Calcium Uptake, Partitioning, and Sinuous Growth in Douglas-Fir Seedlings
Sinuosity is a growth deformation affecting Douglas-fir [Pseudotsuga menziesii (Mirb.) Franco] and other conifers. Ca, an essential nutrient in tree growth and cell development, may be deficient in these stands and could be causing sinuous growth. An experiment was conducted to test whether low Ca availability causes sinuous growth in Douglas-fir seedlings. Douglas-fir 1 + 1 seedlings were grown in a greenhouse with high to low Ca availability. After 6 months of growth, the seedlings were measured for sinuosity and separated into new-needles, new-stem, old-needles, old-stem, and roots. High Ca fertilized seedlings had greater new-needle biomass and growth than low Ca fertilized seedlings. High Ca availability also led to higher Ca concentration and content, including higher foliar membrane-associated Ca, Ca-pectate, and Ca-oxalate than low Ca seedlings. Low Ca availability had no significant effect on sinuosity. Although high Ca availability did not alleviate sinuous growth in Douglas-fir seedlings, it did lead to higher growth, foliar biomass, and membrane-associated Ca.