Colpus Length Research Articles

Quantitative evaluation of pollen polymorphism in a tristylous weed,Lythrum salicaria(Lythraceae)

Tristylous breeding system consists of three different forms of flowers that differ reciprocally in the heights of stigmas and anthers within flowers. Apart from the style and stamen lengths, heterostylous species also demonstrate pollen and stigma polymorphisms. Tristylous Lythrum salicaria L. bears trimorphic, striate, tricolporate pollen with three true colpi and three pseudocolpi. Using a scanning electron microscope, we quantified pollen polymorphism in L. salicaria by measuring the length and diameter of pollen, and the length of colpi and pseudocolpi. Pollen grains from the long stamens are significantly larger than those from the mid stamens, followed by those from the short stamens. Despite significant differences in pollen size among long, mid, and short stamens, pollen morphometric traits demonstrate overlap among morphs. Pollen diameter also differed significantly between source populations. A discriminant function analysis separated long-level pollen from mid- and short-level pollen based on the canonical scores of measurements of pollen structure. The polymorphism of pollen in conjunction with that of the stigma may play a functional role in self-incompatibility mechanisms.Key words: Lythrum salicaria, purple loosestrife, Lythraceae, heterostyly, incompatibility, pollen polymorphism.

Pollen morphology in Lyperia (Scrophulariaceae) and related taxa with a multivariate analysis of the major patterns of pollen character variation in tribe Manuleae

The pollen of all six species of Lyperia (Scrophulariaceae, tribe Manuleae) was investigated by light microscopy and scanning electron microscopy of whole and fractured grains. Pollen grains in Lyperia antirrhinoides (L.f.) Hilliard, Lyperia formosa Hilliard, Lyperia tenuiflora Benth., and Lyperia violacea (Jarosz) Benth. differed from those in Lyperia tristis (L.f.) Benth. and Lyperia lychnidea (L.) Druce in number and length of colpi, sculpturing of the colpus margin, reduction of apocolpial lumina size, reduction of exine thickness toward the colpi, ornamentation of the outer nexine surface, arrangement of columellae beneath the muri, direction of cross-sectional compression in elliptical muri, and relative dimensions of the muri and columellae. Pollen grains from 50 representative species of the putatively related genera Sutera and Jamesbrittenia were also examined. Correlations among quantitative pollen characters of tribe Manuleae and the Sutera complex were investigated by principal components analysis. Morphological similarities in the pollen of Lyperia, genera of the Sutera complex, and other Manuleae were summarized by ordination of the principal components data and (or) cluster analysis. The pollen grains of L. lychnidea and L. tristis differed from those of other Lyperia and stood apart from those of Jamesbrittenia, Sutera, and all other Manuleae. Pollen morphology in Sutera and Jamesbrittenia intergrades with that in tricolporate species of Lyperia.Key words: pollen morphology, Scrophulariaceae, Lyperia, Jamesbrittenia, Sutera.

Quantitative evaluation of pollen polymorphism in a tristylous weed, <i>Lythrum salicaria</i> (Lythraceae)

Tristylous breeding system consists of three different forms of flowers that differ reciprocally in the heights of stigmas and anthers within flowers. Apart from the style and stamen lengths, heterostylous species also demonstrate pollen and stigma polymorphisms. Tristylous Lythrum salicaria L. bears trimorphic, striate, tricolporate pollen with three true colpi and three pseudocolpi. Using a scanning electron microscope, we quantified pollen polymorphism in L. salicaria by measuring the length and diameter of pollen, and the length of colpi and pseudocolpi. Pollen grains from the long stamens are significantly larger than those from the mid stamens, followed by those from the short stamens. Despite significant differences in pollen size among long, mid, and short stamens, pollen morphometric traits demonstrate overlap among morphs. Pollen diameter also differed significantly between source populations. A discriminant function analysis separated long-level pollen from mid- and short-level pollen based on ...

Interspecific and intraspecific variation in pollen morphology in four species of Salix

A study of inter- and intra-specific variation in pollen grain polar axis length, pollen equatorial diameter, colpus length, and colpus width in Salix discolor, S. eriocephala, S. lucida, and S. petiolaris demonstrated significant interspecific variation, unequal distances between the species, and various degrees of intraspecific variation. The taxonomic value of the pollen morphology parameters measured was found to vary according to species. A relationship between the pollen parameters measured to the ploidy level of the species is hypothesized. Key words: Salix, pollen, taxonomy.

Taxonomic study of the polycolpate pollen grains from the Indian tertiary sediments with special reference to nomenclature

The present paper incorporates a critical discussion on the taxonomy and nomenclature of the Indian Tertiary polycolpate pollen grains in order to clear up the presently existing confusion in this group. All the known Indian polycolpate pollen genera and species have been sorted out for taxonomic evaluation and it has been observed that most of the genera are either synonyms or are invalidly published. As such their species have been transferred into some other suitable valid genera as new combinations. Exine ornamentation and exinal thickenings are recommended here as criteria for generic differentiation while number, nature and length of colpi, exine stratification and thickness, breadth of mesocolpia, overall shape and size of the pollen etc. are considered as characters of specific level. In addition, the diagnoses of Polycolpites and Retistephanocolpites are emended and redefined; the former including clavate polycolpate pollen grains while the latter including reticulate, foveolate of foveoreticulate polycolpate pollen grains.

A Factor Analysis Study of the Functional Significance of Angiosperm Pollen

A Factor Analysis Study of the Functional Significance of Angiosperm Pollen

Morfología polínica de Staelia s.l. (Rubiaceae) .

Este trabajo trata el estudio de los granos de polen de Staelia s.l. Actualmente, es un grupo escasamente estudiado en este aspecto, ya que solo se describieron cuatro de 25 especies. Se estudió el polen de todas las especies de Anthospermopsis, Planaltina, Tessiera y Staelia s.s. Como resultado, se encontró una notable homogeneidad de caracteres polínicos dentro de cada género, que se pone de manifiesto en un único tipo de polen para cada taxón, excepto para Anthospermopsis. Tessiera y Planaltina se diferencian de Staelia por el tamaño de los granos (P=42-75 y E=50-78,4 vs. P=21-34 y E=20-30,8 µm) y longitud de los colpos (LC/P= 0,22-0,31 vs. 0,57-0,77 µm), mientras que Anthospermopsis es prácticamente indistinguible de las otras especies de Staelia. Además, los tres tipos polínicos son similares a los establecidos para especies de Spermacoce de África y Australia. El tipo polínico de Staelia también es compartido con Emmeorhiza. Por estas razones, se propone incorporar a la clasificación de los tipos polínicos descritos anteriormente para Borreria y Spermacoce (designados con números arábigos, del 1-20) a los géneros aquí estudiados. Los tres tipos polínicos son descritos e ilustrados mediante imágenes de microscopio electrónico de barrido. El interior de la nexina es también analizada a partir de granos rotos.