Intro to Plant Science - Exam 2

Protoplast

organized living unit of single cell

Middle Lamella

Holds cells together

Plasmodesmata

Channels between plant cell walls that allow communication and transport of substances between adjacent cells.

What are the functions of the cell wall

• protects protoplast

• provides structure

Primary cell wall

made of cellulose

Plasma Membrane

• Lipid bilayer

• semipermeable

Cytoplasm

• gel-like fluid in plasma membrane

• allows smooth movement of compounds among organelles

Rough ER

• network of membranes with ribosomes

• ribosomes - site of amino acid and protein synthesis

Smooth ER

Synthesizes and stores lipids

Golgi Apparatus

• has vesicles and folded membranes

• sorts and processes proteins

Main Root Functions

• anchor plants in soil

• absorb water and nutrients

• store carbohydrates

Seminal Roots

• secondary root that emerges from seed 

Nodal Root

• roots that emerge from mesocotyl part of the stem (above seed)

Primary Roots

• Tap root for dicots

• Provide stability

• Larger in diameter

Secondary and Tertiary Roots

• Secondary - originate from primary roots

• Tertiary - fine root form the secondary roots

Meristems

Region of cell division on roots

Allelopathy

root gives off chemicals to inhibit growth of surrounding plants

Stems main fuctions

• structure

• support

• translocation

Primary Stems

• stalks (monocots)

• trunks

• central stem

Tillers

additional stems on grasses

Types of Stems

• Cladophyll - flattened stem

• Vine - helps optimize light absorption

• Stolens - aboveground 

• Underground - stores carbohydrates 

Trichomes

hairs that emit chemicals, toxins, or nectars

Apical Meristems

• primary growth

• tips of shoots

• produces leaves

Cotyledon

leaf from seed

Leaves main purpose

• photosynthesis

• Gas exchange through stomata

• Controls transpiration

Monocot leaves

• parallel veins

• leaf forms sheath that clasps around stem

Dicot leaves

• netted veins

• petiole that attaches leaf to stem

Lamina

Green photosynthetic tissue

Monocot leaf parts

Monocot leaf parts

Abscission

leaves cut off from water/nutrients then fall to ground

Dicot leaf parts

Dicot leaf parts

Colorful Bract

modified leaf that attracts pollinators

Leaf Structures and Purpose Dicot leaf

• Cuticle - protection

• Epidermis - protection

• Lower Epidermis - protection

• Palisade mesophyll - photosynthesis

• Spongy mesophyll - photosynthesis

• Stomata - gas exchange

• Vein - water and nutrient transport

Monocot Flower parts

Monocot flower parts

Fertilization

formation of zygote due to the union of egg and sperm nuclei

Monoecious

stamen and pistil on same plant

Dioecious

stamen and pistil on different plants

Fruit

Ripened ovary of the flower which is controlled by ethylene

Pericarp - ovary wall 

• exocarp

• mesocarp

• endocarp

Parthenocarpy

hormones induce fruit set without pollination

3 main seed components

• Embryo

• Endosperm/cotyledons

• seed coat

Gibberellins

plant hormone that is produced when in contact with water

Epigeal Germination

cotyledons are pushed above soil surface

Hypocotyl

Region of stem between cotyledons and radicle

Epicotyl

Region of stem above cotyledons

Hypogeal Germination

cotyledon stays below soil

Coleoptile

protects shoot as it emerges from soil

Dormancy

delay in germination also known as rest

Physiological Dormancy

specific treatment must be given to embryo to initiate growth

Physical Dormancy

when a hard seed coat prevents imbibition (need scarification)

Monocot seed parts

Monocot seed parts

Dicot seed parts

Dicot seed parts