Final Exam

-Cells can divide -Individual cells can grow larger

change in phase of life or change in life process

-genetic -environmental -hormones

Seed Germination, Vegetative Growth, Reproductive Growth, Senescence

*Inbibition–a dry seed soaking up water *increase in biological activity–all sorts of biochemical processes begin, hormones and enzymes become active *radicle growth–to absorb more water *cotyledon emerges *cell division begins and primary shoot as well. as first true leaves are growing

-Shoot Growth -Root Growth

*flowers and fruit develop -this may be done during or at the end of vegetative growth, depending on the plant

loss of leaves and/or plant death

Annuals, Biennials, Perennials

*complete vegetative and reproductive cycle in one growing season -usually herbaceous plants

*perform vegetative growth the first year and sexual reproductive growth the second year -many are only grown annually

live many years and reproduce several years out of their life cycle

*sexual–seed *asexual–through vegetative structures

Sexually Pros: Genetic Variation -seeds can survive long periods of dormancy/adverse conditions -seeds can spread a long way -adapt to new weather, pests Asexually Pros: No pollination reliance -if adapted to current conditions, all offspring will be adapted -less energy intensive for the plant

-pollen (male gamete) landing on the receptive stigma of a flower -insect, vertebrae and wind pollination

*process of nuclei from the pollen traveling down to the ovary to fertilize the egg *several nuclei are involved–double fertilization -2 nuclei are in pollen -3 nuclei are in egg *1 nucleus from pollen builds pollen tube down to ovary *1 nucleus from pollen combines with 1 from egg to form zygote *other 1 nucleus from pollen combines with 2 remaining nuclei from egg–forms endosperm *endosperm is food storage tissue for egg–high in carbohydrates for germination

*in many plants, only a small percentage of flowers develop into fruits -some dont become pollinated -some dont become fertilized -some abort after fertilization *very complex processes, some will not understand *several plant hormones are involved *For farmers–sometimes need to find right balance of furit–not too little and not too many -larger=less fruit -smaller=more fruit *undergo a period of rapid division, followed by rapid expansion *starch accumulates & cells continue to expand *starch remains or breaks down into sugars as ripening occurs

act as signaling compounds that tell the plant to begin, increase, decrease or cease any processes

-cell division -entering dormancy -starting reproduction -seed germination -root formation -cell & tissue death

True

*be endogenous–produce within the plant *be an organic compound (carbon-containing) *be present in low concentrations *able to be translocated through the plant *not a plant nutrient *plant growth regulators–mimic of naturally produced plant hormones (we apply them to plants in AG)

*Auxin *Giberrelin (s) *Cytokinin (s) *Abscisic Acid *Ethylene

*stimulate cell growth–used as rooting hormones in nurseries *responsible for apical dominance–plants ability to grow/stand upright *responsible for phototropism–how plants bend towards light *responsible for thigmotropism–growth of a plant around an object *certain synthetic auxins (2, 4-D)–used as a herbicide, causes uncontrolled cell division and eventual plant death

responsible for: -stem growth -transition from juvenile to adult phases of perennials -floral initiation -sex determination -seed germination *sometimes added with seeds or certain plant species that are hard to germinate *Gibberellin inhibitors are sometimes sprayed on ornamental plants to keep them compact *Sprayed on certain fruits to increase size