A Comprehensive Glossary of Plant Science Terms: Delving into the World of Botanical Research

Hunter Weber

April 18, 2023 at 6:21 pm | Updated April 18, 2023 at 6:21 pm | 9 min read

Welcome to the fascinating world of plant science! This comprehensive glossary overviews essential plant research, physiology, and horticulture terms. Whether you’re a student, researcher, or plant enthusiast, understanding these terms will deepen your knowledge and appreciation of plants’ diverse and complex lives. Explore the glossary to discover the mechanisms behind plant growth, reproduction, adaptation, and interactions with their environment.

Abscisic acid (ABA) – A plant hormone involved in various developmental processes, such as seed dormancy, germination, and the regulation of stomatal closure in response to stress.

Absorption spectrum – The range of wavelengths of light that a pigment can absorb, with chlorophyll absorbing most efficiently in the blue and red regions of the spectrum.

Adventitious buds – Buds that develop in unusual locations, such as on roots, leaves, or internodes, rather than in the leaf axils.

Adventitious roots – Roots that arise from non-root tissues, such as stems or leaves, often in response to stress or injury.

Allele – One of two or more alternative forms of a gene occupying the same chromosome position.

Allelopathy – The influence of chemicals produced by one plant on the growth and development of nearby plants.

Angiosperms – Flowering plants that produce seeds enclosed within a fruit.

Apical dominance – The suppression of lateral bud growth by the apical bud, often regulated by auxin and cytokinin hormone levels, which allows the plant to grow primarily in the vertical direction.

Apomixis – Asexual reproduction in plants that occurs through seeds without fertilization.

Autotroph – An organism that produces food from inorganic substances, such as carbon dioxide and water, using light or chemical energy.

Auxin – A class of plant hormones that regulate cell elongation, apical dominance, and other aspects of plant growth and development.

Bark – The protective outer covering of woody stems and roots, consisting of periderm, cortex, and phloem, provides structural support, protection from physical damage, and insulation.

Biennial – A plant that completes its life cycle within two years, typically growing vegetatively in the first year and producing flowers and seeds in the second year.

Biocontrol – The use of living organisms, such as predators, parasites, or pathogens, to control pests and plant diseases.

Brassinosteroid – A class of plant hormones that regulate cell division, elongation, differentiation, stress responses, and senescence.

Bryophyte – Non-vascular plants that lack true roots, stems, and leaves, including mosses, liverworts, and hornworts.

Bundle sheath cells – A layer of specialized cells surrounding the vascular bundles in leaves, which play a crucial role in C4 photosynthesis by concentrating CO2 for Calvin cycle enzymes.

CAM photosynthesis – Crassulacean Acid Metabolism, a specialized form of photosynthesis where plants open their stomata at night to minimize water loss.

Casparian strip – A band of suberin and lignin in the cell walls of endodermal cells in plant roots, acting as a barrier to prevent the passive diffusion of water and solutes between the cortex and the stele.

Cell differentiation – The process by which unspecialized cells develop into specialized cells with distinct structures and functions.

Chemoautotroph – An organism that obtains energy by oxidizing inorganic compounds, such as hydrogen sulfide or ammonia, and uses this energy to produce organic compounds from carbon dioxide.

Chitin – A complex polysaccharide found in fungal cell walls and the exoskeletons of insects and other arthropods.

Chlorophyll – A green pigment in plants that captures light energy for photosynthesis.

Chloroplast – An organelle found in plant cells that contains chlorophyll and is the site of photosynthesis, responsible for converting light energy into chemical energy stored as sugars.

Companion cells – Specialized plant cells closely associated with sieve tube elements in the phloem, providing metabolic support and regulating the transport of sugars and other nutrients.

Cytokinin – A class of plant hormones that promotes cell division and shoot formation.

Deciduous – Refers to plants that shed their leaves seasonally, typically during periods of environmental stress, such as drought or winter, to conserve water and reduce metabolic activity.

Dicotyledon (dicot) – A group of flowering plants with two seed leaves or cotyledons.

Double fertilization – A unique process in angiosperms where one sperm nucleus fuses with the egg cell to form a zygote, and the other sperm nucleus fuses with two polar nuclei to form the endosperm.

Ecosystem services – The benefits humans derive from ecosystems, such as crop pollination, carbon sequestration, and soil formation, supported by plant communities and their interactions with other organisms.

Ectomycorrhiza – A type of mycorrhizal association where fungal hyphae form a sheath around the root tips but do not penetrate the root cells, instead exchanging nutrients and water through an interfacial matrix.

