Effects of high temperatures on mature pollen grains in wild and cultivated maize accessions

Euphytica ◽  
1991 ◽  
Vol 55 (3) ◽  
pp. 203-207 ◽  
Author(s):  
V. A. Lyakh ◽  
A. N. Kravchenko ◽  
A. I. Soroka ◽  
E. N. Dryuchina
Keyword(s):  
High Temperatures ◽  
Pollen Grains ◽  
Mature Pollen

scholarly journals Transformation of Seed Non-Transmissible Hop Viroids in Nicotiana benthamiana Causes Distortions in Male Gametophyte Development

Plants ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 2398
Author(s):  
Lenka Steinbachová ◽  
Jaroslav Matoušek ◽  
Gerhard Steger ◽  
Helena Matoušková ◽  
Sebastjan Radišek ◽  
...  
Keyword(s):  
Nicotiana Benthamiana ◽  
Male Gametophyte ◽  
Pollen Grains ◽  
Potato Spindle Tuber Viroid ◽  
Apple Fruit ◽  
Mature Pollen ◽  
Rare Occurrence ◽  
Gametophyte Development ◽  
Male Gametophyte Development ◽  
Marker Proteins

Viroids are small, non-coding, parasitic RNAs that promote developmental distortions in sensitive plants. We analyzed pollen of Nicotiana benthamiana after infection and/or ectopic transformation with cDNAs of citrus bark cracking viroid (CBCVd), apple fruit crinkle viroid (AFCVd) and potato spindle tuber viroid (PSTVd) variant AS1. These viroids were seed non-transmissible in N. benthamiana. All viroids propagated to high levels in immature anthers similar to leaves, while their levels were drastically reduced by approximately 3.6 × 103, 800 and 59 times in mature pollen of CBCVd, AFCVd and PSTVd infected N. benthamiana, respectively, in comparison to leaves. These results suggest similar elimination processes during male gametophyte development as in the Nicotiana tabacum we presented in our previous study. Mature pollen of N. benthamiana showed no apparent defects in infected plants although all three viroids induced strong pathological symptoms on leaves. While Nicotiana species have naturally bicellular mature pollen, we noted a rare occurrence of mature pollen with three nuclei in CBCVd-infected N. benthamiana. Changes in the expression of ribosomal marker proteins in AFCVd-infected pollen were detected, suggesting some changes in pollen metabolism. N. benthamiana transformed with 35S-driven viroid cDNAs showed strong symptoms including defects in pollen development. A large number of aborted pollen (34% and 62%) and a slight increase of young pollen grains (8% and 15%) were found in mature pollen of AFCVd and CBCVd transformants, respectively, in comparison to control plants (3.9% aborted pollen and 0.3% young pollen). Moreover, pollen grains with malformed nuclei or trinuclear pollen were found in CBCVd-transformed plants. Our results suggest that “forcing” overexpression of seed non-transmissible viroid led to strong pollen pathogenesis. Viroid adaptation to pollen metabolism can be assumed as an important factor for viroid transmissibility through pollen and seeds.

scholarly journals On the Mature Pollen Grains in Angiosperms

1937 ◽  
Vol 51 (606) ◽  
pp. 524-529 ◽  
Author(s):  
Nobuhide Suita
Keyword(s):  
Pollen Grains ◽  
Mature Pollen

Gametogenesis in Galbulimima belgraveana (Himantandraceae)

1984 ◽  
Vol 32 (6) ◽  
pp. 605 ◽  
Author(s):  
N Prakash ◽  
DB Foreman ◽  
SJ Griffith
Keyword(s):  
Close Relationships ◽  
Embryo Sac ◽  
Pollen Grains ◽  
Mature Pollen ◽  
Ovule Development ◽  
Abaxial Side ◽  
Polygonum Type ◽  
Early Stages

The flowers of Galbulimima belgraveana (F. Muell.) Sprague are bisexual, calyptrate and protogynous. The numerous free stamens are laminar and arranged spirally on an elongated receptacle; only the middle stamens are fertile. There are four microsporangia embedded on the abaxial side of the microsporophyll. The tapetum is secretory and often double. A variety of spore tetrad types is produced. The mature pollen grains are single, monosulcate, scabrate, atectate, spheroidal and 2-celled. The carpels of a flower are initially free but later become concrescent so that a single fruit is formed. The ovules are anatropous, crassinucellar and bitegminal, and show an elongated embryo sac that conforms to the polygonum type of development. There is a massive parietal tissue in early stages of ovule development. In its embryological features, the species shows close relationships to the families Annonaceae and Degeneriaceae and, to a slightly lesser extent, the Magnoliaceae and Eupomatiaceae.

