THE CAUSES OF THE CYTOLOGICAL RESULTS OBTAINED IN SPECIES CROSSES IN WHEAT

1934 ◽  
Vol 10 (2) ◽  
pp. 190-198 ◽  
Author(s):  
W. P. Thompson
Keyword(s):  
Chromosome Numbers ◽  
Pollen Germination ◽  
Low Frequency ◽  
Pollen Grains ◽  
Abnormal Development ◽  
Genetic Types

There are several possible causes of the absence or low frequency of many chromosomal and genetic types in crosses between 42- and 28-chromosome species of wheat. The actual effects of these possible causes are:1. Pre-gametic causes — effect small. Among pollen grains which develop normally all chromosomal types are found but not quite in theoretical proportions; those with chromosome numbers intermediate between the 14 and 21 of the parents are somewhat deficient. Intermediate numbers are more abundant among retarded grains.2. Gametic(a) Male(1) Outright abortion of pollen grains — 5 to 10%.(2) Retardation of development — 25 to 30%.(3) Failure of pollen germination — the above 25 or 35%, plus probably as much more.(4) Competition and selective fertilization — impossible to determine accurately but probably some effect.(b) Female — very little. Apparently nearly all female gametes are capable of functioning but 50% usually remain unfertilized.3. Endospermic — abortion and abnormal development cause important effects particularly in relation to female gametes but they cannot be separated completely from possible direct embryonic effects.4. Embryonic — about half the embryos abort before the seed is ripe and at least half the F2 seeds usually fail to germinate. These are in part and may be wholly endospermic effects.The gametic and endospermic influences are such as to reduce the proportion of plants with chromosome combinations intermediate between those of the parents.

TRISOMIC TRANSMISSION IN LOTUS PEDUNCULATUS

1968 ◽  
Vol 10 (3) ◽  
pp. 648-654 ◽  
Author(s):  
Chi-Chang Chen ◽  
W. F. Grant
Keyword(s):  
Pollen Germination ◽  
Transmission Rate ◽  
Extra Chromosome ◽  
Low Frequency ◽  
Pollen Grains ◽  
Tube Growth ◽  
Male Gametes ◽  
Meiotic Irregularities ◽  
Significant Difference ◽  
Lotus Pedunculatus

Transmission of the extra chromosome was studied for four primary trisomic types of Lotus pedunculatus Cav., named Broad, Pointed, Narrow, and Small (trisomic for chromosomes 3, 4, 5 and 6, respectively). Despite the low frequency of transmission (average 9.2%), parental trisomics were recovered in all of the four trisomic types. No significant difference was found between pollen and ovule transmission. It was suggested that either there is no difference in germination and tube growth between the n and n + 1 pollen grains, or selection against the n + 1 male gametes in pollen germination and tube growth is balanced by the mechanism (s) selecting against the n + 1 female gametes. Although there were variations in transmission rate within the same trisomic types, the shorter extra chromosomes tended to be transmitted more frequently than the longer ones. This was interpreted as reflecting the degree of genic unbalance created by the extra chromosome in gametes and zygotes. The longer the extra chromosome, the greater would be the unbalance, and hence the less chance there would be for the n + 1 gametes and 2n + 1 zygotes to be viable. The trisomic types Small and Narrow produced a few unrelated trisomics in their progenies. It was considered that meiotic irregularities in these trisomic types could account for the production of such unrelated trisomics.

