On the culture behaviour of a species ofRosellinia

Summary

The present paper deals mainly with the effect of various chemicals (asparagin, KNO₃, acid, alkali and C/N ratio) on the production of perithecia in a species ofRosellinia and supplements the results given in a previous paper (Das Gupta, 1937). The stimulating effect of a bacterium on the formation of perithecia is briefly dealt with.

The following are the main points:—

Thenumber of perithicia formed in a medium decreases with the increase in the concentration of asparagin, potassium nitrate, acid and alkali. In simple agar medium the higher agar concentration the greater the number of perithecia formed. Innumerable perithecia appear in media combining relatively high content of potassium nitrate with moderate amount of glucose.

Thesize of the perithecia is only slightly reduced in media combining relatively high concentration of asparagin and potassium nitrate with low concentrations of glucose. The size is greatly reduced in the media where KNO₃ content and glucose content are both relatively high.

Addition of glucose in a medium having relatively high KNO₃ content has adeleterious effect on the production of asci and ascospores.

Development of perithecia is inhibited much before the vegetative growth of the fungus is retarted due to high concentrations of chemicals except in the cases of the acid and alkali series where the perithecia develop as long as vegetative growth is not totally checked.

Regional distribution of perithecia in different modified media is briefly dealt with.