Patterns of plant biomass allocation and functional adjustments along climatic gradients are poorly understood, particularly belowground. Generally, low temperatures suppress nutrient release and uptake, and forests under such conditions have a greater proportion of their biomass in roots. However, it is not clear whether 'more roots' means better capacity to acquire soil resources. Herein we quantified patterns of fine-root anatomy and their biomass distribution across Scots pine (Pinus sylvestris) populations both along a 2000-km latitudinal gradient and within a common garden experiment with a similar range of populations. We found that with decreasing mean temperature, a greater percentage of Scots pine root biomass was allocated to roots with higher potential absorptive capacity. Similar results were seen in the common experimental site, where cold-adapted populations produced roots with greater absorptive capacity than populations originating from warmer climates. These results demonstrate that plants growing in or originated from colder climates have more acquisitive roots, a trait that is likely adaptive in the face of the low resource availability typical of cold soils.
Bibliographical noteFunding Information:
This research was supported by the National Science Center, Poland (2011/02/A/NZ9/00108) and the Institute of Dendrology of the Polish Academy of Sciences. M.L.M. was supported by the Chinese Academy of Sciences (No. 2013Y1ZB0004) and the National Natural Sciences Foundation of China (No. 31350110503). Special credit is due to Bengt Nihlgård (Lunds Universitet), Roma Żytkowiak, Krzysztof Ufnalski, Maciej Sękiewicz (Institute of Dendrology) and Tomasz Wyka (Adam Mickiewicz University) for valuable help given during field trips in Sweden. We are grateful to Darius Danusevičius for providing access to the Scots pine common garden experiment in Lithuania. The authors are grateful to Dominik Tomaszewski for the preparation of Fig. We thank numerous students involved in root dissections, and especially P. Sroka and A. Talaśka who greatly contributed to root microtome sectioning. This manuscript was greatly improved by helpful suggestions from anonymous reviewers.
© 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.
- Scots pine (Pinus sylvestris) ecotypic variation
- genetic control of root development
- latitude gradients
- root cold-adaptation
- roots absorptive capacity