An anatomical study of epicormic bud strand structure in Eucalyptus cladocalyx (Myrtaceae)

2000 ◽  
Vol 48 (2) ◽  
pp. 233 ◽  
Author(s):  
G. E. Burrows
Keyword(s):  
Transverse Section ◽  
Secondary Xylem ◽  
Large Diameter ◽  
Anatomical Study ◽  
Leaf Primordia ◽  
Bark Thickness ◽  
Outer Bark ◽  
Epicormic Shoots ◽  
Vascular Connections ◽  
Do So

Epicormic bud strands in Eucalyptus cladocalyx F.Muell. extended from the pith to the outer bark. In large-diameter stems (30 cm diameter, 2 cm bark thickness) the epicormic bud strands had their greatest anatomical complexity at the level of the vascular cambium. At this level the epicormic bud strand was about 3 mm wide × 5 mm high in transverse section and within it were 22–40 radially arranged strips of cells of meristematic appearance embedded in a mainly parenchymatous matrix. Well-developed buds with leaf primordia and vascular connections were never observed in intact trees, although when stimulated each meristem strip could produce numerous bud primordia. Toward the bark surface the epicormic bud strands became progressively simpler in structure. On the stem surface, the position of the epicormic bud strand was shown by a number of adjacent small protrusions which appeared to have no meristematic potential. From the outer secondary xylem to the pith the bud strand usually became slightly smaller in diameter and its cells, although nucleated, had thick lignified walls and the meristem strips were much reduced or were not present. In most previously investigated angiosperm tree genera epicormic shoots develop from suppressed buds embedded in the bark. Eucalyptus appears to be unique in that suppressed buds are not present in the bark and that each epicormic bud strand has the potential to form numerous bud primordia when stimulated to do so.

scholarly journals Chloroplast Distribution in the Stems of 23 Eucalypt Species

Plants ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 1814
Author(s):  
Geoffrey E. Burrows ◽  
Celia Connor
Keyword(s):  
Woody Plants ◽  
Secondary Xylem ◽  
Narrow Band ◽  
Large Diameter ◽  
Small Diameter ◽  
High Density ◽  
Outer Bark ◽  
Leaf Mesophyll ◽  
Eucalypt Species ◽  
Wide Range

Small diameter branchlets and smooth barked stems and branches of most woody plants have chloroplasts. While the stems of several eucalypt species have been shown to photosynthesise, the distribution of chloroplasts has not been investigated in detail. The distribution of chloroplasts in branchlets (23 species) and larger diameter stems and branches with smooth bark (14 species) was investigated in a wide range of eucalypts (species of Angophora, Corymbia and Eucalyptus) using fresh hand sections and a combination of bright field and fluorescence microscopy. All species had abundant stem chloroplasts. In both small and large diameter stems, the greatest concentration of chloroplasts was in a narrow band (usually 100–300 μm thick) immediately beneath the epidermis or phellem. Deeper chloroplasts were present but at a lower density due to abundant fibres and sclereids. In general, chloroplasts were found at greater depths in small diameter stems, often being present in the secondary xylem rays and the pith. The cells of the chlorenchyma band were small, rounded and densely packed, and unlike leaf mesophyll. A high density of chloroplasts was found just beneath the phellem of large diameter stems. These trees gave no external indication that green tissues were present just below the phellem. In these species, a thick phellem was not present to protect the inner living bark. Along with the chlorenchyma, the outer bark also had a high density of fibres and sclereids. These sclerenchyma cells probably disrupted a greater abundance and a more organised arrangement of the cells containing chloroplasts. This shows a possible trade-off between photosynthesis and the typical bark functions of protection and mechanical strength.

