Early root development of poplars (Populus spp.) in relation to moist and saturated soil conditions

ABSTRACT

Poplars (Populus spp.) are among the fastest growing trees raised in temperate regions of the world. Testing of newly developed cultivars informs assessment of potential planting stock for local environments. Initial rooting by nine poplar clones was tested in moist and saturated soil conditions during an 18-day greenhouse experiment. Clones responded differently to soil moisture, particularly in number of roots, root distribution, and root dry mass accumulation. About 73% of cuttings planted in moist soil produced roots from callus tissue, whereas only 1% of cuttings planted in saturated soil developed such roots. This drove root distribution towards the basal section of cuttings in moist soil, while in saturated soil roots were more evenly distributed among all three below-ground sections of cuttings. Roots originating from the basal section of cuttings planted in moist soil were longer than roots originating from apical and middle sections. Conversely, roots from the apical and middle sections of cuttings planted in saturated soil were longer than those originating from the basal section. Initial rooting among poplar clones established under two soil moisture regimes has implications for genotype deployment in the field, but long-term effects in the field are still unknown.

KEYWORDS:

• Flooding
• genotype
• greenhouse experiment
• regeneration
• unrooted cutting

Acknowledgement

Thank you Bernie McMahon (University of Minnesota) for providing us with plant material. Thanks to Ray Souter (USDA Forest Service), Per Magnus Ekö (Swedish University of Agricultural Sciences, SLU) and the Biostochastics unit (SLU) for statistical support.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This study was financed by Anna- Britta and Vadim Söderström’s scholarship, the Foundation for Forest Science Research, the USDA Forest Service, the Nordic Energy Research's project Wood Based Energy Systems from Nordic Forests (ENERWOODS), and the frame program of The Forestry Research Institute of Sweden (Skogforsk).