Origins of Mendelism / Robert C. Olby, with an introduction by Professor C. D. Darlington.

  • Olby, Robert C. (Robert Cecil), 1933-
Date:
1966
Catalogue details

Licence: Attribution-NonCommercial 4.0 International (CC BY-NC 4.0)

Credit: Origins of Mendelism / Robert C. Olby, with an introduction by Professor C. D. Darlington. Source: Wellcome Collection.

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    164 Appendix curious. It is the tube itself that elongates bit by bit, descends through the style and comes into contact with the nucleus [ovule]. To each ovule there is one tube. Perhaps it will occur to you to ask how, in several plants where the style is very long, the pollen tube can cover such a long distance. The pollen grain is not sufficiently large to house so long a tube. I have also reflected on this problem, and I can only explain the fact of the elongation of the pollen tube, upon which I have not the slightest doubt, by supposing that once it has entered the conduct¬ ing tissue, the tube receives nourishment and a supply of material from this tissue so that it can extend to the re¬ quired length. Amici, G. В. 1830. Note sur le mode d'action du pollen sur le stigmate; extrait d'une Lettre de M. Amici à M. Mirbel. Ann. Sci. Nat. sér. i, 27, 331-332. Amici: Schleiden^s Theory ef Fertilisation refuted Is fertilisation in phanerogamic plants achieved, as Schleiden claims, by means of the extremity of the pollen tube which, penetrating into the integuments of the ovule and pushing back the membrane of the embryo sac, there forms a depression in which it lodges and then produces the genuine embryo? The special studies which I have carried out on the gourd {Cucurbita pepo) have convinced me that in this plant fertilisation takes place in a very different manner. At the assembly of the savants of Padua I showed that the pollen tube penetrates into the neck or tip of the nucellus to a certain depth, but never succeeds in penetrating into the embryo sac which already exists and is visible in the nucellus before the introduction of the pollen tubes into the ovules. Probably the prolific humour, which has been deposited close to or even on the surface of the membrane which forms the embryo sac, is absorbed imperceptibly by this membrane, and thus passes into the interior where