Plant Kingdoms, Families, Tissues

Hierarchical Classification

A system of organizing diverse biological life into levels and sub-groups, based on shared characteristics.

Taxonomic Ranks (from broadest to most specific)

Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species.

Binomial Nomenclature

A system of naming organisms using two parts: the Genus and the Species.

Cultivar

A cultivated variety that has been deliberately bred and selected by humans for specific traits, maintained through cloning methods.

Variety (botanical)

A naturally occurring subcategory within a species that exhibits distinct characteristics, emerging in the wild due to natural factors.

Archaea Domain

Prokaryotic, unicellular organisms that acquire energy by oxidation/reduction reactions, reproduce asexually, and live in extreme environments.

Bacteria Domain

Prokaryotic, unicellular organisms that acquire food through absorption and some photosynthesis, reproducing asexually by fission.

Eukarya Domain

The domain that includes multicellular organisms, encompassing the Protista, Myceteae (Fungi), Plantae, and Animalia kingdoms.

Protista Kingdom

Eukaryotic, unicellular and multicellular organisms that acquire food through absorption and some photosynthesis, reproducing asexually.

Fungi Kingdom (Myceteae)

Eukaryotic multicellular organisms that acquire food through absorption, reproducing both sexually and asexually.

Plantae Kingdom

Eukaryotic, multicellular organisms that acquire food through photosynthesis, reproducing sexually or asexually.

Animalia Kingdom

Eukaryotic, multicellular organisms that acquire food through ingestion, reproducing sexually with rare asexual propagation examples.

Carl Linnaeus

A renowned botanist (1707-1778) known for his contributions to taxonomy and the formalization of binomial nomenclature.

Dichotomous Key

A tool used to identify organisms by presenting a series of two choices, leading to the correct identification.

Bryophytes

A phylum within the Plantae Kingdom consisting of non-vascular plants, meaning they do not have vessels or food conduction cells (e.g., Liverworts, Hornworts, Mosses).

Tracheophytes

A phylum within the Plantae Kingdom consisting of vascular plants, which possess xylem and phloem tissues for carrying water, minerals, and manufactured sugars (e.g., Angiosperms, Gymnosperms, Fern-like).

Monocots (Liliopsida Class)

Plants characterized by having one cotyledon in the seed, fibrous roots, parallel leaf veins, scattered vascular bundles in the stem, and flower parts in threes or multiples of three.

Dicots (Magnoliopsida Class)

Plants characterized by having two cotyledons in the seed, a tap root system, netted leaf veins, vascular bundles in a distinct ring in the stem, and flower parts in fours or fives or their multiples.

Family (Taxonomic Rank)

A grouping of individuals with similar characteristics, typically with names ending in '-aceae' for plants (e.g., Poaceae).

Genus (Taxonomic Rank)

A category above species, grouping species that share common identifiable similarities in habitat and flower structures (e.g., Brassica).

Species (Taxonomic Rank)

The specific individual capable of interbreeding with members of its own kind, representing the most specific taxonomic level.

Poaceae (Grass Family)

Monocots with fibrous roots, parallel veins, no vascular cambium, spike and panicle inflorescence, three anthers, and producing a caryopsis (grain).

Brassicaceae (Mustard Family)

Dicots with tap roots, broad leaves, netted veins, flower parts in 4s, raceme inflorescence, and small round seeds.

Fabaceae (Legume Family)

Dicots with tap roots, compound (trifoliate) leaves, often associated with Rhizobium for N fixing, butterfly-shaped flowers (parts in 5s), raceme inflorescence, and producing legumes.

Asteraceae (Sunflower Family)

Dicots with tap roots, netted leaves, flowers in 5s, ray or disc flowers, capitulum inflorescence, and producing an achene.

Linaceae (Flax Family)

Dicots with tap roots, simple leaves, flowers in 5s, disc flowers, cymose inflorescence, and producing a capsule fruit.

Crop

A community of plants harvested by man for food or other economic purposes.

Weed

Generally a herbaceous plant not valued for its use or beauty, growing wild, and regarded as using ground or hindering the growth of useful vegetation.

Cereal

Grass family members having large seeds.

Pulse

Any of the large seeded legume plants.

