Topic 3 - The morphology of reproductive organs Flashcards
Flower
Flos, Anthos
A reproductive shoot with determinate growth, short internodes and modified (bract) leaves
Typical attributes of families and genera
Basic floral terms
Groups according to non-reproductive leaves
Heteroclamydeus flower
Homochlamydeus flower
Groups according to reproductive leaves
Bisexual
Monosexual
Heteroclamydeus flower
Perianth is divided into sepals (calix) and petals (corolla)
Majority of dicots
Homochlamydeus flower
Perianth is not divided into sepals (calix) and petals (corolla)
Perigonium consists of tepals (non-divided sepals and petals)
Some dicots, and all the monocots
Bisexual flowers
Staminate and pistillate structures both present
Monosexual
Separated on different flowers
On the same individuals: monoecious
On different individuals: dioecious
Main parts of the flower
Pistill (pistillum) Stigma (stigma) Style (stylus) Ovary (ovarium) Stamen (stamen) Anther (anthera) Filament (filamentum) Petal (petalum) Sepal (sepalum) Receptacle (receptaculum) Stalk (pedunculus)
Androeceum
Male reproductive organ consisting of stamens and anthers
Gynoecium
Female reproductive organ called the carpel consisting of stigma, style and ovary
May contain:
- single carpel
- Several carpels → free = gymnosperms
- Fused carpels → Forming hollow pistil = angiosperms
Non-reproductive leaves
Perianth
Calix —> petals
Corolla —> sepals
Perigonium —> tepals
Complete flowers
Have all parts: calix, corolla and perigonium
Incomplete flowers
Does not have all parts
Calix
Consists of sepals
Generally green → photosynthesis, but it can be colorful
Free or fused forms
Drop off before (field poppy) or after (general) fertilization
Remains on fruits (rose hip)
Modify into a pappus (Asteraceae) which helps propagation
Corolla
Consists of petals
Colorful – antoyanins, antoxanthin, carotenoids helps pollination
Free or fused forms
Perigonium
Consists of tepals
Green, sepal-like or colorful, petal-like
Free and fused forms
Flower symmetry
Zigomorphic - one axis: ↑
Bilateral - two perpendicular axis of symmetry: ✛
Actinomorphic - radial, three or more axis of symmetry: ❋
Asymmetric - lacking any symmetry
Floral formula
Helps to describe species and genera
↑ ⚤ K(5)[C(5)A2+2] G(2)
↓ ↓
Number of Ovary position
floral elements
( ) = fusion of similar floral elements
[ ] = fusion of different floral elements
Inflorescence
= group of flowers, or a flowering stem
Solitary flowers Clusters (short internodes, flowers, from many buds) Real inflorescence (from one bud, branched structure)
Major types of inflorescence
Racemose - intermediate
Major axis grows continously
No terminal flower
Cymose - determinate
Terminal flower determinate growing
Lateral branches overgrow the main axis
Compound inflorescence
Connection of simple inflorescence
Fruit (fructus)
Ovules → seed, ovary wall → fruit wall, ovary → fruit
No seed or not viable seed (seedless watermelon, banana)
Parthenocarpy
Induced production of fruit without fertilisation of ovules
Types of fruit
True fruit: derived only from the ovary
Accessory fruit: derived not only from the ovary
Multiply fruit: formed from a cluster of flowers
Fleshy fruits
Mature fruits has fleshy (parenchymatic) fruit wall
Certain types use as forage (pepo)
Feed of game species
Dried fruits
Mature fruits has dry (schlerechymatic) fruit wall
Certain types used as forage (caryopsis, nut)
Consumption of the fruit wall can lead to digestion problems (achene)
Dehiscent (capsule), indehiscent (nut) and split up (schizocarp) types
Seeds (semen)
Ovule
Integumentum
Seed coat
Zygote
Embryo
Endo- and/or perisperm
Lack of this → store nutrients
Parts of dicot embryo
Plumule → shoot
Radicule → roots
Hypocotyl - Embryonic shoot below cotyledons
Epicotyl - embryonic shoot above cotyledons
Cotyledon - embryonic leaves
Importance of embryo
Nutrient storage specific for species, genera families
Forage importance
Germ → forage (food) supply
Stamens
Spiral or cyclic arrangement
Stalk / stamen = filaments
Different filament length
Tetradynamous (Brassicaceae)
Didynamous (Lamiaceae)
Fused filament (Fabaceae)
Fused anthers (Solanaceae)
Anthers
Top of stamen that produces pollen grains
Pollen grains
Produce sperm cells necessary for sexual reproduction
The pollen
Specific surface pattern
Pores, grooves, thickenings
Cell wall proteins —> allergic reactions
Stigma
The top of the carpel → receptive area for pollen
Style
Tube structure connecting the stigma to the ovary
Ovary
At the bottom of the carpel
Ovules attached to the placenta in the middle of the ovary, containing an egg cell
