Variation in Photosynthetic Pigments and Plastoquinone Contents in Sugar Beet Chloroplasts with Changes in Leaf Copper Content

Abstract

The changes in the contents of chlorophyll (Chl) a, Chl b, carotenoid, and plastoquinone in sugar beet (Beta nulgaris) chloroplasts were investigated during Cu deficiency and resupply. With the onset of Cu deficiency, extrachloroplastic Cu decreased more rapidly than chloroplast Cu, which eventually accounted for all of the Cu present in the leaf. The ultrastructure of Cu-deficient chloroplasts did not differ from the control except in very young, severely deficient leaves. During Cu depletion and resupply, Chl a, Chl b, carotenoid, and plastoquinone contents changed concomitantly. Because of the concurrent changes in the contents of terpenoid-containing pigments and plastoquinone with Cu depletion and resupply, we suggest that Cu might be involved in the regulation of the early steps of terpenoid biosynthesis prior to the formation of geranylgeranyl-pyrophosphate.

Physiological integration ameliorates effects of serpentine soils in the clonal herb Fragaria vesca

“…Although there is a wealth of evidence demonstrating the negative effects of heavy metal toxicity on the photosynthetic apparatus (Barceló et al 1986, Droppa et al 1984, Lindon and Henriques 1992, Singh 1988), our results indicate that offspring ramets growing in serpentine soils did not show decreased photosynthetic efficiencies or chlorophyll contents as long as they remained connected to parents. This positive effect of integration on photosynthetic efficiency was even more evident when in the eighth week of the experiment we severed the parent–offspring connections: this brought about a rapid and statistically significant decrease in the maximum quantum yield of offspring ramets growing in serpentine soils but not of offspring ramets growing in potting compost.…”

Copper in photosystem II: association with LHC II

“…This is consistent with the inhibitory effects of low Cu on Chl, carotenoid, and benzoquinone synthesis that they observed. Inhibition of Chl and plastoquinone synthesis has been reported by Droppa et al [9]. Horvath et al [16] found that under Cu deficiency a protein of about 29 kD was missing from spinach thylakoids.…”

Changes in carotenoids and fatty acids in photosystem II of Cudeficient pea plants

“…However, some authors reported that Cu may also influence other chioropiast processes. Droppa et al (1984) and Horvath et al (1983) demotistrated a decreased pigment atid plastoquinone synthesis. In addition, Baszynski et al (1978) and Henriques (1989) fotitid a disintegration of the thylakoid membranes of chloroplasts from Cu-deficients plants.…”

“…Recent work has reported a decrease in PSII activity in Cu-deficient spinach chloroplasts (Baron et al 1990, Droppa et al 1984, Henriques 1989. Droppa et al (1987) concluded that severe Cu deficiency changes the thylakoid membranes, and modifies the microenvironment of the PSII acceptor side.…”