Term | Definition |
Anther | 4 pollen sacs |
Tapetum | Elongated cells inside of pollen sac wall that serve as nutritive tissue for developing gametophyte and will make up the exine |
Intine | Smooth layer inside exine made up of cellulose and pectin |
Microsporocytes | Precursors to pollen grains |
2-cell stage | 75% of plants release pollen in this immature stage |
25% of plants | Let generative cells divide before releasing mature pollen |
Apertures | Openings in pollen grains |
Egg apparatus | Synergids plus egg |
Chalazal end | End of ovule opposite from egg |
Micropylar end | End of ovule where the egg is |
Filiform apparatus | Ingrowth of synergid cell walls to form transfer cells |
Polygonum | 75% of plants have this pattern of megasporogenisis and megagametogenesis |
Megasporocyte | Turns into embryo sac |
Pollination | Pollen grain transferred from anther to stigma, pollen tube grows down style to ovary, enters ovule through micropyle, penetrates a synergid which breaks down, and both sperm released through pore |
Double fertilization | One sperm unites with egg to form embryo, and the other sperm unites with polar nuclei to form endosperm |
Seed coat | Developed from integuments |
Fruit | Developed from pericarp |
Pericarp | Ovary wall |
Fruit | Mature ovary and accessory tissue |
Fruit function | Protection and dispersal |
Exocarp | Outer layer of pericarp |
Mesocarp | Middle layer of pericarp |
Endocarp | Inner layer of pericarp |
Simple fruit | Develops from a single ovary |
Fleshy simple fruits | Mesocarp is at least partly fleshy |
Berries | Fleshy simple fruit with many seeds and difficult to distinguish endocarp from mesocarp, like tomatoes, grapes, and peppers |
Pepo | Berry with thick exocarp (rind) like a pumpkin |
Hesperidium | Berry with leathery exocarp like citrus |
Drupe | Fleshy simple fruit with a single seed with a hard endocarp (stone) like peaches |
Pome | Fleshy simple fruit with many seeds and that develops from an inferior ovary so most of the "fruit" comes from receptacle, like an apple |
Dry simple fruit | Mesocarp is dry throughout |
Dehiscent | Dry simple fruit that splits at maturity |
Follicle | Dehiscent that splits along one line |
Legume | Dehiscent that splits along two lines, like beans or peas |
Capsule | Dehiscent that splits along 3 or more lines, like cotton or irises |
Most common dehiscent dry fruit | Capsule |
Silique and silicles | 2 fused carpels that split along 2 sides leaving seeds exposed on a septum between 2 valves |
Silique | 4 times longer than wide |
Silicles | About as long as wide |
Indehiscent | Simple dry fruit that does not split at maturity |
Achene | Indehiscent that has one seed attached at the base of the pericarp and is easy to separate, like sunflower |
Cypsela | Indehiscent that is an achene-like fruit developed from an inferior ovary |
Samara | Indehiscent that is like an achene with pericarp extended to form a wing to aid in wind dispersal |
Schizocarp | Two or more united carpels that partly separate at maturity into one-seeded sections, like carrots |
Nut | Larger and with a thicker and harder pericarp than achenes, developed from a compound ovary, like acorns |
Caryopsis | Seed coat tightly fused to fruit wall and can't be separated, like grains |
Compound fruit | Develops from several ovaries |
Aggregate | Compound fruit that develops from a single flower with several ovaries, like blackberries and strawberries |
Multiple | Compound fruit that develops from several flowers within an inflorescence, like pineapple and fig |
How are fleshy edible fruits dispersed | Resistant seed coat allows them to be eaten then pooped out later somewhere else, with a fertilizer package as bonus |
Wind dispersal | Seeds either light weight (orchids) or have seed or fruit modifications like wings or plumes |
Water dispersal | Modified for floating with air pockets and aerenchyma, like coconuts |
Animal attachment dispersal | Adaptations such as hooked hairs, spines, or sticky substances |
Myrmecohory | Ant dispersal, produce elaiosomes on outside of seed so ants carry the seeds back to feed queen and when it grows into a new plant the ants protect it as a food source |
Elaiosomes | Pigmented appendages on seed coats containing lipids, proteins, sugars, and vitamins |
What plants use ant dispersal | Thousands of plants; in North America most are spring ephemerals |
Secondary compounds | Not needed for the plant to maintain life, used as protection against herbivory |
Mustard oil glycosides | Enzymes break down glycosides into toxic compounds that release pungent odors which prevents most insects from eating the plants |
Cardiac glycoside | Found in foxglove and used to treat heart failure by regulating heart beat |
Taxol | Alkaloid found in yew and used to treat melanoma and ovarian and breast cancer |