Standards of Learning (SOL) & Testing

Cooke (1976) studied the effect of fluoride (200 mg/litre) on common sunflower () seeds grown in sand culture. No effect on total dry weight was observed; however, there were significant reductions in leaf growth. Keller (1980) grew Norway spruce () cuttings in sand and watered with 100 mg fluoride/litre during winter until bud break. Watering with sodium fluoride significantly depressed the carbon dioxide uptake of shoots. Although the previous year’s needles did not show signs of injury, most of the new needles were killed immediately after flushing with fluoride. Exposure to fluoride significantly increased the susceptibility of plants to sulfur dioxide in subsequent fumigation experiments. Zwiazek & Shay (1987) grew jack pine () seedlings in sand culture at 3 or 15 mg fluoride/kg dry weight. Wilting was the first sign of fluoride injury and occurred in approximately 50% of plants after 25–26 h at 15 mg fluoride/kg and 2–6 h later in only 7% of plants exposed to 3 mg/kg. Fluoride-induced injuries to mesophyll and guard cells were similar to those caused by drought and included the appearance of lipid material in the cytoplasm during early stages of injury, suggesting cell membrane damage. Plants exposed to 3 mg/kg for up to 168 h showed significant reductions in water content. Respiration was significantly reduced after 24 h, but not after longer exposure times, while photosynthetic oxygen release was significantly reduced at 48 and 91 h but had recovered after 168 h (Zwiazek & Shay, 1988a). Zwiazek & Shay (1988b) reported that 3 mg fluoride/kg significantly reduced growth (as measured by fresh weight) and acid phosphatase activity and increased total organic acid content of jack pine () seedlings.

b) functions and processes of cells, tissues, organs, and systems (respiration, removal of wastes, growth, reproduction, digestion, and cellular transport).

Environmental Health Criteria 227

At the cellular level, copper inhibits a large number of enzymes and interferes with several aspects of plant biochemistry (including photosynthesis, pigment synthesis and membrane integrity) and physiology (including interference with fatty acids, protein metabolism and inhibition of respiration and nitrogen fixation processes).

LS.6 The student will investigate and understand the basic physical and chemical processes of photosynthesis and its importance to plant and animal life. Key concepts include

Copper (EHC 200, 1998) - INCHEM

They found that none of the physiological processes that were tested (cell viability, net photosynthesis, intracellular potassium and dimethylsulfoniopropionate content) were affected by the highest exposure concentration with the tolerant isolate.

Thus copper is present in enzymes involved in cellular respiration, free radical defence, neurotransmitter function, connective tissue biosynthesis and cellular iron metabolism.