Seasonal changes of Rubisco content and activity in Fagus sylvatica and Picea abies affected by elevated CO2 concentration

Abstract

We studied Rubisco (ribulose-1,5-bisphosphate carboxylase/oxygenase) content and activity in juvenile tree species — broadleaved Fagus sylvatica L. and coniferous Picea abies (L.) Karsten exposed for three growing seasons to ambient (A = 385 μmol mol−1) and elevated (E = 700 μmol mol−1) CO2 concentrations. Rubisco content was determined by the SDS-PAGE method, Rubisco activity was assayed spectrophotometrically. The highest content of Rubisco enzyme in F. sylvatica was measured immediately after full leaf development followed by a gradual decrease throughout the growing season. By contrast, Rubisco content in P. abies increased markedly during the growing season. In both tree species, down-regulation of Rubisco content in trees cultivated under elevated CO2 concentration was observed. Rubisco activity was stimulated in F. sylvatica by E treatment but not in P. abies. Because no significant differences were found in Rubisco activation state between A and E, we assume that stimulation of Rubisco activity in E is not a consequence of higher carbamylation but could be caused by the release of inhibitors from active sites of Rubisco under elevated CO2.

Modulation of plant functional traits under essential plant nutrients during seasonal regime in natural forests of Garhwal Himalayas

“…Moreover, water transportation through xylem during this season was high, due to this it exerts turgor pressure on the stomatal guard cell resulting in the opening of stomata thereby leading to a higher rate of transpiration and carbon assimilation in the plant system (Wang et al 2008). The rainy season distresses the plant metabolism resulting in increased Rubisco activity and the rate of electron transport in the plant system thus increasing all physiological characteristics of a plant in this season (Hrstka et al 2012). However, these traits were declined in summer, and winter season in all forest land uses which might be due to the limited water availability.…”

Optimization of Terrestrial Ecosystem Model Parameters Using Atmospheric CO2 Concentration Data With the Global Carbon Assimilation System (GCAS)

“…Growth/senescence of leaf area and increase/decrease in leaf photosynthetic capacity occur simultaneously in the yearly cycle, leading to the similar seasonal variation patterns between LAI and optimized for midlatitude and high‐latitude plant functional types. This broad pattern of synchronicity between LAI and could be partly explained by the allocations of leaf nitrogen to Rubisco (Hrstka, Urban, & Babák, ; Wilson et al, ) and leaf chlorophyll pigments (Croft et al, ) that increase most rapidly in growing leaves or decrease rapidly in senescing leaves. So far there have been limited reports on the seasonal variations of leaf chlorophyll content and .…”