During Plant Fertilization, the Egg Leads (2 of 4) (IMAGE)
Caption
A flower of Arabidopsis thaliana. The male and female reproductive structures (anthers and pistil, respectively) are visible on the left. The pistil consists of the stigma that receives the pollen, the style, and the ovary. The scheme on the left describes the inside of an Arabidopsis ovary with 40 to 50 ovules, each attached to the inner surface of the ovary. The scheme on the right shows a close-up of one ovule. The two female gametes are the egg cell (in red) and the central cell (in blue). The accessory synergid cells (in orange) are involved in attracting pollen tubes to the ovule. Two male gametes (sperm cells) are delivered into the female gametophyte by the growing pollen tube. When one pollen tube enters the ovule it interacts with one of the synergid cells, the tube tip bursts, and the two sperm cells are discharged and reach the site of gamete fusions. Double fertilization follows: one sperm cell fuses with the egg cell and the second with the central cell to produce the embryo and endosperm of the seed. This image relates to a paper that appeared in the Nov. 23, 2012, issue of Science, published by AAAS. The paper, by Stefanie Sprunck at University of Regensburg in Regensburg, Germany, and colleagues was titled, "Egg Cell–Secreted EC1 Triggers Sperm Cell Activation During Double Fertilization."
Credit
Image courtesy of Stefanie Sprunck
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