Microsporogenesis in Larix laricina

1982 ◽  
Vol 60 (6) ◽  
pp. 797-805 ◽  
Author(s):  
J. Peter Hall
Keyword(s):  
Propionic Acid ◽  
Seed Yield ◽  
Pollen Development ◽  
Abnormal Chromosome ◽  
Acid Mixture ◽  
Larix Laricina ◽  
Normal Pattern ◽  
Mother Cells ◽  
Male Strobili

Microsporogenesis was studied in Larix laricina in eastern Newfoundland at weekly intervals from October to April in four successive seasons. Male strobili were fixed in a 3:1 ethanol – propionic acid mixture, stained in alcoholic carmine, and squashed in 45% acetic acid.Pollen mother cells began development from interphase in early October and passed through leptotene, zygotene, and pachytene by mid-November. They remained in diplotene until mid-March to early April when meiosis was completed over a 2-to 4-week period. Microspores were produced by early May. The pattern of meiotic divisions, their duration, and variability within and between trees in L. laricina was similar to those reported for L. decidua, L. kaempferi, L. sibirica, and L. eurolepis.Deviation from the normal pattern occurred infrequently. In six trees the "resting diplotene" of winter was interrupted on one occasion and some male strobili had a "delayed meiosis" which occurred several days after meiosis in all other sampled strobili. Abnormal chromosome separations were observed on a few occasions; these consisted mostly of lagging chromosomes, a common abnormality in Larix meiosis. The implications for pollen development and seed yield are discussed.La microsporogénèse chez Larix laricina dans l'est de Terre-Neuve a été étudiée à intervalles hebdomadaires d'octobre à avril, pendant quatre années successives. Les strobiles mâles étaient fixés dans un mélange 3 : 1 d'éthanol – acide propionique, colorés au carmin alcoolique et écrasés dans l'acide acétique 45%.

scholarly journals Chemicals with a natural reference for controlling water hyacinth, Eichhornia crassipes (Mart.) Solms

2015 ◽  
Vol 55 (3) ◽  
pp. 294-300 ◽  
Author(s):  
Tarek Abd El-Ghafar El-Shahawy
Keyword(s):  
Acetic Acid ◽  
Citric Acid ◽  
Formic Acid ◽  
Propionic Acid ◽  
Water Hyacinth ◽  
Eichhornia Crassipes ◽  
Effective Control ◽  
Acid Mixture ◽  
Aquatic Weeds ◽  
Herbicide Glyphosate

AbstractLife cannot exist without water. Appropriate management of water, from the water’s source to its utilization, is necessary to sustain life. Aquatic weeds pose a serious threat to aquatic environments and related eco-environments. Short- and long-term planning to control aquatic weeds is extremely important. Water hyacinth,Eichhornia crassipes(Mart.) Solms, is one of the world’s worst pests with a bad reputation as an invasive weed. In this study we are seeking the possibility of using certain chemicals with a natural background, for controlling water hyacinth since there is a delicate balance that needs to be taken into account when using herbicides in water. Five compounds, namely: acetic acid, citric acid, formic acid, and propionic acid, in three concentrations (10, 15, and 20%) were applied (i.e. as a foliar application under wire-house conditions) and compared with the use of the herbicide glyphosate (1.8 kg ∙ ha−1). All of the five compounds performed well in the control of the water hyacinth. As expected, the efficacy increased as the concentration was increased from 10 to 20%. With formic and propionic acids, the plants died earlier than when the other acids or the herbicide glyphosate, were used. Acetic acid came after formic and propionic acids in terms of efficacy. Citric acid ranked last. Formic acid/propionic acid mixtures showed superior activity in suppressing water hyacinth growth especially at the rate of (8 : 2) at the different examined concentrations (3 or 5 or 10%) compared to the formic acid/acetic acid mixtures. Using the formic acid/propionic acid mixture (8 : 2; at 3%) in the open field, provided good control and confirmed the viability of these chemicals in the effective control of water hyacinth. Eventually, these chemical treatments could be used on water for controlling water hyacinth. In the future, these chemicals could probably replace the traditional herbicides widely used in this regard. These chemicals are perceived as environmentally benign for their rapid degradation to carbon dioxide and water. For maximum efficiency thorough coverage especially in bright sunlight is essential.

