Chapter 3 - Plant Structure (PPT) Flashcards
How are plant cells different from other cells? What are the functions of these structures?
- Cell wall: enable plants to be rigid and grow tall
- Chloroplasts: help plants make their own food
Meristems (tissue)
- Located at growing points
- Regions of rapidly diving cells
- Responsible for MOST plant growth
Meristem (tissue) types
- Apical: located at root or shoot tips
- Intercalary: special type grasses have that allows them to be mowed
- Secondary (vascular cambium): makes tree rings and expands their trunks
Epidermis (tissue)
- Like plant skin
- Often covered by waxy cuticle
- In woody plants is eventually replaced by bark on older tissues
- Allows for gas and water exchange through stomata
- May also have trichomes (hairs or spines)
Periderm (Bark) (Tissue)
- extra protection
- made from cork cells
- suberin in bark cells repels water
Phloem (tissue)
- Vascular tissue that moves food around plants
- LIVING
- Has fibers for strength (think celery)
Xylem (tissue)
- Vascular tissue that moves water up through the plant
- DEAD when mature
- Woody parts of plants is old, dead xylem
Roots (organ)
- support/anchor the plant
- take up water and nutrients (especially root hairs)
Roots (organs) Name three types
-Adventitious roots: arise from organs that are NOT roots, ESSENTIAL for some plant propagation
Types: contractile roots, brace or prop roots, holdfasts of vines
Tuberous roots
thickened and fleshy for storage (sweet potato, dahlia)
How do you know it’s a root?
NO eyes (buds)
Stems (organs)
- have nodes and internodes
- have buds
Stems - description
-compressed juvenile stems, most have scales (but some don’t)
- Terminal
- Axillary (lateral)
Stems - bud arrangements
- Alternate: 1 bud per node
- Opposite: 2 buds per node
- Whorled: 3+ buds per node
Modified Stems (name types)
- Tubers (potatoes)
- Corms (gladiolus, crocus)
- Bulbs (mostly leaves): Tunicate (onion) or Scaly (lily)
- Rhizomes and stolons: horizontal stems
- Runners
- Crown (herbaceous perennials): part of stem near soil surface (can be divided)
- Spur (some fruit trees): short stem where flowers and fruit appear
- Suckers (at the base of the tree)
- Watersprouts (up in canopy)
- Tendrils
- Thorns, spines, & prickles
Leaves (organ)
- Usually where photosynthesis takes place
- Blade, Apex, Vein, Mid rib, Petiole, Stipule, Axil
Simple Leaves
-the blade is not divided
Compound Leaves
The leaf blade is DIVIDED into leaflets
Leaf Venation Types
- Pinnate
- Palmate
Compound Leaf Venation examples: palmately compound where each leaf has pinnate venation, pinnately compound where each leaflet has pinnate venation
Leaf structure
- Upper Epidermis
- Mesophyll: Palisade layer (spongy)
- Lower Epidermis
- Veins
Modified Leaves
-Bracts (right below flower, may be large and colorful)
Fall Color Leaves
- Chlorophyll is lost
- Xanthophyll (yellow), carotene (orange) become visible
- Anthocyanins (reds, purples) intensify - especially with sunny days and cool nights
Leaf Abscission (falling)
- Shorter days (or stress) triggers
- Suberin forms an abscission layer (seals wound, leaf falls easily)
Juvenility
Juvenile plants CANNOT flower - even under the correct conditions
- Juvenile citrus often have thorns
- Juvenile oaks and beeches often hold onto dried leaves throughout winter
Phase Change
- Juvenility can last a few weeks to many years
- Triggers: age (weeks to years), size, temperature (usually cool)
Flowers (Organs) - Name their parts
- Corolla (all petals)
- Calyx (all sepals)
- Nectaries
Complete vs. Incomplete flowers
Complete: has calyx, corolla, pistil and stamen
Incomplete: missing one or more of those parts
Perfect vs. Imperfect flowers
Perfect: has both sexual parts (pistil and stamen)
Imperfect: has only pistil OR only stamen
Regular vs. Irregular flowers
Regular: displays radial symmetry
Irregular: displays bilateral symmetry
Monoecious vs. Dioecious flowers
Monoecious (one house): plant has male AND female flowers OR perfect flowers
Dioecious (two houses): one plant has ONLY male flowers or ONLY female flowers
Flower Inflorescence types
Solitary, Spike, Raceme, Panicle, Corymb, Umbel, Compound Umbel, Cyme, Capitulum (composite head)
Fruits (Organ)
- ripened ovary and/or associated parts
- sometimes called pericarp
- has layers: endocarp, mesocarp, exocarp
Multiple fruits
- several flowers fuse during ripening
- have a core
- pineapple, fig, mulberry, beet seeds
Aggregate fruits
- several ovaries are produced by one flower
- raspberries, blackberries, strawberries
Simple fruits
-two types: fleshy and dry
Fleshy fruits - Berry
- berry: tomato, blueberry, eggplant, cranberry (NOT strawberries or raspberries!)
- pepo: has a thick, hard rind at maturity (squash, melons)
- hesperidium: juicy flesh is segmented, leathery rind (citrus)
Fleshy fruits - Dupe
- fleshy, one-seeded fruit with a stony endocarp (pit)
- cherry, plum, peach, almond
- has an ASS
Fleshy fruits - Pome
- endocarp is cartilaginous (core)
- apple, pear, quince
Dry Fruits
-dehiscent and indehiscent
Dry Fruits - Dehiscent
- splits naturally at maturity*
- Follice: splits on one seam (milkweed & delphinium)
- Legume (pod): splits on two seams (all bean family! Fabaceae)
- Silique: splits on two seams, but chamber is split down the middle with a wall-like structure (Brassicaceae family - mustards)
- Capsule: splits on multiple sutures at maturity (poppy & okra)
Dry Fruits - Indehiscent
- does NOT split naturally at maturity, usually one or 2 seeds*
- Caryopsis: one-seeded fruit with fused pericarp and seed coat (corn, many grasses)
- Achene: one-seeded fruit where the pericarp separates easily (sunflower seeds, strawberry seeds)
- Samara: one- or two-seeded fruit with wing-like outgrowths (helicopter seed thingies, maple, ash, elm)
- Nut: extremely hardened pericarp (oaks, pecans, walnuts)
- Schizocarp: compound fruit with two single-seeded halves (carrot, parsley, dill)
Parthenocarpic fruit
- fruits that form WITHOUT fertilization (seedless)
- banana, navel orange
Seeds (organ)
- Develop as a result of fertilization
- Parts: Embryo, seed coat (except gymnosperms), food storage
Apomixis
- process where seeds develop WITHOUT fertilization (clones)
- not common, but useful
- occurs frequently in citrus
Germination
-water enters the seed and the embryo emerges
Epigeous (bean) vs hypogeous (pea) germination
- Epigeous: seed raises above ground
- Hypogeous: seed stays underground
