Degradation of chlorophyll (Chl) by Chl catabolic enzymes (CCEs) causes the loss of green color that typically occurs during senescence of leaves. In addition to CCEs, staygreen1 (SGR1) functions as a key regulator of Chl degradation. Although sgr1 mutants in many plant species exhibit a stay-green phenotype, the biochemical function of the SGR1 protein remains elusive. Many recent studies have...

A previously published working model for the regulation of chlorophyll formation has been tested studying early steps of chlorophyll and porphyrin biosynthesis in developing cotyledons of Helianthus annuus. The activities of delta-aminolevulinate synthetase (ALAS), delta-aminolevulinate dehydratase (ALAD), and the porphobilinogenase complex (PBGase) at any given time have been found to be stron...

Autumnal tints are one of the most fascinating natural phenomena, but the molecular mechanism of chlorophyll (Chl-)degradation in deciduous trees has not been fully understood. In this study, from the leaves of Ginkgo biloba, chlorophyllase-homologous GbCLH was cloned by RT-PCR with degenerated primers. The expression of GbCLH in different yellowing stages was analyzed by Northern hybridization...

The effect of optimal and stress temperatures on the growth kinetics of the Phaeodactylum tricornutum CCAP/1055/1 strain (a model diatom with a known genome sequence) in batch cultures was examined. The analysis of the obtained results showed two phases of culture growth. There were significant positive correlations between OD increase of chlorophyll a chlorophyll c and protein concentration at...

The effects of pulse treatment with gibberellin A3 (GA3), silveT thiosulfate complex (STS), and with or without sucrose on chlorophyll degTadation and vase life of cut flowers of Narcissus tazetta var. chinensis were investigated. The 20-hr pulsing treatment with STS extended the vase life of cut fiowers of IVL tazetta var. chinensis, Pulse treatments with GA3 delayed degradation of chlorophyll...

Tocopherols, a subclassof tocochromanols that contain a phytol attached to the head group, act as antioxidants to protect lipids from oxidative damage, a particularly important function in chloroplasts and for seed longevity (reviewed in Maeda and DellaPenna, 2007). One pathway for tocopherol biosynthesis involves de novo synthesis from geranylgeranyl-diphosphate; the other pathway uses phytols...