We examined the relationship between meristem allocation and plant size for four annual plant species: Arabidopsis thaliana, Arenaria serphyllifolia, Brassica rapa, and Chaenorrhinum minus. Gradients of light and nutrient availability were used to obtain a range of plant sizes for each of these species. Relative allocation to reproductive, inactive, and growth meristems were used to measure rep...

During the last century, two key hypotheses have been proposed to explain apical dominance in plants: auxin promotes the production of a second messenger that moves up into buds to repress their outgrowth, and auxin saturation in the stem inhibits auxin transport from buds, thereby inhibiting bud outgrowth. The recent discovery of strigolactone as the novel shoot-branching inhibitor allowed us ...

The soybean gene Glyma10g34760 appears to encode a RAV2-like transcription factor orthologue (DQ147914; hereafter GmRAV) based on sequence similarity. The gene is a member of the ERF/AP2 transcription factor family that has been shown to be increased in transcript abundance by cytokinins (CKs). Transgenic GmRAV-overexpressing (-ox) tobacco plants exhibited increased CK signalling-related phenot...

Endoreduplication, the replication of the genome without mitosis, leads to endopolyploidy, an increase in cellular chromosome number. Although endoreduplication is widespread among angiosperms and other groups of eukaryotes, the degree to which this process is plastic under varying environmental conditions and its potential adaptive significance are not known. Here, using flow cytometry, we mea...

Correlative control (influence of one organ over another organ) of seeds over maternal growth is one of the most obvious phenotypic expressions of the trade-off between growth and reproduction. However, the underlying molecular mechanisms are largely unknown. Here, we characterize the physiological and molecular effects of correlative inhibition by seeds on Arabidopsis (Arabidopsis thaliana) in...

This paper characterizes the growth and crown morphology of young balsam ®r saplings naturally regenerated under a gradient of understory light environments and intraspeci®c competition densities for two size classes (50±100 cm and 100± 200 cm). Most growth and crown morphological parameters investigated were strongly related to the natural light gradient investigated (3±83% full sunlight), but...

Terminal buds and successively subjacent lateral buds of the water fern, Marsilea drummondii, were examined to determine the pattern of hormone distribution in relation to apical dominance. Quantitative levels of indole-3-acetic acid (IAA), abscisic acid (ABA), zeatin and zeatin riboside (Z and ZR), and isopentenyladenosine (iPA) were determined by a solid-phase immunoassay using polycional ant...

Switchgrass (Panicum virgatum L.) has been developed into a dedicated herbaceous bioenergy crop. Biomass yield is a major target trait for genetic improvement of switchgrass. microRNAs have emerged as a prominent class of gene regulatory factors that has the potential to improve complex traits such as biomass yield. A miR156b precursor was overexpressed in switchgrass. The effects of miR156 ove...

Apical dominance is one of the fundamental developmental phenomena in plant biology, which determines the overall architecture of aerial plant parts. Here we show apex decapitation activated competition for dominance in adjacent upper and lower axillary buds. A two-nodal-bud pea (Pisum sativum L.) was used as a model system to monitor and assess auxin flow, auxin transport channels, and dormanc...