EnvReg213-page10

EnvReg213-page10 - prior to abscission are activated by...

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Plant Environmental Regulators - 10 Cells of shade leaves elongate and are thinner than cells in full sun exposure. Far-red light is transmitted through leaves so leaves in shade get more far-red light than red light. The increase in far-red light is detected by phytochrome, which activates the elongation responses. Phytochrome activates chlorophyll synthesis in proplastids, as seen in germinating seedlings. The signal transduction pathway for the "greening" response involves G-protein receptors, cGMP and Ca ++ secondary messengers as well as protein kinase cascades. Anthocyanin production and the changes that occur in chloroplasts and plastids
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Unformatted text preview: prior to abscission are activated by phytochrome. Phytochrome promotes flower bud formation in light-dependent flower producing plants. (See discussion in photoperiodism and flowering) Photoperiodism - Circadian Rhythms Activities that occur in "daily" cycles are known as circadian rhythms. Many flowers and leaves open in daylight and close at night. Photosynthesis, auxin production and cell division rates also have circadian rhythms in plants. Circadian rhythm in flowering...
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