plants-12-03594.pdf

Citation:Belousova,D.A.;Shishov,V.V.;Arzac,A.;Popkova,M.I.;Babushkina,E.A.;Huang,J.-G.;Yang,B.;Vaganov,E.A.VS-Cambium-Developer:A NewPredictive Model of CambiumFunctioning under the Influence ofEnvironmental Factors.Plants 2023,12,3594.https:/doi.org/10.3390/plants12203594Academic Editors:Chengliang Sunand Yiquan YeReceived:6 August 2023Revised:1 October 2023Accepted:6 October 2023Published:17 October 2023Copyright:2023 by the authors.Licensee MDPI,Basel,Switzerland.This article is an open access articledistributedunderthetermsandconditions of the Creative CommonsAttribution(CC BY)license(https:/creativecommons.org/licenses/by/4.0/).plantsArticleVS-Cambium-Developer:A New Predictive Model of CambiumFunctioning under the Influence of Environmental FactorsDaria A.Belousova1,*,Vladimir V.Shishov2,Alberto Arzac3,Margarita I.Popkova1,Elena A.Babushkina4,Jian-Guo Huang5,Bao Yang6and Eugene A.Vaganov31Research Department,Siberian Federal University,660041 Krasnoyarsk,Russia;2Institute of Fundamental Biology and Biotechnology,Siberian Federal University,660041 Krasnoyarsk,Russia;3Institute of Ecology and Geography,Siberian Federal University,660041 Krasnoyarsk,Russia;(A.A.);evaganovsfu-kras.ru(E.A.V.)4Khakass Technical Institute,Siberian Federal University,655017 Abakan,Russia;babushkina70mail.ru5College of Life Sciences,Zhejiang University,Hangzhou 310058,China;6School of Geography and Ocean Science,Nanjing University,Nanjing 210023,China;*Correspondence:Abstract:Climate changes influence seasonal tree-ring formation.The result is a specific cell structuredependent on internal processes and external environmental factors.One way to investigate andanalyze these relationships is to apply diverse simulation models of tree-ring growth.Here,we haveproposed a new version of the VS-Cambium-Developer model(VS-CD model),which simulates thecambial activity process in conifers.The VS-CD model does not require the manual year-to-yearcalibration of parameters over a long-term cell production reconstruction or forecast.Instead,itestimates cell production and simulates the dynamics of radial cell development within the growingseasons.Thus,a new software based on R programming technology,able to efficiently adapt to theVS model online platform,has been developed.The model was tested on indirect observations of thecambium functioning in Larix sibirica trees from southern Siberia,namely on the measured annualcell production from 1963 to 2011.The VS-CD model proves to simulate cell production accurately.The results highlighted the efficiency of the presented model and contributed to filling the gap inthe simulations of cambial activity,which is critical to predicting the potential impacts of changingenvironmental conditions on tree growth.Keywords:cambial activity;cell differentiation;VaganovShashkin model;climatic factors;Larixsibirica1.IntroductionAnnual rings on tree stems,roots and branches result from the cambial activity duringthevegetationperiod(orgrowingseason)indifferentclimateconditions1,2.Thecambiumis a thin layer of small,thin-walled cells between the xylem and phloem,capable ofmultiple divisions 3.Thus,the cells produced within a growing season by the divisionof the cambium form a tree ring 35.Seasonal tree-ring formation involves interrelatedprocesses at different levels:cell division,enlargement and differentiation,controlledby hormonal balance,whereas nutrient availability,cell growth and cell wall formationdepend on internal biochemical processes 3,6,7,directly influenced by external climaticfactors 810.In conifers,the result of these processes leads to a specific cell structure within thering,from wide and thin-walled earlywood cells to narrow and thick-walled latewoodcells,oriented toward different functions(Figure 1)and influenced by the environmentduring their formation over the growing season 11,12.Individual tracheids constituteup to 95%of the xylem in conifers 13,derived from the corresponding cambial zone andPlants 2023,12,3594.https:/doi.org/10.3390/plants12203594https:/ 2023,12,35942 of 16consisting of a single initial and several mother cells 14.The production of mother cells inthe xylem significantly exceeds that of the phloem(up to ten times)2.Therefore,it can beassumed that the number of xylem mother cells is significantly higher than the number ofphloem cells.Plants2023,12,xFORPEERREVIEW2 of 17duringtheirformationoverthegrowingseason11,12.Individualtracheidsconstituteupto95%ofthexyleminconifers13,derivedfromthecorrespondingcambialzoneandconsistingofasingleinitialandseveralmothercells14.Theproductionofmothercellsinthexylemsignificantlyexceedsthatofthephloem(uptotentimes)2.Therefore,itcanbeassumedthatthenumberofxylemmothercellsissignificantlyhigherthanthenumberofphloemcells.Figure1.LarixsibiricathinsectionfromsouthernSiberiashowingdifferentcellphases.Maturedcells(MC),cellwallthickeningphase(WTC),cellsintheenlargingzone(EZ),cellsinthecambialzone(CZ),phloemcells(P).Earlywood/latewoodborderisshowninyellow.