Interrelated Effects of Thermo- and Photo-periodism on Growth and Development of Ornamental Woody Plants
Year: 1978
Type: article
Abstract: Effects of fall chilling on responses of sweet viburnum (Viburnum Awabuki K. Koch) cuttings and Japanese black pine (Pinus ThunbergiiParl.) seedlings to the subsequent daylength and temperature treatments were investigated. The chilling treatments were continued for 70 days at 3°C in the dark from October 15, 1976.1) Shoot emergence of viburnum cuttings was promoted by long days and high ambient temperatures when cuttings were not subjected to fall chilling. The amount of shoot growth was greater in the long day lots than in the short day lots. The higher the ambient temperature, the greater the amount of shoot growth. In the lots receiving the long day and 25°C treatment, the shoot was elongating along a rectilinear growth curve during the entire course of growth measurement.On the other hand, subsequent daylength and temperature treatments had almost no influence on the onset of shoot emergence when cuttings were subjected to fall chilling. As for the shoot growth, responses of viburnum cuttings to photoperiod seemed long-day-dependent in subsequent high temperature regimes, faculative-short-day-dependent in intermediate temperature regimes, and daylength-independent in low temperature regimes. The shoot growth of viburnum cuttings was quite active even under low temperature conditions. The shoots elongated along a rectilinear growth curve under 10°C like under 25°C.2) Shoot emergence of pine seedlings was fairly promoted by long days and high ambient temperatures when seedlings were not subjected to fall chilling. In general, the shoot growth of pine seedlings was stimulated by long days and high ambient temperatures. However, when seedlings were subjected to fall chilling, the onset of shoot emergence was affected only slightly by subsequent daylength and temperature treatments. The shoot growth was greater in the long day lots than in the short day lots. The lower the ambient temperature, the greater the shoot growth of pine seedlings.From the results obtained, it may be concluded that if viburnum cuttings and pine seedlings are subjected to fall chilling, subsequent optimum temperatures for the shoot growth of both species tested tend to shift from higher to lower regimes. Furthermore, both viburnum cuttings and pine seedlings that are subjected to fall chilling may show a markedly flourishing shoot growth under subsequent short day conditions.
DOI: 10.2503/jjshs.47.425
Institution: Aichi Agricultural Research Center
Language: English
Subfield: Plant Science
Domain: Life Sciences
Open Access status: diamond
OpenAlex ID: W1999457808