North American black‐fruited hawthorns. II. Floral development of 10‐ and 20‐stamen morphotypes in<i>Crataegus</i>section<i>Douglasii</i>(Rosaceae: Maloideae)

Evans, Rodger C.; Dickinson, Timothy A.

doi:10.1002/j.1537-2197.1996.tb12793.x

Cited by 19 publications

(3 citation statements)

References 51 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Altogether, these data suggest that the control of floral organ identity in different species is similar in many respects. The formation of common primordia, as opposed to discrete petal and stamen primordia, have been described in many legume and non-legume plants (Tucker 1989;Kamenetsky and Akhmetova 1994;Delaet et al 1995;Evans and Dickinson 1996;Kirchoff 1997). In these model plants, the initiation of the primordia of the floral organs is a centripetal and sequential process (Smyth et al 1990;Sommer et al 1990).…”

Section: Discussionmentioning

confidence: 99%

Floral development of the model legume Medicago truncatula: ontogeny studies as a tool to better characterize homeotic mutations

et al. 2003

View full text Add to dashboard Cite

This work provides new evidence of the complex genetic regulation necessary to accomplish flower development in legumes. Using scanning electron microscopy (SEM) analysis, we have characterized the early developmental events of the wild type Medicago truncatula flower and selected morphological characters as markers to break it down into eight different developmental stages. The order of floral organ initiation in M. truncatula and pea (Pisum sativum L.), in contrast to Arabidopsis and Antirrhinum, is unidirectional in all whorls starting from the abaxial position of the flower with a high degree of overlap. Another main difference is the existence of four common primordia from which petals and stamens differentiate. The formation of common primordia, as opposed to discrete petal and stamen primordia, has been described in many legume and nonlegume plants. The main differences between pea and M. truncatula floral ontogeny are in carpel and fruit development. We also used these morphological markers as tools to characterize early alterations in the flower development of a male-sterile M. truncatula floral homeotic mutant named mtapetala. This mutant displays a phenotype resembling those of weak class B mutants with homeotic conversions of floral organ whorls 2 and 3 into sepaloid and carpelloid structures, respectively. Ontogeny studies of the mtapetala mutant flowers showed similarities with the effects of previously described loss-of-B-function mutations. Differences between ontogeny of wild type and mtapetala flowers could not be detected during the first stages (1-5) of flower development. In late stage 5, abnormal-shaped petals with acute lobes and trichomes as well as abnormal-shaped stamens were visible in whorls 2 and 3. At stage 6, the morphology of petals began to change, developing enlarged sepaloid struc-tures bearing trichomes and first the antesepalous stamens and then the antepetalous stamens began to differentiate carpelloid anthers from filaments. Third whorl organs presented different degrees of carpelloidy. The present study should provide tools for the characterization and comparative analyses of new Medicago floral homeotic mutants and could be useful in elucidating how floral organ identity functions work in legumes.

show abstract

Section: Discussionmentioning

confidence: 99%

Floral development of the model legume Medicago truncatula: ontogeny studies as a tool to better characterize homeotic mutations

et al. 2003

View full text Add to dashboard Cite

show abstract

“…Another main difference is the existence of common primordia from which petals and stamens differentiate [Tucker, 1989;Ferrá ndiz, 1996]. The formation of common primordia, as opposed to discrete petal and stamen primordia, has been described in many legume and nonlegume plants [Tucker, 1989;Kamenetsky and Akhmetova, 1994;Evans and Dickinson, 1996;Delaet et al, 1995;Kirchoff, 1997]. The common primordia in pea are established at the adaxial and abaxial flower positions, and at the two sides of the adaxial-abaxial floral axis, limiting externally with the sepal primordia and internally with the carpel primordium.…”

Section: Introductionmentioning

confidence: 99%

Flower development inPisum sativum: From the war of the whorls to the battle of the common primordia

et al. 1999

View full text Add to dashboard Cite

“…In species with 42 chromosomes here considered as diploids, do they behave as 21 pairs of bivalents or as six groups of seven chromosomes that can pair in different combinations? Detailed studies of meiotic pairing behavior are needed, as done, e.g., for Crataegus [50]. (2) Are individuals of naturally occurring different ploidy levels with a "species" evolutionarily independent?…”

Section: Discussionmentioning

confidence: 99%

Guard cell sizes and ploidy levels in Polylepis (Rosaceae)

Espinoza

Popp²,

Kessler

2020

Neotropical Biodiversity

View full text Add to dashboard Cite

The Andean tree genus Polylepis (Rosaceae) has recently been recognized to include polyploid species, but their occurrence within the genus is still incompletely known, especially in light of a forthcoming taxonomic treatment based on a narrow species concept including morphological, climatic and biogeographic distinctness that recognizes 45 species. We obtained guard cell measurements as proxies of ploidy level from 114 individuals of 33 species of Polylepis, including all species for which no previous measurements were available. In combination with previously published data, also on nucleus mass and chromosome counts, we infer that on current knowledge 19 (42%) species are probably purely diploid, 15 (33%) purely tetraploid, and one (2%) purely octoploid. The remaining eight (18%) species have mixed ploidy levels, with three (7%) being di-and tetraploid, two (4%) di-and hexaploid, and one each tetra-and hexaploid, tetra-and octoploid, and di-, tri-, tetra-and hexaploid. Based on our understanding of the evolutionary relationships in Polylepis, it would appear that polyploidy has originated at least about eight times independently in the genus, sometimes as autopolyploidy, sometimes as a result of interspecific hybridization, and sometimes in relation to cultivation. The taxonomic implications of the ploidy levels are complex, in some cases supporting species-level distinction and in others posing the question whether different ploidy levels within a species should better be treated as distinct species. Ploidy level needs to be taken into account for the conservation of the genus, as for example if different populations of a species have different ploidy levels, mixing these origins in reforestation schemes may lead to the formation of sterile hybrids. Guard cell measurement is a low cost and simple technique that can be readily used on both live and dried plant material for such applications, but it has limitations and further data on chromosome counts and nucleus mass are also needed to fully understand the evolution of ploidy levels in Polylepis and its implications.

show abstract

North American black‐fruited hawthorns. II. Floral development of 10‐ and 20‐stamen morphotypes inCrataegussectionDouglasii(Rosaceae: Maloideae)

Cited by 19 publications

References 51 publications

Floral development of the model legume Medicago truncatula: ontogeny studies as a tool to better characterize homeotic mutations

Floral development of the model legume Medicago truncatula: ontogeny studies as a tool to better characterize homeotic mutations

Flower development inPisum sativum: From the war of the whorls to the battle of the common primordia

Guard cell sizes and ploidy levels in Polylepis (Rosaceae)

Contact Info

Product

Resources

About