Trichomes, Cannabis and Light Microscopy

Cystolith hairs can be found in many plant families (Nakamura 1969; Mitosinka et al. 1972). Several plant genera have trichomes (hairs) such as: Humulus, Cannabis, Lantana, Lippia and Anchusca (Mitosinka et al. 1972). For this reason just the presence of cystolith hairs cannot be reliable enough for the identification of marijuana (Nakamura 1969; Mitosinka et al. 1972). Observing the morphological characteristics of Cannabis sativa L. may be important in the drug identification especially in incidences where other characteristics are insufficient (de Pasquale et al. 1974). Observing the morphology of marijuana can also be of great legal importance, because the observation of specific morphological features, such as cystolith, capitate glandular and covering trichomes can be of value (de Pasquale et al. 1974). Identification of Cannabis sativa L. through light microscopy depends on examining the presence of non-glandular and glandular hairs on the surface of the plant (Thornton and Nakamura 1972). The purpose of this study was to use trichomes as a reference for the identification of Cannabis sativa L. These references will be used to identify marijuana that is used for recreational, spiritual, medical and religious purposes. The objectives of the study were to identify the trichome types found on Cannabis sativa L. and measure these trichomes to differentiate them from other trichomes.
             Materials and Methods.
             Experimental Design and Protocol.
             The female specimens of Cannabis sativa L. were obtained from the Herbarium at the University of the Witwatersrand. A Zeiss stereo binocular microscope was used to observe the trichomes on the different plant parts. During every session the camera of the stereo binocular microscope was checked and secured on the microscope (Figure 1). After checking the camera the microscope and the light equipment were turned on, than the computer connected with the microscope software, called AxioVision Software, was switched on.