Stem anatomy of Grewia caffra (Malvaceae): an uncommon cambial variant in the order Malvales

2021 ◽  
Vol 307 (2) ◽  
Author(s):  
Gugu Gama ◽  
Alexei Oskolski
Keyword(s):  
Stem Anatomy ◽  
Cambial Variant

Structure of the secondary xylem and development of a cambial variant in Serjania mexicana (Sapindaceae)

IAWA Journal ◽  
2021 ◽  
pp. 1-11
Author(s):  
Kishore S. Rajput ◽  
Amit D. Gondaliya ◽  
Roger Moya
Keyword(s):  
Secondary Xylem ◽  
Secondary Growth ◽  
Stem Anatomy ◽  
The Family ◽  
Ray Cells ◽  
Cambial Variant ◽  
Proportional Increase ◽  
Plant Families ◽  
Ray Parenchyma Cells ◽  
Cambial Variants

Abstract The lianas in the family Sapindaceae are known for their unique secondary growth which differs from climbing species in other plant families in terms of their cambial variants. The present study deals with the stem anatomy of self-supporting and lianescent habit, development of phloem wedges, the ontogeny of cambial variants and structure of the secondary xylem in the stems of Serjania mexicana (L.) Willd. Thick stems (15–20 mm) were characterized by the presence of distinct phloem wedges and tangentially wide neo-formed cambial cylinders. As the stem diameter increases, there is a proportional increase in the number of phloem wedges and neo-formed vascular cylinders. The parenchymatous (pericyclic) cells external to phloem wedges that are located on the inner margin of the pericyclic fibres undergo dedifferentiation, become meristematic and form small segments of cambial cylinders. These cambia extend tangentially into wide and large segments of neoformations. Structurally, the secondary xylem and phloem of the neo-formed vascular cylinders remain similar to the derivatives produced by the regular vascular cambium. The secondary xylem is composed of vessels (wide and narrow), fibres, axial and ray parenchyma cells. The occurrence of perforated ray cells is a common feature in both regular and variant xylem.

Development of cambial variant and parenchyma proliferation in Hewittia malabarica (Convolvulaceae) from India and South Africa

IAWA Journal ◽  
2020 ◽  
pp. 1-14
Author(s):  
Kishore S. Rajput ◽  
Amit D. Gondaliya ◽  
Himansu Baijnath
Keyword(s):  
South Africa ◽  
Secondary Xylem ◽  
Secondary Growth ◽  
Stem Anatomy ◽  
Histological Techniques ◽  
The Family ◽  
Ray Cells ◽  
Meristematic Activity ◽  
Cambial Variant ◽  
Interxylary Phloem

Abstract Members of the Convolvulaceae are characterized by the climbing habit and occurrence of variant secondary growth. From a histological perspective, the genus Ipomoea L. is the most extensively studied, while other genera have been less studied. Here, stem anatomy of the least studied genus in the family, Hewittia Wight & Arn., represented by Hewittia malabarica (L.) Suresh was investigated using classical histological techniques. In both the samples collected from India and South Africa, stem thickness increased by developing different types of cambial variants such as: neo-formed vascular cylinders, parenchyma proliferation at the phloem wedges, ray-derived cambia from dilating phloem rays, internal cambium, intra- and interxylary phloem. Neo-formed vascular cylinders develop from the parenchyma cells external to the phloem as a meristemoid in thick stems and later in dilating ray cells. With the increase in stem diameter, cells of the phloem wedges showed proliferation by meristematic activity, which form a connection with the cortex by rupturing the primary tissue ring of eustele. Subsequently, development of cambium in phloem wedges and deposition of its derivatives increased the tangential width of rays. Mature thick stems (25–30 mm) give rise to a fissured stem. Intraxylary (internal) phloem development on the pith margin was observed from primary growth onwards and in thick stems secondary intraxylary phloem developed from the internal cambium. Internal cambium is functionally bidirectional and produces secondary xylem internally and secondary phloem externally. In all the samples, patches of unlignified parenchyma embedded within the secondary xylem dedifferentiate and mature into interxylary phloem with the increasing age. Development of cambial variant and structure of the secondary xylem is correlated with the functional significance of the climbing habit.

Hymenachne acutigluma (Steud.) Gilliland in GBS 20:314 - An exceptionally important perennial grass for anatomy and indigenous practice.

2016 ◽  
Vol 5 (04) ◽  
pp. 4958
Author(s):  
Dulal De
Keyword(s):  
Perennial Grass ◽  
Secondary Growth ◽  
Grass Species ◽  
Stem Anatomy

Hymenachne acutigluma (Steud.) Gilliland, a robust rhizomatous perennial grass spreads on moist and swampy land and also floating in water. Being a grass species, they do not have any cambium for secondary growth. A peculiarity in stem anatomy especially the spongy pith of secondary tissues found in absence of the cambium. The origin and development of the parenchymatous pith tissues has been investigated in the present study. Economically this spongy pith is of very much potent for its high absorbing and filtering capacity and also used as a good fodder.

