Articles
DIF AND TEMPERATURE DROP RESPONSES IN SDP AND LDP, A COMPARISON
Article number
378_2
Pages
27 – 33
Language
Abstract
A comparison of the response to DIF (difference between day and night temperature) and a short (about 2 hours) temperature drop on plant height (internode length) and other plant characteristics has been investigated in a number of short day plants (SDP) such as poinsettia, Begonia x hiemalis and Kalanchoe blossfeldiana and some long day plants (LDP) such as Campanula isophylla, Petunia x hybrida and Melissa officinalis. In general, the response to negative DIF (DT<NT) on the retardation of internode elongation and plant size was good in both SDP and LDP, except for Kalanchoe where zero DIF (DT=NT) resulted in highest plant quality.
Positive DIF (DT > NT) enhanced internode elongation and plant height in all SDP. A 2-hour temperature drop resulted in excellent height control in the SDP poinsettia and rather good in the SDP Begonia.
The plants were most sensitive to temperature drop at the end of the night and the beginning of the day.
A short temperature drop (2–3 hours) had no or very small effect on the LDP’s Campanula, Petunia and Melissa when grown in long days.
Increasing the duration of low temperature drop from 3 to 9–12 hours during the day reduced significantly the internode length and final plant height at flowering of Campanula.
The effect of negative DIF on stem length in Petunia was more pronounced in LD (16 h) than SD (10 h). Rate of flower development was mainly controlled by average daily temperature in Begonia.
However, high NT may result in a delay of flowering in poinsettia.
The involvement of phytochrome and gibberellins in the response of DIF and temperature drop on morphogenesis and flowering will be discussed.
Positive DIF (DT > NT) enhanced internode elongation and plant height in all SDP. A 2-hour temperature drop resulted in excellent height control in the SDP poinsettia and rather good in the SDP Begonia.
The plants were most sensitive to temperature drop at the end of the night and the beginning of the day.
A short temperature drop (2–3 hours) had no or very small effect on the LDP’s Campanula, Petunia and Melissa when grown in long days.
Increasing the duration of low temperature drop from 3 to 9–12 hours during the day reduced significantly the internode length and final plant height at flowering of Campanula.
The effect of negative DIF on stem length in Petunia was more pronounced in LD (16 h) than SD (10 h). Rate of flower development was mainly controlled by average daily temperature in Begonia.
However, high NT may result in a delay of flowering in poinsettia.
The involvement of phytochrome and gibberellins in the response of DIF and temperature drop on morphogenesis and flowering will be discussed.
Authors
R. Moe, K. Willumsen, I.H. Ihlebekk, A.I. Stupa, N.M. Glomsrud, L.M. Mortensen
Keywords
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