Welander M
Swedish University of Agricultural Sciences, Department of Horticulture, Box 55, S-230 53 Alnarp, Sweden.
Tree Physiol. 1995 Jan;15(1):11-8. doi: 10.1093/treephys/15.1.11.
Differences in rooting ability of birch (Betula pubescens J.F. Ehrh.) cuttings were observed as a result of differences in genotype and physiology of the stock plants. The uniformity in response among cuttings from micropropagated plants compared with cuttings from seed plants confirmed the advantage of using micropropagated plants to study environmental effects. Shoot morphology of the seed stock plants was influenced by both photoperiod and thermoperiod. A day/night temperature of 15/25 degrees C reduced stem elongation compared with a day/night temperature of 25/15 degrees C regardless of photoperiod, and a continuous light regime resulted in more shoots per plant in both temperature regimes than a 16-h photoperiod. A reduction in the supply of macronutrients did not influence shoot morphology, but increased rooting substantially and seemed to override the effects of environmental factors. In cuttings of seed plants, the highest rooting percentage and number of roots were obtained in a 16-h photoperiod with a day/night temperature of 15/25 degrees C. In micropropagated stock plants, there was a positive correlation between shoot length and number of leaves per shoot and topographical distribution of light within the plants, but there was no correlation between these parameters and rooting ability of the cuttings. A rooting temperature of 16 degrees C delayed the rate of root production compared with the rate at higher temperatures, but the final rooting percentage was the same over the range from 16 to 28 degrees C. Root branching increased with temperature. At all temperatures, there was a large increase in sucrose content at the base of the cuttings during rooting, whereas the concentration of nontranslocated sugars remained constant. The carbohydrate content at the base of cuttings from micropropagated stock plants was three times higher than at the base of cuttings from seed stock plants, but the higher carbohydrate content was not correlated with a higher rooting potential.
由于母株基因型和生理状态的差异，观察到白桦（Betula pubescens J.F. Ehrh.）插条生根能力存在差异。与种子繁殖植株的插条相比，微繁殖植株插条反应的一致性证实了使用微繁殖植株研究环境影响的优势。种子繁殖母株的茎形态受光周期和温度周期的影响。无论光周期如何，15/25℃的日/夜温度与25/15℃的日/夜温度相比，茎伸长减少，并且在两种温度条件下，连续光照处理的单株茎数均多于16小时光周期处理。大量元素供应减少不影响茎形态，但显著增加生根，且似乎能抵消环境因素的影响。在种子繁殖植株的插条中，16小时光周期、15/25℃日/夜温度条件下生根率和根数最高。在微繁殖母株中，茎长与单茎叶片数以及植株内光照的地形分布之间呈正相关，但这些参数与插条生根能力之间无相关性。与较高温度下的生根速率相比，16℃的生根温度延迟了生根速率，但在16至28℃范围内最终生根率相同。根分枝随温度增加。在所有温度下，生根期间插条基部蔗糖含量大幅增加，而未转运糖的浓度保持不变。微繁殖母株插条基部的碳水化合物含量是种子繁殖母株插条基部的三倍，但较高的碳水化合物含量与较高的生根潜力无关。
