04. Plant Form and Function [DEFINITIONS] Flashcards
Plant Tissue
A tissue is a group of one or more cell types which carries out specialized function(s)
Meristems
Plants have undifferentiated tissues called meristems, consisting of cells which constantly divide under suitable conditions and produce new cells.
Apical Meristems
These meristems are located at root tips and shoot tips. They add new cells that enable increase in length.
Lateral Meristems
Vascular cambium and cork cambium are lateral meristems. They are found in woody plants and involve in secondary growth in increasing circumference of roots and stems.
Intercalary Meristems
Some monocots such as grasses show meristematic activity at the bases of stems leaves (nodes) These are known as intercalary meristems.
Primary Growth of the Shoot
Elongation of the shoot is due to the activity of primary meristem located in the shoot apex, and is called the primary growth of the shoot.
Shoot Apical Meristem
A shoot apical meristem is a dome-shaped mass of dividing cells located at the shoot tip.
Plant Tissue System
The new cells originating from the meristems are differentiated to perform specialized functions and form a plant tissue system.
Dermal Tissue System
This is the outer protective covering of plants.
Ground Tissue System
Ground tissue fills the gap between dermal tissue and vascular tissue, mainly consists of the cortex (outer to vascular tissue) and pith (inner to vascular tissue)
Plant Growth
Growth involves irreversible increase of dry mass associated with the development of an organism.
Secondary Growth
increase in diameter of stems and roots in plants due to the new cells produced by lateral meristems is called secondary growth.
Heartwood
As a woody plant ages, the older layers of secondary xylem no longer transport water and minerals. These layers are called heartwood because they are close to the center of the stem/root.
Heartwood
As a woody plant ages, the older layers of secondary xylem no longer transport water and minerals. These layers are called heartwood because they are close to the center of the stem/root.
Sapwood
The newest outer layers of secondary xylem, still transport xylem sap are known as sapwood.
Growth Rings
The thickness of secondary xylem and the lumen of vessels are larger in periods of warm and wet seasons compared to the other growth season of the year. These differences are visible in a cross section as lighter and darker rings and are called growth rings.
Stomata
Stomata are pores surrounded by guard cells in the epidermis of the leaves and stems of plants which can open and close.
Guard Cells
Guard cells are modified epidermal cells which have a distinct shape and are the only epidermal cells that contain chloroplasts.
Diffusion
In the absence of other forces, the movement of molecules of a substance from a place where it’s more concentrated to a place where it is less concentrated, due to random motion of molecules is called diffusion.
Osmosis
Osmosis is a special type of diffusion where free water molecules diffuse across a selectively permeable membrane.
Imbibition
The physical absorption of water molecules by hydrophilic materials is called imbibition.
Facilitated Diffusion
Facilitated diffusion is the movement of water and hydrophilic solutes across the membranes passively with the help of transport protein that span the membrane.
Bulk Flow
Bulk flow is the movement of liquid and materials (entire solution) in response to pressure gradient.
Water Potential
The physical property that predicts the direction in which water will flow governed by solute concentration and applied pressure is called water potential.
Solute Potential / Osmotic Potential
Solute potential is directly proportional to the molarity of a solution.
Pressure Potential
Pressure potential is the physical pressure on a solution
Water Potential of a Cell
Radial Transport
Transport of water and minerals entered from soil to root cortex into the xylem of the root is known as radial transport.
Apoplastic Route
The apoplastic route consists of everything external to the plasma membrane of living cells and includes cell walls, extracellular spaces and the interior of dead cells such as vessel elements and tracheids.
Symplastic Route
Transmembrane Route
The transmembrane route requires repeated crossing of plasma membranes as water and solutes exit one cell and enter the next.
Phloem Translocation
The transport of the product of photosynthesis is carried out by the phloem tissue and is known as phloem translocation.
Transpiration
Removal of water from leaves and other aerial parts of the plant body as water vapor by diffusion is known as transpiration
Guttation
Due to root pressure, more water enters the leaves than lost by transpiration. This results in removal of water droplets from leaf tips or leaf margins of some herbaceous plants. This process is known as guttation.
Nutrition
Nutrition is the process of acquiring raw materials and energy from the environment for the metabolic activities of organisms.
Autotrophic Nutrition (Autotropism)
The organisms who exhibit autotropism are autotrophs.
Symbiosis
Symbiosis is an ecological relationship in which two species live in close contact with each other.
Mutualism
Mutualism is a symbiotic relationship in which both participants are benefitted.
Commensalism
It is an interaction between two species in which benefits one of the species and neither harms nor benefits the other.
Parasitism
it is a close association between two different species which is beneficial to one (the parasite) and harmful to the other (the host)
Carnivorous Plants
These plants are photosynthetic but obtain nitrogen and minerals by killing and digesting insects and other small animals.
Essential Elements
Elements which are required for a plant to complete its life cycle and produce another generation.
Macronutrients
Plants need these elements in large amounts.
Micronutrients
Plants require these elements in small amounts.
Fertilization
Seed
Seed is the dispersal unit of seed plants which contains the embryo and stored food, surrounded by the seed coat.
Fruit
Fruit protect the enclosed seeds.
Photomorphogenesis
Light triggers many key events in plant growth and development, collectively called photomorphogenesis.
Seed Germination
Plant Spacing
Photoperiod
The photoperiod is the interval in a 24hour period in which the plant gets exposed to light.
Phototropism
The growth of a shoot towards light (positive) or away from it (negative)is called phototropism
Gravitropism
The shoot of the plant grows upwards while root grows downwards, due to their response to gravity or gravitropism.
Hormones
Hormones in general are signaling molecules which are produced in small quantities, get transported from the place they are produced to other parts of the organism and trigger responses in target cell or/and effect on plant growth and development.
Stress
Certain factors in the environment may have potentially adverse effects on plants survival, growth and reproduction. This is stress.
Drought Stress
Plants may wilt when water loss by transpiration exceeds water absorption.
Cold Stress
When the cell membrane cools below a critical temperature it looses its fluidity due to the lipids become locked in to crystalline structure.
Salt Stress
An excess if salts (high salinity) in soil lowers the water potential of soil resulting in reduced water potential gradient from soil to root.
Biotic Stress
How plants defend themselves against pest and pathogens attack
