Plants Flashcards
Dicots:
Net veins in leaves, floral parts in 4 or 5s, tap root.
Monocots:
Parallel veins in leaves, floral parts in 3s, fibrous root.
Tap root -
A thicker root that stores a lot of starch. The starch is used to grow a new shoot the following season.
Fibrous root -
A highly branched root that serves as a good anchor and stores less starch.
Root hairs -
Microscopic structures on roots that absorb water and minerals from the soil.
Adventitious roots -
Root found above ground or in unusual places. I.e. Corn, banyan tree.
Terminal bud
Occurs at the apex of the plant, and is followed by a compact series of nodes and internodes.
Auxiliary bud
Found in the angle between the petiole and the stem. Usually dormant.
Node
The point on the stem where the petiole of the leaf attaches to the stem.
Internode
The space on the stem between the nodes.
Apical dominance
Auxin is produced in the top 4 inches of the plant and keeps axillary buds dormant. As you move down the plant, there is a lower concentration of auxin and the auxiliary buds begin to grow. This gives plants a pyramidal shape.
Petiole
The stem of the leaf.
Blade
What you think of as a leaf.
Bulb
Often mistaken for a root, it is a series of storage leaves. I.e. an onion.
Rhizomes
Horizontal underground stems.
Stolons
Horizontal above ground stems. I.e. strawberry
Protoplast
The cytoplasm of a plant cell.
Tonoplast
The sap or water vacuole in the plant cell which exerts turger pressure when filled with water. This pressure keeps the planet standing erect.
Plasmadesmata
Tubes or channels between plant cell walls which allow communication between plant cells.
Cell wall
Composed of starch and lignin. It gives rigidity to the plant.
3 plant tissue types
- Dermal or epidermis
- Vascular
- Ground
- Dermal tissue
A single layer of tightly packed cells which cover and protect young plants parts.
Or Epidermis - “skin” of the plant
Specialized functions: root hairs - extension of root epidermis.
Stem and leaf epidermis produces the cuticle or waxy covering of the leaf and stem system. It retains water.
- Vascular tissue
Xylem and phloem
- Ground tissue
A general tissue type that is used for photosynthesis, support and storage. Young plants are composed mostly of ground tissue.
Mostly parenchyma, the bulk of the plant material.
Parenchyma
A generalized type of plant cell. This is the least specialized type of cell, but conducts most of the plants metabolism.
Collenchyma
These cells lack a secondary wall, and are grouped into cylinders. They support young plant parts.
Sclerenchyma
Cells with a thick secondary wall. They may be dead at functional maturity.
Root cap
A protective layer of cells which produce a carbohydrate slime to aid root penetration into the soil.
Apical meristem
Embryonic tissue which produces primary meristems and replaces root cap cells. Another apical meristem is found at the tip of the shoot.
Zone of differentiation
Root cells mature into 1 of 3 tissue types.
Zone of elongation
Root cells elongate to 10X their original length, and push the apical meristem of the root deeper into the ground.
Quiescent center
A group of specialized cells in the center of the apical meristem. They grow very slowly and are resistant to damage by radiation and chemicals. They are a foundation of youth of forever embryonic cells.
Xylem
Vascular tissue that carries water and minerals up in a plant.
Phloem
Vascular tissue that carries sugar and nutrients down from the leaves to the other parts of the plant. Excess sugar is then stored in the root of the plant.
Palisade parenchyma or mesophyll
Leaf cells which are responsible for the majority of photosynthesis in a leaf.
Spongy mesophyll
These cells perform some of the photosynthesis of the leaf. They have air spaces between the cells and allow O2 to exit the stomata, and CO2 to enter.
Upper epidermis
Upper tissue layer of the leaf.
Lower epidermis
Lower tissue layer of a leaf. Contains stomata for gas exchange.
Cuticle
A waxy coating that reduces water loss from the leaf.
