The Development of the Pollen-tube and the Division of the Generative Nucleus in certain Species of Pines

Ferguson, Margaret C.

doi:10.1093/oxfordjournals.aob.a088817

Cited by 9 publications

(7 citation statements)

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“…In a fully developed aster, there is usually an increase in the diameter of the ray at the centrosphere (Plate XXVI, Figs. 13 and 16), and occasionally a slight enlargement at the Hautschicht An enlargement of the ends of the rays, as shown in Fig. 13, is just what should be expected if there is a streaming of material.…”

Section: The Second Mitosis In the Germinating Spore With Remarks On Apical Cellmentioning

confidence: 76%

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Mitosis in Pellia, by Charles J. Chamberlain ...

Chamberlain¹

1903

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Section: The Second Mitosis In the Germinating Spore With Remarks On Apical Cellmentioning

confidence: 76%

“…The system first appears as a few fibers converging to a point which is usually in contact with the nuclear membrane or very near to it (Figs. [11][12][13], but, in some instances, may be at a considerable distance from the nucleus (Figs. 14-16).…”

Section: The Second Mitosis In the Germinating Spore With Remarks On Apical Cellmentioning

confidence: 99%

Mitosis in Pellia, by Charles J. Chamberlain ...

Chamberlain¹

1903

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“…I do not, therefore, think that these observations of Coulter and Chamberlain are confirmed by more modern researches. Pinus sylvestris I therefore regard as falling into line with the other pines as they have been described by Miss Ferguson (8). Professor Blackman's isolated instance of equal male nuclei in P. sylvestris is probably a reversion to the time when equal nuclei were formed.…”

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confidence: 73%

“…I am inclined to interpret this observation, as Miss Ferguson did in the case of Pi/ms Strobus (8), that is to say that in their journey down the nucellus the difference between the nuclei gets more and more pronounced. The instance noticed above, when Professor Blackman found equal male nuclei quite near an archegonium, seems to be against this view, and suggests that Pinus sylvestris presents a state of affairs intermediate between Pintis Strobus (8) and Piuus Laricio, as described by Coulter (5), forming at one time equal and at another time different grades of dissimilar nuclei. That is to say, if one regards the form with the equal nuclei as more primitive than the one with the unequal, Pinus sylvestris is a transition form from one state to the other.…”

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confidence: 93%

On the Meaning of the Various Forms of the Male Gametes in the Pines and Allied Conifers.

Cutting

1908

New Phytologist

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Male Gametes in Pines and Allied Conifers. 171 these rivers. At Lamberhurst it occupys the lower facings of the sandstone bridge which spans the River Teise and just before reaching Battle it is found occupying the sandstone escarpments by the roadside. At Ecclesbourne and Fairligbt Glens, Hastings, it is found fruiting regularly in April. The plants however growing on the banks of the rivers do not fruit periodically except in those situations where they are not liable to prolonged submersion during periods of flood, such as upon arches bridging streams. From the fact that Fegatella conica and Pellia epiphylla are found so extensively lining water courses and rarely elsewhere we may reasonably conclude that they owe their present distribution entirely to water carriage, not only of spores, but also of detached plants during periods of flood. We may also conclude that since these plants are able to complete their life cycle annually under the present conditions of our climate they have a greater chance of survival with us than Dumortiera and Lunularia, which show a waning sexual activity.

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“…After arriving in the pollination drop, pollen grains pass through the micropylar canal to the pollen chamber and on to the receptive surface of the nucellus (Fig. 1) (Ferguson 1901, rev. McWilliam 1958, Doyle and O'Leary 1935, Doyle 1945, Sarvas 1962.…”

Section: Pollen Competitionmentioning

confidence: 99%

The role of pollen in the changing environmental conditions of Scots pine

Varis¹

2010

Diss. For.

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Rapid climate warming poses a challenge to forest trees adapted to cooler conditions. However, a genetic safety net may exist for wind pollinated tree species in the form of long distance gene flow mediated by pollen containing alleles that are (pre)adapted to a warmer climate. In order to examine long distance gene flow in Scots pine (Pinus sylvestris L.), we monitored flowering phenology in central, northern, and northernmost Finland and measured the amount and viability of airborne pollen over four years. Viable airborne pollen grains were detected during female flowering periods and prior to local pollen shedding in all study sites. Depending on the year and study site, female flowers were exposed only to pollen originating elsewhere for between one and four days. Foreign airborne pollen represented 2.3% of all viable grains detected and varied between years and study sites. Artificial pollination trials were conducted to evaluate the effect of pollen origin on seed siring success. Pollen genotypes originating from southern Finland sired 76% and 48% of seeds in competition experiments where pollen from both populations was introduced simultaneously into the female strobilus. Furthermore, we investigated the importance of pollen arrival order by introducing pollen of northern and southern genotypes in to the strobilus at two-hourly intervals. Northern genotypes sired 76% of the analysed seeds when injected first but when southern genotypes were supplied first, both pollen types enjoyed equal success. The first pollen grain in the pollen chamber did not always fertilize the ovum. Instead there is likely a more subtle and complex form of competition between genotypes and their pollen grains. To examine chemically-mediated pollen interactions we conducted an in vitro germination experiment where different genotypes were in chemical but not physical contact. Both positive and negative interactions were found. We found highly negative effects in the germinability of northern pollen grains when in contact with southern pollen, and an increase in the germinability of southern pollen when in contact with northern pollen. There was no variation in the size of dry pollen grains between sources, but after hydration and germination, northern pollen grains were larger than southern pollen. Genotypes with high hydration rates had low germinability and slow pollen tube growth rates. This suggests that early germination and growth of the pollen tube is more dependent on pollen storage materials and less dependent on water intake. Pollen source affected the outcome of competition experiments and therefore is an important factor in long distance gene flow. However, genotype also plays a role and must be taken into account.

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The Development of the Pollen-tube and the Division of the Generative Nucleus in certain Species of Pines

Cited by 9 publications

References 0 publications

Mitosis in Pellia, by Charles J. Chamberlain ...

Mitosis in Pellia, by Charles J. Chamberlain ...

On the Meaning of the Various Forms of the Male Gametes in the Pines and Allied Conifers.

The role of pollen in the changing environmental conditions of Scots pine

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