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  • Author or Editor: Kent D. Kobayashi x
  • Journal of the American Society for Horticultural Science x
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Abstract

Temperature requirements for rest development were determined and used in developing an empirical model for predicting rest development in terminal vegetative buds of Cornus sericea L. Vegetatively mature plants were exposed to 5° to 20°C under a 12-hr photoperiod (SD) in growth chambers, and depth of rest was measured by days to terminal bud break at 20°/15° (day/night) under a 16-hour photoperiod (LD). Rest development proceeded only after vegetative maturity was attained. Time from vegetative maturity to maximum rest decreased with decreasing temperature. Rate of rest development at all temperatures varied and was dependent on growth stage. The annual growth cycle and rest development were described and quantified by a degree growth stage (°GS) model. Using temperature and accumulating °GS, the model predicted maximum rest within 2 days in both years.

Open Access

Abstract

Effects of temperature on cold acclimation and deacclimation of red-osier dogwood (Cornus sericea L. syn. Cornus stolonifera Michx.) plants were determined at different stages of plant development. Results were used to develop models for predicting stem hardiness. Acclimation and deacclimation rates were related to temperature and plant developmental stage (expressed as degree growth stage, °GS). Decreasing temperature promoted increasing acclimation. Maximum acclimation rates in the temperature range of 5° to 20°C occurred at maximum rest (270°GS). During the decreasing rest phase (270 to 315°GS), deacclimation occurred at temperatures from 7° to 20°C. At earlier stages of development (315° and 335°GS) during the quiescent phase (315 to 360°GS), 5°C was the only temperature that promoted hardiness, whereas at a later stage (341°GS) all temperatures tested caused deacclimation. The models, using bihourly temperatures and accumulating °GS, predicted hardiness within an average deviation of 4.7°C.

Open Access