Xylogenesis of compression and opposite wood in mountain pine at a Mediterranean treeline

Abstract

& Key message Comparisons between compression and opposite wood formation in prostrating Pinus mugo indicate that the secondary meristem can produce more tracheids with thicker walls by also increasing the number of contemporaneously differentiating cells, rather than only increasing the duration or the rate of cell formation. & Context Although cambium tissues within a stem experience the same climatic conditions, the resulting wood structure and properties can strongly differ. Assessing how meristem differently regulates wood formation to achieve different anatomical properties can help understanding the mechanisms of response and their plasticity. & Aims We monitored the formation of compression (CW) and opposite (OW) wood within the same stems to understand whether achieved differences in wood structure are caused by modifications in the process of cell formation. & Methods We collected weekly microcores of compression and opposite wood from the curved stem of ten treeline prostrating mountain pines (Pinus mugo Turra ssp. mugo) at the Majella massif in Central Italy. & Results Results indicate that cambium formed approximately 1.5 times more cells in CW than OW, despite that CW cell differentiation only extended 2 weeks longer and the residence time of CW cells in the wall-thickening phase was only 20% longer. Differences in their formation were thus mainly related to both the rates and the width of the enlarging and wall-thickening zones (i.e., the number of cells simultaneously under differentiation) and less to duration of cell formation. & Conclusion We conclude that to achieve such a different wood structures, the efficiency of the secondary meristem, in addition of altered rate of cell division and differentiation, can also modify the width of the developing zones. Thus, deciphering what rules this width is important to link environmental conditions with productivity.

Intra-annual dynamics of cambial and xylem phenology in subalpine conifers at Deogyusan National Park in the Republic of Korea

“…Several past studies reported that intra-annual xylem formation follows a sigmoid curve [32,33,36,37,48,49,53,62,73]. This intra-annual dynamics of wood-formation was confirmed as well in our study of coniferous tree species growing at a subalpine site in the Republic of Korea.…”

“…beginning and end of May (DOY 124-146) ( Table 2). Based on these observations, it was verified that A. koreana (three in five trees), P. koraiensis (one in five trees), and P. jezoensis (one in five trees) required at least 73 Table 2). The cambium cells are vulnerable meristematic tissues under cold condition [39].…”

Climate–growth relationships at the transition between Fagus sylvatica and Pinus mugo forest communities in a Mediterranean mountain

“…Nevertheless, at the highest elevation in PE, the positive correlation between RWI and maximum temperatures in October of the current and previous year would suggest that an elongation of the growing season may occur, with consequent increase in stem radial growth. Palombo et al (2018), at the tree line on the Majella Massif, observed that the growing season can be consistently longer compared with Alpine environment, lasting from May to October. Dolschak et al (2019), modeling the water balance of European beech stands, along a gradient of declining annual precipitation, observed that an increase in stand productivity, caused by longer assimilation periods under optimal conditions, could be counterbalanced by soil moisture deficit in the middle of summer.…”

“…The prostrate habit of mountain pine results in a dense and impenetrable cover mat over the whole area; the main difficulty was to distinguish individual stems from the branches. Mountain pine trees were cored close to the base of the trunk and on the cross-slope side of the trunk to avoid sampling on branches and compression wood (Palombo et al 2018). European beech trees were sampled at breast height (1.3 m).…”

Intra-Annual Wood Formation of Cryptomeria fortunei and Cunninghamia lanceolata in Humid Subtropical China

“…The two species (C. fortunei and C. lanceolata) included in this study started growing between March and April, while temperate and boreal conifer species started in April-May (Cuny et al, 2015;Rossi et al, 2016;Chen et al, 2019). Mediterranean species started between late March and early May (Camarero et al, 2010;Palombo et al, 2018;Antonucci et al, 2019). C. fortunei and C. lanceolata stopped growing from October to November (Camarero et al, 2010;Vieira et al, 2014;Antonucci et al, 2019).…”