Characean cells develop alternating alkaline and acid bands on their surface upon illumination. However, the mechanism of band formation is not fully understood. In the present study, we succeeded in inducing a new alkaline band at an original acid band in internodal cells of Chara corallina. Chloroplasts in an acid band were locally removed by wounding the cell in the absence of the cell turgo...

The Nilella intermodal cell is formed by a division of the segment cell, the latter being a direct derivative of the shoot apical cell. The internodal cell is remarkable in that it elongates from an initial length of about 20 microns to a mature length of about 60 millimeters. The structures of the apical and segment cells, and the internodal cells in all stages of development were examined wit...

It has been argued theoretically and confirmed experimentally that conduction velocity (theta) should be proportional to nerve fibre diameter for myelinated fibre tracts, such as normal peripheral nerve, exhibiting 'structural' similarity'. In some axons, however, the nodes of Ranvier are more closely spaced than in normal peripheral nerve. Analytic arguments have suggested that when internodal...

common precipitating factors. Atrial dilatation was common but the SA node and internodal tracts were within normal limits. In contrast patients with long-term atrial fibrillation showed combinations of nodal artery stenosis, muscle loss in the SA node or internodal tracts, and atrial dilatation. The pathological conditions found most commonly were chronic rheumatic valve disease, ischaemic hea...

High frequency somatic embryogenesis and plant regeneration was achieved on calli developed from internodal and flower buds of E. foetidum. The explants were cultured on Murashige and Skoog medium supplemented with different concentrations and combinations of BA and IAA. The nodal explants produced multiple adventitious shoots while the internodal and flower buds induced callus, from which mult...

Predictions that conduction velocities are sensitive to the distance between nodes of Ranvier in myelinated axons have implications for nervous system function during growth and repair. Internodal lengths defined by Schwann cells in hindlimb nerves, for example, can undergo a 4-fold increase during mouse development, and regenerated nerves have internodes that are uniformly short. Nevertheless,...

The vertical distribution of foliage biomass is important because it is associated with photosynthesis and is closely related to some wood quality attributes such as branch diameter and sapwood content. In this article we propose a model to predict foliage biomass distribution within the crown for jack pine trees in Eastern Canada. This model has two parts. The first one distinguishes the propo...

Myelin sheath geometry, encompassing myelin sheath thickness relative to internodal length, is critical to optimize nerve conduction velocity and these parameters are carefully adjusted by the myelinating cells in mammals. In the central nervous system these adjustments could regulate neuronal activities while in the peripheral nervous system they lead to the optimization and the reliability of...

Measurements were made of (45)Ca influx into isolated internodal cells of Chara corallina and also into internodal cells of intact plants. (45)Ca influx was closely related to growth. In rapidly expanding internodal cells, the influx was approximately 1.4 nmol m(-2) s(-1) compared to the influx in mature cells from slow-growing cultures of 0.2 nmol m(-2) s(-1). Isolated internodal cells had inf...

Multihop networks must pass messages between source and destination nodes via intermediate links and nodes. Assuming propagation delay is ignored, the mean amount of time the average message stays in a multihop network is directly proportional to the mean distance, in hops, between nodes. Thus, the aggregate link capacity of the network is also directly proportional to this "mean internodal dis...