User:Dbarnha1/sandbox

Leymus arenarius is a rhizomatous plant, meaning that the root system is composed of a mass of rhizomes, and is usually found underground. The root system of L. arenarius is used extensively along sandy barrens in both costal and inland regions Iceland, Poland, the UK, and Denmark in order to stabilize the soil. Furthermore, sand accretion and soil salinity are two important factors thought to influence the growth and survival of L. arenarius in regions of sandy barrens. In Iceland, sand accretion in the summer can reach up to 50 cm over 3 months near the outwash of glacial rivers. The germinating seedlings of L. arenarius show the greatest potential for elongation during periods of darkness, also known as etiolation. The degree of etiolation depends on the level of sand accretion, and is a good predictor of L. arenarius ability to emerge from the sand. When sand accretion accumulates over 20 cm, the germinated seedlings were not able to emerge from under then sand. However, if sand accretion only reaches 15 cm, 40% of the germinating seedlings was able to emerge. Another factor affecting the growth of L. arenarius is soil salinity. The growth response of L. arenarius improved when grown in moderate salinity along costal regions (200-400 mM NaCl). The populations of L. arenarius grown along the coast presented with greater root biomass and greater leaf area. For these reasons, land conservationists have begun to sow the seeds from coastal populations of L. arenarius in order stabilize coastal sandy barrens. The germination process is a delicate operation. The time of harvest affects the newly germinated seedlings. Seeds harvested earlier possess lower total germination than the seeds harvested later in the germination process. Seed germination has shown to be problematic in the field, in that, the seeds from L. arenarius grown in domesticated plots are exported from wild strands, with consequent variation in quality, germinability, and seed mass. Seeds of exported L. arenarius have been reported to exhibit strong dormancy rates. A seed is classified as dormant if they fail to produce seedlings given appropriate conditions for germination. However, certain conditions have shown to produce near 100% germination among L. arenarius species. Such conditions include growing the species in continuous darkness, under alternating temperatures with an amplitude of 10-20 °C on a 12-hour cycle. One of the major causes of dormancy is a lack of nutrients. Dune sands are notably characterized as nutrient deficient, especially in Nitrogen (N) and Phosphorus (P). The black, volcanic sands around the coast of Iceland are no exception, with nitrogen being the main limiting element. Fertilizers containing nitrogen, phosphorus, and potassium allow populations of L. arenarius growing in sandy costal regions to increase in spike density. In recent years conservationists have used fertilizer treatment in managing the production of seeds, as well as to facilitate the establishment and survival of seedlings.