New root growth of Douglas-fir seedlings at low carbon dioxide concentration.


New root growth of conifer nursery seedlings is dependent on light, but whether this is necessary only for photosynthesis, or also has some other root growth promoting effect is unknown. This question was investigated using one-year-old Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) seedlings grown at two nurseries from the same seed lot and taken from… (More)