Response of the vascular cambium to reorientation in patch grafts

1976 ◽  
Vol 54 (3-4) ◽  
pp. 361-373 ◽  
Author(s):  
B. W. Thair ◽  
T. A. Steeves

The vascular cambium was reoriented in square 5-mm panels of bark at 90° and 180° from the normal position in three varieties of Malus baccata and Malus sylvestris (ornamental crabapple), Cornus stolonifera, Sorbus aucuparia, and Thuja occidentalis, Douglasii pyramidalis. Panels grafted in the normal orientation served as controls. The cambium in the panels continued to function normally, and where it was reoriented, it retained the imposed orientation. The secondary vascular tissues that were produced likewise retained the imposed orientation, a feature which was particularly striking in the case of transversely oriented panels. In early growth after the grafting, the secondary xylem showed some histological abnormalities particularly in abnormally oriented panels, but these diminished in later-formed xylem in the case of normally and transversely oriented panels. It is concluded that the cambial initials possess a high degree of autonomy which is reflected in their resistance to realignment which would correspond to the lines of flow of nutrients and water in an axis into which they are grafted.

1955 ◽  
Vol 33 (1) ◽  
pp. 113-138 ◽  
Author(s):  
M. W. Bannan

The vascular cambium, to use the term in the general sense as designation for the entire meristem producing secondary xylem and phloem, consists of the self-perpetuating uniseriate initiating layer and the derived tissue mother cells. In the dormant condition the cambium in the stems of mature trees is one to four, usually two to three, cells wide. The one to three tangential tiers of cells toward the xylem are made up of xylem mother cells, and the single tier next the phloem is composed of initial cells. On reactivation all cambial cells expand radially. Periclinal divisions soon follow, usually according to a sequence in which the xylem mother cells in the tier contiguous to the late wood are the first to divide and the initial cells last, although some variation occurs. The zone of periclinal division rapidly widens to 100-300 μ in vigorous open-grown trees, the center of activity during this vernal surge of growth clearly being among the dividing and redividing xylem mother cells. Thereafter, from mid-June to August, a continued decline in cell production follows as the zone of xylem mother cells decreases from many tangential rows to few. The initiating layer becomes relatively more important as the center of cell generation, and toward the end of the growing season the initial cells undergo those changes which modify the cellular pattern of the cambium and hence of the derived tissues. Phloem development begins later than that of xylem, and at the end of May the new phloem varies from none to four cells as compared with a xylemward production of 30-60 cells in vigorous trees. Phloem expansion continues at a more or less steady rate from June to the termination of cambial activity in August or early September. The annual phloem increments vary less in width than those of xylem.


IAWA Journal ◽  
2021 ◽  
pp. 1-16
Author(s):  
Bei Luo ◽  
Arata Yoshinaga ◽  
Tatsuya Awano ◽  
Keiji Takabe ◽  
Takao Itoh

Abstract We studied the time-course of stem response for six months following complete girdling in branches of Aquilaria sinensis to determine the potential role of interxylary phloem (IP) in this response. It was found that the vascular cambium, as well as its derivative secondary xylem and phloem, regenerated fully through redifferentiation of IP. We confirmed that vascular cambium regenerated within one month after girdling based on observation of new vessels, IP, and secondary phloem fibers. The time-course study showed that IPs made connections with each other, merged, and became larger through the proliferation of IPs parenchyma cells and the cleaving of secondary xylem in a narrow zone 400 to 1000 μm deep inside the girdled edge. This led to the formation of a complete circular sheath of vascular cambium, followed by the regeneration of vascular tissue. It is worth noting that the secondary xylem is regenerated always following the formation of a thick belt of wound xylem.


