Anatomical features at the disarticulation zone in florets of fatuoid and nonfatuoid oat (Avena sativa L.)

2001 ◽  
Vol 79 (12) ◽  
pp. 1409-1416 ◽  
Author(s):  
G J Hoekstra ◽  
S J Darbyshire ◽  
D E Mather
Keyword(s):  
Avena Sativa ◽  
Small Cells ◽  
Vascular Bundles ◽  
Stages Of Development ◽  
Abscission Layer ◽  
Anatomical Features ◽  
Early Stages ◽  
Anatomical Basis

In oat (Avena sativa L.), the manner by which mature florets separate from the inflorescence depends on whether the plant is fatuoid or nonfatuoid and on whether it has naked or hulled grain. The anatomical basis for these differences is not well understood. Here, anatomical features were examined at the intersection of rachilla and lemma callus (disarticulation zone) in florets of fatuoid hulled-grain oat, which "shatter", and of nonfatuoid hulled-grain oat, fatuoid naked-grain oat, and nonfatuoid naked-grain oat, none of which shatter. A layer of one to several rows of small, thick-walled cells usually occurred at the disarticulation zone of fatuoid hulled-grain florets. This layer was less frequently observed at the disarticulation zone of nonfatuoid florets or fatuoid naked-grain florets. Visible at the early stages of development, these rows of small cells apparently form an abscission layer in mature florets of hulled-grain fatuoids. Disarticulation of florets is further assisted by the disintegration of medial parenchyma tissues of the lemma callus, resulting in the formation of lacunae around the vascular bundles. Although a layer of small cells in the disarticulation zone was often seen in mature fatuoid naked-grain florets, it did not function as an abscission layer.Key words: Avena, oat, fatuoid, disarticulation, abscission, shattering.

Anatomical Basis of Shatter-Resistance in the Oilseed Brassicas

1986 ◽  
Vol 34 (5) ◽  
pp. 595 ◽  
Author(s):  
GP Kadkol ◽  
VC Beilharz ◽  
GM Halloran ◽  
RH Macmillan
Keyword(s):  
Abscission Layer ◽  
Anatomical Features ◽  
Anatomical Basis ◽  
Layer Orientation ◽  
Oilseed Brassicas ◽  
High Level ◽  
Brown Sarson

Anatomical features of the siliqua valve and suture were studied in 13 Brassica accessions representing B. napus, B. campestris and B. juncea in order to investigate the basis of shatter-resistance and the mechanism of shattering (dehiscence). The high level of shatter-resistance of certain accessions of B. campestris var. Yellow Sarson and var. Brown Sarson was associated with the absence of an abscission (separation) layer in the region of attachment of the siliqua valve to the replum. There were no differences in this regard between intermediate shattering and shatter-susceptible accessions; both these types had a completely developed abscission layer. Orientation of the tissue and of the microfibrils of the cells of the siliqua valve did not differ between different layers of the valve in any of the accessions studied. This implied that the forces giving rise to dehiscence (shattering) are unlikely to develop within the siliqua and thus the mechanism of dehiscence is most likely passive.

Cambial Variant in the Stem of Serjania Corrugata (Sapindaceae)

IAWA Journal ◽  
2006 ◽  
Vol 27 (3) ◽  
pp. 269-280 ◽  
Author(s):  
Gabriel U.C. Araújo ◽  
Cecilia G. Costa
Keyword(s):  
Cross Section ◽  
Vascular Bundle ◽  
Vascular Ring ◽  
Cambial Activity ◽  
Vascular Bundles ◽  
Stages Of Development ◽  
Early Stages ◽  
Meristematic Activity ◽  
Cambial Variant

The establishment of the cambial variant and the development of the stem of Serjania corrugata Radlk. (Sapindaceae) was analyzed. In the early stages of development, the stem is lobed, with five lobes and five furrows in cross section. Around the fourth internode, each lobe has a vascular arc with one or two more developed central vascular bundles, two lateral bundles and phloem in the interfascicular regions. Procambial strands are also found in perimedullary position, producing only phloem elements. At this stage, the beginning of the cambial activity can be seen in the central vascular bundle in each lobe. This activity then extends to the lateral vascular bundles and to the perimedullary phloem. Parenchymatic cells, located between the vascular ring of the lobe and the perimedullary phloem, dedifferentiate and initiate meristematic activity, uniting these two regions. The development of xylem masses (one in each lobe) that characterizes the adult stem results from this cambial activity. The development of the cambial variant in S. corrugata is quite similar to that previously described in S. elegans Cambess.

Comparative leaf development of aerial and aquatic growth forms of Myriophyllum aquaticum

Botany ◽  
2013 ◽  
Vol 91 (7) ◽  
pp. 421-430 ◽  
Author(s):  
M.D. Shafiullah ◽  
Christian R. Lacroix
Keyword(s):  
Apical Meristem ◽  
Epidermal Cells ◽  
The Other ◽  
Developmental Study ◽  
Growth Forms ◽  
Myriophyllum Aquaticum ◽  
Stages Of Development ◽  
Qualitative And Quantitative ◽  
Early Stages ◽  
Other Hand

Myriophyllum aquaticum (Vell.) Verdc. produces two morphologically different forms of leaves based on whether they are aerial or aquatic. The objective of this study was to determine whether there are any similarities or differences between these two growth forms during their early stages of development. A comparative developmental study of aerial and aquatic growth forms of M. aquaticum was conducted from a qualitative and quantitative perspective using a scanning electron microscope. The pattern of leaf and lobe initiation such as their origin and shape were similar in both growth forms until the fourth plastochron (stage P4). Differences between the two growth forms became evident from stage P5 onward, where a larger shoot apical meristem (SAM), elongated epidermal cells, shorter and slightly more numerous lobes, as well as the presence of appendage-like structures characterized aquatic growth forms. On the other hand, aerial growth forms had smaller SAM, bulb-like epidermal cells, and longer and slightly less numerous leaf lobes. Significant differences between growth forms were noted for parameters such as volume of SAM, length of terminal, first, and middle lobes, as well as the length from first to last lobes. The volume of the SAM of aquatic shoot tips was always greater than aerial forms. On the other hand, lobes of aerial forms were always longer than the aquatic counterpart during early stages of development. This study on the development of M. aquaticum shows that the aerial and aquatic growth forms diverge from their early stages of development.

