Letâs look at ferns as an example of alternation of generations. The fern plants you see out in the woods, or in a garden, or by a river are sporophytes. They produce spores. If you turn over a fern frond (thatâs just a fancy word for leaf), sometimes youâll see little circles all over the underside of the leaf.
Tricyclic Antidepressant (TCA) Overdose. California Poison Control 1-800-876-4766. Pediatric considerations. Low toxicity threshold of TCAs. Therapeutic doses range from 2-4 mg/kg/d. Toxicity is observed at doses of 10-20 mg/kg. Ingestion of only two 50-mg tablets in a 10-kg toddler can be sufficient. to produce symptoms of toxicity.
The toxicity of substances can be observed by (a) studying the accidental exposures to a substance (b) in vitro studies using cells/ cell lines (c) in vivo exposure on experimental animals. Chemical toxicants include inorganic substances such as, lead, mercury, hydrofluoric acid, and chlorine gas, and organic compounds such as methyl alcohol, most medications, and poisons from living things.