Pseudotransverse divisions and intrusive elongation of fusiform initials in the storeyed cambium of Tilia

Abstract

ZAGORSKA-MAREK, B. 1984. Pseudotransversc divisions and intrusive elongation of fusiform initials in thc storcyed cambium of Tilitr. . The inclination. shape, and disappearance of individual fusiform initials wcrc studicd in thc storcycd cambium of Tilin. Changes in inclination wcrc accomplished through oricntcd cell-end shifting and pscudotransvcrsc divisions combined with intrusive elongation. Rapid reorientation was associated with an increase in both radial and pseudotransversc anticlinal divisions, resulting in an ovcrproduction of daughter cells; surplus cells wcrc climinated. creating spacc for the intrusive elongation of adjoining initials. The storeyed pattern was both disrupted and restored as a consequence of pseudotransverse divisions and intrusive elongation. Abnormally elongated cell ends shortened to thc level of the storey border. Movement between storeys occurred as a result of intrusive elongation of one cell end in association with either pseudotransversc division or a gradual shortening of the opposite end. The combined findings of fluctuations in cell inclination, movement between storeys, and continual disturbance and restoration of the storeyed pattern indicate that dcvelopmental changes in the storeyed cambium are much more dynamic than previously suspected. ZAGORSKA-MAREK, B. 1984. Pseudotransverse divisions and intrusive elongation of fusiform initials in the storeyed cambium of ti lit^. Can. J. Bot. 62: 20-27. L'inclinaison, la forme et la disparition de ehaque initiale fusiforme ont CtC dtudiCes dans du cambium bien CtagC de Tilin.

Ontogenetic development of storied ray pattern in cambium of Hippophaë rhamnoides L.

“…2: 93-101, 2004 99 ACTA SOCIETATIS BOTANICORUM POLONIAE 1927;Butterfield 1972;Zagórska-Marek 1977Cumbie 1984;W³och, Szendera 1989;Kojs 1999), specifically in Aeschynomene virginica where Cumbie (1984) observed the storeys forming near the pith because of numerous divisions of this type. We have found no evidence of dynamic formation and maintenance of storeys through controlled extensive intrusive elongation of fusiform initials and their pseudotransversal divisions described by Zagórska--Marek (1984) for storied cambium of Tilia. This however cannot be excluded, as acting in the first two years of cambial ontogeny, when, due to discontinuous record of cambial patterns in the wood (in terminal parenchyma only), tracing the derivatives of multiplying quickly fusiform initials was practically impossible.…”

“…According to this view the storey of fusiform initials should be regarded as a single clone composed of cells which all developed from one ancestral, pro-cambial cell. Further investigations pointed to the possibility of dynamic maintenance of storied structure being often disturbed and subsequently repaired by excessive intrusive growth of fusiform initials and their pseudotransverse, shortening divisions (Zagórska-Marek 1984). Such atypical cellular events not only brake the clonal homogeneity of the storeys, they also prove that the storied pattern is not a rigid structure, a mere result of longitudinal, anticlinal divisions, but rather functions in a tissue, prior to becoming materialized visually, as a supracellular morphogenetic map with some sort of positional information for growing and dividing cambial cells.…”

Rearrangement of cells in storeyed cambium of Lonchocarpus sericeus (Poir.) DC connected with formation of interlocked grain in the xylem

“…As for the storeyed cambium, its cells divide longitudinally and their intrusive growth is connected only with a change of their inclination (Hejnowicz and Zagórska-Marek 1974;Krawczyszyn 1977;Włoch and Połap 1994). Intrusion into another storey occurs occasionaly (Włoch and Zagórska-Marek 1982;Zagórska-Marek 1984).…”

“…The rearrangement of cells is a result of the oriented intrusive growth at the apical and lateral radial edges of fusiform cells (Hejnowicz and Zagórska-Marek 1974;Włoch and Zagórska-Marek 1982;Zagórska-Marek 1984). The intrusive growth of cells on a given tangential surface of cambium occurs irregularly.…”

Formation of spiral grain in the wood of Pinus sylvestris L.

“…On the basis of the number of oblique anticlinal divisions and the rate of intrusive growth, however, he came to the conclusion that the intensity of those events suffices merely for the change of cell orientation of 0.2°for each 1 mm of growth. Zagórska-Marek (1984) observed that the rate of change in the investigation with Tilia averaged 1°/mm of radial width and the number of anticlinal pseudotransverse divisions was width, and pseudotransverse division dominated (Hejnowicz and Zagórska-Marek 1974).…”