BioImages: The Virtual Field-Guide (UK)

PLANTAE (plants)

Lab. techniques

Nail Varnish peels for surface microsculpture

Nail varnish peels provide a method of studying the surface structure of glabrous or sparsely haired leaves, often without damaging the plant. The method can also be applied to stems, petals, sepals, bud or cone scales or bark etc where these are large enough, although thin petals tend to shrivel. It could perhaps also be used for cut surfaces of wood, so long as these are first shaved smooth with a sharp knife.

Thick leaves like Ivy appear to suffer no ill effects, but thinner leaves like Wood Sorrel and most petals are killed by the nail varnish solvents.

Equipment: clear nail varnish, fine forceps, microscope slides, compound microscope.

Paint a thin patch of transparent nail varnish onto the surface to be studied. Leave to dry and peel off. Don't be tempted to apply a second coat as this just pevents it lying flat on the slide. Place on a microscope slide (shiny side down) and run a drop of water under the film to hold it flat against the slide. Examine under the microscope at magnification of x40 to x400. The shapes of epidermal cells, stomata and any surface sculpture are clearly visible.

The patch should be about 10mm diam, but, with practice, smaller patches can be used if the plant part is small. For standardisation, leaf patches should be applied at a point between half and two-thirds of the distance from the end of the petiole to the leaf apex. They should start at the midrib and cover part of the adjacent lamina. But try patches elsewhere to compare morphology. Use a mature leaf, but again, compare younger and senescent leaves.

The upper and undersides of leaves are often different and should both be sampled. Be careful to distinguish the two peels. (If in doubt, the lower surface often has more stomata.)

Ideally the varnish should be applied to living material in the field. The peels should be placed in separate labelled tubes or packets. Alternatively, wait until the varnish is at least half-dry then detach the leaf and take it home. Drying is quite quick in warm weather, but at lower temperatures it may be necessary to leave the film for several hours or over night. Sometimes the peel develops a "snake-skin" appearance due to the formation of tiny pits on the outer surface as it dries. This may be due to condensation but has not been investigated. Take care to ignore such artefacts when interpreting films.

When studying picked plant material, the varnish should be applied before wilting to avoid shrinkage or changes of shape due to loss of turgor.

Leaf microstructure is often assymmetrical. Try to keep track of the orientation of the peel, although this can sometimes be inferred from the veination.

Thin peels adhere well to the slide (van der Waals forces) and are reasonably tough. Each peel can be anchored with a small piece of exhibition tape for additional security. For long term storage slides should be labelled and need little more than wrapping in aluminium foil for protection, with the name repeated on the foil.

Records (and photo sets)

Taxon	Summary	Date	Vice-county	Country
Plantae?		14 June 2007	West Cornwall	England	5

Subtaxa

Rank	Taxon
Subkingdom	BRYOPHYTA (mosses and Liverworts)	213	952	506	570	28	172
Subkingdom	CHLOROPHYTA (green algae)	65	47	146	255	14
Subkingdom	PTERIDOPHYTA (ferns and allies)	62	329	145	90	45	129
Phylum	RHODOPHYTA (red algae)	8	40	31	17	6
Subkingdom	SPERMATOPHYTA (vascular plants)	2624	8356	4493	474	418	21417

Suggested Literature

Identification Works

Petraco, N. & Kubic, T., 2003

Color Atlas and Manual of Microscopy for Criminalists, Chemists, and Conservators

General Works

Plant Ecology	Journal
Royal Botanic Gardens, Kew - RBG(K): http://www.rbgkew.org.uk/	Web Site/Page
Coyle, H.M., 2004	Forensic Botany: Principles and Applications to Criminal Casework
Flora of Berkshire (web site): http://www3.imperial.ac.uk/lifesciences/research/floraberkshire	Web Site/Page
Crawley, M., 2005	The Flora of Berkshire
DEFRA Plant Health - Pests and Diseases: http://www.defra.gov.uk/planth/pests.htm	Web Site/Page
Leake, J.R., 2005	Plants parasitic on fungi: unearthing the fungi in myco-heterotrophs and debunking the "saprophytic" plant myth
Rich, T., 2003	Global strategy for plant conservation: targets to be achieved by 2010
Notes from the Royal Botanic Garden, Edinburgh	Journal
Kew Bulletin	Journal
Botanical Dermatology Database (BoDD) (Allergens)	Web Site/Page

PLANTAE may also be covered by literature listed under:

BIOTA
(living things)

Eukaryota
(eukaryotes)