Water uptake by black spruce seedlings from rooting media (solution, sand, peat) treated with inorganic and oxalated aluminum

Abstract

Experiments with solution cultures revealed that 1-yr-old black spruce (Picea mariana [Mill.]) seedlings growing in nutrient solutions experienced reductions in water uptake and moist plant weight when treated with water-soluble inorganic Al at the time of rapid shoot elongation. These reductions occurred with solution concentrations for Al at ≥ 16 mg L−1. Wilting was noticed with Al ≥ 8 mg L−1. In contrast, oxalated Al treatments had no visible effects on either water uptake or moist plant weight during shoot elongation. Later, near the time of budset, neither inorganic nor oxalated Al had an effect on moist plant weight or water uptake. This suggests that black spruce seedlings may or may not be susceptible to water-soluble inorganic Al depending on the degree of Al complexation afforded by the rooting medium, and by the plant roots at different times of the growing season. Water uptake was affected by the type of rooting medium in which the seedlings grew. For example, water uptake from peat was greater than water uptake from solution. Water uptake from sand was intermediate. Water uptake from solution-only cultures was probably affected by restricted O2 supply.