A natural intergeneric hybrid of Gesneriaceae from Brazil

Phytotaxa ◽  
2021 ◽  
Vol 497 (2) ◽  
pp. 79-96
Author(s):  
ANDRÉA ONOFRE DE ARAUJO ◽  
MAURO PEIXOTO ◽  
CINTIA NEVES DE SOUZA ◽  
EDUARDO CUSTÓDIO GASPARINO ◽  
JULIANA TOLEDO FARIA ◽  
...  
Keyword(s):  
Chromosome Numbers ◽  
Pollen Morphology ◽  
Pollen Grains ◽  
Intergeneric Hybrid ◽  
Morphological Characters ◽  
Natural Hybrid ◽  
Pollen Data ◽  
Cytological Data ◽  
High Viability ◽  
Structural Abnormalities

A natural hybrid between Goyazia and Mandirola (Gloxiniinae, Gesneriaceae) from Cerrado (Brazil) is here described, supported by pollen morphology, cytological data and morphological characters. The microsporogenesis of Mandirola hirsuta and that of the hybrid were analyzed in order to evaluate the cytogenetic characteristics. The haploid chromosome numbers observed were n = 12 for M. hirsuta and n = 11, 13, 16 and 26 for the hybrid. Structural abnormalities (monads, dyads, triads and micronuclei) were observed at the final of the hybrid’s meiosis. High viability rates of the pollen were recorded for Goyazia and Mandirola (>90%) and low viability for the hybrid (34.7%). The pollen grains were acetolyzed, measured and photographed for pollen morphology analysis. Quantitative pollen data were analyzed through descriptive and multivariate statistics. The hybrid has intermediate pollen characteristics between G. petraea and M. hirsuta; it is more related to G. petraea by the measures of diameters and ectoapertures; it is more similar to M. hirsuta mainly regarding the microreticulum on the mesocolpium region. The hybrid and Mandirola share vegetative and flower size, while the colors of the hybrid are similar to Goyazia. Pollen morphology, cytological data and morphological characters brought clear evidence for the recognition of the intergeneric hybrid, which we named as Goydirola x punctata.

scholarly journals Relationship between pollen morphology and chromosome numbers in Brazilian species of Lippia L. (Verbenaceae)

2013 ◽  
Vol 85 (1) ◽  
pp. 147-157 ◽  
Author(s):  
Saulo M. Sousa ◽  
Patrícia M.O. Pierre ◽  
Giovana A. Torres ◽  
Lisete C. Davide ◽  
Lyderson F. Viccini
Keyword(s):  
Chromosome Numbers ◽  
Pollen Morphology ◽  
Pollen Grains ◽  
Positive Association ◽  
Single Species ◽  
Morphological Data ◽  
Prolate Spheroidal ◽  
Oblate Spheroidal ◽  
Exine Ornamentation ◽  
Different Types

The pollen morphology and exine structure of 17 species of Lippia L. were investigated in this work using light and scanning electron microscopy. Among the species studied, 14 showed tricolporate pollen grains, two had tri- and tetracolporate pollen grains and a single species exhibited, only tetracolporate pollen. The amb ranged from triangular to square, and the shape varied from oblate-spheroidal to prolate-spheroidal. Three different types of exine ornamentation were observed: psilate, scabrate and perforate. In addition to morphological data, we found positive association between the chromosome numbers and size of pollen grains, and also between the length and width of the colpi. The results indicate that the characteristics of pollen grains in Lippia may be used as an additional taxonomic character of the genus.

scholarly journals Морфологические особенности пыльцы «ведьминых мётел» мутационного типа у сосны обыкновенной (Pinus sylvestris L.)

2017 ◽  
Vol 7 (4) ◽  
pp. 234-239
Author(s):  
M. S. Yamburov ◽  
S. B. Romanova ◽  
A. S. Prokopyev
Keyword(s):  
Pinus Sylvestris ◽  
Comparative Study ◽  
Scots Pine ◽  
Pollen Morphology ◽  
Pollen Grains ◽  
Abnormal Development ◽  
Tree Crown ◽  
Normal Part ◽  
Study Results ◽  
The Comparative Study

