TITLE:
Mineral Balance Plasticity of Cloudberry (Rubus chamaemorus) in Quebec-Labrador Bogs
AUTHORS:
Léon Etienne Parent, Serge-Étienne Parent, Valérie Hébert-Gentile, Kristine Naess, Line Lapointe
KEYWORDS:
Al Toxicity; Cloudberry; Compositional Data Analysis; Isometric Log Ratio; Nutrient Balance; Ionome
JOURNAL NAME:
American Journal of Plant Sciences,
Vol.4 No.7,
July
17,
2013
ABSTRACT: The “ionome”,
or plant elemental signature, is the elemental composition of an organisms, that may vary with genotypic traits and phenotypic plasticity. Cloudberry (Rubus chamaemorus L.) is a circumboreal wild berry naturally
growing in oligotrophic oceanic bogs ofQuebecandLabrador. Our objective was to relate
cloudberry stand productivity to the ionomes of female ramets and explore the
cause of nutrient imbalance in low-performing stands. We analyzed 13 elements
in female ramets collected in 86 natural sites where crop productivity varied
widely. We computed orthogonally arranged balances reflecting plant
stoichiometric rules and soil biogeochemistry. Balances were expressed as
isometric log ratios (ilr) between ad hoc sub-compositions. Balances were
synthesized into a Mahalanobis distance optimized based on receiving operating
characteristics (ROC). The critical Mahalanobis distance was found to be 5.29
for cutoff berry yield of3.8 g.m-2 with test performance of 0.88, as measured by the area
under the ROC curve. Although past research on cloudberry focused mainly on the
N/P ratio, this exploratory mineral balance analysis indicated that imbalance
in the [P,N | S,C] and [Al | Nutrients] partitions appeared to
be the factors limiting the most cloudberry productivity in the bogs.
Some highly productive stands showed relatively high C fixation and K use
efficiency. Due to the complexity of interactions, diagnosis should be
conducted computing first a global imbalance index (Mahalanobis distance), then
examining in the balance domain binary partitions departing most from
reference, and finally appreciating relative shortage, sufficiency or excess of
elements in the concentration domain.