Direct inhibition of photosynthesis by Cd dominates over inhibition caused by micronutrient deficiency in the Cd/Zn hyperaccumulator Arabidopsis halleri

Copyright © 2020 Elsevier Masson SAS. All rights reserved..

This work reveals, by imaging in vivo measurements in the Cd/Zn hyperaccumulator Arabidopsis halleri, in how far Cd stress affects macronutrient (Ca, K) and micronutrient (Fe, Zn) distribution in the leaves. We directly correlate these changes with biophysics of the photosynthetic light reactions. Plants were grown for 2 months at 10 μM Zn (=control), and supplemented with 10, 15, 50 or 75 μM Cd. Direct imaging of OJIP transients revealed that bundle sheath cells were more sensitive to Cd toxicity than mesophyll cells further from the vein. Progressive inhibition of photosystem (PS) II reaction centres and decrease in quantum yield of electron transport between QA and QB and further to PSI acceptors was observed. This was correlated with the decreased dynamics of QA re-oxidation and lower operating efficiency of PSII. Analysis by a benchtop micro X-ray fluorescence device showed that Cd mostly accumulated in the veins, and restricted Fe and Zn distribution from the veins, especially in the 75 μM Cd, while K concentration increased in the whole leaf. Calcium distribution was apparently not affected by Cd, but Cd excess inhibited trichome formation and thereby diminished total Ca concentration in the leaves. The results point to differential tissue sensitivity to Cd, evident by heterogeneous inhibition of photosynthesis. Part of this may be a result of selective disturbances in the leaf nutrient homeostasis. The better photosynthetic performance away from the veins compared to the bundle sheath cells, however, indicates that direct inhibition of photosynthesis by Cd dominates over inhibition caused by micronutrient deficiency.

Medienart:

E-Artikel

Erscheinungsjahr:

2020

Erschienen:

2020

Enthalten in:

Zur Gesamtaufnahme - volume:155

Enthalten in:

Plant physiology and biochemistry : PPB - 155(2020) vom: 05. Okt., Seite 252-261

Sprache:

Englisch

Beteiligte Personen:

Morina, Filis [VerfasserIn]
Küpper, Hendrik [VerfasserIn]

Links:

Volltext

Themen:

μXRF
00BH33GNGH
1406-65-1
Arabidopsis halleri
Cadmium
Chlorophyll
Chlorophyll fluorescence kinetics
J41CSQ7QDS
Journal Article
Micronutrients
OJIP
Tissue-specific metal distribution
Zinc

Anmerkungen:

Date Completed 17.12.2020

Date Revised 17.12.2020

published: Print-Electronic

Citation Status MEDLINE

doi:

10.1016/j.plaphy.2020.07.018

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM313561001