Two novel reports of semidry stigmatic surface in Asteraceae

Flora ◽  
2011 ◽  
Vol 206 (4) ◽  
pp. 328-333 ◽  
Author(s):  
Simone de Pádua Teixeira ◽  
Liana Carneiro Capucho ◽  
Sílvia Rodrigues Machado
Keyword(s):  
Stigmatic Surface

scholarly journals Stigmatic surface in the Vochysiaceae: reproductive and taxonomic implications

2009 ◽  
Vol 23 (3) ◽  
pp. 780-785 ◽  
Author(s):  
Renata Carmo-Oliveira ◽  
Berta Lange de Morretes
Keyword(s):  
Histological Analysis ◽  
Developmental Stages ◽  
Phylogenetic Reconstruction ◽  
Breeding Systems ◽  
Stigmatic Surface ◽  
Central Brazil ◽  
Fresh Material ◽  
The Family ◽  
Taxonomic Implications ◽  
Trees And Shrubs

The Vochysiaceae are Neotropical trees and shrubs, common in the savanna areas in Central Brazil (Cerrados). The family has been traditionally divided into two tribes: Erismeae, with three genera, and Vochysieae, with five genera. We investigated the stigmatic surface of six Vochysiaceae species, belonging to four genera of Vochysieae: Vochysia, Salvertia, Callisthene and Qualea. Flowers and buds at different developmental stages were collected. Morphological features were observed on fresh material and stigmatic receptivity was inferred based on esterasic activity. Pistils were fixed and embedded in paraplast and sectioned on a rotary microtome; the sections were stained before histological analysis. Stigmas of open flowers were also observed by scanning electron microscopy. Stigmas of all species were wet and showed esterasic activity at pre-anthesis and anthesis stages. Stigmatic surface was continuous with transmitting tissue of glandular nature. Vochysia and Salvertia stigmatic surfaces were formed by multicelular uniseriate hairs, and species of the remaining genera showed papillate surface. The exudate over mature stigmas in all species flowed without rupture of stigmatic surface and pollen tubes grew down between hairs or papillae. Differences on the stigmatic surface agreed with a phylogenetic reconstruction that separated two clades and indicated that Vochysieae is not monophyletic. Stigmatic features could not be associated with pollination and breeding systems.

SPONTANEOUS SELF-FERTILIZATION IN RELATION TO SEED PRODUCTION IN SWEET CLOVER (MELILOTUS)

1931 ◽  
Vol 5 (6) ◽  
pp. 660-664 ◽  
Author(s):  
L. E. Kirk ◽  
T. M. Stevenson
Keyword(s):  
Seed Production ◽  
Pollen Grains ◽  
Sweet Clover ◽  
Flower Structure ◽  
Melilotus Officinalis ◽  
Stigmatic Surface ◽  
Melilotus Alba ◽  
Self Fertilization ◽  
Determining Factor ◽  
Selection Of

The chief determining factor in spontaneous self-fertilization in white sweet clover (Melilotus alba) appears to be the distribution of pollen within the unopened flowers. This in turn depends on (1) length of stamens, (2) length of style, (3) amount of pollen, and (4) size of cavity within the upper part of the keel. When the flower structure and quantity of pollen is such as to insure the deposition of pollen grains on the stigma before the blossom is likely to be disturbed by insects, the plant will be normally self-fertilized. In the yellow flowered species of sweet clover (Melilotus officinalis) spontaneous self-fertilization is effectively prevented, except in certain varieties, by a characteristic of the stigma which makes it unreceptive. Scarification of the stigmatic surface appears to be necessary before fertilization can take place. Variation occurs also, as in M. alba, in the length of stamens and style, size of keel cavity, and the amount of pollen.There is a high correlation in M. alba between the percentage of flowers which are naturally self-pollinated and the percentage of flowers which produce pods when the plants are caged to exclude insects. Selection of plants which are normally self-fertilized can be made by examining the early flowers, thus obviating the necessity of bagging or caging plants which do not possess this character.A strain of M. alba which is normally self-fertilized was found to produce almost twice as much seed as another strain which is normally cross-pollinated under comparable conditions in the field.

Self- and cross-incompatibility in Asparagus officinalis and Asparagus densiflorus cv. Sprengeri

1996 ◽  
Vol 74 (10) ◽  
pp. 1621-1625 ◽  
Author(s):  
O. N. Marcellán ◽  
E. L. Camadro
Keyword(s):  
Fluorescence Microscopy ◽  
Reproductive Isolation ◽  
Pollen Tubes ◽  
Asparagus Officinalis ◽  
Valuable Source ◽  
Stigmatic Surface ◽  
Commercial Cultivars ◽  
Garden Asparagus ◽  
Internal Barriers ◽  
Incompatibility Reactions