Oil Seeds

Oil bearing seed plants whose oil content is greater than 17% by weight.

Forage

The above ground vegetative matter of a plant species used for animal feed.

Hay

A forage crop with less than 25% moisture.

Silage

A forage crop with greater than 50% moisture.

Fibre Crop

Crops grown for the primary purpose of producing fibrous products such as paper, cloth, or rope.

Green Manure (Plow Down Crop)

A crop grown with the intent of returning the plant material to the soil without harvesting.

Annual

A plant whose life cycle from seed to mature seed is completed in the same growing season.

Winter Annual

A herbaceous plant germinating in the fall, surviving a cold season, and flowering the next spring before dying.

Biennial

A plant that completes its life cycle over two growing seasons.

Perennial

A plant that lives three years or more.

Meristematic Tissues

Plant tissues capable of growth by mitotic division.

Non-meristematic Tissues

Plant tissues capable of growth only by enlargement.

Apical Meristem

Meristematic tissue found at the tip of the root or stem, responsible for growth in length.

Lateral Meristem

Meristematic tissue found in buds on the sides of stems, responsible for branch growth.

Intercalary Meristem

Meristematic tissue found in grasses in the region between the nodes or joints, responsible for growth by stretching.

Vascular Cambium

Meristematic tissue found only in dicot stems and roots, responsible for growth in diameter by adding secondary vein tissue.

Cork Cambium

Meristematic tissue found in woody perennials on the outside of the vascular cambium, responsible for growth of bark and other protective tissues.

Parenchyma

Spherical non-meristematic tissue with thin walls, acting as packing tissue (e.g., Chlorenchyma in leaves).

Collenchyma

Elongate non-meristematic supportive tissues with thickened walls; protoplasts are alive but cannot divide.

Sclerenchyma

Non-meristematic tissue found in woody perennial plants and veins of annuals, containing hemicelluloses and lignin, providing protection and strengthening, with dead cells forming fibers or sclerids.

Vascular Tissues

Complex tissues, including xylem and phloem, that form the major transportation system of the plant.

Xylem

Vascular tissue with hollow vessel elements and tracheids that carries water and dissolved mineral nutrients up from the roots to the leaves.

Phloem

Vascular tissue that carries water and dissolved sugars up and down between leaves and roots.

Root Structures (4 main regions)

Maturation, Elongation, Apical Meristem, and Root Cap.

Root Cap

Parenchyma tissue that is lubricated (mucigel), detects gravity, senses dry soil to stop growth, and protects the root tip.

Apical Meristem

A hidden and protected region of the root that regenerates primary tissues.

Elongation Region

The root region where cells stretch and push, and new tissue configurations form, but root hairs are absent.

Mature Region (Root)

The root region with differentiated tissue where root hairs develop, and tissues can take up water and nutrients. A cortex of parenchyma tissue provides sugar and water storage.

Root Hairs

Responsible for dramatically increasing the surface area of the root for water and nutrient uptake.

Dicot Root Structures

Include epidermis, cortex, pericycle, endodermis, vascular cambium, xylem, and phloem.

Monocot Root Structures

Include epidermis, cortex, endodermis, pericycle, phloem, xylem, and pith.

Cortex (Root)

A region of parenchyma tissue in the mature root that provides sugar and water storage.

Symplastic Pathway

Water and nutrient uptake pathway where substances move through the cytoplasm of cells, connected by plasmodesmata.

Apoplastic Pathway

Water and nutrient uptake pathway where substances move through the cell walls and extracellular spaces between cells.

Casparian Strip

A waxy barrier in the endodermis that blocks the apoplastic route, forcing water and minerals to enter the living cells (symplast) for selective uptake.

Endodermis

A layer of cells in the root responsible for selective mineral uptake, as minerals must pass through its cells due to the Casparian strip.

Mycorrhizae

A symbiotic relationship between fungi (mycelium) and plant roots, where mycelium penetrates the root cortex (but not the endodermis) to enhance nutrient uptake for the plant in exchange for plant sugars.

Passive Transport (Diffusion)

The free movement of ions from an area of high concentration to an area of low concentration until equilibrium is reached, under their own kinetic energy.

Facilitated Diffusion

A type of passive transport where specialized cells help move larger molecules across the membrane.

