Materials and methods - Practical microtechnique

Materials and methods

Any readily available plant can be used to teach or learn plant anatomy. Over the years a rather small number of species have become ‘approved’ as ‘standard’ plants for study. This has had an incredibly stultifying effect on the study of plant anatomy generally, with the result that many biology teachers have forgotten that there are many plants that can be used for study in the classroom. Indeed, many university botany departments, adhere to a generalized ‘standard plant list’ in teaching plant structure as well. The plants chosen are in many cases thought of as ‘typical’, but often they are quite atypical. Many botanists go through their lives thinking that Zeamaize is a typical monocotyledon, but grasses in general are very specializedand represent a very restricted view of monocotyledons as a whole. We fre-quently adhere to peas, lettuce, maize and sunflower, barley, tobacco and beet in our physiological work, because botanists are often unaware that other plants, which can be grown with equal ease, are more varied and in-teresting in their structure. Scanning the literature will demonstrate just how often a species has been used.

Material is best if collected fresh. It can be examined fresh for cell con-tents, cytoplasmic movement and so forth. But when studies involve cell structure and histology, it is better to fix the fresh material by chemical means. Fixatives, when correctly formulated, will kill the plant material, preserve its general shape and size, and render the tissues suitable for sec-tioning and, depending on their potency, preserve the cellular detail. Dried herbarium material can be used for anatomical studies. Some plants revive easily, but others are unsatisfactory. If there is no fresh material available, then dried material can be fixed after boiling in water for about 15 minutes and after this allowing the material to cool. A few drops of detergent may be added to aid wetting the specimens.