Trade-off between root porosity and mechanical strength in species with different types of aerenchyma

• Autores: Striker, Gustavo Gabriel; Insausti, Pedro; Grimoldi, Agustin Alberto; Vega, Andrea Susana
• Año de publicación: 2007
• Idioma: inglés
• Tipo de recurso: artículo
• Materia: AERENCHYMA ARRANGEMENT; CYPERUS ERAGROSTIS; FLOODING; PASPALIDIUM GEMINATUM; PLANTAGO LANCEOLATA; ROOT DIAMETER; ROOT STRENGTH; RUMEX CRISPUS; SOIL COMPACTION
• Institución: Consejo Nacional de Investigaciones Científicas y Técnicas

The objective of this work was to study the existence of a trade-off between aerenchyma formation and root mechanical strength. To this end, relationships among root anatomical traits and mechanical properties were analysed in plant species with contrasting root structural types: Paspalidium geminatum (graminaceous type), Cyperus eragrostis (cyperaceous type), Rumex crispus (Rumex type) and Plantago lanceolata (Apium type). Variations in anatomical traits and mechanical strength were assessed as a function of root diameter by exposing plants to 0, 7, 15 and 30 d of control and flooded conditions. For each species, the proportion of root cortex was positively associated with the increment of root diameter, contributing to the increase in root porosity under both control and flooded conditions. Moreover, cell lysis produced an additional increase in root porosity in most species under flooded conditions (except R. crispus). Both structural types that presented a uniseriate layer (epidermis) to cope with compression (Rumex and Apium types) were progressively weakened as root porosity increased. This effect was significant even when the increment of root porosity was solely because of increased root diameter (R. crispus), as when both processes (root diameter and cell lysis) added porosity to the roots (P. lanceolata). Conversely, structural types that presented a multiseriate ring of cells in the outer cortex (graminaceous and cyperaceous types) maintained mechanical strength over the whole range of porosity, in spite of lysogenic processes registered in the inner cortex. In conclusion, our study demonstrates a strong trade-off between aerenchyma formation and mechanical strength in root structural types that lacked a multiseriate ring of tissue for mechanical protection in the outer cortex. The results suggest that this ring of tissue plays a significant role in maintaining the mechanical strength of roots when flooding induces the generation of additional aerenchyma tissue in the root cortex.
Fil: Striker, Gustavo Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura; Argentina
Fil: Insausti, Pedro. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura; Argentina
Fil: Grimoldi, Agustin Alberto. Universitat Technical Zu Munich; Alemania. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura; Argentina
Fil: Vega, Andrea Susana. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Recursos Naturales y Ambiente. Cátedra de Botánica Agrícola; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina