Permanent slides for morphological studies of small crustaceans: Serban’s method and its variation applied on Bathynellacea (Malacostraca)

Morphological studies of small invertebrates often involve the preparation of slides to observe minute body parts under a compound microscope. Preparation should facilitate observation, through traditional optical microscopy, of small surface structures on different planes, like pores, spines and setae. Various methods and techniques, using different mounting media that specialists have adopted to observe and preserve small crustaceans, have their advantages and disadvantages. Within the order Bathynellacea, specimens in the family Bathynellidae are particularly challenging due to their small size (0.5 to 2.25 mm body length) and very delicate exoskeleton, which tends to be completely digested when using common clearing mounting media, making future consultations impossible. Permanent slides are fundamental to preserve small specimens for scientific collections, because temporary slide preparations can easily result in the loss of body parts in the passage between slide and vial and vice versa. Dr Eugene Serban worked on Bathynellacea for more than 40 years, improving the preparation and preservation of delicate specimens using a stained glycerol-jelly and double cover slip mounting technique. His method is described here with a variation that speeds up the original procedure and was implemented in most recent years by one of the authors (A.I.C.). The technique provides excellent preservation and visualization of body parts on permanent slides, which do not need curation tasks and can last for many years.

Plant succession in a forest on the Lower Northeast Slope of Serra Geral, Rio Grande do Sul, and Holocene palaeoenvironments, Southern Brazil

The study of plant succession provides information on vegetation dynamics of a region and, therefore, improves our understanding of the natural trends of present ecosystems. With this objective, plant succession based on palynology of a sediment profile in a swamp forest was studied on the Lower Northeast Slope of Serra Geral, Rio Grande do Sul. Samples were treated with HCl, HF, KOH and acetolysis; slides were mounted in glycerol-jelly. For each sample a minimum of 500 grains of pollen + pteridophyte and bryophyte spores was counted and other palynomorphs were counted in parallel. Tilia and Tilia Graph software were used to construct percentage and concentration diagrams, with three 14C datings. The results show a local water reservoir in the beginning of the Holocene (± 9800 yrs. BP), creating a herbaceous plant marsh by hydrosere. The initial colonization of the marsh by trees occurred about 8800 yrs. BP, with tropical species from the Coastal Plain migrating in an east-west direction. Afterwards, there was a dry phase between 7000-5000 yrs. BP. The second appearance of regional tree species began at about 5000 yrs. BP, resulting in the present forest and in the west-east migration of tropical species from interior lowlands, like this one, to re-colonize the coast after the last marine regression.

Making and Using Aqueous Mounting Media, or Why Buy a Premixed Medium when it's Cheap and Easy to make your own?

Instructions are given as follows for making five aqueous mounting media: glycerol jelly, buffered glycerol with anti-fade, fructose syrup, Apathy's gum-syrup, and a polyvinylpyrrolidone medium whose composition can be varied to suit the user's needs, For each, hints are given on usage and the preservation of the coverslipped preparations. Media made in the laboratory are cheaper than commercial aqueous mountants, and do not contain any secret ingredients.

Apparent Male Fertility in Musa Germplasm

Current efforts to produce improved genotypes of plantain and banana (Musa spp.) depend on crossing female-fertile clones with accessions that produce viable pollen. Musa accessions (168) were screened for production of viable pollen based on staining with acetocarmine glycerol jelly. Diploid hybrids and landraces produced significantly more pollen than triploids and tetraploids, suggesting more successful crosses when using diploid accessions as male parents. There was a positive correlation between the amount of pollen produced and the level of viability in both hybrids (r = 0.65, P≤ 0.01) and landraces (r = 0.61, P≤ 0.01). This finding suggests that closely associated genetic factors determine these characteristics in Musa, while environmental conditions also may influence the quality and quantity of pollen produced. Pollen production at anthesis was absent in 28 accessions. Of the 140 accessions with pollen, 67 were sufficiently fertile for use as male parents in the breeding program.

Fibre length by electronic image analysis

A number of electronic image analysis techniques have been applied to preparations of glass fibres obtained from polymer based composites (PES and PPS matrix) in order to automate length measurements. The image analysis sequence developed is described in detail. The functions of the sequence are based mainly on aspects of filtering in the spatial domain by means of convolution, mathematical morphology and conditional measuring. The key image analysis function is directional erosion. Using glycerol jelly strew preparations and transmitted light, the length of 500 glass fibres can be automatically measured in approximately 15 minutes with an array processor-based image analysis system (IBAS 2). The image analysis method is tolerant of impurities and variations in fibre preparation density; the method produces consistent results and errors due to misinterpretation are negligible.