Abstract Detail

Forest Tree Responses to a Changing Climate

Sala, Anna [1], Martínez-Vilalta, Jordi [2], Asencio, M. Dolores [2], Lloret, Francisco [2], Palacio, Sara [3], Galiano, Lucía [2], Hoch, Guenter [4], Piper, Frida [5].

Concentration and dynamics of non-structural carbohydrates in plants: implications under global change.

Evidence points to increasing climate-change induced stress as a primary driver of recent forest mortality. Predicted increases of drought under climate change are expected to exacerbate forest mortality with profound effects on global carbon cycles. Therefore, understanding and predicting forest responses to climate change is an urgent priority. Plants use carbohydrates primarily for metabolism and growth. A small fraction is retained in the form of non-structural carbohydrates (NSC), which buffer periods of stress when carbon supply via photosynthesis is not sufficient to meet demand. NSC storage is therefore critical for survival under stress and is increasingly acknowledged as an important missing component in most ecosystem models. However, our current understanding of the role, regulation and dynamics of NSC in plants remains very limited, thus impairing progress. Here, we assembled a global database to examine broad patterns of seasonal NSC variation across organs, life forms and biomes. We addressed very basic questions: how variable are NSC concentrations across organs, functional types and biomes? Does the seasonal variation of NSC depend on plant functional type and biome? To what extent do plants seasonally deplete NSC storage? We compiled seasonal data for ca. 200 wild species under natural conditions. Organ accounted for the largest differences in NSC concentrations with ca. 14, 11 and 7 % in leaves, belowground organs and stems, respectively. The variance explained by functional type was very small and that explained by biome was even smaller. For all organs, NSC and its fractions were generally higher in herbaceous than in woody species. Among woody species, conifer stems had lower NSC concentrations, while those in foliage tended to be higher. Few significant differences were found among biomes. The most pronounced seasonal variations occurred in conifers and herbaceous plants. Overall, seasonal NSC variation was not necessarily greater in deciduous relative to evergreen species. We found that depletion of NSC was rare, with minimums remaining at least at 30% of the maximum, and often above. In general, starch depletion was more common than that of soluble sugars, consistent with the storage role of starch and multiple functions of soluble sugars. Whether the maintenance of high NSC we found reflects surplus carbon or is a targeted strategy remains an open question. However, the generally lower depletion of soluble sugars relative to starch points towards important functions of soluble sugars unrelated to storage, including osmotic regulation to cope with winter cold and summer drought.

1 - University Of Montana, Division Of Biological Sciences, Missoula, MT, 59812, USA
2 - CREAF. University Autonomous of Barcelona, Bellaterra, Barcelona, Spain
3 - Instituto Pirenaico de Zaragoza (CSIC), Jaca, Huesca, Spain
4 - University of Basel, Institute of Botany, Basel, Switzerland
5 - Centro de Investigación en Ecosistemas de la Patagonia (CIEP), Coyhaique, Chile

Keywords:
none specified

Presentation Type: Symposium Presentation
Session: SY13
Location: Hall A/The Shaw Conference Centre
Date: Wednesday, July 29th, 2015
Time: 9:15 AM
Number: SY13004
Abstract ID:1337
Candidate for Awards:None