Plant hormone:
Auxin
Found in the top 3-4 inches of the shoot. It prevents leaf drop and promotes ovary wall growth. A summer hormone.
Plant hormone:
Gibberellins
Promotes germination in grass seed.
Plant hormone:
Ethylene
A gas. It causes fruit to ripen.
Plant hormone:
ABA or abscissic acid
This hormone is at it’s highest concentration in the fall. Cold degrades it, and rain water washes it away. This hormone maintains dormancy.
Plant hormone:
Photochrome
A pigment that is light sensitive. It changes chemically in the presence of light and promotes stem growth and seed germination. gg cell
Soil
Is a combination of weathered rock, living organisms, and partly decayed organic material.
Clay
Particles have a negative charge. Nitrate, phosphate, and sulfur will bind to the soil, not leak out, and not contaminate water.
Fertilizers
Have been used ever since cave man realized that grass and plants grew better where animals left droppings.
Irrigation
Should only be used sparingly. As the water evaporates, salt and minerals are left in the soil. Irrigation over long periods of time make the soil too salty to be farmed.
The earth’s atmosphere is composed of…
80% nitrogen. Plants can only assimilate nitrate and ammonium ions.
Egg cell
The female cell, that when fertilized results in an embryonic plant.
Pollen
Contain 2 sperm cells. One fertilizes an egg cell, the other fertilizes the polar nuclei to make endosperm.
Pollen tube
A tube which grows down the sticky stigma to the ovary. The sperm swim down the tube and fertilize.
2 polar nuclei
Left over from meiosis which made the egg cell. These nuclei will combine with one sperm and form endosperm, or the starchy material in a seed.
Multiple fruit
A fruit that develops from a tightly clustered group of separate flowers. When the ovary walls thicken, they fuse together. I.e. Pineapple
Composite fruit
I.e. Raspberries
Simple fruit
I.e. Apple, cherry
Complete flower
Has sepals, petals, stamens, and a carpel.
Incomplete flower
lacking sepals, petals, stamens or carpels.
Missing one or more of the above.
Imperfect flower
Flowers that lack either a stamen or a carpel.
Indeterminate growth
Growth throughout life
Determinate growth
Stops at a certain size. I.e. An animal
Embryonic plant tissue
Always at their meristem.
Initials
Perpetual embryonic cells
Derivitaves
Cells displaced from the meristem and develop into other tissues
Primary growth -
Is elongation and from the apical meristems.
3 tissues: dermal, vascular, ground
Herbaceous and young woody plants are in primary growth.
Secondary growth -
Is thickening of roots and shoots from the lateral meristems
Annual life style
1 yr life:
Sprout, grow, flower, set seed, die
I.e. Petunia
Biennial life style
2 yr life:
1st yr - sprout, grow
2nd - grow, flower, set seed, die
I.e. Sweet William, silver dollar plant
Perennials life style
Many yr life
I.e. Trees, rose bushes
I.e. Buffalo grass in the North American plains - sprouted from seeds at the end of the ice age.
Primary growth of roots
Pushes root through soil.
Root cap
Root cap
Protects meristemic tissues.
Secretes a polysaccharide slime to lubricate soil and aid root penetration.
3 zones of growth:
From the tip - 1. Zone of cell division
- Zone of cell elongation
- Zone of differentiation
- Zone of elongation
Apical meristem and its derivatives called primary meristems produce cells to replace the broken root cap cells.
- Quiescent center
- protoderm, procambium, ground meristem
Quiescent center
Group of cells which divide more slowly than other meristem cells. Not damaged by radiation or toxic chemicals.
Protoderm
Dermal tissue of the root
Procambium
Vascular tissue of the root
Ground meristem
Ground tissue of the root
- Zone of cell elongation
Cells elongate to 10X their original length. Elongation pushes the root tip forward into the soil.
- Zone of differentiation
Root cells become specialized for structure and function
Perfect flower
Flower with both a stamen and a carpel.
Carpelate flowers
Imperfect and have only a carpel, no stamens.
