Lewis J. Feldman

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The phytohormone auxin has wide-ranging effects on growth and development. Genetic and physiological approaches implicate auxin flux in determination of floral organ number and patterning. This study uses a novel technique of transiently applying a polar auxin transport inhibitor, N-1-naphthylphthalamic acid (NPA), to developing Arabidopsis flowers to(More)
The expression of the floral regulators LEAFY, APETALA1 and AGAMOUS-LIKE8 was examined during light treatments that induced flowering in Arabidopsis, and was compared to time points at which floral determination occurred. Extension of an 8-hour day by either continuous red- or far-red-enriched light induced LEAFY and AGAMOUS-LIKE8 expression within 4 hours.(More)
Intercellular signaling is essential for the coordination of growth and development in higher plants. Although hundreds of putative receptors have been identified in Arabidopsis (Arabidopsis thaliana), only a few families of extracellular signaling molecules have been discovered, and their biological roles are largely unknown. To expand our insight into the(More)
Embedded within the meristem of all Angiosperm roots is a population of slowly dividing cells designated the quiescent center (QC). In maize roots the QC can constitute upwards of 800-1200 cells, most of which spend an extended period of time (180-200 hours) in the G(1) phase of the cell cycle. How the QC forms and is maintained is not known. Here we report(More)
CLE peptides, named for the CLV3/ESR-related peptide family, participate in intercellular-signaling pathways. Here we investigated members of the CLE-like (CLEL) gene family that encode peptide precursors recently designated as root growth factors [Matsuzaki Y et al. (2010) Science 329:1065-1067]. CLEL precursors share a similar domain structure with CLE(More)
In this study we investigated Arabidopsis thaliana (L.) Heynh. inflorescence development by characterizing morphological changes at the shoot apex during the transition to flowering. Sixteen-hour photoperiods were used to synchronously induce flowering in vegetative plants grown for 30 d in non-inductive 8-h photoperiods. During the first inductive cycle,(More)
Studies of plant tropisms, the directed growth toward or away from external stimuli such as light and gravity, began more than a century ago. Yet biochemical, physiological, and especially molecular mechanisms of plant tropic responses remain for the most part unclear. We examined expression of 8,300 genes during early stages of the gravitropic response(More)
Arabidopsis (Arabidopsis thaliana) was transformed with a redox-sensing green fluorescent protein (reduction-oxidation-sensitive green fluorescent protein [roGFP]), with expression targeted to either the cytoplasm or to the mitochondria. Both the mitochondrial and cytosolic forms are oxidation-reduction sensitive, as indicated by a change in the ratio of(More)
This is the first report on using green fluorescent protein (GFP) as a pH reporter in plants. Proton fluxes and pH regulation play important roles in plant cellular activity and therefore, it would be extremely helpful to have a plant gene reporter system for rapid, non-invasive visualization of intracellular pH changes. In order to develop such a system,(More)