Abstract

Results from a controlled growth-analysis experiment were used to illustrate some methods for measuring and describing root system topology. The experiment was performed in a nutrient solution system with an exponential nutrient supply and steady-state growth, to achieve well-defined levels of whole-plant nutrient status. Five naturally coexisting grassland species were included: The slow-growing forbs Polygala vulgaris L. and Crepis praemorsa (L.) F. L. Walth., and the grass Danthonia decumbens (L.) DC. were compared with the more common, fast-growing grasses Agrostis capillaris L. and Dactylis glomerata L. The most marked difference in morphological indices was a much higher specific root length in the grasses than in the forbs, which implies thinner roots. In contrast to the conclusions of previous studies, an index of the topology for the grasses was very similar to that for the forbs. The specific root lenght and link length apparently vary more between species and nutrient levels than topology does, and may therefore be more ecologically important. The only clear plastic response to growth-limiting nitrogen supply was a markedly increased link length in P. vulgaris. There were also indications that nitrogen limitation led to more herringbone-like root systems in P. vulgaris and C. praemorsa. In general, there was a clear tendency for the estimates of topology to change with plant size, which may make many topological indices, especially those based on regression slopes, very difficult to interpret. Until interactions with plant size, other morphological parameters and among-plant competition can be properly understood, the relevance of root topology for plant performance remains unclear.

Keywords

adventitious roots; nitrogen limitation; root system architecture; steady-state nutrition; topology

Published in

Plant and Soil
2000, Volume: 227, number: 1-2, pages: 249-256
Publisher: KLUWER ACADEMIC PUBL

SLU Authors

• Glimskär, Anders

  • Department of Ecology, Swedish University of Agricultural Sciences
    

UKÄ Subject classification

Botany
Ecology


Publication identifier

DOI: https://doi.org/10.1023/A:1026531200864

Permanent link to this page (URI)

https://res.slu.se/id/publ/79663