High impact information on Pulvinus

• Leaflet movements in the legume Samanea saman are dependent upon massive redistribution of potassium (K), chloride (Cl), and other solutes between opposing (extensor and flexor) halves of the motor organ (pulvinus) [1].
• Second, a transient gradient of free indole-3-acetic acid (IAA) across the pulvinus was apparent shortly after initiation of gravistimulation [2].
• This is based on the observation that N-1-naphthylphthalamic acid will not inhibit gravitropic responses when applied to pulvinus tissue after the free IAA gradient peak has occurred [2].
• In the graviresponding pulvinus, hexose sugars (D-Glc and D-Fru) accumulated asymmetrically across the pulvinus [2].
• Over 4 h of gravistimulation, a gradual increase in the association of calreticulin and calmodulin transcripts with polyribosomes was seen predominantly in the lower one-half of the maize pulvinus; the association of transcripts for vacuolar invertase with polyribosomes did not change over this period [3].

Anatomical context of Pulvinus

• Leaflet movements of Samanea saman (Jacq.) Merr. depend in part upon circadian-rhythmic, light-regulated K+ fluxes across the plasma membranes of extensor and flexor cells in opposing regions of the leaf-moving organ, the pulvinus [4].
• Protoplasts isolated from the laminar pulvinus of Phaseolus vulgaris and bathed in a medium containing KCl as the major salt were found to swell in response to IAA and to shrink in response to ABA [5].

Associations of Pulvinus with chemical compounds

• A gravity-induced increase in pulvinus thickness was observable within 40 degrees of the vertical in coumarin-treated pulvini [6].
• The amount of annexin in the pulvinus increased at night and was sensitive to abscisic acid; however, there was no detectable induction of annexin by cold or mechanical stimulus [7].

Gene context of Pulvinus

• PEPC transcripts were also found in vascular tissue of roots and nodules and in the pulvinus of petioles [8].
• [3H]Gibberellin A20 (GA20) of high specific radioactivity (49.9 gigabecquerel per millimole) was applied equilaterally in a ring of microdrops to the internodal pulvinus of shoots of 3-week-old gravistimulated and vertical normal maize (Zea mays L.), and to a pleiogravitropic (prostrate) maize mutant, lazy (la) [9].
• The resulting curvatures of a responding pulvinus can be expressed mathematically by relating the angle of curvature (theta) to the original length (L0) and the maximal length of the lower surface (L1) and the diameter of the organ (D), using the equation, theta = (L1-L0)/D, where theta is in radians [10].

References