Bark in Woody Plants: Understanding the Diversity of a Multifunctional Structure

2019 ◽  
Vol 59 (3) ◽  
pp. 535-547 ◽  
Author(s):  
Julieta A Rosell
Keyword(s):  
Woody Plants ◽  
Fire Regime ◽  
Soluble Sugars ◽  
Plant Performance ◽  
Functional Ecology ◽  
Bark Thickness ◽  
Outer Bark ◽  
Plant Parts ◽  
Selective Forces ◽  
Plant Ecological

Abstract Most biological structures carry out multiple functions. Focusing on only one function to make adaptive inferences overlooks that manifold selection pressures and tradeoffs shape the characteristics of a multifunctional structure. Focusing on single functions can only lead to a partial picture of the causes underlying diversity and the evolutionary origin of the structure in question. I illustrate this discussion using bark as a study case. Bark comprises all the tissues surrounding the xylem in woody plants. Broadly, bark includes an inner and mostly living region and an outer, dead one. Of all plant structures, bark has the most complex anatomical structure and ontogenetic origin involving two (and often three) different meristems. Traditionally, the wide diversity in bark traits, mainly bark thickness, has been interpreted as the result of the selective pressures imposed by fire regime. However, recent research has shown that explanations based on fire regime cannot account for salient patterns of bark variation globally including the very strong inner bark thickness–stem diameter scaling, which is likely due to metabolic needs, and the very high intracommunity variation in total, inner, and outer bark thickness, and in inner:outer proportions. Moreover, explanations based on fire disregard that in addition to fire protection, bark carries out several other crucial functions for plants including translocation of photosynthates; storage of starch, soluble sugars, water, and other compounds; protection from herbivores, pathogens, and high temperatures; wound closure, as well as mechanical support, photosynthesis, and likely being involved in xylem embolism repair. All these functions are crucial for plant performance and are involved in synergistic (e.g., storage of water and insulation) and trade-off relationships (e.g., protection from fire vs photosynthetic activity). Focusing on only one of these functions, protection from fire has provided an incomplete picture of the selective forces shaping bark diversity and has severely hindered our incipient understanding of the functional ecology of this crucial region of woody stems. Applying a multifunctional perspective to the study of bark will allow us to address why we observe such high intracommunity variation in bark traits, why some bark trait combinations are ontogenetically impossible or penalized by selection, how bark is coordinated functionally with other plant parts, and as a result, to understand how bark contributes to the vast diversity of plant ecological strategies across the globe.

scholarly journals The onset of xylogenesis in Smith fir is not related to outer bark thickness

2019 ◽  
Vol 106 (10) ◽  
pp. 1386-1391
Author(s):  
Xiaoxia Li ◽  
Sergio Rossi ◽  
Eryuan Liang
Keyword(s):  
Bark Thickness ◽  
Outer Bark

Comparative developmental anatomy of the taproot of the cucurbitaceous vines Citrullus colocynthis (perennial), Citrullus lanatus (annual) and Cucumis myriocarpus (annual)

2014 ◽  
Vol 62 (7) ◽  
pp. 537 ◽  
Author(s):  
Geoffrey E. Burrows ◽  
Razia S. Shaik
Keyword(s):  
Secondary Xylem ◽  
Citrullus Lanatus ◽  
Large Diameter ◽  
Small Diameter ◽  
Low Density ◽  
Citrullus Colocynthis ◽  
Xylem Parenchyma ◽  
Developmental Anatomy ◽  
Ray Parenchyma ◽  
Ecological Differences

The genus Citrullus (Cucurbitaceae) consists of four species of desert vines. Two species (Citrullus colocynthis and Citrullus lanatus) are widespread weeds on several continents. Above ground, they can be relatively difficult to distinguish apart. However, Citrullus colocynthis is a perennial with a tuberous taproot, whereas Citrullus lanatus is an annual with a slender taproot. We studied the morphology and anatomy of taproot development to better understand their structural and ecological differences. The annual Citrullus lanatus reached close to its maximum taproot diameter (~3 mm) soon after germination. The vascular cambium formed four relatively broad triangular sectors of fibres in which were embedded relatively large diameter vessels. These sectors were separated by narrower triangular areas of secondary ray parenchyma. In contrast, the taproot diameter of the perennial Citrullus colocynthis continued to increase during the study, reaching ~20 mm after 14 weeks. Most of this substantial root consisted of secondary xylem parenchyma, with a low density of relatively small diameter vessels and few fibres. The remarkable differences in root morphology and anatomy of the studied species of Citrullus are related to differences in their annual and perennial lifecycles. Interestingly, the slender taproots of Citrullus lanatus were calculated to have a similar theoretical hydraulic conductance to that of Citrullus colocynthis (large diameter taproot).

