Selective Chinese Viviparous Ferns, Their Bioactive Principles and Economical Values
Parimelazhagan Thangaraj in Medicinal Plants, 2018
Julius von Sachs, a German botanist (1832–1897) suggested that plants produce, transport and perceive ‘organ-forming substances’ which are responsible for the formation and growth of different plant organs. Plant hormones such as abscisic acid (ABA), gibberellins (GA), ethylene, brassinosteroids (BR), auxins, cytokinins and other signalling molecules have profound effects on plant development at low concentrations. Hormones are chemical messengers which are useful to communicate between cells, tissues and organs of higher plants. Plant seeds contain an embryo surrounded by covering layers and have the important function of ensuring the establishment of a new plant generation. Plant hormones are extremely important for the regulation of seed dormancy and germination (Koornneef et al. 2002; Finkelstein 2004). Moreover, plant hormones are a special group of chemical substances which control growth and development in plants. Hormones play a vital role in the plant’s life cycle, such as cell division and extension, seed and bud dormancy, seed germination, flowering, fruit set and ripening and cutting rooting (Preece and Read 1993; Unsal 1993; Foskett 1994; Eris 1995; Hartmann et al. 1997).
The Multi-Regulatory Properties of Melatonin in Plants
Akula Ramakrishna, Victoria V. Roshchina in Neurotransmitters in Plants, 2018
Melatonin, a classical animal hormone, was discovered in plants in 1995 and was soon seen to have multiple possible roles in plant physiology. Its protective function against biotic and abiotic stressors is now fully accepted and may be very relevant for application in agronomic techniques to improve crop yield. Its implication in photosynthesis efficiency, CO2 assimilation, the carbohydrates/lipid/nitrogen metabolisms, and osmoregulation appears clear although some important aspects remain to be understood. Melatonin shows some activities similar to classical auxin. Its role as a modulator of growth and rooting has led to it being considered a plant hormone. Nevertheless, the fact that its receptor in plants has not been identified and the scarce data concerning its mechanism of action means that we are still at the beginning of this exciting road.
Bioactive Compounds in Marine Macro Algae and Their Role in Pharmacological Applications
Parimelazhagan Thangaraj in Phytomedicine, 2020
Plant growth hormones are available in seaweed extracts, which are used to induce plant growth and to improve the photosynthesis. Cytokinins are plant growth regulators that protect plants from temperature variations (Tarakhovskaya et al. 2007; Zhang et al. 2010), and these are synthesized by means of the bio-chemical modification of adenine. Other plant hormones are auxin, abscisic acid, and betaines that are found in macro algal extracts. Auxin functions to start the root formation and reduce its elongation, their concentration may vary, and it depends up on the species. Gibberellins play a major role to start seed germination and are formed in developing seeds from glyceraldehydes-3-phosphate. They were first identified in two brown algal extracts, such as a Fucus vesiculosus and Fucus spiralis (Tarakhovskaya et al. 2007). Abscisic acid is formed from carotenoids by more than 60 species of algae, and betaines are not usual plant hormones, which are also found in seaweed extracts (MacKinnon et al. 2010), and their role is to guard the plants from drought and frost (Craigie 2011). The brown algal extract, Ascophyllum nodosum, has a rich source of betaines (Khan et al. 2009; Craigie 2011).
Novel approaches to targeted protein degradation technologies in drug discovery
Published in Expert Opinion on Drug Discovery, 2023
Yu Xue, Andrew A. Bolinger, Jia Zhou
Multiple plant hormone signaling pathways are regulated by UPS [14]. Retrospective studies demonstrated that these plant hormones functioned as MGs, exemplified by auxin, jasmonates, and gibberellin. Auxin (1) (chemical structure shown in Figure 2) regulates gene expression through promoting E3 ligase Skp1-cullin 1-F-box (SCF)-catalyzed degradation of the Aux/IAA transcription repressors [15]. A ternary complex co-crystal of auxin, transport inhibitor response 1 (TIR1), and Aux/IAA disclosed the mechanism, by which auxin enhanced the TIR1–substrate interactions as an MG, thereby inducing the degradation of Aux/IAA [3]. Jasmonates are reported to regulate the degradation of jasmonates ZIM-domain (JAZ) protein family in response to host immunity and stress response by binding to SCF substrate coronatine insensitive 1 (COI1) [16]. A co-crystal of JA-Ile (2, a jasmonate derivative) conjugate demonstrated the promotion of physical interaction between COI1 and JAZ1 [4]. Gibberellin was originally identified as a mycotoxin. Model studies of gibberellin signaling in plants suggest that it functions as an MG [5]. Through binding to gibberellin A3 (GA3, 3), gibberellin insensitive dwarf 1 (GID1) is induced to undergo a conformational switch, which in turn promotes the recognition of transcriptional regulator DELLA proteins (a SCF substrate) by SCFSLY1/GID2, thereby being ubiquitinated and degraded [17].
A novel and effective technique to reduce electromagnetic radiation absorption on biotic components at 2.45 GHz
Published in Electromagnetic Biology and Medicine, 2022
Meenu L, Aiswarya S, Sreedevi K. Menon
This experiment is a direct validation and serves as a proof of concept that the EMR exposure rate, time and intensity has an adverse effect on the plant tissues. The study shows that the variation in secretion of plant hormones like Gibberellins, Cytokinins, Abscisic Acid and Auxins had led to the retardation in the complete growth of the plant (Naqvi 1999) – (Arteca 1996.). The radiation is mainly due to the antenna present in the gadgets and these radiations will be absorbed by the vegetation. This is measured in terms of SAR for a given tissue. SAR depends upon dielectric property, conductivity, mass density, electric field strength of the tissues etc. The absorption of radiation by pea seeds near to the router is more as it receives more power in the vicinity of the router. So the variation in absorption results in growth retardation even from its initial stage of the germination. This effect in the sprouting stage makes changes in the entire life cycle of each plant community. These continuous exposure reduces the nutrient capability of vegetations and it makes them unhealthy to human life.
Evaluation of the optimum threshold of gamma-ray for inducing mutation on Polianthes tuberosa cv. double and analysis of genetic variation with RAPD marker
Published in International Journal of Radiation Biology, 2023
Hanifeh Seyed Hajizadeh, Seyed Najmedin Mortazavi, Morteza Ganjinajad, Volkan Okatan, İbrahim Kahramanoğlu
Increasing the radiation dose did not significantly increase this trait in general, so the treatments of 20, 30, and 40 Gy doses of γ-ray did not significantly differ from the control, and only the treatment of 50 Gy showed a significant difference compared to the control and other lower levels of radiation (Table 3). Ling et al. (2008) reported that plants grew more at 10 Gy, while doses above 10 Gy inhibited plant growth, indicating that increased radiation increases the plant’s tolerance to γ-radiation. It may be explained by a decrease in the amount of endogenous plant hormones, especially cytokinin, which results in cytokinin degradation or lack of biosynthesis due to irradiation. It is clear that damage to the cells of tuberose was so serious at the gamma-ray dose of 50 Gy.
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