asexual reproduction - results in genetically identical offspring
- self-pollination still generates genetic variability
- found in unchanging environments >> plant less likely to survive if environment suddenly changes
- most asexual plants found in harsh environments
- vegetative reproduction - new plants cloned from parts of adults
- runners - long stems growing along the soil surface, new shoot grows from each 2nd node
- rhizomes - underground horizontal stems, new shoot can grow from each node
- suckers - sprouts from roots that can become new plants
- adventitious plantlets - reproductive leaves
- apomixes - seeds produced asexually from parent
- requires seed dispersal
plant tissue culture - cloning plants from tissues w/ growth hormones
- cell wall removed >> protoplast (plant cell enclosed only by plasma membrane)
- protoplasts can fuse >> create hybrids (form of genetic engineering)
- cell wall can regenerate
plant life span - age dependent on species
- annual plants - grow, flower, form fruits/seeds within a growing season
- includes most crop plants
- almost entirely herbaceous (non-woody)
- starves itself to death after flowering (senescence)
- biennial plants - 2 year life cycles, only flowers once
- stores photosynthate underground during 1st year
- flowering stems produced in 2nd year using energy from underground storages
- mostly harvested for roots (carrots, beets, cabbage)
- perennial plants - herbaceous/woody, continues to grow yearly
- majority of vascular plants
- trees either deciduous (leaves fall once a year) or evergreen (plants never bare)
- abscission - process by which leaves/petals are shed
- gets rid of unproductive parts
- takes place in abscission zone at base of petiole
- protective layer filled w/ suberin (fat) on stem side of petiole
- separation layer develops on leaf side of petiole >> weakened connections between stem/leaf
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