pine life cycle Flashcards
(start with mature sporophyte) what will each pine tree contain?
ovulate and pollen cones
how will microsporocytes divide?
by meiosis to form haploid microspores which develops into a pollen grain (n)
how many ovules does each scale in the ovulate cone have and what does it contain?
2 and contains megasporangium
when does pollination occur?
when a pollen grain reaches the ovule and germinates to produce the pollen tube
what happens to the megaspore as the pollen tube is forming?
megaspore undergoes meiosis to produce 4 haploid cells (only one lives)
what happens to the surviving megaspore?
it develops into a female gametophyte with 2-3 archegonia each forming an egg
what happens by the time the eggs are mature?
sperm cells have developed in the pollen tube and fertilization occurs when the nuclei unites (more than one year after pollination)
what happens to each fertilized egg?
it develops into a zygote which develops into an embryo
what happens to the ovule after the embryo is developed?
it becomes a seed containing food supply and protective coat
how are pine seeds dispersed?
by wind
how long does it take a pine life cycle to complete?
about 3 years ago
