Abstract Photomorphogenesis, light-mediated development, is an essential feature of all terrestrial plants. While chloroplast development and brassinosteroid (BR) signaling are known players in photomorphogenesis, proteins that regulate both pathways have yet to be identified. Here we report D E-ETIOLATION IN THE DARK A ND Y ELLOWING LIGHT (DAY) , a membrane protein containing DnaJ-like domain,...

Arabidopsis seedlings display contrasting developmental patterns depending on the light environment, e.g. photomorphogenesis in the light and skotomorphogenesis (etiolation) in darkness. Recent studies have implicated protein degradation as a means of regulating this developmental switch (Osterlund et al., 2000). For example, HY5, a positive photomorphogenic regulator that acts to promote the l...

An accompanying paper reports the accumulation of photoactive protochlorophyllide (Pchlide) in the innermost leaf primordia of buds of many tree species. In this paper, we describe plastid differentiation, changes in pigment concentrations and spectral properties of bud scales and leaf primordia of horse chestnut (Aesculus hippocastanum L.) from January until the end of bud break in April. The ...