Analysis of Some Parameters of the Photosynthetic Activity of Norway Spruce (Picea abies (L.) Karst.)

1991

S. 109-116

2 Abb., 2 Tab., 25 Lit. Ang.

Unselbständiges Werk

200062085

Lesnictvi 1991 ; 37(2), S. 109-116

Differentiated conditions of the distribution of photosynthetically active radiation (PAR) in tree crown layer are a reason of the functional stratification of photosynthetic produce. The parameters of photosynthetic activity are markedly differentiated in vertical direction. This vertical differentiation is reflected not only in the absolute values of some characteristics (e.g. photosynthesis rate), but also in different performance and adaptation of individual sequences of reactions which are part of photosynthesis. The highest photosynthetic activity is concentrated in the upper layers of tree crowns. This photosynthetic activity is a result of the effectiveness of needle carboxylation apparatus. Perfect adaptation to shadow, which is markedly characteristic of the needles of the lower layer of tree crowns, underlies the sufficient utilization of PAR of very low intensities. But the processes of carbon dioxide fixation are less efficient than those in the upper layers of tree crowns. The vertical topography of photosynthetic activity inside the tree crowns of Norway spruce demonstrates different nature of the adaptation of photochemical and biochemical components of photosynthesis to the radiation conditions in the tree crown.