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

2000 ◽  
Vol 78 (8) ◽  
pp. 1086-1094 ◽  
Author(s):  
Tarun K Mal ◽  
Brian P Hermann

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.

2015 ◽  
Vol 67 (3) ◽  
pp. 973-980 ◽  
Author(s):  
Marina Macukanovic-Jocic ◽  
Snezana Jaric ◽  
Mica Mladenovic

The pollen morphology of Dianthus petraeus (Caryophyllaceae), which is endemic to the Balkans, has been examined by both light and scanning electron microscopy in order to provide taxonomically valuable characters that might be used in the classification of the Caryophyllaceae, as well as to contribute to the pollen atlas of Serbian apiflora. The pollen grains of D. petraeus are radially symmetrical, apolar, spheroidal and medium-sized. The mean of the pollen diameter is 45.5?1.4 ?m. The sculpturing pattern of exine is microechinate-microperforate, and the tectum is covered with minute echini averaging 0.8?0.1 ?m in length, more or less evenly distributed between the perforations. The microechini average number per sample area of 5 ?m x 5 ?m is 3.2?0.6. In view of the number, position and type of the apertures, the grains are polypantoporate, with about 13 operculate pores, averaging 6.4?0.7 ?m in diameter. Each operculum is covered with 4-6 conical spinules, which are longer than those on the exine surface. The mean interporal distance is 13.3?1.3 ?m. The obtained palynological results provide information that contribute towards a better understanding of the taxonomic status of D. petraeus.


Author(s):  
V. Martynyuk ◽  
N. Karpenko ◽  
O. Tsarenko

Silene sytnikii Krytzka, Novosad et Protopopova is a local endemic species of the Ukrainian flora, which sometimes is considered as a synonym to the S. frivaldszkyana Hampe from the Balkans and is related to the widespread species S. chlorantha (Willd.) Ehrh. The aim of the present study is to investigate micromorphological features of seeds, pollen grains and leaf surface ultrastructure of foregoing species and make a comparison. Both light and scanning electron microscopy were used in the study. S. sytnikii and S. frivaldszkyana are slightly different in the size of exotesta cells and their anticlinal teeth in distal row of seeds, pollen diameter and microechinate number on the pore, size of leaf spinule, epidermal cells and stomata. S. chlorantha significantly differs from them by smaller seeds and exotesta cells, and also longer leaf spinules. Thus, S. sytnikii and S. frivaldszkyana are quite similar in their micromorphology, while S. chlorantha is clearly distinct from them.


1938 ◽  
Vol 16c (11) ◽  
pp. 445-455 ◽  
Author(s):  
F. H. Peto

Complete analyses of pollen-mother-cell nuclei at first metaphase, percentage good pollen, pollen diameter and pollen-size distribution were determired for the following poplar species and natural hybrids: Populus grandidentata Michx., P. tremuloides Michx., P. eugenei Simon Louis, P. alba L., P. canescens Sm., natural hybrids of P. alba × P. grandidentata and of P. alba × P. tremuloides.Both of the P. alba and two of the four P. canescens trees examined were triploids (2n = 57) while all other trees examined were diploids (2n = 38). Meiotic observations on the natural hybrids indicated a high degree of homology between the chromosomes of P. alba and the native aspens (P. grandidentata and P. tremuloides), since 17 to 19 bivalents were usually found at first metaphase. In collections from one triploid P. canescens and two diploid alba-grandidentata hybrid trees, failure of a high proportion of the chromosomes to pair was attributed to genetic factors limiting pairing, rather than to non-homology.Pollen characters such as percentage good pollen, pollen diameter, and pollen size distribution were, in most cases, not indicative of the chromosome number or pairing relations at first metaphase. Consequently, triploids could not be detected by pollen observations under the conditions of this experiment. In spite of the lack of correlation between first metaphase and pollen observations, abnormally large pollen grains were observed in collections from several of the trees, and these were considered to contain the diploid or unreduced chromosome complement. The tendency for the poplars to produce unreduced pollen grains probably accounts for the number of triploid trees discovered in Canada and Sweden.


2015 ◽  
Vol 22 (2) ◽  
pp. 99-110 ◽  
Author(s):  
Maryam Naderifar ◽  
Ali Sonboli ◽  
Abbas Gholipour

Pollen morphology of 11 Iranian Dracocephalum L. species was investigated using light and scanning electron microscopy to evaluate their taxonomic significance for the infrageneric classification of the genus. Pollen grains of all examined taxa were isopolar, hexacolpate, circular in polar view and spheroidal to prolate in equatorial view (P/E = 1.0?2.0). The smallest pollen grains were observed in D. aucheri (P = 29.7 ?m, E = 22.6 ?m), while the largest pollen was found in D. lindbergii (P = 45.1 ?m, E = 33.7 ?m). The highest and lowest apocolpium index (AI) were measured in D. aucheri (AI = 0.27) and D. surmandinum (AI = 0.08), respectively. Colpus membrane was egranulate in all examined species except for D. multicaule and D. ghahremanii. The main exine ornamentation type was characterized as bireticulate including five different subtypes. The results revealed that the exine ornamentation is a diagnostic character useful for the classification of Dracocephalum.Bangladesh J. Plant Taxon. 22(2): 99-110, 2015 (December)


2012 ◽  
Vol 26 (1) ◽  
pp. 46-57 ◽  
Author(s):  
BenoÎt Loeuille ◽  
Raquel Maria Batista Souza-Souza ◽  
Vanessa Holanda Righetti Abreu ◽  
Cláudia Barbieri Ferreira Mendonça ◽  
Vania Gonçalves-Esteves

In order to evaluate the significance of the pollen morphology for generic and infrageneric taxonomy of the genus Eremanthus (Vernonieae, Asteraceae), and to provide additional data for its phylogenetic reconstruction, the pollen of 20 of the 23 species of the genus was examined using light and scanning electron microscopy. Acetolysed pollen grains were measured, described, and illustrated using light microscopy, while non-acetolysed pollen grains were analyzed using scanning electron microscopy. Pollen grains of these species are isopolar, oblate-spheroidal in most of the species, more rarely prolate spheroidal or suboblate, subtriangular amb, tricolporate and subechinolophate. The variation among quantitative characters does not correlate with the macromorphological subdivision of the genus or with the generic or specific limits.