Pollen exine substructure In Fagus (Fagaceae): role of tufts in exine expansion

1990 ◽  
Vol 68 (10) ◽  
pp. 2195-2200 ◽  
Author(s):  
Don Claugher ◽  
John R. Rowley
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
High Resolution ◽  
Pollen Grains ◽  
Mature Pollen ◽  
Similar Range ◽  
Fagus Sylvatica L ◽  
Microscopy Images ◽  
Scanning Electron

We compare results obtained from mature pollen of Fagus sylvatica L. using high-resolution scanning electron microscopy with fransmission electron microscopy images from several stages, from the early free microspore through to mature pollen grains. Exine processes (tufts) on young and mature grains are rodlike, with cross striations 10–15 nm wide. The total diameter of the tufts is 70–100 nm on exines of young microspores and up to 200–250 nm on mature exines. Tufts about 70 nm wide on the young microspores contain about five stacks of loops about 30 nm in diameter, whereas larger tufts on more mature exines have many stacks of the 30 nm wide loops. At maturity there is a mixture of large (200–250 nm wide) and small (70–100 nm wide) tufts and some tapering down from over 200 nm in width to less than 100 nm. There is continuity and a similar range of widths between the tufts as they occur as bacules and components of the tectum. We conclude that either new large-sized tufts are inserted during growth or some of the small (original sized) tufts increase in diameter from their bases toward the outer tip, or that both of these processes occur.

scholarly journals Abnormal Microspore Development Leads to Pollen Abortion in a Seedless Mutant of ‘Ougan’ Mandarin (Citrus suavissima Hort. ex Tanaka)

2007 ◽  
Vol 132 (6) ◽  
pp. 777-782 ◽  
Author(s):  
Zhiyong Hu ◽  
Min Zhang ◽  
Qigen Wen ◽  
Jie Wei ◽  
Hualin Yi ◽  
...  
Keyword(s):  
Pollen Viability ◽  
Pollen Grains ◽  
Pollen Grain ◽  
Mature Pollen ◽  
Abnormal Development ◽  
Microspore Development ◽  
Wild Type ◽  
Pollen Abortion ◽  
Tetrad Stage ◽  
In The Wild

Seedlessness is of commercial importance in citrus (Citrus L.). Seedless ‘Ougan’ mandarin (C. suavissima) was selected from a bud sport mutation that occurred in ‘Ougan’ mandarin. We analyzed their pollen viability through KI-I2 and FDA staining, and examined the anthers of wild-type (seedy) and seedless mutant ‘Ougan’ mandarin using histological and cytochemical methods to characterize the process of pollen development. No pollen fertility was detected in this mutant. Pollen abortion in anthers of the mutant occurred at the tetrad stage of microspore development, and almost all the tetrads were abnormal. The mutant had heterogeneous microspore populations, including monads, dyads, triads, tetrads, and polyads in the same microsporangium. Pollen grain number per anther of the mutant was 21.9% less than the wild type. Morphology of mature pollen grains using SEM showed that the shape of mature pollen grains from both wild type and mutant is similar, but the microsporangia of the latter contained pollen grains of more variable sizes. At the early mature pollen grain stage, abundant starch grains and lipids appeared in the wild type's pollen, but fewer amounts were observed in the mutant. Moreover, the tapetal cells of the wild type accumulated lipids, but not those of the mutant. Results indicated that the abnormal development of the microspore led to pollen abortion in the mutant, and this could be the reason for its seedlessness. However, the genetic reasons for the aberrant tetrads are not clear and are under investigation.

scholarly journals Some features of biology of the species genus Crocus (family Iridaceae)

2020 ◽  
pp. 94-100
Author(s):  
S. V. Shevchenko ◽  
N. N. Miroshnichenko
Keyword(s):  
Embryo Sac ◽  
Pollen Grains ◽  
Mature Pollen ◽  
Polygonum Type ◽  
Male And Female ◽  
Research Results ◽  
Nest Box

