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Green light attenuates blue‐light‐induced chloroplast avoidance movement in Arabidopsis and Landoltia punctata
Author(s) -
Schmalstig Judy G.,
Jainandan Kenneth
Publication year - 2021
Publication title -
american journal of botany
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.218
H-Index - 151
eISSN - 1537-2197
pISSN - 0002-9122
DOI - 10.1002/ajb2.1717
Subject(s) - chloroplast , arabidopsis , blue light , biology , shade avoidance , phototropism , arabidopsis thaliana , biophysics , phytochrome , phototropin , botany , mutant , red light , biochemistry , physics , optics , gene
Premise Chloroplast movement to the anticlinal walls in excess light, referred to as chloroplast avoidance movement, is one strategy to prevent high light damage. Chloroplast avoidance movement is mediated by the blue‐light photoreceptor phototropin. Since some blue‐light effects are reversed by green light, we investigated the effect of green wavelengths on chloroplast avoidance. Methods Chloroplast position was visualized via microscopy and by transmission of red light through the leaves of Arabidopsis thaliana and Landoltia punctata (duckweed). Results Green light reduced blue‐light‐induced chloroplast avoidance movement but only when green light was presented simultaneously with blue light. Green light alone had no effect on chloroplast position. An action spectrum for green‐light attenuation of chloroplast avoidance in duckweed revealed peaks at 510, 550, and 590 nm. Blue‐light‐induced chloroplast avoidance movement in three Arabidopsis mutants with reduced nonphotochemical quenching, npq1, npq4 , and npq7 was not affected by green light. Conclusions The action spectrum does not conform to any known photoreceptor. The lack of a green‐light response in the npq mutants of Arabidopsis suggests a possible role for the xanthophyll cycle or a signal from the chloroplast in control of chloroplast avoidance movement.