Pollen tube the pollen tube responds to extracellular guidance signals to achieve fertilization. Pollen tubes are produced by the male gametophytes of seed plants. They act as conduits to transport the male gamete cells from the pollen grain—either from the stigma (in flowering plants) to the ovules at the base of the pistil or directly through ovule tissue in some gymnosperms. Pollen tubes were first discovered by Giovanni Battista Amici. Pollen tube formation is important for sexual reproduction to occur in seed plants. Plants have separate structures such as microsporocytes and megasporocytes and the pollen grains are transported to the female gametophyte
Development of Spore pack has been revealed so far, called "galactic adventures" . It will include an adventure editor, as well as many new items and the ability for a player to go down to a planet's surface. On June 24, 2008, the "Spore: Galactic Edition" was announced. This special edition game is priced at $79.99, and includes a "Making of Spore" DVD video, a "How to Build a Better Being" DVD video, by National Geographic Channel (not included in all countries), a "The Art of Spore" hardback mini-book, a fold-out "Spore" poster and a 100-page Galactic Handbook. "Spore" extensively uses procedural generation,