Articles
CONTROL OF PLANT MORPHOGENESIS AND FLOWERING BY LIGHT QUALITY AND TEMPERATURE
Article number
272_11
Pages
81 – 90
Language
Abstract
Elongation of plant stems, flower stalks and leaf petioles, lateral branching, shoot and leaf orientation, and leaf pigmentation are influenced by both light quality and temperature.
Morphological responses to light and temperature are referred to as photomorphogenesis and thermomorphogenesis, respectively.
Red light (R) or light with a high R/FR ratio (e.g. fluorescent lamps) applied as day-extension or night-interruption (NI) suppresses stem elongation and promotes lateral branching.
Far-red light (FR) or light with a low R/FR ratio (e.g. incandescent lamps) strongly enhances stem elongation and inhibits lateral branching.
The DIFference between day temperature (DT) and night temperature (NT) defined as DT minus NT = DIF strongly influences internode length and plant height in a wide range of pot and bedding plants, while average daily temperature only slightly influences internode length.
Plants grown with a positive DIF (DT>NT) are taller at maturity than plants grown with a negative DIF (DT<NT). The response to DIF is quantitative.
For many morphological characteristics, thermomorphogenesis is similar to photomorphogenesis in the following manner: 1) R light (high R/FR ratio) = negative DIF, 2) FR light (low R/FR ratio) = positive DIF. In the long day plant (LDP) Campanula isophylla, DIF interacts with lamp types (high R versus high FR) which indicates that DT/NT alternations interfere with phytochrome mode of action.
Leaf unfolding rate and flower development are not affected by DIF, but by average daily temperature.
Incandescent (FR) and fluorescent (R) lamps are almost equally effective in promoting early flowering. in some LDP. Incandescent lamps, however, cannot be recommended as proper lamp type for photoperiodic lighting to induce flowering in LDP if compact, well-branching plants are desired.
Lamp types with a high R/FR ratio should be used.
Practical application of DT/NT treatments and light quality manipulations with different lamp types and time of applications, including elimination of twilight or selective screening of the daylight spectrum, will be discussed.
Morphological responses to light and temperature are referred to as photomorphogenesis and thermomorphogenesis, respectively.
Red light (R) or light with a high R/FR ratio (e.g. fluorescent lamps) applied as day-extension or night-interruption (NI) suppresses stem elongation and promotes lateral branching.
Far-red light (FR) or light with a low R/FR ratio (e.g. incandescent lamps) strongly enhances stem elongation and inhibits lateral branching.
The DIFference between day temperature (DT) and night temperature (NT) defined as DT minus NT = DIF strongly influences internode length and plant height in a wide range of pot and bedding plants, while average daily temperature only slightly influences internode length.
Plants grown with a positive DIF (DT>NT) are taller at maturity than plants grown with a negative DIF (DT<NT). The response to DIF is quantitative.
For many morphological characteristics, thermomorphogenesis is similar to photomorphogenesis in the following manner: 1) R light (high R/FR ratio) = negative DIF, 2) FR light (low R/FR ratio) = positive DIF. In the long day plant (LDP) Campanula isophylla, DIF interacts with lamp types (high R versus high FR) which indicates that DT/NT alternations interfere with phytochrome mode of action.
Leaf unfolding rate and flower development are not affected by DIF, but by average daily temperature.
Incandescent (FR) and fluorescent (R) lamps are almost equally effective in promoting early flowering. in some LDP. Incandescent lamps, however, cannot be recommended as proper lamp type for photoperiodic lighting to induce flowering in LDP if compact, well-branching plants are desired.
Lamp types with a high R/FR ratio should be used.
Practical application of DT/NT treatments and light quality manipulations with different lamp types and time of applications, including elimination of twilight or selective screening of the daylight spectrum, will be discussed.
Publication
Authors
R. Moe, R. Heins
Keywords
Online Articles (51)