Embryo sac – The female gametophyte in angiosperms, containing the egg cell, two synergids, a central cell with two polar nuclei, and three antipodal cells, all enclosed within the ovule.

Endosperm – Nutritive tissue within seeds, providing nourishment to the developing embryo.

Epiphyte – A plant that grows on another plant but is not parasitic, obtaining its nutrients from the air, rain, or debris accumulating around it.

Ethylene – A gaseous plant hormone that regulates plant growth and development, including fruit ripening, leaf abscission, and senescence.

Etiolation – The abnormal elongation and pale coloration of plants grown without light, resulting in reduced chlorophyll production.

Fertilization – The fusion of male and female gametes to form a zygote, which marks the beginning of the development of a new individual in sexually reproducing plants.

Flavonoid – A diverse group of plant secondary metabolites that serve various functions, such as UV protection, signaling, and defense against herbivores and pathogens.

Gametophyte – The haploid (single set of chromosomes) stage in the life cycle of plants and algae that produces gametes (eggs and sperm) through mitosis.

Genotype – The genetic constitution of an organism, determining its inherited traits.

Germination – The process by which a seed develops into a new plant, beginning with the emergence of the radicle (root tip).

Gibberellin – A plant hormone class that regulates stem elongation, seed germination, and other aspects of plant growth and development.

Grafting – A horticultural technique in which a section of a stem or shoot (scion) is joined to a rootstock, allowing the scion to grow and develop using the rootstock’s established root system.

Guard cells – Paired specialized cells surrounding the stomata and regulating their opening and closing by changing shape in response to environmental signals.

Gymnosperms – Seed-producing plants that do not form flowers or fruits, such as conifers and cycads.

Haustorium – A specialized structure formed by parasitic plants and some fungi, which penetrates the host tissue to absorb water and nutrients.

Hemiparasite – A parasitic plant that obtains water and nutrients from its host but can also photosynthesize and produce some organic compounds.

Heterotroph – An organism that obtains organic compounds from other organisms by consuming them directly or breaking down their remains.

Holoparasite – A parasitic plant that relies entirely on its host for water, nutrients, and photosynthates, as it lacks chlorophyll and is incapable of photosynthesis.

Hybridization is crossing two genetically different individuals to produce offspring with new combinations of traits.

Hydroponics – A method of growing plants without soil, using a nutrient-rich water solution to deliver essential elements directly to the roots.

In vitro – Meaning “in glass” refers to experiments or techniques performed outside the living organism, often in test tubes, Petri dishes, or other laboratory containers.

Induced systemic resistance (ISR) – A plant defense mechanism that is activated in response to localized infection, producing defense-related compounds and increasing resistance to subsequent pathogen attacks.

Internode – The region of a plant stem between two successive nodes, where leaves and buds are attached.

Jasmonic acid – A plant hormone that regulates plant defense responses, such as the production of secondary metabolites and the induction of systemic acquired resistance.

Kranz anatomy – A specific arrangement of mesophyll and bundle sheath cells in the leaves of C4 plants, where the mesophyll cells concentrically surround the bundle sheath cells, facilitating the C4 photosynthesis process.

Lateral root – A secondary root that arises from the pericycle of the primary source, contributing to the overall root system architecture.

Leaf abscission – The process by which plants shed leaves or other organs, often in response to environmental cues or hormonal signals.

Lignin – A complex organic polymer that provides structural support and rigidity to plant cell walls, particularly in woody tissues.

Megasporangium – The structure within which megaspores are produced in seed plants and some ferns, eventually developing into ovules containing the female gametophyte.

Megaspore – A giant spore produced by some plants during sexual reproduction, which develops into the female gametophyte.

Meristem – A region of undifferentiated plant cells capable of dividing and giving rise to new cells and tissues.

Micropropagation – The process of rapidly multiplying plant material in vitro, using tissue culture techniques to generate large numbers of genetically identical plants.

Monocotyledon (monocot) – A group of flowering plants with one seed leaf or cotyledon.

Mycorrhizae – Symbiotic associations between plant roots and fungi, in which the fungi provide increased nutrient uptake and the plant provides carbohydrates.

Nastic movements – Non-directional plant movements that respond to external stimuli, such as touch (thigmonasty) or temperature changes (nyctinasty).

Nectary – A specialized glandular structure in flowers that secretes nectar, a sugary solution that attracts pollinators such as insects, birds, and bats.

