| Popis: |
Reproductive and vegetative characteristics of raspberry and blueberry plants were monitored at six sites downwind from a phosphorus plant which emitted gaseous and particulate fluorides. Atmospheric fluoridation rates ranged from an average of 347.4 μg F∙dm−2∙week−1 (or 11.38 μg F∙m−1) at 1.4 km to 2.5 μg F∙dm−2∙week−1 (or 0.08 μg F∙m−3) at 18.7 km from the source. The highest fluoridation levels were in July, the month in which flowering in the two species reached its peak. At the most polluted site, flower mortality was 89% for blueberry and 78% for raspberry; this accounted for most of the loss in reproductive potential. Comparative values of the control site (18.7 km from source) were 27 and 26%, respectively. There were 21- and 10-fold decreases in seed production per plant in blueberry and raspberry, respectively, as well as significant decreases in the size, number, and dry weight of fruit. Fluoride damage to blueberry plants did not result in any effects being passed on to seedlings, except for a slightly accelerated germination rate. Fluoride accumulations in the foliage of plants 1.4 km from the source were 403 ppm for raspberry and 216 ppm for blueberry but only 8 and 9 ppm, respectively, at the control site. Fluoride-affected raspberry plants also showed foliar injury, enhanced vegetative spread, and delayed leaf fall in the autumn. |