Garden asparagus, Asparagus officinalis L. (off), is dioecious and reproductively isolated from a related ornamental, monoecious Asparagus densifiorus (Kunth) Jessop cv. Sprengeri (spr). Since the latter is a potentially valuable source of germplasm, a study was initiated to identify hybridization barriers. Intra- and inter-specific crosses were made using 32 plants of two commercial cultivars of off and 17 plants of three introductions of spr. Part of the pollinated pistils were fixed and examined via fluorescence microscopy. In some combinations of genotypes, incompatibility reactions were detected: (i) off × off: in the stigmatic tissue, (ii) spr × spr: on the stigmatic surface and in the style, and (iii) spr × off: on the stigmatic surface, in the stigmatic tissue, and in the style. Although pollen tubes reached the ovules in most combinations of genotypes, seeds were only produced in intraspecific crosses. It is concluded that two types of internal barriers are acting: cross-incompatibility at the pollen–stigma and pollen–style levels, and stronger post-stylar barriers that had not been determined yet. Keywords: Asparagus densifiorus cv. Sprengeri, Asparagus officinalis, cross-incompatibility, reproductive isolation.

The gynoecial infection pathway of Monilinia vaccinii-corymbosi in lowbush blueberry (Vaccinium angustifolium)

1996 ◽  
Vol 76 (3) ◽  
pp. 493-497 ◽  
Author(s):  
T. C. Shinners ◽  
A. R. Olson
Keyword(s):  
Key Words ◽  
Pollen Tubes ◽  
Fungal Colonization ◽  
Vaccinium Angustifolium ◽  
Stigmatic Surface ◽  
Lowbush Blueberry ◽  
Fruit Wall ◽  
Brightfield Microscopy ◽  
Infection Pathway

Monilinia vaccinii-corymbosi (Reade) Honey is an economically important pathogen of lowbush blueberry (Vaccinium angustifolium Aiton) which causes blighting of leaves and flowers and mummification of fruits. This study was conducted to determine if infection of lowbush blueberry gynoecia occurs through colonization of the stigma. Sections of gynoecia inoculated with conidia were examined by brightfield microscopy. Conidia germinated on the stigmatic surface 1–3 d following inoculation to form hyphae winch invaded the stylar canal and other tissue down to the ovules. The infection pathway observed was identical to that of pollen tubes following pollination. After invasion of the ovary fungal colonization continued until the entire fruit wall was colonized with mycelium. Key words: Mummy berry, stigma colonization, pseudosclerotium

Floral Microcharacters in South American species of Senecio s.str. (Asteraceae) with considerations on the circumscription of this genus

Phytotaxa ◽  
2016 ◽  
Vol 244 (1) ◽  
pp. 1 ◽  
Author(s):  
Luciana Salomón ◽  
Marcelo Paulo Hernández ◽  
Daniel Alejandro Giugliano ◽  
Susana Edith Freire
Keyword(s):  
The Other ◽  
South American ◽  
South American Species ◽  
Stigmatic Surface ◽  
As Species ◽  
Micromorphological Characters

Senecio L. s.str. is the largest genus in the tribe Senecioneae (Asteraceae) and it has been commonly characterized by its truncate, penicillate stylar tips, separated stigmatic lines, and stamens usually with ecaudate anther bases and balusterform filament collar. A micromorphological study was carried out to determine if South American species of Senecio s.str. present these diagnostic micromorphological characters, as a contribution towards a circumscription of this genus supported by morphology. The study included 72 South American Senecio species from eight sections and 16 series, as well as species from six other genera of subtribe Senecioninae (Delairea, Dendrophorbium, Dendrosenecio, Graphistylis, Lomanthus, Pentacalia), three genera of subtribe Tussilagininae (Aequatorium, Nordenstamia, Roldana), and one of subtribe Brachyglottidinae (Acrisione). The studied characters include: style branches (stigmatic surface, and apices), anthers (filament collar, bases, and appendages), as well as pollen features (shape, size, and sculpture). Analyses of these characters suggested that Senecio s.str. can be defined only by the presence of balusterform filament collars, which are present in 61 out of the 72 studied Senecio s.str. species (vs. cylindrical collar in remaining species). The genera Graphistylis and Delairea also show this trait, however, Graphistylis presents some microcharacters (e.g. “banded” stigmatic surface) that are rather infrequently found in Senecio s.str. Senecio grandis showed cylindrical collars and sagittate anther bases and should be excluded from the genus. The other microcharacters analyzed appeared to be taxonomically uninformative, since their predominant states were found in Senecio s.str. as well as in other genera of Senecioneae.

Demographics of pollen tube growth in Cucurbita pepo

1995 ◽  
Vol 73 (4) ◽  
pp. 583-589 ◽  
Author(s):  
James A. Winsor ◽  
Andrew G. Stephenson
Keyword(s):  
Pollen Tube ◽  
Pollen Tube Growth ◽  
Cucurbita Pepo ◽  
Uv Light ◽  
Pollen Tubes ◽  
Tube Growth ◽  
Pollen Competition ◽  
Stigmatic Surface ◽  
Germinated Pollen ◽  
Female Flowers

