Soil and climate affect foliar silicification patterns and
silica-cellulose balance.
Abstract
Silicon (Si) has beneficial effects in a variety of plant species and
environments. Soil and climate affect silica accumulation in given plant
species. Their roles on biosilicification patterns and balance between
silica and C-rich biopolymers as structural components is poorly known.
Here, we studied silica deposition in situ in sugarcane leaves collected
in three tropical environments differing in soil and climate. Plant
silica deposits were physically extracted from leaves through wet
digestion. Leaves were observed and mapped for Si by ESEM-EDX. The
C-rich biopolymers in leaves were determined by the Van Soest method.
Silicon accumulation in leaf was related to bioavailable Si in soil and
plant transpiration. Epidermal silica deposits were either limited to
silica cells or expanded to long and short cells arranged in prominent
veins fully silicified, depending on whether the leaf Si concentration
was lowest or highest. The size of silica deposits increased with
increasing leaf Si through an increasing number of conjoined silicified
cells. Ash-free cellulose and Si concentrations were negatively
correlated. Soil and climate impacted markedly the magnitude of
biosilicification and the counterbalance between silica and cellulose as
leaf structural components.