Histochemical studies on the distribution of 5-nucleotidase in the germinating pollen grains ofEschscholtzia californica cham.

1972 ◽  
Vol 14 (4) ◽  
pp. 269-272 ◽  
Author(s):  
H. B. Tewari ◽  
C. P. Malik ◽  
P. P. Sood
Keyword(s):  
Pollen Grains ◽  
Germinating Pollen

scholarly journals Tradescantia bracteata pollen in vitro: pollen tubes development and mitosis

2015 ◽  
Vol 46 (4) ◽  
pp. 587-598 ◽  
Author(s):  
E. Lewandowska ◽  
M. Charzyńska
Keyword(s):  
Pollen Tube ◽  
Generative Cell ◽  
Metaphase Plate ◽  
Pollen Grains ◽  
Neutral Red ◽  
Generative Nucleus ◽  
Mitotic Spindles ◽  
Germinating Pollen ◽  
Vacuolar System

About 90 per cent of <i>Tradescantia bracteata</i> pollen germinates <i>in vitro</i> after 15 min. Mitosis starts in the pollen tube after about 3 h. The mitotic trans-formations of chromosomes within the generative nucleus are not synchronized. They involve succesively the linearly arranged chromosomes in the elongated generative nucleus. In metaphase the chromosomes are arranged tandem-like linearly along the pollen tube. The chromatides translocate in anaphase from various distances to the poles in a plane parallel to the metaphase plate. This suggests that chromosomes have individual mitotic spindles and that coordination of the chromosome transformations in the generative cell is much less strict than in a typical somatic mitosis. Starch is the storage material of pollen grains. In the vegetative cytoplasm of mature pollen grains minute reddish-orange vesicular structures are visible after staining with neutral red. They do not fuse with the vacuoles proper arising in germinating pollen grains to form the vacuolar system of the pollen tube.

scholarly journals Metabolomic Analysis of Pollen Grains with Different Germination Abilities from Two Clones of Chinese Fir (Cunninghamia lanceolata (Lamb) Hook)

Molecules ◽  
2018 ◽  
Vol 23 (12) ◽  
pp. 3162 ◽  
Author(s):  
Seif Aldin Dawina Abdallah Fragallah ◽  
Pei Wang ◽  
Nuo Li ◽  
Yu Chen ◽  
Sizu Lin
Keyword(s):  
Pollen Germination ◽  
Early Stage ◽  
Pollen Grains ◽  
Chinese Fir ◽  
Tube Growth ◽  
Metabolomic Analysis ◽  
Factors Affecting ◽  
Germination Process ◽  
Germinating Pollen

Pollen grains produce certain metabolites, which can improve or inhibit germination and tube growth. Metabolomic analysis of germinating and growing Chinese fir pollen has not been reported. Therefore, this study aimed to analyse metabolites changes, content and expression in the germinating pollen of Chinese fir. To understand the metabolic differences, two clones from Chinese fir were selected. Metabolomics analyses were performed on three stages (1-, 24- and 48-h) during in vitro pollen germination. The metabolites profiles at different time points were analyzed by using liquid chromatography-mass spectrometry. The results showed that 171 peaks were screened; the corresponding differential metabolites of 121 peaks were classified into nine types of substances. The expression of metabolites showed significant differences across and between clones, and the variation was evident at all germination stages. The expression was obvious at the early stage of germination, which differed clearly from that of the late stage after pollen tube growth. Moreover, the metabolites were mainly enriched in 14 metabolic pathways. Pollen germination and tube growth and metabolites expressions changed per incubation time. Since this work is preliminary, we suggest further investigations to understand the relationship between the differential metabolites and pollen development, and factors affecting pollen germination process.

DNA uptake during electroporation of germinating pollen grains

Plant Science ◽  
1990 ◽  
Vol 70 (2) ◽  
pp. 181-190 ◽  
Author(s):  
Aref A. Abdul-Baki ◽  
James A. Saunders ◽  
Benjamin F. Matthews ◽  
George W. Pittarelli
Keyword(s):  
Pollen Grains ◽  
Dna Uptake ◽  
Germinating Pollen

scholarly journals Dasykothon leptomiscus gen. et sp. nov., a fossil flower of possible Lauralean affinity from Myanmar amber

2020 ◽  
Vol 14 (1) ◽  
pp. 65-71
Author(s):  
George O. Poinar, Jr. ◽  
Kenton L. Chambers
Keyword(s):  
Floral Morphology ◽  
Pollen Grains ◽  
Peculiar Feature ◽  
Taxonomic Assignment ◽  
Modern Family ◽  
Germinating Pollen

A new fossil angiosperm, Dasykothon leptomiscus, is described from mid-Cretaceous amber deposits in the Hukawng Valley of northwestern Myanmar (Burma). The flower is post-anthesis except for one stamen that retains its pollen. The perianth is slightly irregular and composed of 5 ovate or lance-linear, erect or incurved sepals. The ca. 12 stamens have slender, elongate filaments and dorsifixed, bithecal, longitudinally dehiscent anthers. The superior ovary bears 2 long, curved styles. Germinating pollen grains observed on the stigmas are monoporate and have the peculiar feature of a grooved ridge encircling the grain from pole to pole. This structure is hypothesized to be an evolutionary elaboration of the meridionally syncolpate sulcus found in some members of the Atherospermataceae. The generalized floral morphology of the fossil prevents ready taxonomic assignment to a modern family.