scholarly journals STOCKPLANT ETIOLATION AND SHOOT AGE EFFECTS ON ANATOMY AND ADVENTITIOUS ROOT FORMATION IN STEM CUTTINGS OF CARPINUS BETULUS `FASTIGIATA

HortScience ◽  
1990 ◽  
Vol 25 (9) ◽  
pp. 1095d-1095
Author(s):  
Brian K Maynard ◽  
Nina L. Bassuk
Keyword(s):  
Shoot Growth ◽  
Secondary Xylem ◽  
Anatomical Study ◽  
Adventitious Root Formation ◽  
Stem Cuttings ◽  
Linear Combinations ◽  
Carpinus Betulus ◽  
Regression Methods ◽  
Root Numbers ◽  
Shading Effects

New shoot growth of Carpinus betulus `fastigiata' was treated with stockplant etiolation and stem banding treatments and sampled for anatomical study at intervals over a 16-week period of greening following etiolation. Shading effects on the anatomy of the stem were also investigated. Numerous anatomical changes were noted with stem age and stockplant treatment. Among these were etiolation effects on the lignification of the secondary xylem, thickness of the periderm, and an increase in the percentage of sclereid-free gaps in the perivascular sclerenchyma, Stem banding increased the widths of the cortex and pith. Concomitant propagation studies revealed significant etiolation, shading, and banding effects on rooting percentages and root numbers. Using multiple linear regression methods rooting capacity was modelled best by linear combinations of the widths of the pith, non-lignified secondary xylem, cortical parenchyma and periderm, as well as the percentage of gaps in the sclerenchymatic sheath remaining non-sclerified. It is proposed that the development of sclereids in potential rooting sites reduces rooting potential. The exclusion of light during initial shoot development retards sclereid development by up to 3 months following treatment, which correlates well with observed increases in the rooting potential of etiolated and/or banded stems.

scholarly journals Systematic wood anatomical study in some species of Sapindaceae Juss. in South-Western Nigeria

2021 ◽  
Vol 3 (2) ◽  
pp. 37-46
Author(s):  
M. Bulama-Modu ◽  
◽  
T. K. Muftaudeen ◽  
A. E. Ayodele ◽  
A. J. Akinloye ◽  
...  
Keyword(s):  
Transverse Section ◽  
Anatomical Study ◽  
Anatomical Studies ◽  
Radial Section ◽  
The Family ◽  
Ray Cells ◽  
Diffuse Porous ◽  
Blighia Sapida

Comparative wood anatomical studies was carried out on ten species in the family Sapindaceae. The species were relatively uniform in the features of their vessels, in which diffuse porous was observed with solitary vessels to pore multiples in transverse section and ray cells were predominantly heterogeneous in radial section. Fibres were long and extensive. The longest fibre was observed in Blighia sapida (1025±28.5 µm), while the shortest fibre was observed in Cardiospermum halicacabum (139±6.5 µm). The longest vessel was observed in Deinbolia pinnata (509±34.9 µm) and the shortest vessel was observed in Cardiospermum halicacabum (85.36±4.9 µm). The implication of these features in the taxonomy of the family was discussed. The Dendrogram based on the quantitative wood characters confirmed Allophylus africanus and Allophylus spicatus belong to the same genus as classified, likewise Blighia unijugata, Blighia sapida but Cardiospermum halicacabum is closely related to Paullinia pinnata while others exhibited distinct generic characters.

The development of cauliflory in redbud, Cercis canadensis (Fabaceae)

1991 ◽  
Vol 69 (9) ◽  
pp. 1956-1963 ◽  
Author(s):  
Shirley A. Owens ◽  
Frank W. Ewers
Keyword(s):  
Woody Plants ◽  
Vascular Tissue ◽  
Stem Elongation ◽  
Third Order ◽  
Epicormic Shoots ◽  
First Order ◽  
Cercis Canadensis ◽  
Foliage Leaf ◽  
Vascular Connections ◽  
Scanning Electron

