10.1021/acsnano.7b05723.s001
Honghong Wu
Honghong
Wu
Nicholas Tito
Nicholas
Tito
Juan P. Giraldo
Juan P.
Giraldo
Anionic
Cerium Oxide Nanoparticles Protect Plant Photosynthesis
from Abiotic Stress by Scavenging Reactive Oxygen Species
American Chemical Society
2017
ratio
leaf mesophyll cells
Scavenging Reactive Oxygen Species Plant abiotic stress
chloroplast
vivo augments ROS
abiotic stress exhibit
plant nanobionics approach
nanoceria
ANC
cerium oxide nanoparticles
plant enzyme scavenger
leaf ROS levels
Arabidopsis thaliana plants
photosynthesis
reactive oxygen species
Rubisco carboxylation rates
sub -11 nm PNC
Anionic Cerium Oxide Nanoparticles Protect Plant Photosynthesis
abiotic stress
carbon assimilation rates
sub -11 nm
II
2017-11-03 00:00:00
Journal contribution
https://acs.figshare.com/articles/journal_contribution/Anionic_Cerium_Oxide_Nanoparticles_Protect_Plant_Photosynthesis_from_Abiotic_Stress_by_Scavenging_Reactive_Oxygen_Species/5588761
Plant
abiotic stress leads to accumulation of reactive oxygen species
(ROS) and a consequent decrease in photosynthetic performance. We
demonstrate that a plant nanobionics approach of localizing negatively
charged, sub-11 nm, spherical cerium oxide nanoparticles (nanoceria)
inside chloroplasts <i>in vivo</i> augments ROS scavenging
and photosynthesis of Arabidopsis thaliana plants under excess light (2000 μmol m<sup>–2</sup> s<sup>–1</sup>, 1.5 h), heat (35 °C, 2.5 h), and dark
chilling (4 °C, 5 days). Poly(acrylic acid) nanoceria (PNC) with
a hydrodynamic diameter (10.3 nm)lower than the maximum plant
cell wall porosityand negative ζ-potential (−16.9
mV) exhibit significantly higher colocalization (46%) with chloroplasts
in leaf mesophyll cells than aminated nanoceria (ANC) (27%) of similar
size (12.6 nm) but positive charge (9.7 mV). Nanoceria are transported
into chloroplasts <i>via</i> nonendocytic pathways, influenced
by the electrochemical gradient of the plasma membrane potential.
PNC with a low Ce<sup>3+</sup>/Ce<sup>4+</sup> ratio (35.0%) reduce
leaf ROS levels by 52%, including hydrogen peroxide, superoxide anion,
and hydroxyl radicals. For the latter ROS, there is no known plant
enzyme scavenger. Plants embedded with these PNC that were exposed
to abiotic stress exhibit an increase up to 19% in quantum yield of
photosystem II, 67% in carbon assimilation rates, and 61% in Rubisco
carboxylation rates relative to plants without nanoparticles. In contrast,
PNC with high Ce<sup>3+</sup>/Ce<sup>4+</sup> ratio (60.8%) increase
overall leaf ROS levels and do not protect photosynthesis from oxidative
damage during abiotic stress. This study demonstrates that anionic,
spherical, sub-11 nm PNC with low Ce<sup>3+</sup>/Ce<sup>4+</sup> ratio
can act as a tool to study the impact of oxidative stress on plant
photosynthesis and to protect plants from abiotic stress.