Tagged: Norway spruce

Example of a tree ring split into ten sectors (A) and representation of the anatomical features measured on each single tracheid (B).

Tree-ring anatomy reveals climatic influence on xylem morphogenesis

During the growing season, the cambium of conifer trees produces successive rows of xylem cells, known as tracheids. Current knowledge on this process mainly stems from xylogenesis monitoring spanning a few years. In this investigation of the effects of long-term inter-annual climate variability on tracheid formation and wall thickening, Castagneri et al. retrospectively study tree-ring xylem anatomy in Picea abies along an altitudinal gradient in the Alps. Climate fluctuations are shown to influence morphogenesis of tracheids sequentially formed in the growing season over successive periods. Morphogenetic mechanisms responsible for different tracheid traits are affected by climate to differing degrees according...

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Temperature responses of photosynthesis under elevated CO2

Plants growing under elevated atmospheric CO2 concentrations often have reduced stomatal conductance and subsequently increased leaf temperature. Šigut et al. find that this is indeed the case for broadleaved Fagus sylvatica and coniferous Picea abies saplings growing under elevated CO2, but that the higher leaf temperatures do not lead to an increased heat stress tolerance of primary photochemical reactions. The increases in temperature optima of photosynthetic CO2 uptake observed under elevated CO2 are instantaneous and are caused by reduced photorespiration and limitation of photosynthesis by RuBP regeneration. However, the increases disappear when plants are exposed to identical CO2 concentrations. The...

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