scholarly journals Role of Indoleacetic Acid and Abscisic Acid in the Correlative Control by Fruits of Axillary Bud Development and Leaf Senescence

1981 ◽  
Vol 68 (2) ◽  
pp. 476-481 ◽  
Author(s):  
Imre A. Tamas ◽  
Carol J. Engels ◽  
Stuart L. Kaplan ◽  
Jim L. Ozbun ◽  
Donald H. Wallace
Keyword(s):  
Abscisic Acid ◽  
Leaf Senescence ◽  
Indoleacetic Acid ◽  
Axillary Bud ◽  
Bud Development

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.

Relationship of indoleacetic acid and tryptophan to dormancy and preharvest sprouting of wheat

2003 ◽  
Vol 30 (9) ◽  
pp. 939 ◽  
Author(s):  
Shashi Ramaih ◽  
Mohammed Guedira ◽  
Gary M. Paulsen
Keyword(s):  
Triticum Aestivum ◽  
Abscisic Acid ◽  
Inhibitory Action ◽  
Indoleacetic Acid ◽  
Triticum Aestivum L ◽  
Preharvest Sprouting ◽  
Synthetic Auxins ◽  
Relationship Of ◽  
Related Compounds

Preharvest sprouting of wheat (Triticum aestivum L.) involves several plant hormones, but a role for indoleacetic acid (IAA) and its precursor, tryptophan, has not been demonstrated. Our objectives were to determine the roles of IAA, tryptophan, and related compounds in germination of cultivars that differed in susceptibility to preharvest sprouting. L-Tryptophan strongly inhibited germination of embryos excised from caryopses that were highly dormant at harvest but not of embryos from caryopses that had little innate dormancy. The embryos responded similarly to indoleacetaldehyde, IAA, and synthetic auxins, suggesting that tryptophan functioned as a precursor of IAA. Indoleacetaldehyde oxidase inhibitors alleviated the adverse effects of tryptophan and indoleacetaldehyde, and an auxin antagonist decreased the inhibitory action of tryptophan and IAA on embryos from dormant caryopses, further suggesting that IAA was involved. Changes in sensitivity to IAA during afterripening also supported a role for auxin in dormancy. Embryos from caryopses that were highly dormant at harvest gradually lost sensitivity to IAA during afterripening, whereas intact caryopses were insensitive to IAA. The results implicated IAA in dormancy of wheat caryopses and indicated that the auxin might complement the role of abscisic acid in germination. The importance of using dormant caryopses and arresting afterripening in investigations of seed dormancy was noted.

The Role of Endogenous Abscisic Acid in the Correlation Between the Cotyledon and Its Axillary Bud in PeaPisum sativum L

1978 ◽  
Vol 20 (4) ◽  
pp. 299-302 ◽  
Author(s):  
J. Šebánek ◽  
J. Hradilík
Keyword(s):  
Abscisic Acid ◽  
Axillary Bud ◽  
Endogenous Abscisic Acid

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 Programmed chloroplast destruction during leaf senescence involves 13-lipoxygenase (13-LOX)

2016 ◽  
Vol 113 (12) ◽  
pp. 3383-3388 ◽  
Author(s):  
Armin Springer ◽  
ChulHee Kang ◽  
Sachin Rustgi ◽  
Diter von Wettstein ◽  
Christiane Reinbothe ◽  
...  
Keyword(s):  
Leaf Senescence ◽  
Critical Role ◽  
Transit Peptide ◽  
Physiological Changes ◽  
Pathogen Defense ◽  
Chloroplast Transit Peptide ◽  
Selective Destruction ◽  
Plastid Envelope ◽  
Volatile Aldehydes

Leaf senescence is the terminal stage in the development of perennial plants. Massive physiological changes occur that lead to the shut down of photosynthesis and a cessation of growth. Leaf senescence involves the selective destruction of the chloroplast as the site of photosynthesis. Here, we show that 13-lipoxygenase (13-LOX) accomplishes a key role in the destruction of chloroplasts in senescing plants and propose a critical role of its NH2-terminal chloroplast transit peptide. The 13-LOX enzyme identified here accumulated in the plastid envelope and catalyzed the dioxygenation of unsaturated membrane fatty acids, leading to a selective destruction of the chloroplast and the release of stromal constituents. Because 13-LOX pathway products comprise compounds involved in insect deterrence and pathogen defense (volatile aldehydes and oxylipins), a mechanism of unmolested nitrogen and carbon relocation is suggested that occurs from leaves to seeds and roots during fall.

