Physiological differences in Rhododendron calophytum seedlings regenerated in mineral soil or on fallen dead wood of different decaying stages

Regeneration substrates may differ in water and nutrient availability, and that may lead to differences in physiological traits among seedlings. This assumption was tested by investigating the effects of different regeneration substrates (fallen dead wood and soil) on physiological traits in seedlings of Rhododendron calophytum Franch. in a subalpine conifer forest, southwest China. The seedlings were divided into three groups according to their regeneration substrates: moderately decayed dead wood (DWm); severely decayed dead wood (DWs) and soil (S). The results showed that there were significant differences in leaf mass per area (LMA), photosynthetic capacity, non-structural carbohydrate composition (NSC), leaf phosphorus (P) concentration, carbon isotope composition (δ¹³C) and ultrastructural morphology, not only between the seedlings regenerated in soil and on dead wood, but also between the seedlings regenerated on dead wood of different decaying stages. Overall, the photosynthetic capacity of the seedlings increased in the order of DWm