IAWA Journal ◽  
2018 ◽  
Vol 39 (2) ◽  
pp. 191-208 ◽  
Author(s):  
Anna B. Wilczek ◽  
Muhammad Iqbal ◽  
Wieslaw Wloch ◽  
Marcin Klisz

ABSTRACTAll cell types of the secondary xylem arise from the meristematic cells (initials) of the vascular cambium and grow under mechanical constraints emerging from the circular-symmetrical geometry that characterises many tree trunks. The course of intrusive growth of cambial initials has been elucidated, but is yet to be described in the case of xylem fibres. This study explains the geometry of intrusive growth of the secondary xylem fibres in the trunk ofRobinia pseudoacacia.Long series of serial semi-thin sections of the vascular cambium and the differentiating secondary xylem were analysed. Since fibres grow in close vicinity to expanding cells of the derivatives of the vascular cambium, we assumed that they have similar growth conditions. Dealing with the cylindrical tissue of the vascular cambium in a previous study, we used a circularly symmetrical equation for describing the growth mechanism of cambial initials. Like the cambial initials, some of the cambial derivatives differentiating into the various cell types composing the secondary xylem also exhibit intrusive growth between the tangential walls of adjacent cells. As seen in cross sections of the cambium, intrusively growing initials form slanted walls by a gradual transformation of tangential (periclinal) walls into radial (anticlinal) walls. Similarly, the intrusive growth of xylem fibres manifests initially as slants, which are formed due to axial growth of the growing cell tips along the tangential walls of adjacent cells. During this process, the tangential walls of adjacent cells are partly separated and dislocated from the tangential plane. The final shape of xylem fibres, or that of vessel elements and axial parenchyma cells, depends upon the ratio of their intrusiveversussymplastic growths in the axial, circumferential and radial directions.


IAWA Journal ◽  
1995 ◽  
Vol 16 (2) ◽  
pp. 151-158 ◽  
Author(s):  
R. W. den Outer ◽  
W. L. H. van Veenendaal

The development of diffuse included phloem strands in Combretum nigricans sterns is described, During a short period of time, a small phloem strand is cut off locally in an inward direction by an otherwise normal bidirectional vascular cambium. This contrasts with previous descriptions and interpretations because these strands are not formed after redifferentiation of secondary xylem parenchyma. A complementary cambium formed at the inner border of the young strand somewhat enlarges the strand and, during a relatively long period, produces secondary phloem outwards. Finally this complementary cambium stops functioning as a cambium and merges with the secondary phloem it has produced. Radial rows of cells are present within the included phloem strands which continue into the later-formed secondary xylem; rays transverse the strands. Crushing of the phloem takes place near the outer border of the strand, forming cap-like tissues of disorganized cells.


Botany ◽  
2015 ◽  
Vol 93 (4) ◽  
pp. 211-220 ◽  
Author(s):  
Arno Fritz das Neves Brandes ◽  
Claudio Sergio Lisi ◽  
Leonardo Davi S.A.B. da Silva ◽  
Kishore S. Rajput ◽  
Cláudia Franca Barros

Cambial activity and the formation of secondary xylem were investigated in the main stem of three arboreal leguminous species and one liana. To compare the seasonal vascular cambium behavior of these species, two methods were concurrently applied: induction of injury in the vascular cambium and anatomical analysis of the vascular cambium and adjacent zones (differentiation zone). One tree species, Pseudopiptadenia contorta (DC.) G.P.Lewis & M.P.Lima, was sampled in three forest formations: alluvial, submontane, and montane. Two more tree species, Apuleia leiocarpa (Vogel) J.F.Macbr. and Pseudopiptadenia leptostachya (Benth.) Rauschert, were sampled in submontane and montane forest, respectively. Dalbergia frutescens (Vell.) Britton var. frutescens, a liana, was sampled in montane forest. All species investigated showed distinctive formation of annual growth rings. Reactivation of the vascular cambium was observed at the end of spring, and it remained active during the summer. Thereafter, cambial activity either ceased or declined dramatically at the end of autumn. Similar to the tree species studied, cambial activity in D. frutescens var. frutescens showed similar seasonal cambial activity throughout the year. Based on both direct and indirect methods, our results showed that cambial activity and wood formation only occurred during the rainy season, suggesting the potential of these species for use in dendrochronological studies.


