Month: September 2022

MAJOR PLANT INNOVATIONS. "Angiosperm fossil records dating back to the Lower Cretaceous (130–140 million years ago) show, in addition to the generation of seeds, the second major functional innovation of the spermatophytes: the evolution of pollen grains which harbor, and thus protect, sperm cells (the male gametes) from drying out." http://www.sciencedirect.com/science/article/pii/S1674205214608996 View in LinkedIn

MALE GERM UNIT. "The male gametophyte (pollen) of angiosperms is among the most reduced independent multicellular organisms in biology." https://lnkd.in/dr5h8s4 View in LinkedIn

SELF-CONTAINED SPACESHIP. "It is now clear that flowering plant sperm cells have their own unique patterns of transcription, their own unique promoters, cell cycle control factors, and silencing elements. Furthermore, sperm cell-expressed genes may even control early embryogenetic effects." https://lnkd.in/dr5h8s4 View in LinkedIn

ARDOUS JOURNEY. "Sperm cells of flowering plants are non-motile and thus require transportation to the egg apparatus via the pollen tube to execute double fertilization. During its journey, the pollen tube interacts with various sporophytic cell types that support its growth and guide it towards the surface of the ovule. The final steps of tube guidance and sperm delivery are controlled by the cells of the female gametophyte." http://www.sciencedirect.com/science/article/pii/S1674205214608996 View in LinkedIn

NUMEROUS AGENDAS. "During fertilization, cell–cell communication events take place to achieve and maximize reproductive success. Additional layers of crosstalk exist, including self-recognition and specialized processes to prevent self-fertilization and consequent inbreeding." https://lnkd.in/d9zxv6K View in LinkedIn

"POLLEN GRAINS can be transported over long distances by wind or animal pollinators, are mostly tolerant of desiccation, and are capable of generating a long tube that grows deeply into the maternal tissues of the ovary that harbor the protected female gametes (egg and central cell). These structural innovations likely exerted a significant influence on the evolution of communication mechanisms in sexual reproduction." http://www.sciencedirect.com/science/article/pii/S1674205214608996 View in LinkedIn

POLLEN TUBES. "The complexity of crosstalk during this journey, associated with self- and non-self-recognition mechanisms, represents not only a major driving force of speciation, but also an exciting and challenging area to investigate the function and evolution of intercellular communication mechanisms in plants." http://www.sciencedirect.com/science/article/pii/S1674205214608996 View in LinkedIn

ANIMAL SPERM COMPETITION. "In vertebrate and invertebrate species millions of sperm cells compete for fertilization with the ova or egg cell. Usually the largest, longest, fastest and physiologically most active sperm cells win the race and defective sperm cells are sorted out. Sperm competition thus represents a powerful selective force to guarantee fertilization and reproductive success." https://lnkd.in/dhgWbCC View in LinkedIn

NO SPERM COMPETITION IN PLANTS. "Sperm competition does not occur in flowering plants as typically only a single pair of sperm cells is delivered for double fertilization. Two recent reports show that plants are capable of avoiding reproductive failure when defective sperm cells are released." http://www.sciencedirect.com/science/article/pii/S096098221200468X View in LinkedIn

POLLEN TUBE COMPETITION. "The reproductive strategy of flowering plants is different and involves competition among growing pollen tubes to enter one ovule and to deliver their sperm cell cargo. The first pollen tube that enters an ovule usually releases its cargo and one sperm cell fuses with the egg cell forming the embryo while the second sperm cell fertilizes the central cell to generate the endosperm. Later-arriving pollen tubes do not enter already targeted ovules." http://www.sciencedirect.com/science/article/pii/S096098221200468X View in LinkedIn