Germination of Chara vulgaris and Nitella flexilis oospores: What are the relevant factors triggering germination?

Experiment 3 compared the germination of C. vulgaris oospores from four ponds contaminated by mining wastes and from a comparatively clean wetland. The oospores were again subjected (or not) to cold pre-treatments, and were drawn from both freshly concentrated sediments and air-dried sediments that had been held in storage for either 97 or 376 days. Notably, a consistent reduction in oospore viability occurred in oospores from a particular mine pond, contaminated by nickel tailings.