The comparative study results of pollen morphology of the mutational witches’ brooms and the normal part of the tree crown in Scots pine are presented. There is a decrease of pollen grains size, especially the sacci, in witches’ brooms. The witches’ brooms with more intensive branching have more expressive changes. Also, the witches’ brooms have more abnormal pollen grains. The data on the occurrence about 10 anomalous morphotypes of pollen grains are reported, most of that are related to the abnormal development of succi: different size of sacci, deformed sacci, reduced sacci, fused sacci, additional sacci, compress sacci, lack of one or both sacci. A high percentage of anomalies in the sacci development may be associated with less developed reticular sculpture of ectexine in witches’ brooms pollen.

scholarly journals Biology of Flowering, Fruit and Viability of Pollen of Varieties and Forms of Quince Cultivated on the Territory of the Nakhchivan Autonomous Republic

2021 ◽  
Vol 7 (3) ◽  
pp. 64-69
Author(s):  
L. Bayramov
Keyword(s):  
Pollen Fertility ◽  
Pollen Germination ◽  
Glucose Solution ◽  
Pollen Viability ◽  
Pollen Grains ◽  
Weather Conditions ◽  
Distilled Water ◽  
Water Control ◽  
Germinated Pollen ◽  
Autonomous Republic

Abstract. The zones of distribution of varieties and forms of quince on the territory of the Nakhchivan Autonomous Republic have been established, phenological observations have been carried out, their flowering and fruiting have been studied. On the territory of the Autonomous Republic, flowering of varieties and forms of quince begins in the second decade of April, depending on the distribution zone, with an average daily temperature of 12–13 °C and lasts 12–13 days, depending on weather conditions. Each flower has 10–12 stamens arranged in one row. The article also studied the viability of pollen in a number of quince varieties. Pollen viability was studied in the varieties Sary, Tursh, Ordubad, Gara and wild forms. Pollen fertility was determined by staining with acetocarmine. Pollen germinates in 2–5–10–15 and 20% glucose solution. Counting of germinated pollen grains was carried out under a microscope. The study showed that of all the experimental varieties, the pollen fertility of the Sary quince and Tursh quince varieties is high (up to 96.6–97.1%). The best medium for the germination of quince pollen is a 10–15% glucose solution. Pollen germination in this solution reaches 47.4–88.0%. In distilled water (control), the germination of quince pollen reached from 9.7% to 35.6% for varieties. Quince pollen remains viable for 31–43 days.

scholarly journals Impact of Manganese on Pollen Germination and Tube Growth in Lily

2021 ◽  
Vol 74 ◽  
Author(s):  
Thomas Sawidis ◽  
Gülriz Baycu ◽  
Elżbieta Weryszko-Chmielewska ◽  
Aneta Sulborska
Keyword(s):  
Pollen Tube ◽  
Pollen Germination ◽  
Surrounding Medium ◽  
Pollen Grains ◽  
Lilium Longiflorum ◽  
Tube Growth ◽  
Low Concentrations ◽  
Main Effect

Abstract In vitro culture of Lilium longiflorum pollen grains was carried out to determine the role of manganese in pollen germination and pollen tube growth. Pollen germination was adversely affected by the presence of manganese (>10 −8 M), whereas low concentrations (10 −12 –10 −10 M) stimulated the process. Manganese caused morphological anomalies during tube growth, characterized by irregular pollen tube thickening and swollen tips. The main effect was the anomalous cell wall formation at the tip, in which the presence of several organelles reduced the number of secretory vesicles. A loose network of fibrillar material and spherical aggregates, mostly in the tip region, was detected, and this material was progressively loosened into the surrounding medium. As a response to potential toxicity, the excess manganese was isolated in vacuoles, which formed an internal barrier against penetration of manganese to the tip area. Elevated manganese concentrations might affect plant reproduction, resulting in anomalies in gamete development. Consequently, the loss in genetic diversity and decreased fruit set ultimately lower yield.

scholarly journals Pollinator effectiveness of a specialist bee exploiting a generalist plant—tracking pollen transfer by Heriades truncorum with quantum dots