scholarly journals The Study of Pollen Development in Nine Cultivars of Hazelnut (Corylusavellana)

HortScience ◽  
2005 ◽  
Vol 40 (4) ◽  
pp. 1117A-1117
Author(s):  
Chantalak Tiyayon ◽  
Anita Nina Azarenko
Keyword(s):  
Pollen Development ◽  
Developmental Stages ◽  
Male Gametophyte ◽  
Male Flower ◽  
Pollen Grains ◽  
Corylus Avellana ◽  
Tissue Sections ◽  
Development And Differentiation ◽  
Mother Cells ◽  
Pollen Shed

Pollen development is an important event in plant reproduction. Hazelnut (Corylus avellana) male flower differentiation starts in summer and pollen shed is in the winter. Hazelnut pollen shed can vary up to 3 months between early to late flowering genotypes. Microsporogenesis and microgametogenesis of hazelnut is not well understood. Pollen development and differentiation of nine genotypes, representing early to late blooming cultivars from the National Clonal Germplasm Repository in Corvallis, Ore., were studied. Catkins were collected weekly from Aug. to Nov. 2002. Tissue sections were examined under the light microscope. Microsporogenesis was divided into five stages: archesporial cells, sporogenous cells and parietal layers, pollen mother cells (PMC), tetrads, and microspores. Microgametogenesis was distinguished between young pollen grains (uninucleate) and mature pollen grains (binucleate). On 4 Aug., cultivars were at different developmental stages of microsporogenesis. Early blooming cultivars had PMCs present. Later-blooming cultivars only contained archesporial cells. PMCs were present in all cultivars by 22 Aug. Microspores were observed on 26 Sept. in all cultivars. This study contributes to a better understanding of male gametophyte development in hazelnut, which has increased our ability to correlate hazelnut pollen development with bloom phenology.

Anther and pollen infection in relation to the pollen and seed transmissibility of two strains of barley stripe mosaic virus in barley

1976 ◽  
Vol 54 (14) ◽  
pp. 1604-1621 ◽  
Author(s):  
Thomas W. Carroll ◽  
Dennis E. Mayhew
Keyword(s):  
Mosaic Virus ◽  
Pollen Development ◽  
Floral Meristem ◽  
Barley Stripe Mosaic Virus ◽  
Seed Transmissibility ◽  
Different Strains ◽  
Mother Cells ◽  
Mitosis And Meiosis ◽  
Normal Mitosis ◽  
Mature Anther

Anther and pollen infection in relation to seed and pollen transmission were studied for two different strains of barley stripe mosaic virus in 'Atlas' barley. Examination of sectioned anthers and pollen revealed that the seed- and pollen-transmitted isolate of the virus (MI-1) invaded the floral meristem of the host early and subsequently infected the pollen mother cells and sperms. During the premeiotic and meiotic stages of anther and pollen development, most virions of MI-1 were seen attached to microtubules, including those of the spindle. In later stages, the association of virions with microtubules diminished. Usually, MI-1 caused no apparent interference with normal mitosis and meiosis during development of anthers and pollen in central florets. Occasionally, however, the virus induced degeneration in anther and pollen-precursor cells before and during meiosis. By comparison, virions of the NSP strain, a strain which is not seed or pollen transmitted, could only be detected in wall cells of a single mature anther. None were discovered in the floral meristem or in pollen. It was also shown with unsectioned material that infection with either virus adversely affected anther and pollen development and that infection by MI-1 increased seed sterility.

scholarly journals 509 A Glycine-rich Protein from Tomato Involved in Pollen Wall Formation

