Relations between plant-plant and plant-symbiotic microbes, especially mycorrhiza, in disturbed areas are easily affected by the biotic and abiotic environments such as nutrient and water availability, hervibory, wind, and so on because they can regulate each other to adapt to and survive in seriously damaged region. To understand the primary succession mechanism, It is essential to clarify the relations among eco-members in disturbed area in the view of nutrient cycle and competition and facilitation via chemical singals in rhizosphere. Usu volcano is seriously damaged by the eruptions of 1977-1978 years and 2000 year and it made many craters around the mountain.The ecosystem around the crater has , seemingly, unique relations between pioneer-species which show facilitation or parasitic relations. Co-occuring plants in volcanic areas seem to be Carex oxyandra(Himethge) and polygonum sachalinense(Ooitadri) in Usu-mountain, Lalix Kaempferi(Karamatsu) and Salix Reinii(Mineyanagi) in Koma mountain, and Ledum palustre (Isotsutsugi) and salix reinii(Mineyanagi). In the nutrient-limited, especially nitorgen-poor region, mycorrizal haphae growth and seed germination rate can be improved through the exudates of host plant. Firstly, the nitrogen cycle and its route will be traced by the stable isotope tracer and the relation and contribution to the nitrogen cycle will be investigated among host plant/mycorriza/parasite plant.
From this winter, greenhouse experiment will be done in order to prelimilarily test the relations between Carex oxyandra(Himethge) and the seed of polygonum sachalinense(Ooitadri) and Lalix Kaempferi(Karamatsu) seedling/seed and Salix Reinii(Mineyanagi). Unfortunately, due to the limited number of samples, well-designed experiment is needed. I hope PE members' kind and invaluable comments.
Representative review references