photomorphogenesis


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Photomorphogenesis

The regulatory effect of light on plant form, involving growth, development, and differentiation of cells, tissues, and organs. Morphogenic influences of light on plant form are quite different from light effects that nourish the plant through photosynthesis, since the former usually occur at much lower energy levels than are necessary for photosynthesis. Light serves as a trigger in photomorphogenesis, frequently resulting in energy expenditure orders of magnitude larger than the amount required to induce a given response. Photomorphogenic processes determine the nature and direction of a plant's growth and thus play a key role in its ecological adaptations to various environmental changes. See Photosynthesis

Morphogenically active radiation is known to control seed and spore germination, growth and development of stems and leaves, lateral root initiation, opening of the hypocotyl or epicotyl hook in seedlings, differentiation of the epidermis, formation of epidermal hairs, onset of flowering, formation of tracheary elements in the stem, and form changes in the gametophytic phase of ferns, to mention but a few of such known phenomena. Many nonmorphogenic processes in plants are also basically controlled by light independent of photosynthesis. Among these are chloroplast movement, biochemical reactions involved in the synthesis of flavonoids, anthocyanins, chlorophyll, and carotenoids, and leaf movements in certain legumes.

McGraw-Hill Concise Encyclopedia of Bioscience. © 2002 by The McGraw-Hill Companies, Inc.

photomorphogenesis

[¦fōd·ō‚mȯr·fō′jen·ə·səs]
(botany)
The control exerted by light over growth, development, and differentiation of plants that is independent of photosynthesis.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
References in periodicals archive ?
Growth and photomorphogenesis of pepper plants under red light-emitting diodes with supplemental blue or far-red lighting.
Light: Light is one of the physical factors that affects many physiological processes of in vitro plantlets, for instance, photomorphogenesis and photosynthesis.
(2008) a red light is important in the development of the photosystem complex providing morphogenetic changes of phytochrome while blue has been identified as affecting chlorophyll concentrations, photomorphogenesis and stomatal openings, thus a combination of blue and red wavebands at intensities which vary according to the species, can result in higher photosynthetic activity and better photomorphogenetic characteristics than red or blue alone.
Scientific evidences suggest that calcium acts as a messenger in metabolic processes related to plant growth and development, such as cell division, differentiation, polarity and elongation; and plant photomorphogenesis, defense and response to biotic or abiotic stresses (Hong-Bo et al., 2008).
(2014) De Novo Transcriptome Assembly and Analyses of Gene Expression during Photomorphogenesis in Diploid Wheat Triticum monococcum.
Chattopadhyaya, "Arabidopsis CAM7 and HY5 physically interact and directly bind to the HY5 promoter to regulate its expression and thereby promote photomorphogenesis," Plant Cell, vol.
Gruber et al., "Interaction of COP1 and UVR8 regulates UV-B-induced photomorphogenesis and stress acclimation in Arabidopsis," EMBO Journal, vol.
Spalding, "A role for ABCB19-mediated polar auxin transport in seedling photomorphogenesis mediated by cryptochrome1 and phytochrome B," The Plant Journal, vol.