Differences of leaf dark respiration and light inhibition between saplings and mature trees of Pinus koraiensis and Tilia amurensis.

Abstract

Leaf dark respiration is an important component of carbon cycle. Understanding the differences of leaf dark respiration and light inhibition between saplings and mature trees is important for accurate estimation of ecosystem gross primary productivity (GPP). We meansured leaf dark respiration of saplings and mature trees of two dominant species (Pinus koraiensis and Tilia amurensis) in light and in darkness in the broadleaved-Korean pine mixed forest on Changbai Mountain. Differences of leaf dark respiration, light inhibition and leaf physiological and ecological parameters between saplings and mature trees were analyzed. The reason of differences on leaf dark respiration and the light inhibition were explored. The results showed that leaf dark respiration of saplings of two species under light was 6.8%-39.6% higher than that of mature trees in growing season. Light inhibition of leaf dark respiration in saplings was 2.5%-14.1% lower than in mature trees. The difference of light inhibition of leaf dark respiration between saplings and mature trees of P. koraiensis was higher than that of T. amurensis, with a maximum difference of 18.6%. The higher leaf dark respiration and lower light inhibition degree in saplings might result from the changes of max net photosynthesis rate, specific leaf area, and stomatal conductance, instead of leaf nitrogen content.