Pollen tube growth rates and pollen tube attrition were examined in Cucurbita pepo plants grown in an experimental garden. Two separate studies were performed utilizing controlled hand-pollinations. First, female flowers were hand-pollinated and collected at intervals over a 22-h period. Examination of stained pollen tubes in these pistils under reflected UV light revealed variation in growth rate: after approximately 7 h, the fastest growing pollen tubes grew at nearly twice the rate of the mass of the pollen tubes. The faster growing tubes reached the top of the ovary well ahead of most of the pollen tubes. Second, density of pollen application was varied and counts of germinated pollen and pollen tubes were made at four points from the stigmatic surface to the receptacle. Attrition was high for all pollen densities, but significantly higher rates occurred at high and medium densities just below the stigmatic surface. Pollen tube attrition at other points in the pistil was associated with constrictions in the stylar tissue and possibly with levels of nutrients in the pistil. Key words: Cucurbita pepo, pollen competition, pollen tube attrition.

scholarly journals Reciprocal intercompatibility between Byrsonima Rich. exKunth species (Malpighiaceae), in an urban ecotonal fragment of Semi-Deciduous Seasonal Forest and Cerrado

2021 ◽  
pp. 211-221
Author(s):  
Frederic Mendes Hughes
Keyword(s):  
Pollen Tube ◽  
Pollen Tube Growth ◽  
Tube Growth ◽  
Self Incompatibility ◽  
Prezygotic Isolation ◽  
Stigmatic Surface ◽  
Cross Pollination ◽  
Self Pollination ◽  
Isolation Mechanisms ◽  
Hypothesis Evaluation

Byrsonima species present floral monomorphism and sharing visitor/pollinator guild. These traits suggest the hypothesis evaluation of reciprocal inter-incompatibility between two syntopic Byrsonima species: B. pachyphylla and B. crassifolia. Pollen tube growth with similar behavior was observed in the stigmatic surface, pistil canal, ovary and micropylar channel to both species. In addition, partial self-incompatibility in self-pollination with greater fruiting in autogamy was observed. Cross-pollination and self-pollination coexist, and reciprocal intercompatibility occurs. Prezygotic isolation mechanisms are unlikely by the absence of abnormal pollen tubes, higher fruiting production and absence of hybrids in the study site. Las especies de Byrsonima presentan monomorfismo floral y comparten gremio de visitantes/polinizadores. Estos rasgos sugieren la evaluación de hipótesis de interincompatibilidad recíproca entre dos especies sintópicas de Byrsonima: B. pachyphylla y B. crassifolia. Se observó el crecimiento del tubo polínico con comportamiento similar en la superficie estigmática, canal del pistilo, ovario y canal micropilar de ambas especies. Además, se describió la autoincompatibilidad parcial en la autopolinización con mayor fructificación en la autogamia. La polinización cruzada y la autopolinización coexisten y se produce una intercompatibilidad recíproca. Los mecanismos de aislamiento precigóticos son improbables por la ausencia de tubos polínicos anormales, producción de frutos y ausencia de híbridos en la área de estudio.

scholarly journals Seed-producing System in Salvias

1996 ◽  
Vol 121 (3) ◽  
pp. 419-422 ◽  
Author(s):  
Daiichiro Miyajima
Keyword(s):  
Pollen Viability ◽  
Pollen Tubes ◽  
Seed Setting ◽  
High Pollen ◽  
Stigmatic Surface ◽  
Salvia Splendens ◽  
Mature Seeds

The seed-producing system of salvias (Salvia splendens Sello) was investigated. The number of florets opening per day per plant increased with the increase in days from anthesis. Pollinators that effectively worked were small-sized insects. High pollen viability was observed on the stigmatic surface, and pollen tubes reached the ovules within 3 hours after pollination. Fertilized ovules became mature seeds within 25 days after fertilization. Pollination within 1 day after opening of florets resulted in a high percentage of seed setting. The pollen-ovule ratios indicated that salvias were facultative xenogamous. Actually, the salvias had heterostyle florets and the ability to set seeds without pollinators.

scholarly journals Effect of Previous Crop Load on Stigmatic Morphology of Apple Flowers

1995 ◽  
Vol 120 (4) ◽  
pp. 566-570 ◽  
Author(s):  
Deborah Buszard ◽  
W.W. Schwabe
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Fruit Set ◽  
Transmitting Tissue ◽  
Crop Load ◽  
Stigmatic Surface ◽  
Previous Crop ◽  
The Poor ◽  
Transmission Electron ◽  
Fruit Setting

`Cox's Orange Pippin' apple (Pyrus domestics Berth.) trees, which were previously heavily cropped compared to previously defruited trees, had smaller flowers, lower initial fruit set, and a shorter effective pollination period (EPP) than defruited trees. The morphology of apple flower styles and stigmas was studied using scanning and transmission electron microscopy. Virgin stigmas from previously unstressed trees had fully expanded papillae, but 7 days after pollination the papillae were collapsed and distinct pollen tubes penetrated the stigmatic surface. Virgin stigmas from flowers of previously heavily cropped trees were smaller than those from previously defruited trees. The virgin stigmas of the flowers of heavily cropped trees showed collapsed papillae, and differences were observed in the intercellular material in the subtending transmitting tissue. These differences may explain the poor fruit setting characteristics of apple flowers on trees that have borne a heavy crop in the previous year.

Sign in / Sign up

Export Citation Format

Share Document