In contrast to vastly studied hypocotyl growth, little is known about diel regulation of leaf growth and its coordination with movements such as changes in leaf elevation angle (hyponasty). We developed a 3D live-leaf growth analysis system enabling simultaneous monitoring of growth and movements. Leaf growth is maximal several hours after dawn, requires light, and is regulated by daylength, su...

The phenomenon of the etiolated hook is not restricted to the hypocotyl of the dicotyledenous plant (e.g., Phaseolus) but appears to serve a similar, adaptive function in the petioles of certain rhizomatous plants. The commonly employed regulants of hypocotyl hook opening were tested for their effect on the petiolar hook of Dentaria diphylla. The hook was found to require both light (red light ...

A large number of studies Cistus ladanifer highlight this Mediterranean shrub as a source the phenolic compounds responsible for allelopathic potential species. There are few present in C. that have not yet been studied. The objective work was to evaluate activity estragole and 2-isopropylphenol on filter paper soil monocotyledons (Allium cepa) dicotyledons (Lactuca sativa). results showed when...

As a member of the CLAVATA3 (CLV3)/EMBRYO SURROUNDING REGION (CLE) family, dodecapeptide tracheary element differentiation inhibitory factor (TDIF) has major impact on vascular development in plants. However, influence polymorphisms TDIF peptide motif activity remains poorly understood. The model plant, Arabidopsis provides fast and effective tool for assaying homologs. Five homologs from group...

As part of a continuing effort to elucidate mechanisms that regulate the magnitude of ethylene signalling, an Arabidopsis mutant with an enhanced ethylene response was identified. Subsequent characterization of this loss-of-function mutant revealed severe hypocotyl shortening in the presence of saturating ethylene along with increased expression in leaves of a subset of ethylene-responsive gene...

Field-emission scanning electron microscopy was used to measure wall thicknesses of different cell types in freeze-fractured hypocotyls of Arabidopsis thaliana. Measurements of uronic acid content, wall mass, and wall volume suggest that cell wall biosynthesis in this organ does not always keep pace with, and is not always tightly coupled to, elongation. In light-grown hypocotyls, walls thicken...

The phytohormone auxin is involved in virtually every aspect of plant growth and development. Through polar auxin transport, auxin gradients can be established, which then direct plant differentiation and growth. Shade avoidance responses are well-known processes that require polar auxin transport. In this study, we have identified a mutant, shade avoidance 4 (sav4), defective in shade-induced ...

Postembryonic de novo organogenesis represents an important competence evolved in plants that allows their physiological and developmental adaptation to changing environmental conditions. The phytohormones auxin and cytokinin (CK) are important regulators of the developmental fate of pluripotent plant cells. However, the molecular nature of their interaction(s) in control of plant organogenesis...

The fhy3 mutation of Arabidopsis impairs phytochrome A (phyA)-mediated inhibition of hypocotyl growth without affecting the levels of phyA measured spectrophotometrically or immunochemically. We investigated whether the fhy3-1 mutation has similar effects on very low fluence responses (VLFR) and high irradiance responses (HIR) of phyA. When exposed to hourly pulses of far-red light, etiolated s...

The GOLVEN (GLV) gene family encode small secreted peptides involved in important plant developmental programs. Little is known about the factors required for the production of the mature bioactive GLV peptides. Through a genetic suppressor screen in Arabidopsis thaliana, two related subtilase genes, AtSBT6.1 and AtSBT6.2, were identified that are necessary for GLV1 activity. Root and hypocotyl...