Surface ornamentation of ascospores inEupenicillium species
The ascospores of 21 species ofEupenicillium were examined for surface ornamentation by means of the scanning electron microscope. Two groups of species could be distinguished: one with, and another without distinct equatorial ridges. The former group was further subdivided into four types according to wall ornamentation: reticulate, ribbed, spinulose, and smooth.Surface ornamentation details may come to range among the most important features to distinguish species that are hardly discernible otherwise.
Ascospores of some common species of Eurotium (Aspergillus glaucus) as shown by scanning electron microscopy
Micrographs of ascospores of Eurotium amstelodami, E. chevalieri, E. repens, E. rubrum and Aspergillus chevalieri var. intermedins taken with the scanning electron microscope and the phase-contrast light microscope are presented. The shape and surface ornamentation of the ascospores under the light microscope are currently the most important features used to distinguish these closely related fungi. The scanning electron microscope revealed certain features, such as pits or holes on the ascospores of E. chevalieri and protuberances on the ascospores of E. repens , too small to be resolved with the light microscope. It also revealed in much greater detail features, such as the roughness of the ascospore faces of E. chevalieri , that are just discernible with the light microscope.
Investigations on the rôle of organic matter in plant nutrition
1. As the result of decomposition of green manure in a swamp soil, the coarse fractions (including coarse and fine sand) of the surface layer (first 3 inches) decreased by 11·2 per cent. while the fine ones (silt+clay) increased by 9·8 per cent. in the course of 43 days. The effect was less pronounced in the manured soil maintained at 60 per cent. saturation, while no alteration was to be noticed in the case of the unmanured specimens. 2. Treatment with dilute hydrochloric acid prior to dispersion had no appreciable effect on the estimates of mechanical composition obtained in the different cases. Loss in solution was also comparatively small. 3. The silica-sesquioxide ratio increased slightly as the result of decomposition of green manure in swamp soil. The composition of the fine fractions was also altered, the total percentages of the oxides of iron, aluminium and silicon increasing from 90·5 to 99·3 in the course of 71 days. 4. The practical significance of the above and related observations has been discussed.