|Authors: ||E.S. Runkle, R.D. Heins|
|Keywords: ||daily light integral, light quality, light quantity, photoperiod|
Photoperiod, light intensity, and light quality influence plant growth and development from seed germination to flowering. Photoperiod has a qualitative or quantitative effect on flower induction and development of some plant species, and no effect on flowering of other plants.
Light quality, or the spectral distribution of light, can influence internode length, flower initiation, and flower development. Light intensity can be described by instantaneous or cumulative (daily light integral, or DLI) measurements and influences photosynthesis and thus parameters of plant quality, e.g., branching, stem thickness, flower number, and flower size. It can also influence time to flower initiation.
Plant biologists and horticulturists throughout the world have described how these three properties of light influence growth and development for model crops (e.g., Arabidopsis and Lolium) and horticultural crops (e.g., Petunia and Viola). Flowering of model crops is often considered to occur when one flower reaches anthesis.
Additional attributes of flowering are considered important by horticulturists, including time to flower, flowering percentage and uniformity within a population of plants, flower number, and other aesthetic attributes.
In this paper, we describe how the various properties of light influence morphogenesis and flowering, with an emphasis on horticultural flowering.
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