The junction of the bryophyta relates to only the foam S in a strict sense, while the term Bryophyte taken in the broad sense applies to the three junctions of terrestrial plants which do not have a true vascular system (Hepaticophyta, Anthocerotophyta and Bryophyta).
Deprived of roots and lignin, their rhizoid allows anchoring the substrate and for certain species a life épiphyte. They are deprived of conducting fabrics comparable with those of the plants with seeds: their vegetative apparatus contains neither xylème, nor phloem.
ClassificationThis junction is divided into 6 classes:
- Sphagnopsida (the Sphaigne S)
- Andreaeopsida (the Andréale S)
- Bryopsida (the true foams)
OrganizationThe structure is simple, few bodies are clearly differentiated, one speaks about a structure “thalloïde”; the sheets are simple (one to three layers of cells) and without Stomate, the stem does not have conducting fabrics comparable with those of the plants with seeds (Spermatophytes) nor even of the fern S, and there are no roots, simply the rhizoid ones being used for the support of the plant.
The bryophyta develop by division of only one cell at the end of each vegetative or reproductive body.
- Asexual: Communition then dispersion of the clusters of cells;
- Sexuée: Alternation of generations with predominance of the gametophytic phase. Their reproductive bodies are archégones and anthéridies. The sporophyte lives fixed on the gamétophyte in total or partial parasite.
LifestyleTheir habitat S is wet places like under wood, the bark or for certain species the rocks, roofs etc Indeed thanks to the phenomenon of Reviviscence these species can survive at the dehydrated state. They are also indicators of pollution.
Foams and environmentThe bryophytes, whose foams are nourished primarily starting from the nutrients brought by the invertebrates (excrements, mucus), or by the rain, capillary and interstitial water and starting from the air gas contributions and nutritive particles.
By doing this, foams play a big role in the air-cleaning. For the same reasons, they accumulate certain resilient pollutants or not Biodégradable S (Heavy metals and Radionucléide S in particular). Certain foams are organizations pioneers which with the algae, the lichens and of the bacteria contribute to fix, protect or create the grounds. They are for this reason very important in several processes of ecological Résilience, after the fires in particular.
The species most sensitive to the devaporized air, the oxidizing pollutants and the pesticides conveyed by the air and the pesticides sometimes disappeared from an important part of their natural biogeographic surface, by losing genetic diversity. The majority of the foam species are like the algae, very sensitive to the Cuivre which kills them as of low dose.
Certain species could be regarded as Bioindicateur S, as regards thermohygrometric quality of the air in particular. From their natural resistance to many pollutants foams are not good bioindicateurs of Pollution, but like Bio-accumulator S, they can make it possible to chart repercussions of pollution. For example were used they to chart pollution by the Plomb, the Cadmium, the Arsenic and other heavy metals in Europe. ( |Example: chart of the atmospheric arsenic repercussions in France, towards 2000/2005). In certain forests of polluted areas, the famous foams most resistant also disappeared.
|Random links:||Florence Aubenas | Resolution 1441 (2002) of the Safety advice of the United Nations | Sly Dunbar | Cassinelle | Gudrun Berend | Accroc_de_clou_de_girofle|