Drought affects tracheid structure, dehydrin expression, and above- and belowground growth in 5-year-old Norway spruce

作者：Eldhuset Toril Drablos; Nagy Nina Elisabeth; Volarik Daniel; Borja Isabella; Gebauer Roman; Yakovlev Igor A; Krokene Paal^*

来源：Plant and Soil, 2013, 366(1-2): 305-320.

DOI：10.1007/s11104-012-1432-z

• Dehydrin
• Fine roots
• Needles
• Norway spruce
• Picea abies
• Tracheid structure

Drought-induced tree susceptibility is a major risk associated with climate change. Here we report how an 11-week drought affected tracheid structure, gene expression, and above- and belowground growth in 5-year-old Norway spruce trees (Picea abies) under controlled conditions.
The canopy of trees subjected to severe drought had significantly less current-year needle biomass, and fewer tracheids and tracheid rows in current-year shoots compared to fully watered control trees. Belowground tissues were more strongly affected by drought than aboveground tissues. In fine roots (< 2 mm diameter) severe drought significantly reduced root biomass, root diameter, root length density and root surface area per soil volume compared to the control. Tracheid diameter and hydraulic conductivity in fine roots were significantly lower and tracheid flatness higher in trees subjected to severe drought than in control trees, both for long and short roots. Transcripts of the drought-related dehydrins PaDhn1 and PaDhn6 were strongly upregulated in stem bark and current-year needles in response to drought, whereas PaDhn4.5 was down-regulated.
This study demonstrates that drought reduces biomass and hydraulic conductivity in fine roots and needles. We suggest that the ratio between PaDhn6 and PaDhn4.5 may be a sensitive marker of drought stress in Norway spruce.

• 出版日期2013-5