1973 ◽  
Vol 184 (1075) ◽  
pp. 149-165 ◽  

The tryphine that coats the pollen grains of Raphanus is tapetally synthesized and is composed of a fibro-granular and a lipidic component. The fibro-granular material is proteinaceous and is secreted by cisternae of the endoplasmic reticulum. The lipidic component is derived, mainly, from degraded elaioplasts. The fibro-granular material is applied to the pollen exine first, followed by the lipidic mass. The tryphine condenses during the final stages of pollen maturation and dries down to form a thick, highly viscous coating. The major part of the condensation appears to result from dehydration. The tryphine, extracted from the pollen by a centrifugal method and mounted in a membrane, appears to be capable of penetrating the outer layers of a stigma of the same species and, if the pollen from which it was derived is incompatible with respect to the stigma, the stimulation of the production of the callosic reaction body in a manner similar to an incompatible pollen tube. It is proposed that, in Raphanus , substances responsible for the initiation of at least two stages in the self-incompatibility system are held in the tryphine.


2012 ◽  
Vol 40 (2) ◽  
pp. 53 ◽  
Author(s):  
Cevriye MERT

This study reports on the arrangement of flower buds and structure of floral organs of cornelian cherry (Cornus mas L.) cultivars local to Turkey. The local cultivars were investigated under stereo microscope, light microscope, and scanning electron microscope (SEM). The results indicate that each node has two oppositely positioned buds on 1-year-old shoot. Inflorescences resembled the umbel structure that enclosed four (two sets of oppositely oriented) bud scales. The mean flower number varied between 16.3 and 19.9 per cluster among the cultivars. The flowers resembled the hermaphrodite type and one flower was found to have four rudimentary sepals, four petals, four stamens, and one pistil. The stamens were noted to be arranged around the base of the ovary. Each normal anther was observed to have two pollen-producing theca, and each theca was found to have two locules. The number of pollen grains per anther varied between 1380 and 4240 among the genotypes. The pistil was noted to have a deeply hollowed papillate stigmatic surface, and the central part of the style had conducting tissue. The ovarium part of the pistil was found to be surrounded by the nectary tissue, inferior type, and had two atropous ovules. The fruit resembled single-seeded, stone fruit type. This study is the first detailed study on the flower morphology and inflorescences of the cornelian cherry cultivars in Turkey.


2012 ◽  
Vol 24 (1) ◽  
pp. 5-13 ◽  
Author(s):  
Olena M. Peregrym ◽  
Zoya M. Tsymbalyuk ◽  
Sergei L. Mosyakin

Abstract Pollen grains of 10 species of Pedicularis occurring in Ukraine were investigated using light and scanning electron microscopy. Palynological data on 6 species are reported for the first time. General pollen morphology of the genus Pedicularis is presented. Three types of apertures (2-syncolpate, 3-colpate, and 3-syncolpate) and seven subtypes of sculpture (3-syncolpate pilate, 3-syncolpate microscabrate-tubeculate, 2-syncolpate microscabrate, 2-syncolpate microscabrate-tubeculate, 2-syncolpate microscabrate-tubeculate-perforate, 2-syncolpate microfoveolate, and 2-syncolpate microscabrate-perforate) are indentified. The subgenus Pedicularis is heterogeneous in its types of apertures and sculpture of the surface, which indicates the need of further taxonomic revision of the group.


2017 ◽  
pp. 117 ◽  
Author(s):  
Victoria Sosa

This work studies 17 species of mexican Araliaceae from the palynological point of view belonging to the genera Aralia, Dendropanax, Didymopanax, Redera, Oreopanax y Sciadodendron . All the pollen descriptions are presented at the generic level. The grains were studied based in scanning electron microscope and light microscope. It includes a dichotomous key for the genera grains. The results showed few differences between the pollen grains of the genera although some exine characters are important. Redera and Didymopanax presented an exine semi-tectate and the rest of the genera had tectate-perforate grains. This paper compared also some pollen characters with morphological ones, finding pollen characters considered primitive correlated with characters of primitive Araliaceae groups .


Author(s):  
Marina Macukanovic-Jocic ◽  
Snezana Jaric

Palynomorphological characteristics of Campanula lingulata, the Balkan-Carpathian endemic species growing in Serbia, have been investigated using light microscopy and scanning electron microscopy for the first time, in order to provide some information helpful for a better understanding of the taxonomic position of this species within the genus, as well as to contribute to the pollen atlas of Serbian apiflora. The pollen grains are radially symmetrical, isopolar, 3-zonoporate and medium-sized monads oblate-sphaeroidal in shape. Mean of the polar axis (P) is 27.6?1.9 ?m, while the average length of the equatorial axis (E) is 28.8?1.6 ?m. The apertures are operculate. The sculpturing pattern of the exine is microre?ticulate-microechinatae. The exine surface is covered with evenly distributed supratectal spinules of variable length and sparse granules. The longest supratectal spinules are 0.64?0.05 ?m in length and the smallest sculptural elements are less than 0.2 ?m high. The microechinae density per sample area of 5 ?m x 5 ?m averages 17.4?2.4.


Sign in / Sign up

Export Citation Format

Share Document