scholarly journals Deciduous and evergreen oaks show contrasting adaptive responses in leaf mass per area across environments

2020 ◽  
Author(s):  
Domingo Sancho‐Knapik ◽  
Alfonso Escudero ◽  
Sonia Mediavilla ◽  
Christine Scoffoni ◽  
Joseph Zailaa ◽  
...  
Keyword(s):  
Leaf Mass Per Area ◽  
Adaptive Responses ◽  
Leaf Mass ◽  
Evergreen Oaks

Photosynthesis and physiological traits of evergreen broadleafed saplings during winter under different light environments in a temperate forest

2006 ◽  
Vol 84 (1) ◽  
pp. 60-69 ◽  
Author(s):  
Yoshiyuki Miyazawa ◽  
Kihachiro Kikuzawa
Keyword(s):  
Temperate Forest ◽  
Light Availability ◽  
Net Photosynthesis ◽  
Carbon Gain ◽  
Leaf Mass Per Area ◽  
Camellia Japonica ◽  
Leaf Mass ◽  
Unit Leaf ◽  
Canopy Trees ◽  
Photosynthetic Traits

Photosynthetic traits of the evergreen broadleafed species Camellia japonica L. and Quercus glauca Thunb. were continuously investigated during autumn and winter using saplings that grew in different light environments (gap, deciduous canopy understory, and evergreen canopy understory) in a temperate forest. Light-saturated rates of net photosynthesis in midwinter and spring were lower than those in autumn. Photosynthetic capacity, scaled to a common leaf temperature of 25 °C, increased or remained stable after autumn and then decreased in spring in most leaves. Photosynthetic traits per unit leaf area were different among leaves in different light environments of both Camellia and Quercus during most periods. However, photosynthetic traits per unit leaf mass did not differ among leaves in different light environments, suggesting that differences in photosynthetic traits were mainly due to different leaf mass per area among leaves. Photosynthetic rates under light availability typical in the environment were lower in winter than in autumn in leaves in the sun in a gap but were not different in leaves in the shade under evergreen canopy trees. Thus, the importance of winter carbon gain for annual carbon gain is small in leaves in a gap but is large in leaves under evergreen canopy trees.

Enriched nutrient availability strengthens the net C uptake of the northernmost ecosystem station in Greenland

2020 ◽  
Author(s):  
Efrén López-Blanco ◽  
Marcin Jackowicz-Korczynski ◽  
Mikhail Mastepanov ◽  
Kirstine Skov ◽  
Andreas Westergaard-Nielsen ◽  
...  
Keyword(s):  
The Arctic ◽  
Leaf Mass Per Area ◽  
Sink Strength ◽  
Sampling Point ◽  
Arctic Ecosystems ◽  
Ancillary Data ◽  
Area Index ◽  
Leaf Mass ◽  
C Cycle ◽  
C Stocks

<p>Although the Arctic tundra is an essential contributor to the global carbon (C) cycle, there is a lack of reference sites from where full C exchange dynamics can be characterized under harsh conditions and remoteness. The Greenland Ecosystem Monitoring (GEM) programme efforts have envisioned integrated and long-term activities to contribute to the basic scientific understanding of the Arctic and their responses to climate changes. Here we present 20+ years across the 2008-2018 period of C flux and ancillary data from two twin ecosystem stations in Greenland: Zackenberg (74°N) and Kobbefjord (64°N). In this project we show that Zackenberg fen has a significant higher C sink strength in a higher latitude during regularly shorter growing seasons compared to Kobbefjord fen. This ecosystem acted as a sink of CO<sub>2</sub> uptaking on average -50 g C m<sup>-2</sup> (range of +21 to -90 g C m<sup>-2</sup>), more than twice compared to Kobbefjord (-18 g C m<sup>-2 </sup>as average and range of +41 to -41 g C m<sup>-2</sup>). We found that Zackenberg is a nutrient richer fen - the increased C uptake strength is associated with 3 times higher levels in soils of dissolved organic carbon and 5 times more plant nutrients, including dissolved organic nitrogen, nitrates. Additional evidences from in-situ sampling point to higher leaf area index (140%), foliar nitrogen (71%), and leaf mass per area (5%) in the northernmost site supporting the nutrient richer hypothesis. To test this overarching hypothesis, we further used the Soil-Plant-Atmosphere (SPA) model. We can explain ~68%, ~80% and ~67% of the variability of daily net ecosystem exchange of CO<sub>2</sub>, photosynthesis and respiration respectively applying the model parameterization previously used in Kobbefjord but with increases in initial C stocks, leaf mass per area, N content and Q<sub>10 </sub>of foliar and root respiration rates. Therefore, we conclude that the limitations of plant phenology timing in Zackenberg regarding net C uptake have not only been counterbalanced but also intensified due to richer compositions of nutrients and minerals. <span>More high-temporal monitoring activities in Arctic ecosystems are needed not only to allow straightforward comparisons of key biogeochemical processes but also to help us understand the underlying differences in sensitive and rapidly changing ecosystems. </span></p>

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