Plants Flashcards
Cuticle
Waxy substance which covers the leaves; prevents water loss
Epidermis
The outer layer of the leaf, provides a protective barrier for the tissues inside the leaf
Stomata
The movement of gases in and out of the leaf occurs in the stomata, it is located on the underside of the leaf
Guard Cells
Surrounds the stomata opening, specialized cells which swell and contract to control gas exchange
Mesophyll
Tissue inside the leaf, made up of thin walled cells containing chloroplast
Palisade Layer
A layer of densely packed, column shaped mesophyll cells in a plant leaf
Spongy Layer
Layer of loosely spaced mesophyll cells in a leaf
Xylem
Vascular tissue that conducts water and minerals from the roots to the leaves
Phloem
Vascular tissue that transports carbohydrates from the leaves to other parts of the plant
what are autotrophs?
Plants use sunlight in order to create their own food for energy. These types of organisms are called autotrophs.
What is the type of leaf structure for Dicots and Monocots?
Monocots → narrow leaves with parallel vein pattern
Dicots → broad leaves and branching veins
How do the vascular bundles in monocots and dicots differ?
Monocot stems have scattered vascular bundles. Dicot stems have their vascular bundles in a ring arrangement. Monocot stems have most of their vascular bundles near the outside edge of the stem. … Dicot roots have their xylem in the center of the root and phloem outside the xylem
Tubers
grow underground and store food (potatoes)
Bulbs
short stems surrounded by modified leaves; grow underground (tulips, onions and daffodils)
Rhizome
thick, fleshy stems that grow on or below surface; develop roots to survive winter; buds grow in spring (irises, canna lilies, grass)
what are the types of stems and what is their purpose?
Stems support the leaves and they transport water and sugars to various regions in the plant
Types of stems:
Herbaceous (Monocot & Dicot)
Woody (Dicot only)
Seed structure
embryo : the young plant within the seed consisting of:
Epicotyl - will form the leaf of a new plant
Hypocotyl - will form the stem of the new plant
Radicle - will form the root of the new plant
Endosperm: food reserve
Cotyledon: serves as food for sprouting plant
Seed coat: outer wall for protection
Micropyle- a hole through the seed coat that water enters
explain what happens during Germination
Gibberellin (a plant hormone) is released from the embryo into the rest of the seed
These hormones promote the formation of digestive enzymes that break down starch molecules in the seed
Increased sugar makes the seed hypertonic to the soil and water will enter vis osmosis
As seed swells, it will crack allowing oxygen to diffuse in
Radicle tip protrudes and begins to elongate
Root length occurs in the zone of elongation
Auxins
Stimulate growth in stems - stimulates elongation of cells on shady side so stem bends toward ligh
Gibberellins
Promote cell division and elongation in shoot tips and roots.
Play a major role in cell elongation during germination.
Cytokinins
Stimulate rapid cell division, active during growth periods of plant life cycle
Ethylene
Range of effects, and it interacts with other regulators for fruit ripening and aging.
Abscisic Acid
An inhibitor - induces dormancy in seeds by inhibiting growth/
During dry conditions it causes the stomata to close
Tropisms
Tropisms happen slowly, and orient plant parts to the resources it needs
Phototropism
Movement in response to light
Shoots show positive phototropism
Cells in the shade elongate faster and further
Roots show negative phototropism
Gravitropism
Movement in response to gravity
Roots show positive gravitropism
Stems show negative gravitropism
Hydrotropism
response to water stimulus
