Plant Structures Flashcards
(14 cards)
Root System
- anchors plant in soil
- absorbs water and minerals
- produces hormones
Root hairs: projections from epidermal root hair cell, greatly increase absorptive capacity of root
Shoot System
- composed of stem branches and leaves
- stem=main axis of plant that elongates and produces leaves
- nodes occur where leaves are attached to stem
internode: regions between nodes - stem has vascular tissue that transports water & minerals
Leaves
- photosynthesis
- foliage leaves are usually broad and thin
Blade: wide portion of foliage leaf
Petiole: stalk attaches blade to stem
Leaf Axil: Axillary bud originates
Tendrils: leaves that attach to objects
Bulbs: stems and leaves that store food
Tissues - (Epi) Dermal Tissues
- contain closely packed epidermal cells
- covered with waxy cuticle
- Roots contain root hairs
- lower leaf face contain stomata
- woody plants covered by cork (bark)
Trichomes (plant hair)
Tissues: Ground tissue forms bulk of a plant: Photosynthesis
Parenchyma cells: least specialized; all organs of plant; divides; metabolic functions, such as photosynthesis, helps repair/heal wounds
Collenchyma cells: thicker primary walls; bundles under epidermis; structural
Sclerenchyma cells: thick 20 walls w/lignin; nonliving; support/structure
Tissues: Vascular Bundles
- Xylem: transport water/minerals from root to leaf; dead cells
- Phloem: transports sucrose and other organic compounds from leaves to the roots; living cells
Root Organization
Root Apical Meristem (RAM)
- located in root tip
- protected by root cap
- primary meristems are in the zone of cell division
Root parts
Epidermis: root hairs
Cortex: starch
Endodermis: Casparian strip
Vascular Tissues: Pericycle (lateral roots)
Root Diversity
Primary Root: fleshy, single root grows straight down, stores food, lateral roots
Fibrous Root System: slender roots & lateral branches, anchors plant to soil
Adventitious roots: above ground, develop from shoot system, anchor increase water flow
Shoot Apical Meristem
- produces new cells that elongate and increase stem length
- protected by terminal bud
- provides support, holds leaves, flowers, and buds
- some cases, stem store food for plant too
- may be unbranched or highly branched
characterized by nodes and internodes
Woody Stem
both primary (roots&shoots) and secondary tissue (lateral)
- woody stems have no vascular bundles, instead three distinct regions: bark, wood, pith
Stem Diversity: Stolons & Rhizomes
Stolons:
- above ground horizontal stems
- produces new plant when nodes touch ground
Rhizomes:
- underground horizontal stems
- contribute asexual reproduction
variations: tubers- enlarged portions functioning in food storage
Corms: underground stems that produce new plants during next season
Leaf Diveristy
Leaf blade: facilitates collection of solar energy; thinnest prevents overheating
Leaves are adapted to environmental conditions
Roles in attachment, attraction & protection
Classification of Leaves
Simple
compound
Stinging nettle: trichomes- protect against excesive UV, light, extreme air temp. herbivore
