Topic 2 - The morphology and main modifications of vegetative organs Flashcards
Major benefit of plant morphology
Helps to study and identify plants
The knowledge of major attributes of higher groups (genera, family) easier identification of non-studied species
Genera and families have typical compounds
Explanations for non-studied plant poisonoings
Major parts of plants
Root (radix) Shoot (cormus) o Stem (caulis) Node (nodus) Internode (internodium) o Leaves (folium) Flower (flos, Anthos) Inflorescence (inforescentia) Fruit (fruktus) o Seed (semen)
Major 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
True roots
Develop from Radicula
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
Cotyledon leafs
= seed leaf, embryonic leaf Remains in the soil - nutrient storage Emerges above ground - photosynthesis Number: many (gymnosperms) 2, 1, Important source of nutrients
Cataphylls
Scales on underground stems that function in protection and storage
Hypsophylls
Mainly floral bracts, function in protection or pollinator attractants —> highly specific
Foliage leaves
The leaf base connects to the stem
Grasses —> leaf sheath
Stipules can be present on both sides
Petiole (leaf stalk) —> holds the leaf blade, but it can be absent (sessile leaf)
Leaf blade —> gas exchange, photosynthesis
Division of the blades of foliage leaves
Undivided
Divided
Palmately
Pinnately
Depth of divisions of foliage leaves
Lobed
Cleft
Parted
Dividied
Heterophylly
Having dissimilar leaves on one plant
Ref. foliage leaves
Leaf margins of foliage leaves
Entire Dentate Serrate Crenate Sinuate
Compound leaves
Single leaves
The blade divided into leaflets
Palmately
Pinnately
Paripinnately (odd-pinnate)
Imparipinnate (even-pinnate)
Bipinnate leaves: leaflets also pinnateVenations (function)
Transport water and nutrients
Strengthening
Types of venations
Dichotomous
Parallel (monocots)
Netted or reticulate (dicots)
Pinnate, palmate
Phyllotaxis
Arrangement of leaves on the stem
Spiral: one leaf per node
Opposite: two leaves per node
Whorled: more than three leaves per node
Important leaf modifications
Leaf tendrils
Spines
Succulent leaves
