scholarly journals Structure of the floral parts of Crocus vernus (L.) Hill.

2012 ◽  
Vol 64 (4) ◽  
pp. 35-46 ◽  
Author(s):  
Elżbieta Weryszko-Chmielewska ◽  
Mirosława Chwil
Keyword(s):  
Glandular Trichomes ◽  
Pollen Grains ◽  
Climatic Conditions ◽  
Epidermal Cells ◽  
The Third ◽  
Flower Stem ◽  
Significant Length ◽  
Perianth Tube ◽  
Narrow Space ◽  
Parenchymal Cells

In the climatic conditions of Lublin, <i>Crocus vernus</i> blooms from the third decade of March until the third decade of April. The flowers live for 3-4 days. Micromorphological investigations of the tepals and perianth tube as well as of the stamens and pistil were carried out using scanning electron microscopy. The anatomical features of the perianth segments and flower stem were examined with the use of light and fluorescence microscopy. Pollen grains were observed under a light microscope. It was found that the adaxial and abaxial epidermal cells formed papillae in the middle and lower part of the tepals. Much smaller papillae are formed in the upper region of the perianth tube. Elongated non-glandular and glandular trichomes, with spherical protrusions at the tip, are found at the base of the filaments. The filaments are distinguished by epidermal cells with a longitudinally striated cuticle and by the presence of papillae of varying number and size. The cylindrical papillae on the stigma of the pistil are covered by a wrinkled cuticle. The style is surrounded by the perianth tube along a significant length. A narrow space is formed between these organs, and it is filled by the nectar. Stylar channels are found in the style. We observed calcium oxalate crystals and numerous plastids in the parenchymal cells surrounding these channels. Inaperturate, spherical pollen grains are covered by numerous tryphine (or pollenkitt) droplets. This paper also discusses the functions of the papillae found in the epidermis of the perianth and filaments.

Vegetative and reproductive development of shoot apices of Pharbitis nil as influenced by photoperiodism

1969 ◽  
Vol 47 (9) ◽  
pp. 1403-1406 ◽  
Author(s):  
D. S. Bhar ◽  
N. W. Radforth
Keyword(s):  
Mitotic Activity ◽  
Dark Period ◽  
Pollen Grains ◽  
Reproductive Development ◽  
Epidermal Cells ◽  
Floral Transition ◽  
Pharbitis Nil ◽  
Shoot Apices ◽  
The Third

In shoot apices of Pharbitis nil, cytohistological zonation is not clearly delineated at germination. With increase in age, zonation develops and the granular appearance of the cytoplasm disappears. After induction by a single 16-hour dark period the first recognizable sign of floral transition becomes evident on the second day, with increase in the mitotic activity of the apex. On the third and fourth days, the sepals are initiated and the petals and stamens are initiated simultaneously on the fifth day. On the sixth day the carpel primordia originate. Between the 11th and 12th days after the inductive dark period, the pollen grains develop and the style extends. Between the 19th and 20th days the epidermal cells of the stigma become secretory.

scholarly journals Micromorphology of endemic Centaurea glaberrima subsp. divergens (Asteraceae)

2022 ◽  
Vol 81 (1) ◽  
Author(s):  
Milan Gavrilović ◽  
Pedja Janaćković
Keyword(s):  
Cell Walls ◽  
Glandular Trichomes ◽  
Pollen Grains ◽  
Involucral Bract ◽  
Epidermal Cells ◽  
Leaf Epidermis ◽  
Abaxial Surface ◽  
Reproductive Structures ◽  
Anomocytic Stomata ◽  
First Time

In this study, the micromorphology of the vegetative and reproductive structures of the endemic Centaurea glaberrima Tausch subsp. divergens (Vis.) Hayek (Asteraceae), using scanning electron microscope (SEM), is presented for the first time. Uniseriate whip-like non-glandular and biseriate glandular trichomes are found on the surface of all aboveground parts (stem, leaves, peduncles, involucral bract). On the adaxial leaf epidermis ribbed thickenings (striation pattern) of outer periclinal cell walls, slightly curved anticlinal cell walls and anomocytic stomata are noticed. Rugose abaxial surface with thorny protuberances of the involucral bract is documented. Corolla is glabrous with longitudinally parallel epidermal cells with distinct straight outline. Isopolar, radially symmetric and tricolporate microechinate pollen grains are seen. Short stylar hairs, without cuticular striations, are present along the outer sides of the style, while the inner sides (abaxial surface) constitute the papillate stigmatic surface. Microcharacters found in cypsela are as follows: slightly ribbed body; rotund base; lateral and concave insertion; short, unicellular curly acute trichomes; smooth epidermis; fine-sulcate ornamentation; rod shaped epidermal cells with short, obtuse end walls and straight anticlinal walls; poorly developed minutely dentate pericarp rim; and dimorphic pappus with bristles of different length and morphology, with pinnules restricted to the margins of the bristles. The results obtained contribute to knowledge about the micromorphology of the studied endemic species and provide features for its better identification. The taxonomic significance of the analyzed characters is discussed. Some well defined microcharacters of the studied species might have taxonomic value

scholarly journals The structure of floral elements of Anchusa officinalis L. creating attractants for insects

