The rate of protein synthesis in needles of Norway spruce (Picea abies): Light stimulation, regulation through photophosphorylation, stress enhancement

Abstract

The incorporation of 14C‐leucine into the total‐protein fraction of needles of Norway spruce (Picea abies [L.] Karst.) during short time incubation was used as a measure of protein synthesis in the light and in the dark. Light saturation curves, obtained for needles of different ages (new flush and 1 and 2 years old) or at different seasons (summer‐winter) followed the Michaelis‐Menten algorithm, exhibiting marked differences with regard to light saturation (Vmax) and the half‐saturation constant (K5. 2). The light saturation curves of ATP level (mg g−1 fresh weight) and of leucine incorporation into protein (nmol mg−1 h−1) matched each other, suggesting that photophosphorylation may be decisive for the rate of protein synthesis in the light. This is confirmed by the action spectrum of leucine incorporation. which resembled an action spectrum of leaf photosynthesis, and also by partial inhibition of protein synthesis by 3‐(3,4‐dichlorophenyl)‐1,1‐dimethylurea (DCMU), an inhibitor of non‐cyclic photophosphorylation. Light stimulated protein synthesis showed pronounced seasonal fluctuations with a summer maximum. Furmigation of 5 years old spruce trees for 3 months with SO2 in combination with O3 and/or NO2 caused a distinct enhancement of the protein synthesis rate in the light and, at a reduced absolute level, also in the dark. A similar result was obtained for 40 to 70 years old spruce stands when healthy and sick trees were compared: the latter being afflicted by the novel type of forest decline, which is characterized by yellowish bronze discolouration of sun‐exposed older needles and partial loss of older needle generations (3 to 4 years old). The 1 year old needles of the unhealthy trees showed a markedly increased 14C‐leucine incorporation rate which, in the dark, was even more pronounced than in the light. Stress‐physiological mechanisms, which could possibly explain this stimulation, are discussed.

Significance of Ozone Exposure for Inter‐Annual Differences in Primary Metabolites of Old‐Growth Beech (Fagus sylvatica L.) and Norway Spruce (Picea abies L.) Trees in a Mixed Forest Stand

“…Additionally, cell wall glycoproteins are enhanced under ozone fumigation in beech, spruce, and pine saplings (Schneiderbauer et al, 1995). Stimulation of protein synthesis as a consequence of stress was also observed in adult spruce trees (Schmitz et al, 1993). These data suggest that an additional synthesis of non-structural proteins, to which defence proteins may have contributed, as a consequence of elevated ozone, was strengthened in spruce but not in old-growth beech trees in the present study.…”

“…Contents of NSP were mostly reduced, whilst total soluble amino compounds increased in shade compared to sun leaves of beech trees. Light stimulates protein synthesis and photophosphorylation is assumed to play an important role for the rate of protein synthesis in Picea abies trees (Schmitz et al, 1993). Eichelmann et al (2005) also showed a decrease in soluble proteins in shade compared to sun leaves of Betula pendula and Tilia cordata and a relative content of Rubisco in soluble protein of about 35 %, with lower contents in shade compared to sun leaves.…”

Photoinactivation of catalase in needles of Norway spruce

“…The catalase activity was high during the night and low during the day. !t seems that the changes in catalase activity are due to changes in photoinaetivation and in the synthesis of catalase, Prolein synthesis in spruce needles is stimulated by lighl (Schmitz et al, 1993), In other plants catalase synthesis was higher during the day than during the night (Redinbaugh et al, 1990, Henwig et al 1992, When spruce needles are exposed to direct sunlighl in the morning the catalase activity probably decreases because in direct sunlight photoinaetivation of catalase is higher than resynthesis. When the needles are shaded between noon and sunset the catalase activity slowly increases because catalase synthesis seems to be slightly higher than its photoinaetivation.…”

Total soluble proteins amount in vegetative buds and needles of norway spruce during the bursting time

“…In early spring, multiplied mitotic activity in embryonic shoot caused the significant enlargement of young shoot (Cesar andBornman 1996, Cesar et al 1997) not followed with equally fast protein synthesis what resulted in decrease of the protein content. New flush was suddenly exposed on light conditions and protein synthesis increased (Schmitz et al 1993). Senser et al (1975) demonstrated that the development of thylakoid system in needle plastids is taking place few weeks after the bud break being complete a month later.…”