Topic 2 - The morphology and main modifications of vegetative organs Flashcards
(37 cards)
Major benefit of plant morphology
Helps to study and identify plants
Genera and families have typical compounds
Explanations for non-studied plant poisonoings
Major parts of plants
Root
Bud
Shoot
* Stem
** Node
** Internode
* Leaves
Flower
Inflorescence
Fruit
* SeedMajor functions of the root system
Anchorage
Uptake of water and minerals
Transport
Storage (photosynthesis)
types of roots
True roots (from radicula)
Adventitous roots
Modified roots
- Interspecific
- Aerial
True roots
Develop from Embryonic root
tap root
branch roots
Adventitious roots
(for organs other than roots)
Fibrous root system
Roots arise on nodes, cut surfaces controlled by hormones
Modified roots
Storage roots o Used as fleshy forages o Mainly sources of carbohydrates o Less amount of thickened cell walls better digestibility o Storage taproot—>carrot Root tubers —> tuberous pea Beetroot —> sugar beet, radish o Fusion of root and stem parts
Interspecific modifications
Nutrient transport between species
Either benefits and harmful effects
Mycorrizal roots
Root nodules
Haustorium
Mycorrizal roots
plant roots associated with beneficial fungus
o Ecto: trees and mushrooms o Endo (arbuscular): present for 85-90% of angiosperms o Better phosphorus uptake o Better resistance o Better assimilation rate
Root nodules
symbiotic interaction between roots and bacteria
o Mainly rhizobium species
o Fabaceae family
o Better nitrogen fixation
o Higher protein level
Haustorium
A structure that grows into or around another structure to absorb water or nutrients
Parasitic and semiparasitic plants
Dodder (Cuscuta) species which can infect crop plants
Low production, phytobezoars
Aerial roots
Specific for genera or species
- Formed by above ground structures (stem)
Buds
Bud (gemma) = embryonic shoot
Vegetative bud of biennial species → forage
Food for game species → ← game damage
Types of buds
vegetative, reproductive, mixed
Function of buds
protection of shoot apex = bud scales
Function of the shoot system
Strengthening Support leaves and flowers Transport Photosynthesis Storage
Types of shoots (stems)
Woody
Herbaceous
Woody stems
Lignification → deposits of lignin in cell walls → decreasing digestibility
Woody stem (secondary growth → increase in thickness of plant)
o Trees
o Shrubs
o Subshrubs
Palm tree (no secondary growth, fused leaf sheats)
Herbaceous stems
Lignification is possible in older organs
Determine forage value
Common dicot stem – with lateral branches and non-conspicuous nodes
Grass stem – in Poaceae family, hollow internodes, thick nodes, no lateral branches
Rosette – circular arrangement of leaves, short internodes
Sedge stem – for certain species of sour grasses (e.g. sedges), short internodes close to the ground, spongy inner parts low feeding value
Major types of modified stem above grounds
Stem tendril (cyrrus): simple (cucumber) or branched (pumpkin) – climbing
Thorns (spina)
simple (firethorn) or
branched (honey locust) – protection
Runner (sarmentum): elongated internodes (strawberry) vegetative reproduction
Succulent stem: cylindrical or spherical – water storage
Phylloclades: leaf-like stem – assimilation (butcher’s-broom)
Major types of modified stems below ground
Generally store starch (or other carbohydrates)
Rhizome (rhizome): short internodes
Ferns, monocots (horizontal)
Dicots (vertical)
Stolon (stolo): elongated internodes – grasses
Bulb (bulbus) – for monocot species, fleshy cataphylls dry bracts
Tuber (tuber) – thickened stem, storage function, forage importance
Bulbotuber – intermediate form (meadow saffron)
Leaf
Phylum, folia
Vegetative organ with determined growth
Functions of the leaf
Photosynthesis, storage
Major leaf types
Cotyledon
Cataphylls
Hypsophylls
