chapter 6C-seeds
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- what kind of plants produce seeds?
- gymnosperms and angiosperms
- where do gymnosperms produce seeds?
- on or near bracts
- what are bracts?
- exposed leaves found on cones
- where do angiosperms produce seeds?
- inside the ovaries
- where do seeds develop from?
- sporagnia attached to modified leaves (the sporophylls of a cone or carpels of a flower). the ovule forms as an attachment to a modified leaf and develops into a seed after fertilization. the outer layers of the ovule (integuments- usually one or two) harden to become the seed coat.
- what are integuments?
- the outer layers of the ovule which harden into a seed coat after fertilization
- in gymnosperms, the ovulate cone typically has __ scales with each fertilized ovule developing into a seed sitting _____ the scale
- 2, atop
- in angiosperms, seeds develop as fertilized ovules inside the ovary, which forms the base of the carpel. the ovary eventually matures into a fruit.
- no question.
- a gymnosperm contains an embryo with several ______ attached to a _________ and an ____________
- cotyledons, short stem, embryonic root
- dicot seeds contain an embryo with ________, prominent cotyledons that contain ________, _________, and _________.
- fleshy, starch, protein, lipids
- in dicots, the cotyledons attach to a _________ that culminates in the embryonic root called a ______________
- short stem, radicle
- in monocot seeds contain a ______ (size) embryo and a ________ (size) endosperm
- small, large
- the monocot embryo has __ (#) cotyledons known as (a) ________
- 1 scutellum
- what is the scutellum (the one cotyledon in monocots) attached to?
- an embryonic axis containing shoot and root meristems
- a layer of protein called the ____________ surround the endosperm in monocot seeds and responds to signals from the scutellum by producing ______ to break down ______
- aleurone, enzymes, starch
- what is the name of a PASSIVE process that begins seed germination in which the dry seed takes up water like a sponge?
- imbibition
- _______ _______ serves as a kind of clock to prevent seeds from germinating during winter warm spells
- abscisic acid
- what is the first sign that germination is occuring?
- the busting of the radicle through the seed coat
- what is the name of the embryonic shoot that begins to grow?
- plumule
- what is the name of the germination that occurs in which the cotyledons remain underground?
- hypogeous
- in what type of plants does hypogeous germination occur?
- some dicots and most monocots
- in what type of germination do the cotyledons push above the soil?
- epigeous
- in what type of plants does epigeous germination occur?
- most dicots and some monocots
- through what process are asexual seeds produced?
- apomixis
- what are 4 functions of the fruit?
-
1. protect embryo from drying out
2. protect from diseases and herbivores
3. promote seed distribution when animals eat fruit
4. provide ready-made fertilizer for seed - what is another name for the ovary wall?
- pericarp
- what are the three parts of the pericarp (ovary wall)?
-
1. exocarp (skin)
2.mesocarp (middle)
3. endocarp (inner) - what are the 3 general types of fruits?
-
1. simple
2. aggregate
3. multiple - what are simple fruits?
- fruits that develop from 1 carpel or several fused carpels
- what are aggregate fruits?
- fruits that originate from one flower that hasd many carpels
- what are multiple fruits?
- fruits that devlop from the carpels of more than one flower ina sincgle inflorescence
- what are the 5 types of simlpe FLESHY fruits and give an example of each.
-
1. berries
2. hesperidia (orange)
3. pepos (pumpkin)
4. drupes (olives)
5. pomes (pears) - what are the 2 main categories of simple DRY fruits?
- dehiscent and indehiscent
- what are dehiscent fruits?
- dry fruits that split open at maturity to shed seeds
- what are indehiscent fruits?
- dry fruits that remain closed at maturity
- what are 4 types w/ examples of dehiscent dry fruits?
-
1. follicles (milkweed)
2. legumes (beans)
3. siliques (cabbage)
4. capsules (poppies) - what are 5 type w/ examples of indehiscent dry fruits?
-
1. nuts
2. schizocarps (carrot)
3. achenes (strawberry)
4. samaras (elm tree)
5. carypses (rice) - how are seeds transported?
- water, air, being eaten, getting stuck on animals