KNAW Repository

Coping with low nutrient availability and inundation: root growth responses of three halophytic grass species from different elevations along a flooding gradient

Bouma, T.J. and Koutstaal, B.P. and Van Dongen, M. and Nielsen, K.F. (2001) Coping with low nutrient availability and inundation: root growth responses of three halophytic grass species from different elevations along a flooding gradient. Oecologia, 126, 472-481. ISSN 0029-8549.

[img]PDF - Published Version
Restricted to KNAW only

284Kb

Official URL: http://dx.doi.org/10.1007/s004420000545

Abstract

We describe the responses of three halophytic grass species that dominate the low (Spartina anglica), middle (Puccinellia maritima) and high (Elymus pycnanthus) parts of a salt marsh, to soil conditions that are believed to favour contrasting root-growth strategies. Our hypotheses were: (1) individual lateral root length is enhanced by N limitations in the soil but restricted by oxygen limitations, (2) the density of root branching within a species is inversely related to the length of the lateral roots, and (3) species from high elevations (i.e. the driest parts of a marsh) are the most responsive to changing soil conditions. Plant growth responses and soil parameters showed that the contrasting but uniformly applied soil treatments were effective. All three species showed a small but significant shift towards a finer root diameter distribution when N was limiting, partly because of the finer diameters of the laterals (Elymus and Spartina) and partly because of increased length of individual Ist-order laterals (Elymus and Puccinellia). The increased length of the I st- order laterals of Elymus and Puccinellia grown under low N indicates that the first part of hypothesis 1 may be true. However, lack of effect of flooding and reduced soil conditions lead us to reject the second part of hypothesis 1. Hypothesis 2 was rejected for these three halophytes, as the branch density of 1st- and 2nd-order laterals appears to be controlled by other factors than length of individual laterals. Hypothesis 3 may be true for specific root characteristics (e.g. length of individual Ist-order laterals), but cannot be generalised (e.g. branch density and topological index). In conclusion, the present data on root growth in contrasting but homogeneous soil conditions indicate that morphological responsiveness of the root systems of these halophytic grass species is limited, regardless of their location along the elevational gradient. [KEYWORDS: root architecture; flooding; phytotoxins; salt marsh; topology Salt-marsh; spartina-alterniflora; architectural approach; coastal louisiana; system topology; plant zonation; salinity; vegetation; nitrate; sulfide]

Item Type:Article
Institutes:Nederlands Instituut voor Ecologie (NIOO)
ID Code:10981
Deposited On:24 Nov 2011 01:00
Last Modified:31 Mar 2014 10:47

Repository Staff Only: item control page