions. Zorial (Norflurazone), an ABA-biosynthesis inhibitor, decreased ABA content and allowed dark germination of the light-requiring Ritsa seeds. A short light break induced germination of Ritsa seeds when applied at 24 and 48 h after imbibition onset, i.e. after the transitory increase of ABA. GA3, on the other hand was effective when applied at the beginning of imbibition. It seems that light induces germination of the photoblastic Ritsa seeds by both inhibiting ABA synthesis and decreasing seed sensitivity to ABA and inhibitory processes induced by it.

scholarly journals Integrative hormone and transcriptome analyses underline the role of abscisic acid in seed shattering of weedy rice

2020 ◽  
Author(s):  
Hong Lang ◽  
Yuting He ◽  
Jian Sun ◽  
Fengcheng Li ◽  
Dianrong Ma
Keyword(s):  
Abscisic Acid ◽  
Rice Variety ◽  
Critical Role ◽  
Weedy Rice ◽  
Seed Shattering ◽  
Expression Of Genes ◽  
Aba Content ◽  
Potential Signal ◽  
Aba Biosynthesis

Abstract Abstract Backgrounds: Weedy rice is one of the most severe weeds in paddy fields, strongly characterized by its high seed shattering level. Abscisic acid (ABA) serves as an abscission-accelerating signal and plays a critical role during abscission. However, mechanisms that link ABA and seed shattering remain elusive. In this study, we compared WR04-6 a shattering, and SN9816 non-shattering rice variety for genetic expression and ABA levels in the abscission zone (AZ) and the spikelet. Results : ABA content in WR04-6, particularly in AZ, was significantly higher than that in SN9816, and it increased remarkably prior to abscission. Transcriptomic analysis and qRT-PCR showed that the expression of NCED , the key gene in ABA biosynthesis, coincided with increased ABA content in AZ and increased significantly during the seed shattering process. Additionally, the expression of genes related biosynthesis and metabolism of IAA, GA, and ETH showed the greatest fold change. Phytohormone levels associated with ABA co-expression-prediction revealed a potential signal transduction network among plant hormones involved in regulating seed abscission. Conclusions: Altogether, our data strongly indicated that ABA contributes to seed shattering and appears to transiently cooperate with other hormones, triggering a hormone imbalance that leads to the downstream activation of AZ

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