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.

Etudes expérimentales sur le rôle des somites au cours des premiers stades du développement du membre antérieur chez l'embryon du Chélonien Emys orbicularis L.

Development ◽  
1974 ◽  
Vol 32 (2) ◽  
pp. 417-430
Author(s):  
Par J. Vasse
Keyword(s):  
Experimental Study ◽  
Developmental Stage ◽  
Limb Development ◽  
Limb Bud ◽  
Stages Of Development ◽  
Emys Orbicularis ◽  
Bud Development ◽  
Early Stages

Experimental study on the role of the somites during the early stages of development of the front limbs of the embryo of the chelonian Emys orbicularis L. Ablation of postotic somites 6–13 on one side in embryos of Emys orbicularis L. at the developmental stage when 20–23 somite pairs were present, led to arrest of forelimb-bud development in the somatopleure adjacent to the ablated somites on the operated side. Limb development in the somatopleure adjacent to intact somites on the operated side was unaffected, attaining the same stage as on the non-operated side. Ablation at later stages (25–33 somite pairs) did not prevent development of the limb adjacent to the ablated somites. When a part of the prospective somatopleure was injured, the remaining part formed a small limb-bud. When an obstacle was placed between the somatopleural mesoderm and the adjacent somite, development of the somatopleure stopped at this level. These results corroborate those obtained from previous studies in various reptilian embryos concerning the role of the ventral somite extensions as activators of proliferation in the somatopleural mesoderm. Injury to the ventral extension alone led to serious disturbances in the somatopleural mesoderm adjacent to this somite.

Anatomical, morphological and growth responses of Thinopyrum ponticum plants subjected to partial and complete submergence during early stages of development

2020 ◽  
Vol 47 (8) ◽  
pp. 757
Author(s):  
María del Rosario M. Iturralde Elortegui ◽  
Germán D. Berone ◽  
Gustavo G. Striker ◽  
María J. Martinefsky ◽  
María G. Monterubbianesi ◽  
...  
Keyword(s):  
Developmental Stage ◽  
Water Level ◽  
Plant Height ◽  
Leaf Blade ◽  
Recovery Period ◽  
Soluble Carbohydrates ◽  
Stages Of Development ◽  
Thinopyrum Ponticum ◽  
Early Stages ◽  
Root Aerenchyma

Seedling recruitment and growth of forage grasses in flood-prone grasslands is often impaired by submergence. We evaluate the responses of Thinopyrum ponticum (Podp.) Barkw. & Dewey to partial and complete submergence at two early stages of development. Two greenhouse experiments were carried out with plants at three expanded leaves (Experiment 1) or five expanded leaves stage (Experiment 2). In each case, three treatments were applied for 14 days: control (C), partial submergence (PS; water level to half plant height), and complete submergence (CS; water level to 1.5 times plant height). Submergence was followed by a recovery period of 14 days at well drained conditions. Assessments included plant survival, height, leaf blade and pseudostem length, soluble carbohydrates in pseudostem, and shoot and root dry mass accumulation at the beginning and end of the submergence, and at the end of the recovery period. Root aerenchyma formation was determined on day 14 in both experiments. Under PS all plants survived, and the impact of the stress was related to the plants’ developmental stage. However, plants with five expanded leaves increased total plant biomass with respect to control by 48%, plants with three expanded leaves reduced it by the same percentage. This response could be related to a higher ability to form root aerenchyma (17 vs 10%), and an enhanced leaf de-submergence capacity due to promoted leaf blade and pseudostem lengthening. Complete submergence treatment compromised the survival of 70% of the individuals with three expanded leaves but did not affect the survival at the five expanded leaves stage. In any developmental stage (three or five expanded leaves) plants fail to promote enough elongation of leaf blades or pseudostems to emerge from the water, so that always remained below the water surface. Root aerenchyma was not increased by CS at either of these two plant developmental stages. The high amount and concentration of pseudostem total soluble carbohydrates of the larger (five expanded leaves) plants facilitated their recovery growth after submergence. Our results predict the successful introduction of this species in areas where water excesses can cause soil waterlogging or shallow-partial plant submergence, but suggest avoidance of areas prone to suffer high-intensity flooding that lead to full plant submergence as this would highly constrain plant recruitment.