HortScience ◽  
1999 ◽  
Vol 34 (3) ◽  
pp. 533C-533
Author(s):  
Alan G. Smith ◽  
Kenneth J. McNeil
Keyword(s):  
Pollen Development ◽  
Polyclonal Antibodies ◽  
Outer Wall ◽  
Protein Levels ◽  
Isolation And Characterization ◽  
Sporophytic Tissue ◽  
Mother Cells ◽  
Transgenic Tomatoes ◽  
And Function ◽  
Glycine Rich Protein

The sporophytic tissue of the anther and, in particular, the tapetum, a cell layer surrounding the pollen sac, is know to be essential for the production of pollen. The isolation and characterization of the gene 92B from tomato that encodes an extracellular glycine rich protein (GRP) has been used to further elucidate the role of the tapetum in pollen development. RNA from the 92B gene accumulates exclusively in the tapetum. Polyclonal antibodies raised against the 92B GRP detect four proteins in stamens with microspores beginning meiosis. In pollen extracts, the antibodies detect a single protein. Expression of the tomato 92B gene in transgenic tobacco indicates that the four protein products are derived from only the 92B gene. The 92B GRP is localized to the tapetum, the callose wall of microspore mother cells, the exine (outer wall) of mature pollen, and orbicules. Orbicules are globular bodies derived from tapetal material that form on the tapetum wall and line the exterior of the pollen sac. Expression of 92B antisense RNA resulted in a significant decrease of 92B RNA and protein levels in transgenic tomatoes. This reduction was correlated with a decrease in pollen germination and an abnormal exine morphology. The function of the 92B protein in pollen development and function will be discussed.

scholarly journals INFLUENCE OF ADDITIVES ON SHORT-TERM PRESERVATION OF WET BREWERS’ GRAIN STORED IN UNCOVERED PILES

1975 ◽  
Vol 55 (4) ◽  
pp. 609-618 ◽  
Author(s):  
W. R. ALLEN ◽  
K. R. STEVENSON ◽  
J. BUCHANAN-SMITH
Keyword(s):  
Formic Acid ◽  
Propionic Acid ◽  
Untreated Control ◽  
Dry Matter ◽  
Storage Period ◽  
High Rate ◽  
Acid Mixture ◽  
Quality Material ◽  
Measuring Ph

Fresh wet brewers’ grains at 23.0% dry matter and 4.7% total nitrogen (dry matter basis) were obtained from a brewery. The effects of the following additives on the preservation of brewers’ grains, stored in uncovered piles, were compared to an untreated control during a 14-day storage period: 85% formic acid at 0.20 and 0.40%; propionic acid and formic–propionic mixture (1:1) at 0.20, 0.30, and 0.40%; and molasses at 2.00%. Piles of brewers’ grains were placed outside on polyethylene sheeting. The quality of the wet brewers’ grains was determined by measuring pH, organic acid and ammoniacal-nitrogen content of surface and subsurface samples taken at three intervals during the 14-day study. As well, visible surface changes were noted daily during the 2-wk period. A rapid increase in acetic acid in the subsurface samples was detected for brewers’ grains treated with the low and medium rates (0.20 and 0.30%) of both propionic and formic–propionic, 2.00% molasses and the untreated control. As well, extensive mold growth, discoloration and dry matter deterioration were noted for these treatments. The two rates (0.20 and 0.40%) of formic acid and the high rate (0.40%) of propionic acid were effective in reducing subsurface deterioration, but were unable to reduce the amount of surface spoilage. The high rate (0.40%) of the formic–propionic acid mixture effectively reduced all aspects of deterioration to maintain quality material during the 14-day study.