Cauliflory, flowering on older branches or trunks of woody plants, in Cercis canadensis was studied using light and scanning electron microscopy and macroscopic bud counts. A linear series of up to 10 floral buds are initiated in the axil of the foliage leaf before stem elongation is completed. These buds sequentially mature into first-order inflorescences over a 5-year period. Although an individual inflorescence flowers only once, second-order reproductive buds are formed in the axils of the basal bud scales of the inflorescence and can produce third-order reproductive buds. Buds and the bases of abscised inflorescences form wens, which are macroscopic swollen areas along the stem, corresponding to the original orthodistichous phyllotaxy. Branching of primary vascular tissue in a wen indicates a continuum of vascular connections between reproductive buds and the vascular traces to the inflorescences can be followed to the pith. The wens often produce epicormic shoots that are themselves cauliflorous with first-order reproductive buds formed in their leaf axils. The shoots usually abscise above the first-order reproductive buds at their base. These buds, along with the higher order reproductive buds, perpetuate the cauiflorous condition throughout the life of the plant. Key words: axillary buds, cauliflory, Cercis canadensis, epicormic shoots, wens.

The effect of tree dimension on the diversity of bark microhabitat structures and bark use in Douglas-fir (Pseudotsuga menziesii var. menziesii)

2011 ◽  
Vol 41 (2) ◽  
pp. 300-308 ◽  
Author(s):  
Alexa K. Michel ◽  
Susanne Winter ◽  
Andreas Linde
Keyword(s):  
Pacific Northwest ◽  
Pseudotsuga Menziesii ◽  
Large Diameter ◽  
Structural Complexity ◽  
Douglas Fir ◽  
Forest Monitoring ◽  
Tree Bark ◽  
Bark Thickness ◽  
Tree Diameter ◽  
The Us

The focus of this study was to investigate the role of tree dimension and associated bark structures for high structural complexity and high natural biodiversity in forest ecosystems. Two-hundred and ninety-one Douglas-fir (Pseudotsuga menziesii var. menziesii (Mirbel) Franco) trees in two regions of the US Pacific Northwest were investigated for the relationship between tree diameter and bark thickness (measured as bark fissure depth) and the relationships of both to bark microhabitats and signs of bark use. Our results emphasize the habitat function of tree bark of large-diameter Douglas-fir trees. Many bark microhabitat types and their total abundance significantly increased with increasing tree diameter and bark thickness. These were bark pockets with and without decaying substrate, bowls in the bark, and signs of bark use, e.g., small holes from woodpecker drillings and large insects, large bark excavations from woodpeckers, spider funnel webs, natural cavities at the stem base without decay, and the occurrence of herb vegetation at the tree base. In forest monitoring, tree diameter may be a good indicator of the number of bark microhabitats and of bark thickness because it is strongly related to both of these variables. However, because of the high variability of bark thickness in large-diameter trees, we suggest monitoring bark fissure depth if an ecological evaluation of Douglas-fir forests is needed.

scholarly journals Anatomical study of Momordica charantia L. from Bangladesh

2018 ◽  
Vol 27 (1) ◽  
pp. 69-74
Author(s):  
Kishwar Jahan Shethi ◽  
Mabia Khanam Doty ◽  
Saima Jahan Liza ◽  
Parveen Rashid
Keyword(s):  
Transverse Section ◽  
Anatomical Study ◽  
Momordica Charantia ◽  
Vascular Bundles ◽  
Lower Epidermis ◽  
Stem Leaf

Recent investigation on the root, stem, leaf and petiole anatomy of Momordica charantia L. completed the detailed anatomical study of the genus Momordica from Bangladesh. Root has tetrach vascular bundles where thick patches of sclerenchyma cells encompassed the vessel cells. Five angular ridges and furrows are visible through stem transverse section typical to Cucurbitaceae. Total nine open, bicollateral fibro-vascular bundles are observed in stem crosssection where three large are in the center and others each are under the ridges. Midrib of the leaf is characterized by several double and scarcely seated stalkless globular cystoliths in the lower epidermis. Configuration of petiole is octagonal in shape with eight ridges where seven fibro vascular bundles situated as a ring. Stem and leaf has multicellular, unisireate blunt ended conical shaped trichomes where petiole has similar trichomes with both blunt and pointed head. Dhaka Univ. J. Biol. Sci. 27(1): 69-74, 2018 (January)

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