The article presents the research results of the genesis of biology of Crocus angustifolius and Crocus speciosus . Some aspects of formation of the male and female gametophytes, pollination and seeds formation have been presented. The wall of microsporangium develops centripetally as monocotyledonous and formed consists of the epidermis, endothecium, 2-3 middle layers and secretory tapetum. A tetrad of microspores is formed simultaneously. Mature pollen grains are 2-cell. The ovary is three-celled, the ovary is anatropic, crassinucellous, bitegmal, funiculous. Polygonum-type embryo sac. Pedestal, podium and hypostasis are formed. Both species are entomophilous plants. The fruit is a multi-seeded three-nest box. Both species propagated by seeds and vegetatively using corms.

scholarly journals A Cytological Study of Anther and Pollen Development in Chinquapin (Castanea henryi)

HortScience ◽  
2020 ◽  
Vol 55 (6) ◽  
pp. 945-950
Author(s):  
Weiping Zhong ◽  
Zhoujun Zhu ◽  
Fen Ouyang ◽  
Qi Qiu ◽  
Xiaoming Fan ◽  
...  
Keyword(s):  
Pollen Development ◽  
Lipid Droplets ◽  
Morphological Characteristics ◽  
Pollen Grains ◽  
Middle Layer ◽  
Anther Development ◽  
Mature Pollen ◽  
Anther Wall ◽  
Male Flowers ◽  
Microspore Stage

The normal development of anthers and the formation of functional pollen are the prerequisites for successful pollination and fertilization. In this study, we observed dynamic changes in inflorescence and anther development in the chinquapin (Castanea henryi) using stereomicroscopy, light microscopy, and transmission electron microscopy. We found that cytokinesis during meiosis in microsporocytes was of the simultaneous type, and that the tetrads were mainly tetrahedral. Mature pollen grains contained two cells with three germ pores. The anther wall was of the basic type and composed of epidermis, endothecium, middle layers, and tapetum. Mature anthers had no middle layer and tapetum. The tapetum was of the glandular type. At the early microspore stage, a large number of starch granules appeared in the endothecium, which was deformed at the late microspore stage. Lipid droplets appeared in tapetum during the early microspore stage, and a few lipid droplets were still found during tapetum degeneration. The mature pollen accumulated a large amount of starch and lipids. These findings demonstrated that the anther wall provides nutrients and protection for pollen development. There is relatively stable correspondence between the external morphological characteristics of male flowers and internal structure of anther development.

Développement de l'anthère et du grain de pollen chez une espèce sauvage apparentée à la canne à sucre (Saccharum spontaneum)

1996 ◽  
Vol 74 (5) ◽  
pp. 788-795 ◽  
Author(s):  
D. Roques ◽  
P. Feldmann
Keyword(s):  
Pollen Development ◽  
Pollen Grains ◽  
Mature Pollen ◽  
Saccharum Spontaneum ◽  
Canne À Sucre ◽  
Secretory Type ◽  
Fertile Male ◽  
La Canne À Sucre

A study of the histocytological characteristics of anthers and pollen development of fertile male genotypes of Saccharum spontaneum L. support the division of microsporogenesis into nine distinct stages: premeiosis, meiosis and tetrad, young uninucleate microsporal stage, median uninucleate microsporal stage, median vacuolized uninucleate microsporal stage, late vacuolized uninucleate microsporal stage, first pollinic mitosis, second pollinic mitosis, mature pollen. Pollen grains are subspherical, monosporal, operculated with verrucose type ornamentations. A secretory type tapetum, present from the very first microsporal stages, is covered with orbicules persisting until anthesis. Keywords: Saccharum spontaneum, microsporogenesis, pollen, tapetum. [Journal translation]

Ultrastructure of pollen of Opuntia polyacantha

1974 ◽  
Vol 52 (2) ◽  
pp. 313-315 ◽  
Author(s):  
Frank Kozar
Keyword(s):  
Endoplasmic Reticulum ◽  
Plasma Membrane ◽  
Pollen Grains ◽  
Mature Pollen ◽  
Starch Granules ◽  
Opuntia Polyacantha

Ultrastructure studies of the pollen grains of Opuntia polyacantha reveal an elaborately sculptured ektexine but no endexine. The mature pollen cytoplasm is non-vacuolated, and contains plastids, starch granules, lipids, endoplasmic reticulum (ER), and relatively few other recognizable structures. Membranes and inclusions taken to be plasmalemmasomes were observed in the intine. Invaginations of the plasma membrane were also observed.

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