scholarly journals A Central Role of Abscisic Acid in Drought Stress Protection of Agrobacterium-Induced Tumors on Arabidopsis

2007 ◽  
Vol 145 (3) ◽  
pp. 853-862 ◽  
Author(s):  
Marina Efetova ◽  
Jürgen Zeier ◽  
Markus Riederer ◽  
Chil-Woo Lee ◽  
Nadja Stingl ◽  
...  
Keyword(s):  
Abscisic Acid ◽  
Drought Stress ◽  
Stress Protection ◽  
Induced Tumors

scholarly journals A possible stress physiological role of abscisic acid conjugates in root-to-shoot signalling

2002 ◽  
Vol 25 (2) ◽  
pp. 223-228 ◽  
Author(s):  
A. Sauter ◽  
K.-J. Dietz ◽  
W. Hartung
Keyword(s):  
Abscisic Acid ◽  
Physiological Role

Notochord to endoderm signaling is required for pancreas development

Development ◽  
1997 ◽  
Vol 124 (21) ◽  
pp. 4243-4252 ◽  
Author(s):  
S.K. Kim ◽  
M. Hebrok ◽  
D.A. Melton
Keyword(s):  
Gene Expression ◽  
Developmental Stage ◽  
Pancreas Development ◽  
Chick Embryos ◽  
Carboxypeptidase A ◽  
Bud Development ◽  
Dorsal Pancreas ◽  
Stepwise Manner

The role of the notochord in inducing and patterning adjacent neural and mesodermal tissues is well established. We provide evidence that the notochord is also required for one of the earliest known steps in the development of the pancreas, an endodermally derived organ. At a developmental stage in chick embryos when the notochord touches the endoderm, removal of notochord eliminates subsequent expression of several markers of dorsal pancreas bud development, including insulin, glucagon and carboxypeptidase A. Pancreatic gene expression can be initiated and maintained in prepancreatic chick endoderm grown in vitro with notochord. Non-pancreatic endoderm, however, does not express pancreatic genes when recombined with the same notochord. The results suggest that the notochord provides a permissive signal to endoderm to specify pancreatic fate in a stepwise manner.

scholarly journals Salt tolerance and regulation of gas exchange and hormonal homeostasis by auxin-priming in wheat

2013 ◽  
Vol 48 (9) ◽  
pp. 1210-1219 ◽  
Author(s):  
Muhammad Iqbal ◽  
Muhammad Ashraf
Keyword(s):  
Abscisic Acid ◽  
Gas Exchange ◽  
Acid Concentration ◽  
Spring Wheat ◽  
Indoleacetic Acid ◽  
Co2 Assimilation ◽  
Assimilation Rate ◽  
Co2 Assimilation Rate ◽  
Net Co2 Assimilation Rate ◽  
Net Co2 Assimilation

The objective of this work was to assess the regulatory effects of auxin-priming on gas exchange and hormonal homeostasis in spring wheat subjected to saline conditions. Seeds of MH-97 (salt-intolerant) and Inqlab-91 (salt-tolerant) cultivars were subjected to 11 priming treatments (three hormones x three concentrations + two controls) and evaluated under saline (15 dS m-1) and nonsaline (2.84 dS m-1) conditions. The priming treatments consisted of: 5.71, 8.56, and 11.42 × 10-4 mol L-1 indoleacetic acid; 4.92, 7.38, and 9.84 × 10-4 mol L-1 indolebutyric acid; 4.89, 7.34, and 9.79 × 10-4 mol L-1 tryptophan; and a control with hydroprimed seeds. A negative control with nonprimed seeds was also evaluated. All priming agents diminished the effects of salinity on endogenous abscisic acid concentration in the salt-intolerant cultivar. Grain yield was positively correlated with net CO2 assimilation rate and endogenous indoleacetic acid concentration, and it was negatively correlated with abscisic acid and free polyamine concentrations. In general, the priming treatment with tryptophan at 4.89 × 10-4 mol L-1 was the most effective in minimizing yield losses and reductions in net CO2 assimilation rate, under salt stress conditions. Hormonal homeostasis increases net CO2 assimilation rate and confers tolerance to salinity on spring wheat.

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