plant hormone

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plant hormone

any of several chemical substances produced in very low concentrations in plants, that control growth and development. They are now usually called growth substances. Plant HORMONES are produced in active MERISTEMS (e.g. root and shoot apices) from where they diffuse to other parts of the plant. A distinct contrast with animal hormonal systems is the fact that plants do not possess specific tissues for hormone production, nor a well-defined distribution system equivalent to the blood system.

Plant hormones are classified generally into several groups, discussed under separate headings: ABSCISSIC ACID, AUXINS, CYTOKININS and GIBBERELLINS.

References in periodicals archive ?
The role of phytohormones such as auxins, gibberellins and cytokinins in fruit ripening is to act as retarders of senescence, while ethylene and abscisic acid are considered as fruit ripening promoters.
The increase of RDM, TDM and NAS due to the presence of Azospirillum brasilense is probably related to phosphate solubilization and/or production of phytohormones by these microorganisms, such as auxins, gibberellins and cytokinins, which evidences the effect of this rhizobacterium as plant growth promoter.
We recommended that more researches about salt stress in arid and semi-arid zones to be conducted and the use of other applications from sources of organic matters with studying the phytohormones (Auxins gibberellins, cytokinis, ethylene, ABA, etc.
A kind of phytohormones substances (IAA) was identified in culture medium from two DSE strains Helgardia ericae (Gay and Debaud, 1987) and Phialophora sp.
Phytohormones are the regulatory molecules produced by plants in very low concentration.
In addition, seed coat structure and chemical composition, especially the phytohormones, should be also studied to assess their role in reported variation in seed germination behaviour.
Circumstantial evidence suggests that the bacterial action on Striga may be mediated through phytohormones.
McCoy, The Effect of Phytohormones on Growth and Artemisinin Production in Artemisia annua Hairy Roots, In Vitro Cellular and Development Biology- Plant, 41, 47 (2005).
Phytohormones, particularly isoflavones, can act as steroidal mimics by filling the stereochemical space that could be occupied by estrogenic compounds.
Our preliminary results indicate that AtGCN2 is involved in immune signaling pathways mediated by the phytohormones salicylic acid and jasmonic acid.
Deviations from standard germination parameters may result from physiological processes in the seed that are affected by phytotoxins, the most reported being the suppression of enzyme activities and / or phytohormones related to the hydrolysis of the reserve materials of the embryo at the beginning of development (SINGH et al.