Cytological Studies of Some Members of the Family Saprolegniaceae. I
The vacuome
1950 年 16 巻 1 号 p. 72-83
詳細
1950 年 16 巻 1 号 p. 72-83
The origin and development of the vacuolar system and the effect of hydrogen-ion concentration on the accumulation of neutral red in the vacuoles of the vegetative mycelium of Achlya sp., Brevilegnia gracilis, Isoachlya anisospora var. indica and Saprolegnia monoica has been studied.
The vacuoles, which are small rounded or oval shaped at the tips of the hyphae, and the vacuolar canal are seen to be composed of a colourless homogeneous solution and appear optically empty under the ultramicroscope.
The vacuolar system becomes more clear with vital dyes. The vacuoles are seen arising de novo at the tips of young hyphae. These small vacuoles fuse to form a network or a chain of round or ellipsoidal vacuoles which in turn fuse again to give rise to a continuous vacuolar canal. At times the vacuolar canal of a parent hypha is seen passing into the daughter hyphae. No metachromatic corpuscles are found in the hyphae of the fungi studied.
When grown in peptone solution with neutral red, numerous vacuolar precipitates, pre-existing corpuscles and sphaerocrystals are seen in the vacuolar canal. The colour and the vacuolar precipitates in the vacuolar canal are retained for a longer time in the hyphae grown on a poor medium. Rapid growth on a rich medium causes the excretion of the dye.
Neutral red accumulates in the vacuoles at pH values between 6 and 8.5. In the case of Brevilegnia gracilis it accumulates at pH between 6 and 8 only.
In conclusion I wish to express my warmest gratitude to Dr. R. K. Saksena for his kind guidance and encouragement throughout the course of the study. I am grateful to Professor S. R. Bose for his help in many ways and to Dr. F. M. L. Sheffield for kindly going through the manuscript.