Transgenic antibiotic resistance may be differentially silenced in germinating pollen grains

1988 ◽  
Vol 7 (7) ◽  
pp. 542-545 ◽  
Author(s):  
Franz Hoffmann ◽  
Robert B. Sibley ◽  
Shyun-Shyun Tsay
Keyword(s):  
Antibiotic Resistance ◽  
Pollen Grains ◽  
Germinating Pollen

FACTORS WHICH INFLUENCE SPONTANEOUS SELF-FERTILIZATION IN SWEET CLOVER (MELILOTUS)

1931 ◽  
Vol 5 (3) ◽  
pp. 313-326 ◽  
Author(s):  
L. E. Kirk ◽  
T. M. Stevenson
Keyword(s):  
Pollen Grains ◽  
Sweet Clover ◽  
Breeding Lines ◽  
Clear Cut ◽  
True Breeding ◽  
Self Fertilization ◽  
Natural Crossing ◽  
Pollen Sacs ◽  
Germinating Pollen ◽  
And Behavior

Seven factors have been described which seem to influence the tendency of sweet clover plants to produce seed by spontaneous self-fertilization. These are: length of stamens; stage of flower development when pollen is liberated from the pollen sacs; distribution of free pollen within the flower; size of cavity in the upper part of the keel; amount of pollen; condition of the pollen; and receptivity of the stigma.Spontaneous self-fertilization is the normal condition in certain plants of white blossom sweet clover, i.e., M. alba. This was not found to occur in any variety of yellow blossom sweet clover with the exception of "Redfield Yellow". True breeding lines of M. alba have been isolated consisting of naturally self-fertilized plants and other lines also which will not produce seed unless the flowers are manipulated. M. alba consists of a mixture of normally self-fertilized plants and plants that are random pollinated. This is especially true of certain varieties such as "Arctic". In some plants of M. alba an abundance of germinating pollen grains were found adhering to the stigmas before the flowers opened, thus precluding the possibility of natural crossing. Practically 100% of the flowers on such a plant produced selfed seed. The character of spontaneous self-fertilization exhibited clear cut segregation in a selfed line of M. alba. The importance of this character in relation to breeding improved varieties and pure seed production is emphasized.The efficiency of the "suction" method of emasculating sweet clover flowers depends on the peculiarities of the latter. This method is quite reliable with many plants but very unsatisfactory with others, depending upon the particular type of flower structure and behavior.

scholarly journals Bumblebees (Bombus terrestris) Improve ‘Hass’ Avocado (Persea americana) Pollination

Plants ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1372
Author(s):  
Raphael A. Stern ◽  
Ada Rozen ◽  
Ravit Eshed ◽  
Tali Zviran ◽  
Isaac Sisai ◽  
...  
Keyword(s):  
Bombus Terrestris ◽  
Total Yield ◽  
Pollen Grains ◽  
Persea Americana ◽  
Snp Analysis ◽  
Yield Increase ◽  
Significant Yield ◽  
Hass Avocado ◽  
Germinating Pollen ◽  
Negative Gradient

Pollination is limiting for avocado production. We examined whether adding bumblebees (BBs; ca. 10 hives/ha) to conventional honeybees (HB; 5 hives/ha) would improve ‘Hass’ avocado pollination and yields. A preliminary trial (2017/18) in an avocado orchard with four consecutive rows of ‘Hass’ followed by one row of ‘Ettinger’ serving as a pollenizer (20% ‘Ettinger’) showed a considerable increase in ‘Hass’ yield in rows adjacent to (up to 80 m from) the BB hives vs. distant rows (=controls). In 2018/19, the trials were extended to three additional orchards. A significant yield increase was obtained in the BB hive-adjacent trees compared to BB hive-distant ones. Similar results were obtained in 2019/20, in experiments conducted throughout the country. The SNP analysis, to determine the parents of ‘Hass’ fruit at varying distances from the BB hives, showed no differences in the cross-pollination rate (‘Hass’ × ‘Ettinger’). However, pollination rates and the number of germinating pollen grains per stigma decreased with distance from the hives, and correlated to the negative gradient in yield. Taken together, our data suggest that adding BB hives to ‘Hass’ avocado orchards, at ca. 10 hives/ha resulting in 0.5–1.0 BB visits/tree per min, increases pollination and, accordingly, total yield.

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