Longitudinal growth

Figure 16 Model of the longitudinal growth of bundle-like nucleus seen from lateral direction. The arrows indicate the direction of longitudinal growth at a velocity u. (From Refs. 104, no, and 111.)...

In fact, the further longitudinal growth of a bundlelike nucleus will be hindered by such factors as chain... 

Fig. 4. Spatial distribution of (a) relative elemental elongation rate (longitudinal growth rate) and (p) osmotic potential in the apical 10 mm of maize primary roots growing at various vermiculite water contents (see Fig. 3). Growth distributions were obtained by time-lapse photographic analysis of the growth of marked roots points are means from 5 or 6 roots. Osmotic potentials were measured on bulked samples from 30-50 roots points are means s.d. (n = 3-7). Root elongation rates (a, inset) were constant when the measurements were made. Modified from Sharp et al. (1988, 1989).

We have already stated In the previous paper O) that, under the supersaturation pressure of 5 to 8 MPa, the longitudinal growth rate of a rectangular pillar-shaped crystal attained 1.0 mm/mln.MPa In the same concentration, whereas the transverse growth rate was too low to detect. 

The anabolic effects of somatropin are mediated by somatomedins or insulin-like growth factors. Somatropin is a synthetic polypeptide identical to the natural occurring growth hormone which stimulates longitudinal growth. Only preparations made with recombinant DNA technology are used nowadays. They can consist of 191 amino acids as growth hormone itself or 192 amino acids with one extra methionine. Somatropin is employed in the treatment... 

Longitudinal growth (primary growth), which takes place in the early season, proceeds at the end of the stem, branches and roots. The growth points are located inside the buds, which have been formed during the preceding autumn. 

The induced inhibition of longitudinal growth by tetcyclacis results both from inhibited cell elongation and from reduced cell division. The relative proportions to which cell elongation and cell division contribute to the shortening effect varied in trials with maize, sunflowers, and soybeans, i.e., the influence effected via cell division increased with an increase in concentration of the PBR. The inhibitory effect on cell division detected in intact plants has been confirmed in cell suspension cultures of the same plant species (11). 

Longitudinal growth may be gradual or in phases, for instance when there are dry or cold seasons, when growth is by shoots or innovations (see also 36,9-16). These, espeoially when young, may have a different colour and pubescence. Here the presence of stipules, which may drop off very soon, is best checked. The first leaves may be reduced to cstsphylls (see 38,3 1). 

B37. Bucher, H., Zapf,., Torresani, T., Trader, A., Froesch, E. R., andlllig, R., Insulin-like growth factors I and II, prolactin and insulin in 19 growth hormone-deficient children with excessive, normal or decreased longitudinal growth after operation for cra-niopharygioma. N. Engl. J. Med. 309, 1142-1146 (1983). 

Treatment with benzoylprop-ethyl hinders the longitudinal growth of Avena sp. stunted plants develop which are unable to compete with the crop. 

Ethylene is a hydrocarbon plant hormone that comes from the methionyl moiety of S-adenosylmethionine. Ethylene stimulates fruit n 2 ripening and the aging of flowers, and it inhibits seedling growth. It also redirects auxin transport (another plant hormone) to promote transverse, rather than longitudinal, growth of plants. 

The most striking physiological effect of GH is the stimulation of the longitudinal growth of bones. GH also increases bone mineral density after longitudinal growth ceases and epiphyses have closed. GH stimulates myoblast differentiation (in experimental animals), increases muscle mass (in human subjects with GH deficiency), increases glomerular filtration rate, and stimulates preadipocyte differentiation into adipocytes. 

Figure 6. Prevention of lAA induced autogenous growth inhibition (bending of bean intemode sections) (upper data) by BR. Bean internode section were pretreated for 1 hour with either lAA (dotted line) or lAA plus 200 pmol of BR (solid line). Data in lower graph show longitudinal growth of the internodes.

Four main classes of natural and synthetic plant growth substances are distinguished 1) The 3-indolylacetic acid derivatives (lAA) and other C-3 substituted indoles, previously known as auxins, induce a pronounced longitudinal growth, stimulate the formation of roots and flowers, the activity of the cambium, and influence fruit ripening and numerous other developmental processes in the plant. In the literature many compounds with different constitutions are also designated as auxins if they have activities similar to those of lAA. These include, e. g., 2-naphthyloxyacetic acid, benzoic acid, phenoxycarboxylic acid derivatives. 

Adapted by permission of John Wiley Sons, Inc. from Pennings, A. J., Bundle-like nucleation and longitudinal growth of fibrillar polymer crystals from flowing solutions , J. Polymer Sci. (Symp) 59, 55 (1977). Copyright 1977 John Wiley Sons, Inc. 

A. Zwijnenburg and A.J. Pennings, Longitudinal growth of polymer crystals from flowing... 

AJ. Pennings, J.C. Torfs, Longitudinal growth of polymo- crystals from flowing solutions- VOL... 

---