Abstract
Although several recent studies point at the importance of seagrass roots for nutrient acquisition in oligotrophic tropical ecosystems, remarkably little is known about the root architecture of tropical seagrasses. The present study provides a detailed description of the root architecture of six seagrass species that were extracted from three sites differing in sediment type and nutrient availability (i.e., except for one species that was not present at one of the sites). Number of roots per node, order of root branching, length and diameter per root order, root hair density and length were determined and used to calculate a topological index for the different species and habitats. Root architecture differed strongly between species. The relatively long-lived and slowly-growing species Thalassia hemprichii and Enhalus acoroides were characterised by short internodes with relatively few unbranched roots per node and a high root hair density. More fast growing species such as Cymodocea rotundata, Cymodocea serrulata and Syringodium isoetifolium had many roots per node, the majority of which were branched. Surprisingly, differences in sediment type and nutrient availability, as present between locations, had little effect on root architecture. We expect this to be due to a relatively homogeneous nutrient distribution at the small scale within water saturated sediments. Overall, all seagrass species had relatively simple branching (topological index > 0.7), comparable to angiosperms of the low temperate salt marsh. We speculate that relatively simple root architecture of plants in flooded systems reflects the need for a minimal path length for oxygen transport from shoots to roots.
Original language | English |
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Pages (from-to) | 235-245 |
Number of pages | 11 |
Journal | Aquatic Botany |
Volume | 90 |
Issue number | 3 |
DOIs | |
Publication status | Published - Apr 2009 |
Externally published | Yes |
Bibliographical note
Funding Information:This research was supported by WOTRO (The Netherlands Foundation for the Advancement of Tropical Research), grant number WT84-422. A. Arifin, and Asep Rasyidin are thanked for their valuable help during the field work. Sara Puijalon is thanked for her help in running the statistical analyses. Two anonymous reviewers are thanked for there valuable comments on a previous version of this manuscript. We like to especially thank the editor Jan Vermaat for his detailed comments that enabled us to significantly improve this MS. This is NIOO-KNAW publication number 4427.
Funding
This research was supported by WOTRO (The Netherlands Foundation for the Advancement of Tropical Research), grant number WT84-422. A. Arifin, and Asep Rasyidin are thanked for their valuable help during the field work. Sara Puijalon is thanked for her help in running the statistical analyses. Two anonymous reviewers are thanked for there valuable comments on a previous version of this manuscript. We like to especially thank the editor Jan Vermaat for his detailed comments that enabled us to significantly improve this MS. This is NIOO-KNAW publication number 4427.
Keywords
- Oligotrophic
- Root architecture
- Root branching
- Toplogical index
- Tropical seagrass