The common reed Phragmites australis (Cav.) Trin. ex Steud. (syn. P. communis Trin.) is a member of Poaceae with a widespread distribution in both the hemispheres, in different habitat types from river/lake shores, wetlands, coastlands and estuarine habitats, to ruderal, disturbed and even urban areas, hence it is considered a sub-cosmopolite species (Bjork 1967, Haslam 1973, Ostendorp 1993, Brix 1999a) In the last decades, reeds are dying back at a fast rate in sizeable areas of Europe, with significant impacts on important wetland functions (biodiversity, stability of river and lake margins, water quality) and local economy (Den Hartog et al. 1989, Van Der Putten 1997, Brix 1999b). Similar symptoms have been detected even in central Italy (Gigante et al. 2011). Besides ecological, morphological or anatomical parameters studies concerning some reproductive aspects might also be interesting in order to detect the health condition of reed-dominated ecosystems. In all the plant species the flower biology can be a good indicator of the health condition as the seed production and the seed viability. In plants exhibiting both vegetative and sexual reproduction, the energy allocation can be shifted from one to the other strategy in response to environmental stress; it is well known that sexual reproduction decreases the vulnerability of a population to disturbances and biotic stresses by increasing the genetic variability (Lei 2010). On this ground, we took into account the reproductive features of a declining reed stand in central Italy, where the die-back syndrome was recently detected (Gigante et al. 2011), with the aims to extend knowledge on sexual reproduction in P. australis and to highlight links between sexual reproduction and die-back symptoms. In this frame, cyto-histological analyses of inflorescences at different developmental stages were carried out in permanent plots where morphological investigation and histochemical analyses were also carried out to verify pollen and seed viability. An interesting link between some decline symptoms and the rate of spikelets containing at least one viable seed was observed. In detail, it appears that higher rates of viable seeds are recorded in the declining reed stands.
Correlation between sexual reproduction in Phragmites australis and die-back syndrome
REALE, Lara;GIGANTE, Daniela;LANDUCCI, FLAVIA;VENANZONI, Roberto;FERRANTI, Francesco
2011
Abstract
The common reed Phragmites australis (Cav.) Trin. ex Steud. (syn. P. communis Trin.) is a member of Poaceae with a widespread distribution in both the hemispheres, in different habitat types from river/lake shores, wetlands, coastlands and estuarine habitats, to ruderal, disturbed and even urban areas, hence it is considered a sub-cosmopolite species (Bjork 1967, Haslam 1973, Ostendorp 1993, Brix 1999a) In the last decades, reeds are dying back at a fast rate in sizeable areas of Europe, with significant impacts on important wetland functions (biodiversity, stability of river and lake margins, water quality) and local economy (Den Hartog et al. 1989, Van Der Putten 1997, Brix 1999b). Similar symptoms have been detected even in central Italy (Gigante et al. 2011). Besides ecological, morphological or anatomical parameters studies concerning some reproductive aspects might also be interesting in order to detect the health condition of reed-dominated ecosystems. In all the plant species the flower biology can be a good indicator of the health condition as the seed production and the seed viability. In plants exhibiting both vegetative and sexual reproduction, the energy allocation can be shifted from one to the other strategy in response to environmental stress; it is well known that sexual reproduction decreases the vulnerability of a population to disturbances and biotic stresses by increasing the genetic variability (Lei 2010). On this ground, we took into account the reproductive features of a declining reed stand in central Italy, where the die-back syndrome was recently detected (Gigante et al. 2011), with the aims to extend knowledge on sexual reproduction in P. australis and to highlight links between sexual reproduction and die-back symptoms. In this frame, cyto-histological analyses of inflorescences at different developmental stages were carried out in permanent plots where morphological investigation and histochemical analyses were also carried out to verify pollen and seed viability. An interesting link between some decline symptoms and the rate of spikelets containing at least one viable seed was observed. In detail, it appears that higher rates of viable seeds are recorded in the declining reed stands.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