2012 ◽  
Vol 62 (1) ◽  
pp. 37-47 ◽  
Author(s):  
Mirosława Chwil ◽  
Elżbieta Weryszko-Chmielewska
Keyword(s):  
Cell Walls ◽  
Lipid Droplets ◽  
Glandular Trichomes ◽  
Pollen Grains ◽  
Epidermal Cells ◽  
Dark Violet ◽  
Sudan Iii ◽  
Light Effects ◽  
Anchusa Officinalis ◽  
Dark Pink

The present study involved the measurement of size and the micromorphology of the floral elements of <i>Anchusa officinalis</i> L. which are attractants for insects. The structure of the epidermis on the surface of the calyx, petals, throat scales, pistil and nectary were analysed using light and scanning electron microscopy (SEM). For light microscopy observations, semi-permanent slides were prepared, which were treated with Lugol's iodine solution, Sudan III and fluoroglucine. The dark violet lobes of the corolla of <i>Anchusa officinalis</i>, with a velvety surface, and the throat scales, contrasting with them, belong to the most important optical attractants which lure insects from large distances. The dark pink colouring of the sepals additionally increases the attractiveness of the flowers. The epidermis covering the calyx formed different-sized non-glandular trichomes as well as glandular trichomes. The glandular trichomes were composed of a uni - or bicellular leg and a unicellular head. The colour of the corolla petals was determined by anthocyanins accumulated in the epidermal cells and in the more deeply situated parenchyma. The velvety surface was formed by the conical papillae, densely growing from the adaxial epidermis. The pink-violet throat scales with white hairs, covering the inlet to the tube of the corolla, were found at the inlet to the corolla throat. The longest trichomes on the surface of the scales were located in their lower and middle parts, whereas the shortest ones at their tips. The epidermis of the central part of the throat scales formed small papillae. The trichomes had thin cell walls, large vacuoles, numerous plastids and lipid droplets. The two-parted stigma of the pistil was covered by characteristic expanded outgrowths with wavy edges which performed the functions of structures facilitating the capture of pollen grains. As a result of the present study it was found that the structures affecting the attractiveness of the flowers, through various light effects within the corolla of <i>Anchusa officinalis</i>, include the papillae on the corolla surface, trichomes of the throat scales and the epidermal cells of the style. The trichomes of the scales can also be responsible for protecting pollen and nectar against rainfall.

scholarly journals Construction of a weight-based seed sorting system for the third-generation hybrid rice

Rice ◽  
2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Jianxin Wu ◽  
Shijun Qiu ◽  
Menglong Wang ◽  
Chunjue Xu ◽  
Xing Wang Deng ◽  
...  
Keyword(s):  
Hybrid Rice ◽  
Pollen Grains ◽  
Third Generation ◽  
Male Sterile ◽  
Specific Expression ◽  
The Third ◽  
Genes Encoding ◽  
Wild Type Male ◽  
Sorting System ◽  
Generation Hybrid

Abstract Background The third-generation hybrid rice technology can be constructed by transforming a recessive nuclear male sterile (NMS) mutant with a transgenic cassette containing three functional modules: the wild type male fertility gene to restore the fertility of the mutant, the pollen killer gene that specifically kills the pollen grains carrying the transgene, and the red fluorescence protein (RFP) gene to mark the transgenic seed (maintainer). The transgenic plant produces 1:1 NMS seeds and maintainer seeds that can be distinguished by the RFP signal. However, the RFP signals in the partially filled or pathogen-infected maintainer seeds are often too weak to be detected by RFP-based seed sorting machine, resulting in intermingling of the maintainer seeds with NMS seeds. Results Here we constructed a weight-based seed sorting system for the third-generation hybrid rice technology by silencing the genes encoding ADP-glucose pyrophosphorylase (AGP) essential for endosperm starch biosynthesis via endosperm-specific expression of artificial microRNAs (amiRNAs). In this system, the NMS seeds have normal endosperm and are heavy, but the maintainer seeds have shrunken endosperms and are light-weighted. The maintainer seeds can be easily and accurately sorted out from the NMS seeds by weight-sorting machines, so pure and fully filled NMS seeds are available. Conclusions The weight-based seed sorting system shows obvious advantages over the RFP-based seed sorting system in accuracy, efficiency, and cost for propagation of pure male sterile seeds. These characteristics will significantly increase the value and transgenic safety of the third-generation hybrid rice technology.

