The influence of soil temperature and water content on belowground hydraulic conductance and leaf gas exchange in mature trees of three boreal species
| Autor: | Roderick C. Dewar, Teemu Paljakka, Anna Lintunen, Anu Riikonen, Yann Salmon, Teemu Hölttä |
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| Přispěvatelé: | INAR Physics, Ecosystem processes (INAR Forest Sciences), Forest Ecology and Management, Institute for Atmospheric and Earth System Research (INAR), Department of Forest Sciences, Micrometeorology and biogeochemical cycles, Viikki Plant Science Centre (ViPS) |
| Jazyk: | angličtina |
| Rok vydání: | 2020 |
| Předmět: |
0106 biological sciences
0301 basic medicine Time Factors Physiology belowground hydraulic conductance Plant Science Alnus 01 natural sciences STEM DIAMETER VARIATIONS MECHANICAL ANALYSIS Soil ASPEN POPULUS-TREMULOIDES LOW ROOT TEMPERATURE Tilia Water content 4112 Forestry Plant Stems biology Temperature Vegetation Canopy conductance Gases ENGELMANN SPRUCE Stomatal conductance STOMATAL CONDUCTANCE TRUNK SHRINKAGE Models Biological 03 medical and health sciences Species Specificity sap flow Xylem SCOTS PINE stomatal control Scots pine Water 15. Life on land Pinus biology.organism_classification 11831 Plant biology cold Plant Leaves 030104 developmental biology Agronomy Boreal Soil water point dendrometer Environmental science water relations 010606 plant biology & botany PLANT WATER |
| Popis: | Understanding stomatal regulation is fundamental to predicting the impact of changing environmental conditions on vegetation. However, the influence of soil temperature (ST) and soil water content (SWC) on canopy conductance (g(s)) through changes in belowground hydraulic conductance (k(bg)) remains poorly understood, because k(bg) has seldom been measured in field conditions. Our aim was to (a) examine the dependence of k(bg) on ST and SWC, (b) examine the dependence of g(s) on k(bg) and (c) test a recent stomatal optimization model according to which g(s) and soil-to-leaf hydraulic conductance are strongly coupled. We estimated k(bg) from continuous sap flow and xylem diameter measurements in three boreal species. k(bg) increased strongly with increasing ST when ST was below +8 degrees C, and typically increased with increasing SWC when ST was not limiting. g(s) was correlated with k(bg) in all three species, and modelled and measured g(s) were well correlated in Pinus sylvestris (a model comparison was only possible for this species). These results imply an important role for k(bg) in mediating linkages between the soil environment and leaf gas exchange. In particular, our finding that ST strongly influences k(bg) in mature trees may help us to better understand tree behaviour in cold environments. |
| Databáze: | OpenAIRE |
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