IAWA Journal ◽  
2016 ◽  
Vol 37 (3) ◽  
pp. 431-443 ◽  
Author(s):  
Kishore S. Rajput ◽  
Himansu Baijnath

The stem anatomy of Passiflora edulis, P. foetida, P. suberosa, P. subpeltata, and P. vesicaria was studied in samples collected in Durban (KwaZulu-Natal Province, South Africa) and Baroda (Vadodara, Gujarat State, India). Radial stem growth in all the species is realized by a single, bidirectional vascular cambium. However, unequal activity in small segments of the cambial cylinder results in a lobed stem outline in P. foetida var. ellisonii, and a furrowed xylem cylinder in P. edulis f. edulis and P. vesicaria var. vesicaria. In P. subpeltata and P. edulis f. flavicarpa the xylem remains cylindrical in outline. In all the species investigated, secondary xylem is diffuse-porous with growth rings indistinct or absent. In transverse view, vessels are round to oval with different diameter categories, including very narrow fibriform vessels intermixed. In P. edulis f. edulis, stems are lobed due to the unidirectional activity of the cambium in small segments. Rays are mostly both narrow (1–3-seriate) and wide (multiseriate). The latter often become aggregate at some distance from the pith.


1972 ◽  
Vol 50 (12) ◽  
pp. 2649-2658 ◽  
Author(s):  
Gar W. Rothwell ◽  
Thomas N. Taylor

The monostelic seed fern Schopfiastrum decussatum Andrews is described from a specimen collected at a Middle Pennsylvanian petrifaction locality in southern Illinois. The specimen measures 24 cm long and is about 1.1 cm in diameter. Two petioles are attached to the axis and abundant foliar material is also present. Leaf arrangement is alternate and distichous. The stem consists of an exarch protostele surrounded by a prominent zone of secondary xylem. Secondary phloem and a vascular cambium are also preserved. The cortex is characterized by an undulating outer epidermal zone consisting of alternating ridges and furrows; internally this zone is delimited by conspicuous lacunae. Sclerenchyma bands occur in the outer cortex, with prominent resin canals present in the inner cortex. The fronds are represented by dichotomizing rachides, primary pinnae, and laminar pinnules. Features of the plant are compared to those of other Carboniferous pteridosperms, and a reconstruction of Schopfiastrum is included.


2021 ◽  
Author(s):  
Yayu Guo ◽  
Huimin Xu ◽  
Hongyang Wu ◽  
Weiwei Shen ◽  
Jinxing Lin ◽  
...  

Abstract Understanding the changing patterns of vascular cambium during seasonal cycles is crucial to reveal the mechanisms that control cambium activity and wood formation, but this area has been underexplored, especially in conifers. Here, we quantified the changing cellular morphology patterns of cambial zones during the active, transition and dormant stages. With the help of toluidine blue and periodic acid Schiff staining to visualize cell walls and identify their constituents, we observed decreasing cambial cell layers, thickening of newly formed xylem cell walls and increased polysaccharide granules in phloem from June to the following March over the course of our collecting period. Pectin immunofluorescence showed that dormant stage cambium can produce highly abundant de-esterified homogalacturonan and (1–4)-β-D-galactan epitopes, while active cambium can strong accumulate high methylesterified homogalacturonan. Calcofluor white staining and confocal Raman spectroscopy analysis revealed regular changes in the chemical composition of cell walls, such as relative lower cellulose deposition in transition stage in vascular cambium, and higher lignin accumulation was found in dormant stage in secondary xylem. Moreover, RT-qPCR analysis suggested that various IAA (Aux/IAA protein), CesA, CslA and HDZ genes, as well as NAC, PME3 and PME4, may be involved in cambium activities and secondary xylem formation. Taken together, these findings provide new information about cambium activity and cell differentiation in the formation, structure, and chemistry in conifers during the active–dormant transition.


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