A Band Model of Cambium Development: Opportunities and Prospects

Eugene A Vaganov,Grigory K Zelenov,Vladimir V Shishov,Ivan I Tychkov,Kevin J Anchukaitis

doi:10.3390/f12101361

Eugene A Vaganov, Grigory K Zelenov + Show 3 more

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https://doi.org/10.3390/f12101361

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Abstract

More than 60% of tree phytomass is concentrated in stem wood, which is the result of periodic activity of the cambium. Nevertheless, there are few attempts to quantitatively describe cambium dynamics. In this study, we develop a state-of-the-art band model of cambium development, based on the kinetic heterogeneity of the cambial zone and the connectivity of the cell structure. The model describes seasonal cambium development based on an exponential function under climate forcing which can be effectively used to estimate the seasonal cell production for individual trees. It was shown that the model is able to simulate different cell production for fast-, middle- and slow-growing trees under the same climate forcing. Based on actual measurements of cell production for two contrasted trees, the model effectively reconstructed long-term cell production variability (up to 75% of explained variance) of both tree-ring characteristics over the period 1937−2012. The new model significantly simplifies the assessment of seasonal cell production for individual trees of a studied forest stand and allows the entire range of individual absolute variability in the ring formation of any tree in the stand to be quantified, which can lead to a better understanding of the anatomy of xylem formation, a key component of the carbon cycle.

Highlights

More than 60% of tree phytomass is concentrated in stem wood, which is the result of periodic activity of the lateral meristem, that is, the cambium [1,2]
In contrast to the kinetic model of cambium used in the traditional VSmodel [27], the new version does not require determination of the positions of new mother cells in the cambium relative to the initial cell, their number during the growing season, or their division rate based on complex calculations and a time-consuming estimation of the 12 cambial block parameters [39,43]
In the band model the entire process of seasonal functioning of the cambium is based on a simple exponential function which can be specified for any individual tree for the study stand

Summary

Introduction

More than 60% of tree phytomass is concentrated in stem wood, which is the result of periodic activity of the lateral meristem, that is, the cambium [1,2]. In the active phase of growth, does the number of cambial cells increase; there exist both initial cells and their derivatives in the cambial zone, namely the mother cells of phloem and xylem In this stage of growth, the cambial zone is the target of and responds to both internal (e.g., hormones, peptides) and external (e.g., climate, competition) factors, including stress-related factors [6,7]. Similar gradients have been identified for several cyclins, namely the hormones involved in the regulation of the individual cell cycle [18,19,20,21] Such gradients are believed to be linked to the differential expression of genes, which regulates the cell division process as well as wall-thickening, maturation, and the transition of cambial mother cells to an enlargement zone. They trigger the process of apoptosis and the formation of xylem cells as a basic component of water-conducting system of a tree stem [22,23]

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