scholarly journals Prunus necrotic ringspot virus Early Invasion and Its Effects on Apricot Pollen Grain Performance

2007 ◽  
Vol 97 (8) ◽  
pp. 892-899 ◽  
Author(s):  
Khalid Amari ◽  
Lorenzo Burgos ◽  
Vicente Pallas ◽  
María Amelia Sanchez-Pina
Keyword(s):  
Developmental Stages ◽  
Generative Cell ◽  
Pollen Grains ◽  
Growth Zone ◽  
Pollen Tubes ◽  
Climatic Conditions ◽  
Pollen Grain ◽  
Ringspot Virus ◽  
Prunus Necrotic Ringspot Virus

The route of infection and the pattern of distribution of Prunus necrotic ringspot virus (PNRSV) in apricot pollen were studied. PNRSV was detected both within and on the surface of infected pollen grains. The virus invaded pollen during its early developmental stages, being detected in pollen mother cells. It was distributed uniformly within the cytoplasm of uni- and bicellular pollen grains and infected the generative cell. In mature pollen grains, characterized by their triangular shape, the virus was located mainly at the apertures, suggesting that PNRSV distribution follows the same pattern as the cellular components required for pollen tube germination and cell wall tube synthesis. PNRSV also was localized inside pollen tubes, especially in the growth zone. In vitro experiments demonstrated that infection with PNRSV decreases the germination percentage of pollen grains by more than half and delays the growth of pollen tubes by ≈24 h. However, although PNRSV infection affected apricot pollen grain performance during germination, the presence of the virus did not completely prevent fertilization, because the infected apricot pollen tubes, once germinated, were able to reach the apricot embryo sacs, which, in the climatic conditions of southeastern Spain, mature later than in other climates. Thus, infected pollen still could play an important role in the vertical transmission of PNRSV in apricot.

scholarly journals Flowering dynamics and pollen production of Laburnum anagyroides Med. under the conditions of south-eastern Poland

2013 ◽  
Vol 57 (2) ◽  
pp. 103-115 ◽  
Author(s):  
Ernest Stawiarz ◽  
Anna Wróblewska
Keyword(s):  
Pollen Grains ◽  
Average Weight ◽  
Pollen Production ◽  
Full Bloom ◽  
Flowering Duration ◽  
The Third ◽  
Laburnum Anagyroides ◽  
Golden Yellow ◽  
Single Flower ◽  
The Common

Abstract A study on the flowering biology and pollen production of the common laburnum (Laburnum anagyroides Med.) was conducted under the conditions of Lublin during the period 2004 - 2006. The flowering of this species began in the second 10-day period of May and lasted for 2.5 - 4 weeks. The flowers of common laburnum are borne in showy golden-yellow pendulous racemes. They develop successively, starting from the base and moving to the tip of an inflorescence. During the growing season, one shrub produces 800 to 3200 racemes, with 14 to 35 flowers in a single raceme. On average, the flowering duration for a raceme was 12.8 days and 8.7 days for a single flower. Throughout the study years, the shrubs proved to be most attractive in the third 10-day period of May when they reached full bloom. The average weight of pollen produced was 6.08 mg per 10 flowers of Laburnum anagyroides, 14.02 mg per raceme, and 26.0 g per shrub. Pollen grains reached average dimensions of 24.01 μm × 24.26 μm.

scholarly journals Barleria gandhii, a new name for Barleria pauciflora (Acanthaceae)

Phytotaxa ◽  
2015 ◽  
Vol 204 (4) ◽  
pp. 300
Author(s):  
RAMALINGAM KOTTAIMUTHU
Keyword(s):  
South Africa ◽  
Species Diversity ◽  
Calcium Oxalate ◽  
Pollen Grains ◽  
Epidermal Cells ◽  
Calcium Oxalate Crystals ◽  
Tropical Africa ◽  
New Name ◽  
Oxalate Crystals

Barleria Linnaeus (1753: 636) is a pantropical genus comprising about 250–300 species (Balkwill & Balkwill 1998, Darbyshire et al. 2012), with its greatest centre of species diversity in tropical Africa, followed by South Africa and Asia (Balkwill & Balkwill 1998, Darbyshire 2010). It can be easily distinguished from other genera of Acanthaceae by a combination of three characters: a 4-partite calyx with 2 large outer (anterior and posterior) segments and 2 smaller inner (lateral) ones, spheroidal, pollen grains with coarsely reticulate exine and the predominance of double cystoliths (calcium oxalate crystals) in the epidermal cells (Balkwill & Balkwill 1997, Champluvier 2011, Darbyshire 2010).