Apidologie ◽  
2019 ◽  
Vol 51 (2) ◽  
pp. 201-211 ◽  
Author(s):  
Sabine Konzmann ◽  
Margareta Kluth ◽  
Deniz Karadana ◽  
Klaus Lunau
Keyword(s):  
Quantum Dots ◽  
Reproductive Success ◽  
Pollen Germination ◽  
Pollen Grains ◽  
Pollen Transfer ◽  
Pollinator Effectiveness ◽  
Flower Constancy ◽  
Single Visit ◽  
Heriades Truncorum ◽  
Open Control

AbstractHeriades truncorum (Megachilidae) is a specialist bee that forages on Asteraceae and collects pollen by tapping its abdomen on pollen-presenting florets which places the grains directly in the ventral scopa. We tracked pollen transfer by female H. truncorum between conspecific inflorescences of Inula ensifolia and Pulicaria dysenterica by labelling pollen with quantum dots. On average, bees transferred 31.14 (I. ensifolia) and 9.96 (P. dysenterica) pollen grains from the last visited inflorescence, 39% and 45% of which were placed on receptive styles. Pollen germination ratio is significantly lower for inflorescences of P. dysenterica visited by one H. truncorum (0.13%) compared with open control inflorescences (0.51%), which suggests that the bees mainly transfer self-pollen of these self-incompatible plants. Thus, a single visit by H. truncorum does not grant the plant high reproductive success, but the bees’ abundance and flower constancy might reduce this disadvantage.

scholarly journals Effect of high temperature on the reproductive development of chickpea genotypes under controlled environments

2012 ◽  
Vol 39 (12) ◽  
pp. 1009 ◽  
Author(s):  
Viola Devasirvatham ◽  
Pooran M. Gaur ◽  
Nalini Mallikarjuna ◽  
Raju N. Tokachichu ◽  
Richard M. Trethowan ◽  
...  
Keyword(s):  
Heat Stress ◽  
High Temperature ◽  
Pollen Germination ◽  
Pollen Viability ◽  
Pollen Grains ◽  
High Temperature Stress ◽  
Pollen Production ◽  
Seed Number ◽  
Controlled Environments

High temperature during the reproductive stage in chickpea (Cicer arietinum L.) is a major cause of yield loss. The objective of this research was to determine whether that variation can be explained by differences in anther and pollen development under heat stress: the effect of high temperature during the pre- and post-anthesis periods on pollen viability, pollen germination in a medium, pollen germination on the stigma, pollen tube growth and pod set in a heat-tolerant (ICCV 92944) and a heat-sensitive (ICC 5912) genotype was studied. The plants were evaluated under heat stress and non-heat stress conditions in controlled environments. High temperature stress (29/16°C to 40/25°C) was gradually applied at flowering to study pollen viability and stigma receptivity including flower production, pod set and seed number. This was compared with a non-stress treatment (27/16°C). The high temperatures reduced pod set by reducing pollen viability and pollen production per flower. The ICCV 92944 pollen was viable at 35/20°C (41% fertile) and at 40/25°C (13% fertile), whereas ICC 5912 pollen was completely sterile at 35/20°C with no in vitro germination and no germination on the stigma. However, the stigma of ICC 5912 remained receptive at 35/20°C and non-stressed pollen (27/16°C) germinated on it during reciprocal crossing. These data indicate that pollen grains were more sensitive to high temperature than the stigma in chickpea. High temperature also reduced pollen production per flower, % pollen germination, pod set and seed number.

scholarly journals Can Selenium and Molybdenum Restrain Cadmium Toxicity to Pollen Grains in Brassica napus?