Active Transport

A process of nutrient uptake that requires energy (ATP) to move ions across a permeable membrane, especially when their electrical charge prevents free movement through the endodermis.

Root Pressure

Osmosis-driven water uptake that can pressurize the vascular cylinder and push xylem sap up the plant, creating an upward flow of water.

Transpiration

The evaporation of water from the top of the plant through the leaves, which creates a pull that draws more water in from the roots.

Guttation

A manifestation of root pressure where excess xylem sap leaks from leaf edges through hydathodes, often appearing as 'dew' on grass.

Tap Roots

A primary tapering main root from which smaller lateral roots arise, such as in dandelions, Shepard's Purse, and cotton.

Fibrous Roots

A root system with secondary or branch roots that are indistinguishable from the primary root, common in wheat, barley, and millet.

Storage Roots

Tap roots that swell with water or carbohydrates, performing storage functions for plant survival, like beets, carrots, and parsnips.

Adventitious Roots

Roots appearing from stem nodes, leaf veins, or old woody roots, taking on various forms like prop roots or N-fixing roots.

Prop Roots

A type of adventitious root that grows from stem tissues to provide support for the plant, seen in corn and bamboo.

N Fixing Roots

Roots that contain bacteria capable of absorbing atmospheric nitrogen and converting it to ammonia for the plant's use.

Creeping Roots

Taproots with extensive horizontal secondary roots containing adventitious buds that can produce new plants, though technically they are stem parts. Examples include Canada Thistle and Perennial Sow-Thistle.

Factors Affecting Root Environment

Lack of water, lack of oxygen, mechanical impedance (compacted soils), root rots, herbicide damage, and salt damage.

Organic Nutrients (Root Nutrition)

Carbon, Hydrogen, and Oxygen, which make up over 90% of the plant mass, derived from air (CO2) and water (H2O).

Nitrogen (N)

Essential macronutrient for proteins and chlorophyll, promoting foliage and green color. Mobile in soil and plant. Deficiency causes chlorosis of older leaves.

Denitrification

The process by which nitrates (NO3) are converted back into gaseous nitrogen compounds (N2, N2O) under anaerobic conditions like excess water or soil compaction.

Phosphorus (P)

Essential macronutrient for DNA, RNA, cell division, energy storage, and root growth. Immobile in soil, mobile in plant. Deficiency causes purpling of stems and leaves, poor early growth.

Potassium (K)

Essential macronutrient for sugar translocation, starch formation, water regulation, disease resistance, and stem strength. Immobile in soil, mobile in plant. Deficiency causes chlorosis and necrosis of older leaf edges, weak stalks.

Sulfur (S)

Essential macronutrient for proteins, seed production, amino acids, and photosynthesis. Mobile in soil, immobile in plant. Deficiency causes yellowing of younger leaves, cupped leaves in canola.

Calcium (Ca)

Essential macronutrient for cell wall stabilization, plasma membrane integrity, and cell growth. Mobile in soil, immobile in plant. Deficiency causes stunted growing points, discoloured root tips, midleaf necrosis.

Magnesium (Mg)

Essential macronutrient, a major component of chlorophyll, involved in protein synthesis and enzyme activation. Immobile in soil, mobile in plant. Deficiency causes interveinal chlorosis and red/purple coloration of older leaves.

Boron (B)

A micronutrient that affects growing points. Mobile in soil, immobile in plant.

Chloride (Cl)

A micronutrient. Mobile in soil and plant. Deficiency causes wilting, excessive branching, and bronzing of leaves.

Copper (Cu)

A micronutrient. Immobile in soil and plant. Deficiency causes wilted, twisted brown leaf tips, and may lead to ergot.

Iron (Fe)

A micronutrient. Immobile in soil and plant. Deficiency causes interveinal chlorosis.

Manganese (Mn)

A micronutrient. Mobile in soil, immobile in plant. Deficiency causes necrotic spots on plant tissues.

Molybdenum (Mo)

A micronutrient. Mobile in soil, immobile in plant. Deficiency can lead to excess NO3 levels in tissue tests.

Zinc (Zn)

A micronutrient. Immobile in soil, mobile in plant. Deficiency causes interveinal chlorosis of middle leaves and shortened internodes.