2 research outputs found
Kaolin spray induces changes in ABA and IAA immunodistribution in olive leaves.
The climate change scenarios predicted the accentuation of drought and high
temperature events during the summer season in the Mediterranean region, coming up
harmful consequences to important crops of this region, such as olive tree (Olea
europaea L.). Stress conditions often stimulate changes in plants production,
distribution or signal transduction of phytohormones as a response, then modifying
their physiology and biochemistry. Kaolin (KL) is a reflecting clay that applied on leaves
surface reduce the common damages promoted by heat load and high irradiance
levels, being important to test its effect on olive tree hormonal dynamics and
physiological parameters. Olive trees of a rainfed orchard in Northeast Portugal, were
sprayed with kaolin 5% (KL) and water (C). The immunodistribution of two hormones,
abscisic acid (ABA) and indoleacetic acid (IAA), and some physiological and growth
responses were accessed. The ABA signal was substantially more pronounced than
the IAA signal in all the analyzed leaves, concomitant with the stressful conditions of
which these plants were subjected. In general, ABA signal showed a uniform
distribution throughout the leaf in both treatments. However, its intensity was higher in
C than in KL-sprayed leaves, reflecting the better water status and higher stomatal
conductance of the last plants. While in C leaves was observed a uniform distribution of
IAA signal trough the leaf limb and an almost absence of signal in the main vascular
tissues, in KL-sprayed leaves was observed a higher signal intensity in the main
vascular tissues and upper palisade parenchyma. These data suggest its transport and
an active growth in KL plants, concomitant with the higher increase of canopy volume.
Thus, immunodetection appears to be an efficient tool to understand the translocation
of IAA and ABA in plants treated with abiotic stress alleviating products and clarify their
role in regulating the physiological responses.info:eu-repo/semantics/publishedVersio
Kaolin and salicylic acid alleviate summer stress effects on rainfed olive orchards through distinct physiological and biochemical processes
In a changing world, the search for new agronomic practices that help crops to maintain and/or increase
yields and quality is a continuous challenge. Olive trees cultivated under rainfed conditions were sprayed
with 5% kaolin (KL) and 100 μM salicylic acid (SA) during two consecutive years in the beginning of the
summer season. Exogenous KL enhanced relative water content (RWC), stomatal conductance (gs) net
photosynthesis (A) and IAA immunodetection, and decreased leaf sclerophylly, secondary metabolites
and non-structural carbohydrates accumulation, ABA signal and DNA methylation, contributing to higher
growth and yield. The plants treated with SA showed an enhancement in RWC, gs, A, soluble proteins,
IAA, ABA and DNA methylation immunodetection and leaf P and Mg concentrations during the summer,
leading to higher yield. Thus, KL and SA alleviated some of the negative effects induced by summer stress
in olive tree performance, allowing a faster restauration of the physiological functions during the stress
relief and leading to higher yieldsThis work was funded by the INTERACT project – “Integrative Research in
Environment, Agro-Chains and Technology”, no. NORTE-01-0145-FEDER-000017, in its lines of research
entitled ISAC, co-financed by the European Regional Development Fund (ERDF) through NORTE 2020
(North Regional Operational Program 2014/2020).info:eu-repo/semantics/publishedVersio