THE CHEMICAL COMPOSITION OF THE HEARTWOOD EXTRACTIVES OF TAMARACK (LARIX LARICINA (DU ROI) K. KOCH)

1959 ◽  
Vol 37 (9) ◽  
pp. 1608-1613 ◽  
Author(s):  
G. V. Nair ◽  
E. Von Rudloff
Keyword(s):  
Fatty Acid Mixture ◽  
Acetone Extract ◽  
Resin Acids ◽  
The Other ◽  
Acid Mixture ◽  
Gas Liquid Chromatography ◽  
Larix Laricina ◽  
Long Chain Fatty Acids ◽  
Heartwood Extractives ◽  
Long Chain

The acetone-soluble constituents of the heartwood of tamarack have been investigated. The flavanonols taxifolin and aromadendrin were isolated in 0.30 and 0.05% yield and a trace amount of quercetin was obtained. Tropolones could not be detected, nor was there any evidence for resin acids. The major portion of the extract consisted of esters of ferulic, phthalic, and long-chain fatty acids. Eicosanyl ferulate was isolated as such, whereas the other constituents were identified after saponification. Gas liquid chromatography of the fatty acid mixture indicated the presence of palmitic, palmitoleic, oleic, linoleic, and linolenic acids as well as small amounts of C14, stearic, and C20 acids. From the non-saponifiable portion β-sitosterol, eicosanol, and nonan-2-ol were isolated. The acetone extract also contained free D-galactose and L-arabinose.

scholarly journals Development of pollen grain in yellow passion-fruit (Passiflora edulis f. flavicarpa; Passifloraceae)

2000 ◽  
Vol 23 (2) ◽  
pp. 469-473 ◽  
Author(s):  
Margarete Magalhães de Souza ◽  
Telma Nair Santana Pereira
Keyword(s):  
Male Gamete ◽  
Optical Microscope ◽  
Pollen Grain ◽  
Passion Fruit ◽  
Normal Pattern ◽  
Passiflora Edulis ◽  
Grain Formation ◽  
Safranin O ◽  
Mother Cells ◽  
Yellow Passion Fruit

To clarify events occurring during pollen grain formation in yellow passion-fruit (Passiflora edulis f. flavicarpa), floral buds were collected at different stages of development. After bracket, petal and sepal removal the anthers were fixed, dehydrated, embedded in paraffin wax, sectioned at 10 mum and after differential dying with safranin O and fast green, mounted in Canada balsam and observed under optical microscope. Formation of the male gamete followed the normal pattern for angiosperms. Observation covered final sporogenic mass phase up to pollen grain formation; microsporangium tissue modifications were also observed. Microsporogenesis was characterized by sporogenic tissue differentiation in microsporic mother cells, followed by meiosis and resulting in tetrads. Microgametogenesis began with callose microspore release, subsequent mitosis, in addition to radial and tangential tapetum wall degradation, parietal layer compression nearer to the tapetum and endothecium widening, terminating in mature pollen grain formation.

scholarly journals Optical and ultrastructural study of the pollen grain development in hermaphrodite papaya tree (Carica papaya L.)

2008 ◽  
Vol 51 (3) ◽  
pp. 539-545 ◽  
Author(s):  
Lídia Márcia Silva Santos ◽  
Telma Nair Santana Pereira ◽  
Margarete Magalhães de Souza ◽  
Pedro Correa Damasceno Junior ◽  
Fabiane Rabelo da Costa ◽  
...  
Keyword(s):  
Carica Papaya ◽  
Generative Cell ◽  
Pollen Grains ◽  
Male Gamete ◽  
Mitotic Division ◽  
Pollen Grain ◽  
Grain Development ◽  
Normal Pattern ◽  
Papaya Tree ◽  
Mother Cells

The objective of this study was to describe the pollen grain development in hermaphrodite papaya tree. The flower buds were collected at different stages of the development and the anthers were treated chemically for observation under optical and electronic transmission microscopes. The pollen grain development followed the normal pattern described for the Angiosperms. The pollen grain development was described from meiocyte to the mature pollen grain. In the microsporogenesis, the microspore mother cells or the meiocytes underwent meiosis giving rise to the tetrads that were enclosed by the calose. Later, the tetrads were released by the dissolution of the calose by calase activity and microspores underwent mitosis. Microgametogenesis was characterized by asymmetrical mitotic division of each microspore giving rise to bi-nucleate pollen grains. The structures similar to the plastids were found in the cytoplasm and close to the nucleus of the generative cell. Gradual degeneration was observed in the tapetum during the male gamete development.

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