Why Winter Experiments on North American Wetland Plants Are Problematic

Seasonal Physiology

Bur-reed, cattail, and bulrush are temperate perennials. They enter dormancy in fall/winter: metabolic activity drops, nutrient uptake ceases, above-ground tissue dies back. Testing chromium absorption during dormancy yields meaningless low numbers.

Herbicide Analogy

Glyphosate (Roundup) only works on actively growing plants (spring/summer). In fall, plants translocate to roots, not shoots. Same principle: uptake and transport require active growth.

Recommendation

Conduct experiments during the active growing season (late spring to early fall). If using a growth chamber, simulate summer conditions (long photoperiod, warm temps) to keep plants physiologically active.