scholarly journals Performance of a French system of vertical flow wetlands (first stage) operating with an extended feeding cycle

2019 ◽  
Vol 80 (8) ◽  
pp. 1443-1455 ◽  
Author(s):  
Camila Maria Trein ◽  
Jorge Alejandro García Zumalacarregui ◽  
Mirene Augusta de Andrade Moraes ◽  
Marcos von Sperling
Keyword(s):  
Oxygen Demand ◽  
Climatic Conditions ◽  
Nitrification Rate ◽  
Vertical Flow ◽  
Intensive Monitoring ◽  
The Third ◽  
Treatment Performance ◽  
N Removal ◽  
Feeding Cycle ◽  
Deposit Layer

Abstract The aim of this work was to evaluate the treatment performance in the first stage of a vertical flow constructed wetland – French system (VCW-FS) over an extended feeding period (seven days), in two parallel units, for a population equivalent (p.e.) around 100 inhabitants (total of 0.6 m²·p.e.−1), under Brazilian tropical climatic conditions. One of the units had a greater surface sludge deposit layer, accumulated over nine years of operation, while the other unit had its sludge removed prior to the experiments. Four intensive monitoring campaigns covering all days of the feeding cycle were undertaken and the results were compared with those obtained from the conventional monitoring. The results indicated that, over the days of the feeding cycle, dissolved oxygen concentrations decreased, but were still kept at sufficiently high values for the removal of organic matter. Therefore, chemical oxygen demand (COD) removal, although not high, remained acceptable for compliance with local discharge standards during the whole the period. The NH4+-N removal efficiency and NO3−-N production were higher at the beginning of the feeding cycle, as a result of the more well-established aerobic conditions, with the nitrification rate decreasing from the third day of feeding. The sludge deposit seemed to hinder liquid percolation, especially at the end of the feeding cycle, thus affecting oxygen transfer. Due to the variability of the results over the feeding cycle, if sampling is to be done once a week, it is important to identify the sampling day that best represents the system's performance.

Changes in haematological parameters during a summer expedition in Antarctica

2019 ◽  
Vol 9 (1) ◽  
pp. 107-113
Author(s):  
Alena Žákovská ◽  
Olivie Zezulová
Keyword(s):  
Climatic Conditions ◽  
Erythrocyte Count ◽  
Haematological Parameters ◽  
P Value ◽  
Research Station ◽  
The Third ◽  
The Antarctic ◽  
Sera Samples

The aim of this study was to examine the effect of extreme climatic conditions and a long stay in isolation on levels of three haematological parameters in the polar expedition participants. This article describes changes in erythrocyte count, hemoglobin and transferrin levels measured on the 9th Czech Antarctic Scientific Expedition during the period of the Antarctic summer. A total of 15 sera samples were collected shortly before the expedition, the second sampling was performed halfway through the stay and the third at the very end of the expedition stationed at the Czech Research Station of J. G. Mendel. The erythrocyte count and the levels of transferrin were significantly increased in between all three sample collections (with p-value < 0.01). A statistically significant increase in hemoglobin levels was only detected between the first and the final sampling (p

Formation of honey bees modern look and their reproduction in the republic of Dagestan

10.12737/6540 ◽  
2014 ◽  
Vol 9 (3) ◽  
pp. 117-119
Author(s):  
Гасанов ◽  
Alibulat Gasanov ◽  
Абакарова ◽  
Muslimat Abakarova
Keyword(s):  
Honey Bees ◽  
Wing Length ◽  
Climatic Conditions ◽  
High Mountains ◽  
Mountainous Areas ◽  
The Third ◽  
Different Populations ◽  
Natural Breeding ◽  
The Republic ◽  
Natural Dispersal

Grey mountain Caucasian bees are of great interest for the selection, as a valuable gene pool of different populations of this race is supported by high mountains and inaccessible gorges of Dagestan, while serving as an isolated mountainous natural breeding areas. The studies were conducted in three different climatic conditions of the republic: the plains, foothills and mountainous areas. In the area of natural dispersal of gray mountain Caucasian bees in Dagestan released several local populations and different backgrounds. Characteristics of the main morphological features of honey bees are the length of proboscis, wing and width of the third tergite and others. These features bees vary, depending on the habitat population. Numerous studies of Dagestan honeybees showed, that the longest proboscis inherent in bees of mountain zone (6.85 ± 0.03 mm). The plain bees have a smaller proboscis (up to 6.71 ± 0.01 mm), and in the foothills bees the proboscis occupies an intermediate position (from 6.69 ± 0.01 to 6.83 ± 0.01 mm). Two other peculiarities (wing length and the third tergite) are subject to variation, depending on the altitude above sea level.

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