Acta Univ Latv (2005) 691: 41–50

Effect of environmental factors on the propagation of deciduous azalea by cuttings. II. Influence of an extended growth period on bud-break, overwinter survival and carbohydrate levels of rooted cuttings

Abstract

The influence of stock-plant forcing in a greenhouse during spring, as well as an expanded photoperiod and ground heating during autumn and winter, on post-rooting growth and overwinter survival of cuttings was tested using cuttings from the deciduous azalea cultivar ‘Polārzvaigzne’. The stock-plant forcing and extended lighting during the autumn supported the development of new shoots in the post-rooting period. During autumn, all starch stored in the leaves of cuttings was transported to perennial parts of plant. During winter, the use of starch depended on temperature. A high temperature (10°C) promoted depletion of starch in the stem of cuttings if it could not be replenished. Additional light and heating promoted the retention of leaves and the photosynthesis ability of cuttings. Overwinter survival was affected by environmental conditions during winter mainly, while stock-plant forcing did not significantly influence survival. An extended light period together with additional heating in winter improved overwinter survival of cuttings, but delayed their further growth in spring.