Soybeans grown with 2 millimolar NO(3) (-), which optimized apparent N(2) fixation by Rhizobium symbionts, showed significantly different rates of apparent photosynthesis and C(2)H(2) reduction during seedling development at two irradiances. Those physiological processes were lower for several weeks in plants grown at 1,500 microeinsteins per meter(2) per second than in those exposed to 700 mic...

Peroxins are genetically defined as proteins necessary for peroxisome biogenesis. By screening for reduced response to indole-3-butyric acid, which is metabolized to active auxin in peroxisomes, we isolated an Arabidopsis thaliana peroxin4 (pex4) mutant. This mutant displays sucrose-dependent seedling development and reduced lateral root production, characteristics of plant peroxisome malfuncti...

Heterotrimeric G proteins are implicated in diverse signaling processes in plants, but the molecular mechanisms of their function are largely unknown. Finding G protein effectors and regulatory proteins can help in understanding the roles of these signal transduction proteins in plants. A yeast two-hybrid screen was performed to search for proteins that interact with Arabidopsis G protein alpha...

BACKGROUND AND AIMS The shrub Viburnum tinus is widely distributed in mattoral vegetation of the Mediterranean basin. The purpose of the present study was to classify the seed dormancy type and examine the requirements for embryo growth, root protrusion and shoot emergence. METHODS Overwintered fruits were collected in western Spain in April 2001 and prepared in three ways: entire pericarp wa...

BACKGROUND AND AIMS Several widespread tree species of temperate forests, such as species of the genus Quercus, produce recalcitrant (desiccation-sensitive) seeds. However, the ecological significance of seed desiccation sensitivity in temperate regions is largely unknown. Do seeds of such species suffer from drying during the period when they remain on the soil, between shedding in autumn and ...

The genetic interactions among mutations that define eight distinct loci involved in light-regulated development in Arabidopsis thaliana are described. The mutations in these eight genes define two distinct phenotypic classes with opposite characteristics. Recessive mutations in either one of two genes, DETL or DET2, result in darkgrown plants that develop as light-grown wild-type seedlings. Mu...

Phytochrome A (phyA) is the primary photoreceptor mediating responses to far-red light. Among the phyA downstream signaling components, Far-red Elongated Hypocotyl 1 (FHY1) is a genetically defined positive regulator of photomorphogenesis in far-red light. Both physiological and genomic characterization of the fhy1 mutants indicated a close functional relationship of FHY1 with phyA. Here, we sh...

SPINDLY (SPY) is a negative regulator of gibberellin (GA) responses; however, spy mutants exhibit various phenotypic alterations not found in GA-treated plants. Assaying for additional roles for SPY revealed that spy mutants are resistant to exogenously applied cytokinin. GA also repressed the effects of cytokinin, suggesting that there is cross talk between the two hormone-response pathways, w...

Ergosterol, a membrane sterol found in fungi but not in plants, was used to estimate live mycelial biomass in ectomycorrhizae. Loblolly pine (Pinus tueda L.) seeds were sown in April 1993 and grown with standard nursery culture practices. Correlations between total seedling ergosterol and visual assessment of mycorrhizal colonization were high during July and August but low as ectomycorrhizal d...

RNA editing in plant organelles post-transcriptionally alters single nucleotides by C-to-U or U-to-C conversions at highly specific sites. Plant editing is generally viewed as a repair mechanism acting at the transcript level by restoring conserved amino acid residues. Here we report that an editing reaction within the ndhB transcript (encoding a plastid NAD(P)H dehydrogenase subunit) is strict...