ISHS Acta Horticulturae 79: Symposium on Propagation and Raising of Nursery Stock
WATER AND CARBOHYDRATE RELATIONSHIPS DURING THE ROOTING OF CUTTINGS |
| Authors: | K. Loach, D.N. Whalley |
| Abstract:
The effects of ambient environmental factors (light, temperature, humidity) on the water status and rooting of cuttings was studied in the glasshouse, in different propagation systems. In winter, cuttings propagated under mist were more water stressed and rooted less well than those under polyethylene. In summer the reverse occurred and when measured leaf water potentials during the day were less than -10 bars, rooting was adversely affected. Under mist, overnight recovery from water stress developed on the previous day was often incomplete, whereas cuttings under polyethylene began each day in a relatively unstressed condition. To minimise water stress and avoid damaging leaf temperatures shading is essential on bright days. Unfortunately this reduces photosynthesis in the cuttings and thus the carbohydrates available for root development. The light requirement for a range of hardy ornamental species was determined in shading experiments. Rooting was greatly reduced when the total daily radiation was less than approximately 1.5 MJ m-2. Pre-soaking cuttings in sucrose solution aided rooting when light was below this level but not at higher light levels. The light level must be adjusted to permit adequate photosynthesis yet avoid water stress. Means of determining this balance are discussed. | |
Download Adobe Acrobat Reader (free software to read PDF files) | |
