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  • pteridophytes Pteridophytes. If we compare the structure of the sporogonium of a moss or liverwort with the plant bearing the ***ual organs, we find that its tissues are better differentiated, and that it is on the whole a more complex structure than the plant that bears it. It, however, remains attached to the parent plant, deriving its nourishment in part through the "foot" by means of which it is attached to the plant. In the Pteridophytes, however, we find that the sporogonium becomes very much more developed, and finally becomes entirely detached from the ***ual plant, developing in most cases roots that fasten it to the ground, after which it may live for many years, and reach a very large size. The ***ual plant, which is here called the "prothallium,". Prothalium is of very simple structure, resembling the lower liverworts usually, and never reaches more than about a centimetre in diameter, and is often much smaller than this. The common ferns are the types of the sub-kingdom, and a careful study of any of these will illustrate the principal peculiarities of the group. The whole plant, as we know it, is really nothing but the sporogonium, originating from the egg cell in exactly the same way as the moss sporogonium, and like it gives rise to spores which are formed upon the leaves There are three well-marked classes of the Pteridophytes: I. the ferns (Filicinæ); (Equisetinæ);and III. the club mosses (Lycopodinæ)
  • spermComp_wText.mpg Sperms in Ferns: Ceratopteris c-Fern student research project 2009 What you see is a male gametophyte (male prothallium) of Ceratopteris thalictroides (Parkeriaceae), releasing its sperms. Spems are contained in special cells (Antheridia), and are squired out at maturity and upon environmental triggers, and in watery conditions (rain). The spems are coiled up spirals with many flagella. The spiral uncoils after release, the flagella are fired up, and off swims the sperm... pour chercher la femme. Research Assistant: Christopher M Young Video editing: Alvaro Vargas Principal Investigator: Matyas Buzgo Louisiana State University Shreveport (LSUS), USA College of Arts and Sciences, CAS
  • 為什麼~~圓頭的精子要把~~卵子通~~電電~~一下? 為什麼圓頭的精子要把卵子通電電一下? 7.9.10 A successful pregnancy and live birth after intracytoplasmic sperm injection with globozoospermic sperm and electrical oocyte activation Akiyoshi Egashira, MSa, Masao Murakami, Ph.Da, Kosuke Haigo, MSa, To***aka Horiuchi, Ph.Db, Takeshi Kuramoto, MDa Received 30 June 2009; received in revised form 1 August 2009; accepted 4 August 2009. published online 01 October 2009. Objective To present the effectiveness of intracytoplasmic sperm injection (ICSI) using globozoospermic sperm and assisted oocyte activation by electrical stimulation. Design A case report. Setting A private IVF center in Japan. Patient(s) A man with globozoospermia. Intervention(s) Acridine orange (AO) test, mouse oocyte activation test, and ICSI with electrical oocyte activation. Main Outcome Measure(s) Fertilization, pregnancy, and live birth. Result(s) In the first ICSI attempt, neither of the two injected oocytes fertilized. Staining of the patient's sperm with AO showed that only 2.9% of the sperm emitted a green fluorescence at the characteristic round head (sperm with native DNA content). The mouse oocyte activation test using the roundheaded sperm showed that the normal fertilization rate was 78.9% when SrCl2 was used for assisted oocyte activation; however, it was 6.0% without assisted oocyte activation. We confirmed that the sperm had defective ability to activate oocytes. In the second ICSI attempt, human oocytes were activated electrically with use ...