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Belowground traits of mediterranean woody plants in a Portuguese shrubland

2002; Volume: 28; Issue: 2 Linguagem: Inglês

10.3406/ecmed.2002.1569

1775-4100

Joaquim S. Silva, Francisco Rego, Maria Amélia Martins‐Loução,

Mycorrhizal Fungi and Plant Interactions

Belowground traits vary widely. Apart from the influence of the environment both genetic and ontogenic factors are responsible for this variation. For mediterranean woody plants there is also evidence of a relationship between regenerative strategies and root system characteristics. With the general aim of studying these different aspects, the root systems of seventeen obligate seeders and sixteen resprouters from ten different species and different developmental stages were excavated at Tapada Nacional de Mafra in Central West Portugal. Root systems were photographed, weighted and measured. Root length and the average root diameter were determined using digital image software. Root-to-shoot ratio (R/ S) and the specific root length (SRL) were computed for all plants. Basal section was used as an indicator of plant development. A principal component analysis (PCA) was performed in order to study the relationships between variables and between plants. The analysis showed a clear distinction of plants according to the respective developmental stage but also according to the regenerative characteristics of the different species. Allometric relationships were found between root biomass, shoot biomass and basal section. Statistical tests showed that resprouters had higher maximum rooting depth, average root diameter and R/ S and lower SRL, than obligate seeders. A decrease of R/ S and SRL with basal section was verified for a sub-sample of four species.