Salix alba Clone Wilting Response to Heat Stress

Abstract

The selection of most suitable propagation material, as well as the adjustment of existing seedling management practices, are gaining increasing importance to ensure the best outcomes under the long-term setting of climate change. One of the factors to consider is a predicted increase in the frequency and duration of high-temperature periods. Since heat often coincides with drought, these factors are typically assessed together, yet heat stress on its own has received less attention. In this study, we examined the effect of supra-optimal ambient temperature on nine Salix alba clone cuttings wilting under greenhouse conditions and sufficient moisture levels. Most plants are especially vulnerable to extreme conditions in early stages of development. Response to heat varied between clones but, overall, shoots that were taller than 350 mm were more sensitive to heat stress. The pruning of excess lateral shoots did not show significant improvement in heat tolerance. In total, 96% of the wilted cuttings proceeded to produce lateral shoots after the cessation of heat stress. It should be studied further if similar patterns are evident in field conditions and if earlier outplanting has a positive effect on cutting vitality.