Brain Stem Anatomy and Surgical Approaches

2019 ◽  
pp. 53-105
Author(s):  
Maximiliano A. Nuñez ◽  
Juan Carlos Fernandez Miranda ◽  
Evandro de Oliveira ◽  
Pablo A. Rubino ◽  
Seclen Voscoboinik ◽  
...  
Keyword(s):  
Brain Stem ◽  
Surgical Approaches ◽  
Stem Anatomy

The rise and evolution of the cambial variant in Bignonieae (Bignoniaceae)

2009 ◽  
Vol 11 (5) ◽  
pp. 465-479 ◽  
Author(s):  
Marcelo R. Pace ◽  
Lúcia G. Lohmann ◽  
Veronica Angyalossy
Keyword(s):  
Cambial Variant

scholarly journals Investigation of stem anatomy in relation to hydraulic conductance, vegetative growth and yielding potential of ‘Summit’ cherry trees grafted on different rootstock candidates

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Tijana Narandžić ◽  
Mirjana Ljubojević ◽  
Jovana Ostojić ◽  
Goran Barać ◽  
Vladislav Ognjanov
Keyword(s):  
Hydraulic Conductivity ◽  
Sweet Cherry ◽  
Correlation Coefficients ◽  
Hydraulic Conductance ◽  
Fruit Production ◽  
Tree Crown ◽  
Stem Anatomy ◽  
Crown Volume ◽  
Cultivar Selection ◽  
Cherry Trees

Abstract Severe climate alterations that seriously challenge fruit production, combined with the demand for healthy, pesticide-free fruits, continuously direct rootstock/cultivar selection towards high adaptable varieties breeding. This study aimed to investigate the rootstocks’ influence on the performance of grafted ‘Summit’ cherry trees, including potentially dwarfing Prunus cerasus, Prunus fruticosa and Prunus mahaleb rootstock candidates. Anatomical properties of rootstock and scion stems were investigated to determine variation among different rootstocks and scion-rootstock combinations and to establish the link between trunk hydraulic conductivity, effective tree crown volume and yielding potential. Cross-section anatomical characteristics varied significantly both in rootstock and scion stems, indicating a clear influence of rootstock genotype on grafted sweet cherry trees. It was observed that all investigated cherry rootstock candidates belong to the low-vigorous rootstocks, based on the estimated effective crown volume of grafted trees compared to ‘Gisela 5’, with values ranging from 0.86 to 2.97 m3 in the fifth year after planting. Results showed a statistically significant positive correlation between trunk hydraulic conductivity, effective tree crown volume and yielding potential, with correlation coefficients up to 0.96. Significantly higher effective crown volume and trunk hydraulic conductance of trees grafted on P. cerasus compared to the trees on control, as well as highest yielding potential, showed better adaptation of these rootstock candidates in the trial without irrigation implemented. It was found that PC_05_04 rootstock candidate could be considered as the most appropriate choice when raising the high-density sweet cherry plantations, due to assessed parameters of vegetative and generative growth.

SECONDARY GROWTH IN THE STEM OF SOME SPECIES OF ALTERNANTHERA AND ACHYRANTHES ASPERA (AMARANTHACEAE)

IAWA Journal ◽  
2000 ◽  
Vol 21 (4) ◽  
pp. 417-424 ◽  
Author(s):  
Kishore S. Rajput ◽  
K.S. Rao
Keyword(s):  
Secondary Growth ◽  
Sieve Tube ◽  
Axial Parenchyma ◽  
Achyranthes Aspera ◽  
Companion Cells ◽  
Cambial Variant ◽  
Mother Cells

Secondary growth in Achyranthes aspera, Alternanthera polygamous, A. pungens, A. sessilis, and A. triandra was achieved by the development of a cambial variant resulting in successive rings of xylem and phloem. Each new cambium was developed at a distance about two to three cells external to the phloem produced by the previous cambium. The development of phloem was not synchronous in the species studied. Phloem development started either simultaneously with xylem or after the formation of a few xylem derivatives. In Achyranthes, xylem production started first followed by the development of phloem. Phloem mother cells differentiated into sieve tube elements, companion cells and axial parenchyma. Xylem was storied and exclusively composed of axial elements. Radial elements were absent in all the xylem rings of the stem. Vessels were angular and mostly solitary, but radial and tangential multiples were also observed occasionally. Xylem fibres were nonseptate and nucleated. Development of phloem and the rayless nature of the xylem is discussed.

Ontogeny of divided vascular cylinders in Serjania: the rise of a novel vascular architecture in Sapindaceae

IAWA Journal ◽  
2021 ◽  
pp. 1-13
Author(s):  
Yanã C. Rizzieri ◽  
Arno F.N. Brandes ◽  
Israel L. Cunha Neto ◽  
Genise V. Somner ◽  
Michaela J.N. Lima ◽  
...  
Keyword(s):  
Vascular Tissue ◽  
Developmental Stages ◽  
Vascular Cylinder ◽  
Peripheral Vascular ◽  
Micro Computed Tomography ◽  
Cambial Variant ◽  
Complex Forms ◽  
Cambial Cells ◽  
Developmental Analysis ◽  
Cambial Variants

Abstract Sapindaceae lianas are remarkable for the diversity of cambial variants found in their stems. One of the family’s exclusive cambial variant is the divided vascular cylinder, which occurs in eight species of the genus Serjania. This cambial variant is marked by 5 peripheral vascular cylinders around a large pith. We performed a comparative developmental analysis, integrating traditional plant anatomy techniques with high-resolution X-ray micro-computed tomography to investigate the structure and development of the stems of three species with divided vascular cylinder. Our observations showed that the initial stages of stem development were similar to those described in the literature, however, on later developmental stages a central vascular cylinder appears in all species. The ontogeny of these stems are marked by three main processes: (i) dissection of vascular tissue from the peripheral vascular cylinders; (ii) development of new cambial arcs through the redifferentiation of pith cells; and (iii) recruitment of cambial cells from the inner portions of the vascular cambium of the peripheral vascular cylinders, forming a novel central vascular cylinder where the pith was, surrounded by five initial peripheral cylinders. As an ulterior developmental stage, some older stems also develop neoformations and connections between the different vascular cylinders. While our findings support previous descriptions of divided vascular cylinders, this is the first study illustrating the formation of the central vascular cylinder in this cambial variant. Our observations further corroborate that Serjania is the lineage with the highest and some of the most complex forms of cambial variants among all vascular plants.

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