2018 ◽  
Vol 19 (8) ◽  
pp. 2163 ◽  
Author(s):  
Marwa Ismael ◽  
Ali Elyamine ◽  
Yuan Zhao ◽  
Mohamed Moussa ◽  
Muhammad Rana ◽  
...  
Keyword(s):  
Heavy Metal ◽  
Brassica Napus ◽  
Pollen Germination ◽  
Foliar Application ◽  
Germination Rate ◽  
Pollen Grains ◽  
Cd Stress ◽  
Cd Uptake ◽  
Physiological Level ◽  
The Impact

Cadmium (Cd) is highly toxic, even at very low concentrations, to both animals and plants. Pollen is extremely sensitive to heavy metal pollutants; however, less attention has been paid to the protection of this vital part under heavy metal stress. A pot experiment was designed to investigate the effect of foliar application of Se (1 mg/L) and Mo (0.3 mg/L) either alone or in combination on their absorption, translocation, and their impact on Cd uptake and its further distribution in Brassica napus, as well as the impact of these fertilizers on the pollen grains morphology, viability, and germination rate in B. napus under Cd stress. Foliar application of either Se or Mo could counteract Cd toxicity and increase the plant biomass, while combined application of Se and Mo solutions on B. napus has no significant promotional effect on plant root and stem, but reduces the seeds’ weight by 10–11%. Se and Mo have decreased the accumulated Cd in seeds by 6.8% and 9.7%, respectively. Microscopic studies, SEM, and pollen viability tests demonstrated that pollen grains could be negatively affected by Cd, thus disturbing the plant fertility. Se and Mo foliar application could reduce the toxic symptoms in pollen grains when the one or the other was sprayed alone on plants. In an in vitro pollen germination test, 500 μM Cd stress could strongly inhibit the pollen germination rate to less than 2.5%, however, when Se (10 μM) or Mo (1.0 μM) was added to the germination medium, the rate increased, reaching 66.2% and 39.4%, respectively. At the molecular level, Se and Mo could greatly affect the expression levels of some genes related to Cd uptake by roots (IRT1), Cd transport (HMA2 and HMA4), Cd sequestration in plant vacuoles (HMA3), and the final Cd distribution in plant tissue at the physiological level (PCS1).

STUDIES ON THE FAILURE OF HYBRID GERM CELLS TO FUNCTION IN WHEAT SPECIES CROSSES

1932 ◽  
Vol 6 (4) ◽  
pp. 362-373 ◽  
Author(s):  
W. P. Thompson ◽  
J. M. Armstrong
Keyword(s):  
Germ Cells ◽  
Chromosome Numbers ◽  
Pollen Grains ◽  
Wheat Species ◽  
Experimental Conditions ◽  
Degree Of Reduction ◽  
Random Segregation ◽  
Nuclear Development

Chromosome numbers were determined in numerous male gametophytes of F1 between 21- and 14-chromosome species of wheat. The results show that pollen grains with various chromosome numbers from 14 to 21 are actually formed and in approximately the theoretically expected proportions. The lack of plants in later generations which should result from the functioning of pollen grains with intermediate numbers is therefore not due to the failure of such grains to be formed because of a lack of random segregation at the second reduction division.Grains with intermediate numbers are retarded in their nuclear development, so that counts made on stamens in which division is most active give a smaller proportion of grains with intermediate numbers and a higher proportion with parental numbers than is expected theoretically. Retardation in nuclear development is correlated with a deficiency in cytoplasmic contents, 10 to 15% of the grains showing little or no cytoplasm, and another 15 or 20% showing some degree of reduction in cytoplasm. AH grains with reduced cytoplasm and some of those with normal contents are so retarded in nuclear development (having only one or two nuclei or no organized male cells) that they could not function when the normal ones are mature and the stamen dehisces. Unfavorable chromosome conditions in grains with intermediate numbers cause a complete abortion of some grains and retardation of nuclear development in others.Under the best available experimental conditions only 11 or 12% of F1 pollen grains germinate, in contrast to 70 or 80% for parental pollen. No grains with reduced cytoplasm germinate, and at least 50% of those with apparently normal cytoplasm fail to germinate.

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