Diel variation in specific hydraulic conductivity ( k s ) was recorded in petioles of two savanna tree species, Schefflera macrocarpa and Caryocar brasiliense , from central Brazil. These two species have compound leaves with long petioles (10–30 cm). In both species, petiole k s decreased sharply with increasing transpiration rates and declining leaf water potentials ( y L ) during the morning...

Like struggling swimmers trying to keep their heads above water, rosette plants lift up their leaves when faced with flooding. Instead of flailing arms and legs, plants use hyponastic petiole growth to improve their chances of keeping leaves in contact with the air. During this hyponastic growth, cells on the abaxial side of the petiole elongate more than those on the adaxial side, changing the...

Vegetables have a relatively high nitrogen requirement and at times growers apply too much fertilizer-N that contributes to ground and surface water pollution. Fertilization can be made more efficient by plant analysis. Plant tissue (petiole) nitrate testing is a way of monitoring the nitrogen condition of the crop during the growing season. This is an especially useful method as the petiole is...

Urtica dioica L. is an Iranian native pharmacological plant for which little attention has been paid to the anatomical structure. Medical applications of this plant include diabetes therapy, digestive improvement, anemia and kidney disease therapy. Because climatic conditions can affect the anatomical structure which in turn affects pharmacological compositions, research on the anatomy of this ...

It has been observed in this laboratory (15) that the normally polar distribution of callus growth on tobacco stem explants becomes non-po'ar in the presence of low levels of 2,3,5-triiodobenzoic acid (TIBA), while the amount of callus growth is not diminished. It was thought that this phenomenon might reflect a specific inhibition by TIBA of the polar transport of auxin. Subsequent studies (10...

Leaf-stem allometry is an important spectrum that linked to biomass allocation and life history strategy in plants, although the determinants and evolutionary significance of leaf-stem allometry remain poorly understood. Leaf and stem architectures - including stem area/mass, petiole area/mass, lamina area/mass, leaf number, specific leaf area (LA), and mass-based leafing intensity (LI) - were ...