|Budget Amount *help
¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 1993: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 1992: ¥1,400,000 (Direct Cost: ¥1,400,000)
In the symbiotic culture of Spiranthes sinensis with its mycorrhizal symbionts, the suitability of nitrogen sources was compared. Alubumin was far superior nitrogen source to inorganic nitrogen. Among 24 amino acids tested, however, arginine was only suitable one at this nitrogen level, and all the others were less suitable or harnful although they varies in their degree. The threshold levels of nitrogen over which detrimental effects appear were far lower at gluten than at powdered sereal grains, e.g. oats or wheats.
The relation between the occurrence of the disorder such as browning of shoot tips and death of protocorms ans nitrogen content in protocorms or in fungal mycelia was investigated. The response of protocorms to gluten levels varied according to fungi : the fresh weight of protocorms with a fungus decreased remarkably with an increase of gluten level, whereas that with another fungus was not much affected at this nitrogen level. Of those decreased in the fresh weight of protocorms, suffered severer disorder, and the nitrogen concentration of the them was increased in protocorms and decreased in fungal body.
In the case of healthy protocorms, the infected area in a protocorm balanced occupying less than a lower half of a protocorm section, thus symbiosis was sustained and elongation of shoot and root rapidly proceeded. In the case of those suffered disorder, infected area increased rapidly and ultimately occupied almost whole protocorm resulting in the death of the protocorm. These observation suggested that this disorder was the result of change from symbiosis to parasitism.