DOI: 10.5061/dryad.j6r5k
title: Data from: Dynamics of non-structural carbohydrates in terrestrial plants: a global synthesis

description: Plants store large amounts of non-structural carbohydrates (NSC). While
 multiple functions of NSC have long been recognized, the interpretation of
 NSC seasonal dynamics is often based on the idea that stored NSC is a
 reservoir of carbon that fluctuates depending on the balance between
 supply via photosynthesis and demand for growth and respiration (the
 source-sink dynamics concept). Consequently, relatively high NSC
 concentrations in some plants have been interpreted to reflect excess
 supply relative to demand. An alternative view, however, is that NSC
 accumulation reflects the relatively high NSC levels required for plant
 survival; an important issue that remains highly controversial. Here, we
 assembled a new global database to examine broad patterns of seasonal NSC
 variation across organs (leaves, stems and belowground), plant functional
 types (coniferous, drought deciduous angiosperms, winter deciduous
 angiosperms, evergreen angiosperms, and herbaceous) and biomes (boreal,
 temperate, Mediterranean and tropical). We compiled data from 123 studies,
 including seasonal measurements for 179 species under natural conditions.
 Our results showed that, on average, NSC account for ~10% of dry plant
 biomass and are highest in leaves and lowest in stems, whereas belowground
 organs show intermediate concentrations. Total NSC, starch and soluble
 sugars (SS) varied seasonally, with a strong depletion of starch during
 the growing season and a general increase during winter months,
 particularly in boreal and temperate biomes. Across functional types, NSC
 concentrations were highest and most variable in herbaceous species and in
 conifer needles. Conifers showed the lowest stem and belowground NSC
 concentrations. Minimum NSC values were relatively high (46% of seasonal
 maximums on average for total NSC) and, in contrast to average values,
 were similar among biomes and functional types. Overall, although starch
 depletion was relatively common, seasonal depletion of total NSC or SS was
 rare. These results are consistent with a dual view of NSC function:
 whereas starch acts mostly as a reservoir for future use, soluble sugars
 perform immediate functions (e.g., osmoregulation) and are kept above some
 critical threshold. If confirmed, this dual function of NSC will have
 important implications for the way we understand and model plant carbon
 allocation and survival under stress.
description: NSCdataThis database contains seasonal non-structural carbohydrates data (NSC; including total NSC, starch and soluble sugars) for terrestrial land plants (global scope), and it is based on a compilation of data from the literature. We selected only data that fulfilled the following criteria: (1) study duration was at least four months, (2) the same individuals or populations were measured at least three times spanning the length of the study, (3) plants were mature, (4) measurements were taken on leaves, stems, or belowground organs, (5) tissue was not bark, phloem or cortex, (6) values reported were total NSC, starch/fructans or soluble sugars, and (7) species were land plants (i.e., saltwater and freshwater species were not included).NSCdata_sourcesThis file lists the sources of all the individual datasets included in our final NSC database (”NSCdata_DRYAD.csv” file).