Photoperiod and floral-bud development in Caryopteris × clandonensis

1978 ◽  
Vol 56 (16) ◽  
pp. 1844-1851
Author(s):  
David B. Layzell ◽  
Roger F. Horton
Keyword(s):  
Floral Development ◽  
Anther Wall ◽  
Stages Of Development ◽  
Bud Development ◽  
Early Stages ◽  
Floral Bud ◽  
Short Days

Floral development in Caryopteris × clandonensis A. Simmonds (C. incana (Houtt.) Miq. × C. mongholica Bunge) from cyme initiation through to anthesis is described, with emphasis on the development of the anthers. The later stages of development and anthesis are completed only on mature plants under short days (SD, 8 h light per day). Under long days (LD, 20 h light per day) senescence occurs in the early stages of anther wall differentiation.

Gli3 and Plzf cooperate in proximal limb patterning at early stages of limb development

Nature ◽  
2005 ◽  
Vol 436 (7048) ◽  
pp. 277-281 ◽  
Author(s):  
Maria Barna ◽  
Pier Paolo Pandolfi ◽  
Lee Niswander
Keyword(s):  
Limb Development ◽  
Limb Patterning ◽  
Early Stages

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.

scholarly journals Regular and Novel Metonymy: Can You Curl up with a Good Agatha Christie in Your Second Language?

2014 ◽  
Vol 37 (2) ◽  
pp. 175-197 ◽  
Author(s):  
Roumyana Slabakova ◽  
Jennifer Cabrelli Amaro ◽  
Sang Kyun Kang
Keyword(s):  
Experimental Study ◽  
Second Language ◽  
English Learners ◽  
Teaching Practices ◽  
Native Speakers ◽  
Native Language ◽  
Stages Of Development ◽  
Psychological Reality ◽  
Experimental Support ◽  
Agatha Christie

Abstract This article presents results of two off-line comprehension tasks investigating the acceptability of unconventional and conventional metonymy by native speakers of Korean and Spanish who speak English as a second language. We are interested in discovering whether learners differentiate between conventional and unconventional metonymy, and whether the acceptability of metonymic expressions in the native language has an effect on learners’ judgments in the second language. The findings of this study constitute further experimental support for the psychological reality of the distinction between conventional and unconventional metonymy, but only in English. Learners of English at intermediate levels of proficiency exhibit transfer from the native language in comprehending metonymic shifts of meanings. Restructuring of the grammar is evident in later stages of development. Finally, complete success in acquiring L2 metonymic patterns is attested in our experimental study. Implications for L2A theories and teaching practices are discussed.

Notochord to endoderm signaling is required for pancreas development

Development ◽  
1997 ◽  
Vol 124 (21) ◽  
pp. 4243-4252 ◽  
Author(s):  
S.K. Kim ◽  
M. Hebrok ◽  
D.A. Melton
Keyword(s):  
Gene Expression ◽  
Developmental Stage ◽  
Pancreas Development ◽  
Chick Embryos ◽  
Carboxypeptidase A ◽  
Bud Development ◽  
Dorsal Pancreas ◽  
Stepwise Manner

The role of the notochord in inducing and patterning adjacent neural and mesodermal tissues is well established. We provide evidence that the notochord is also required for one of the earliest known steps in the development of the pancreas, an endodermally derived organ. At a developmental stage in chick embryos when the notochord touches the endoderm, removal of notochord eliminates subsequent expression of several markers of dorsal pancreas bud development, including insulin, glucagon and carboxypeptidase A. Pancreatic gene expression can be initiated and maintained in prepancreatic chick endoderm grown in vitro with notochord. Non-pancreatic endoderm, however, does not express pancreatic genes when recombined with the same notochord. The results suggest that the notochord provides a permissive signal to endoderm to specify pancreatic fate in a stepwise manner.

Sign in / Sign up

Export Citation Format

Share Document