XV. On the development of the parasitic isopoda

1878 ◽  
Vol 169 ◽  
pp. 505-521 ◽  
Keyword(s):  
The Body ◽  
The Other ◽  
Stages Of Development ◽  
Early Stages ◽  
Abdominal Appendages ◽  
Pair Of Antennae

The following paper contains an account of observations on the development of the species Cymothoa œstroides and C . parallela of Milne Edwards; but the forms of the young seem to show that several species are really included under these two names. In the early stages of development the only observable difference that exists between the embryos is one of size, but in the later stages they differ very markedly from each other in their external characters. From adult individuals answering the description of C . œstroides I have obtained four varieties of embryos: two with long antennae and two with short.* In the two former the first pair of antennae are but slightly longer than the head, while the second pair are longer than the body; the eyes are small. In one of the varieties thus characterised the abdominal appendages are fringed with long hairs (fig. 20), and in the other they are smooth.

Morphological variations of Phrosina semilunata Risso, 1822 juveniles (Crustacea: Amphipoda: Hyperiidea), new evidence from the Gulf of Mexico

Zootaxa ◽  
2021 ◽  
Vol 4995 (3) ◽  
pp. 594-600
Author(s):  
MARCO VIOLANTE-HUERTA ◽  
LAURA SANVICENTE-AÑORVE ◽  
MARGARITA HERMOSO-SALAZAR ◽  
AURORA MARRÓN-BECERRA
Keyword(s):  
Gulf Of Mexico ◽  
Monotypic Genus ◽  
Stages Of Development ◽  
Morphological Variations ◽  
Stages Of Growth ◽  
Early Stages ◽  
Southern Gulf Of Mexico ◽  
New Evidence ◽  
Lack Of Knowledge

Lack of knowledge of morphological variations during growth of amphipod crustaceans can result in misidentification of species. In this study, we advance the knowledge of morphological variations of juveniles of the monotypic genus Phrosina Risso, 1822 collected in the oceanic province of the southern Gulf of Mexico. The juveniles differed from the adults mainly in the morphology of pereopods 3 & 4 in that the carpal process is parallel to the propodus, also the rami of the pleopoda consist of only four segments, uropoda 3 are more lanceolate, and the uropoda bear a large prominent spine terminally. These morphological variations have not been described for the species previously. Therefore, the current observations enrich the description of P. semilunata in the early stages of growth and support the need for further taxonomical studiest that could help identify species at different stages of development.  

Baby steps: a report exploring the development of neonatal music therapy programmes in Estonia, Greece and Wales

2021 ◽  
Vol 13 (2) ◽  
pp. 132-137
Author(s):  
Elizabeth Coombes ◽  
Marion Musting ◽  
 Ivad Al-Muzzafar ◽  
Christina Kalliodi 
Keyword(s):  
Music Therapy ◽  
Family Members ◽  
European Countries ◽  
Treatment Goals ◽  
Stages Of Development ◽  
Early Stages ◽  
Client Population ◽  
Growing Body ◽  
Therapy Interventions ◽  
Future Growth

There is a growing body of music therapy work addressing the needs of infants born prematurely. This also includes work with parents and other family members during hospitalisation. A variety of music therapy interventions are utilised to support a range of treatment goals for this client population. This report describes and discusses such work that is in the early stages of development in 3 European countries: Estonia, Greece and Wales. The development and content of the interventions in each country is described, with recommendations as to the sustainability and future growth of each programme

Etude expérimentale sur les premiers stades du développement du membre antérieur chez l'embryon du Chélonien Emys orbicularis L.: détermination en mosaïque et régulation

Development ◽  
1977 ◽  
Vol 42 (1) ◽  
pp. 135-148
Author(s):  
J. Vasse
Keyword(s):  
Experimental Study ◽  
Developmental Stage ◽  
Limb Development ◽  
Stages Of Development ◽  
Emys Orbicularis ◽  
Bud Development ◽  
Early Stages ◽  
Regional Determination

Experimental study on the early stages of development of the front limbs of the embryo of the chelonian Emys orbicularis L.: mosaic determination and regulation Ablation of postotic somites 6–13 on one side in embryos of Emys orbicularis L. or injury to the adjacent somatopleure at the developmental stage when 15–21 somite pairs were present, led to arrest of forelimb-bud development in this part of the somatopleure on the operated side. Limb development in the remaining part of prospective somatopleure on the operated side was investigated 5–11 days after the operation. When this part of somatopleure was adjacent to cranial somites 6–9 or 6–10, the development stopped at the start of the apical crest as in Anguis or Scelotes forelimb-buds. A part of somatopleure adjacent to caudal somites 8–12, 9–12 or 10–12 developed into a normal limb with three segments; a part of somatopleure adjacent to 1–2 somites only, developed into a reduced limb, scarcely swelling. Each somitic level developed in relation to its initial regional determination dependent on position in the cephalocaudal axis; to its environment (cranial or caudal bud) and to the quantity of somatopleural material in the bud.

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