P lant root hairs are experimental model systems for research on plant cell growth. The involvement of protons and reactive oxygen species (ROS) in root hair growth and development has been the subject of significant research effort (e.g., refs. 1–4). pH specifically has been implicated in the control of plant cell expansion (5), including that in root hair cells (6). ROS have recently come to ...

The hyperpolarization-activated cation channels (I(h)) play a distinct role in rhythmic activities in a variety of tissues, including neurons and cardiac cells. In the present study, we investigated whether Ca(2+) can permeate through the hyperpolarization-activated pacemaker channels (HCN) expressed in HEK293 cells and I(h) channels in dorsal root ganglion (DRG) neurons. Using combined measure...

Short term (10 min) influx of (86)Rb-labeled potassium into corn (Zea mays L. WF9 x M14) root segments was inhibited by La (NO(3))(3) or LaCl(3). Half maximal inhibition of K(+) influx from 0.25 mm KCl was obtained with 0.025 mm La(3+). Kinetic analysis indicated the inhibition to be of a competitive nature. With absorption periods exceeding one hour, La(3+) no longer inhibited, but rather stim...

This paper introduces a family of Askey-Wilson type orthogonal polynomials in n variables associated with a root system of type BCn. The family depends, apart from q, on 5 parameters. For n = 1 it specializes to the four-parameter family of one-variable Askey-Wilson polynomials. For any n it contains Macdonald’s two three-parameter families of orthogonal polynomials associated with a root syste...

Least squares estimator of the stability parameter ̺ := |α|+ |β| for a spatial unilateral autoregressive process Xk,l = αXk−1,l +βXk,l−1 +εk,l is investigated and asymptotic normality with a scaling factor n5/4 is shown in the unstable case ̺ = 1. The result is in contrast to the unit root case of the AR(p) model Xk = α1Xk−1+ · · ·+αpXk−p+εk, where the limiting distribution of the least squares e...

Throughout their life cycle, plants produce new organs, such as leaves, flowers, and lateral roots. Organs that have served their purpose may be shed after breakdown of primary cell walls between adjacent cell files at the site of detachment. In Arabidopsis, floral organs abscise after pollination, and this cell separation event is controlled by the peptide INFLORESCENCE DEFICIENT IN ABSCISSION...

In this paper we develop a test of the joint null hypothesis of parameter stability and a unit root within an ADF style autoregressive specification whose entire parameter structure is potentially subject to a structural break at an unknown time period. The maintained underlying null model is a linear autoregression with a unit root, stationary regressors and a constant term. As a byproduct we ...

Understanding the kinetics of Zn absorption by roots and its effect on morphology this organ is relevant for improving crop management, but still poorly studied common beans. Therefore, an experiment was conducted in a hydroponic system with five initial concentrations (CZnI): 0.0; 1.0; 4.0; 16.0 48.0 µmol L-1. The installed plants at V3 stage development aliquots solution collected over 24 h. ...