Nitrogen fixation – The process by which certain bacteria and cyanobacteria convert atmospheric nitrogen gas (N2) into ammonia (NH3), making it available for plant uptake and assimilation.

Nucleotide – The building block of nucleic acids (DNA and RNA), consisting of a sugar molecule, a phosphate group, and a nitrogenous base (adenine, guanine, cytosine, thymine, or uracil).

Osmosis – The movement of water molecules across a selectively permeable membrane from an area of lower solute concentration to an area of higher solute concentration.

Osmotic potential – The potential energy of water due to its concentration of solutes, affecting the movement of water across membranes by osmosis.

Palisade mesophyll – A layer of elongated, tightly-packed photosynthetic cells located just below the upper epidermis in leaves, responsible for most of the light absorption and photosynthesis.

Pedicel – The stalk that supports an individual flower within an inflorescence.

Perennials – Plants that live for more than two years, often producing flowers and seeds annually or at regular intervals.

Phenotype – The observable physical or biochemical characteristics of an organism, determined by the interaction of its genotype with the environment.

Photoinhibition – The decrease in photosynthetic efficiency caused by exposure to high light intensity damages the photosynthetic machinery.

Photoperiodism – A plant’s response to changes in the duration of daylight, which often influences flowering, dormancy, and other developmental processes.

Photosynthesis – The process by which plants convert light energy into chemical energy, using carbon dioxide and water to produce glucose and oxygen.

Phytochrome – A light-sensitive pigment in plants that regulates growth and development, such as germination, flowering, and phototropism.

Phytoremediation – Using plants to remove, degrade, or immobilize contaminants from soil, water, or air, often through phytoextraction, phytodegradation, or phytostabilization.

Plant pathology – The study of plant diseases, their causes, and control methods.

Plant taxonomy – The science of identifying, naming, and classifying plants based on their morphological, physiological, and genetic characteristics.

Plasmodesmata – Microscopic channels through plant cell walls, allowing for communication and transport of substances between adjacent cells.

Plasmolysis – The shrinking of the cytoplasm away from the cell wall due to water loss, often occurring when a plant cell is placed in a hypertonic solution.

Pollination – The transfer of pollen from the male part of a flower (anther) to the female part (stigma), enabling fertilization and seed production.

Protoplast – A plant cell with its cell wall removed, leaving the plasma membrane, cytoplasm, and nucleus intact.

Pteridophyte – A group of vascular plants that reproduce via spores rather than seeds, including ferns, horsetails, and club mosses.

Quiescent center – A group of slowly dividing cells in the root apical meristem that maintain the surrounding initials and participate in tissue regeneration after damage.

Rhizome – A modified subterranean stem that grows horizontally, often giving rise to new plants at the nodes.

Rhizophore – A root-like structure in Selaginella plants that grows downward from the stem, producing true roots upon contacting the soil. It provides support and aids in vegetative reproduction.

Saprophyte – An organism that obtains nutrients by breaking down dead organic matter, playing an essential role in nutrient cycling and decomposition.

Senescence – The process of aging and deterioration in plants, leading to eventual death.

Sporophyte – The diploid (two sets of chromosomes) stage in the life cycle of plants and algae that produces spores through meiosis.

Stomata – Small openings or pores on the surface of plant leaves through which gas exchange occurs.

Symbiosis – A close and long-term biological interaction between two or more different species, which may be mutually beneficial (mutualism), harmful to one participant (parasitism), or neutral (commensalism).

Thigmotropism – The directional growth or movement of a plant in response to touch or physical contact.

Transgenic plants – Plants genetically modified by introducing foreign DNA, often to improve traits such as resistance to pests, diseases, or environmental stressors.

Transpiration – The process of water being lost from plants, primarily through stomata, as water vapor.

Tropism – The directional growth or movement of a plant in response to an external stimulus, such as light (phototropism) or gravity (gravitropism).

Xerophyte – A plant adapted to survive in arid or drought-prone environments, often possessing specialized structures and physiological mechanisms to conserve water, such as succulent leaves, reduced leaf surface area, and CAM photosynthesis.

We hope this extensive glossary of plant science terms has been informative and helpful in your journey to understanding the captivating world of plants. As you continue to explore the field of botany, this glossary can serve as a valuable reference guide. Remember, the study of plants is essential for understanding ecosystems, environmental conservation, and survival, as plants are the basis of the food chain and provide numerous resources that sustain life on Earth. Keep learning and growing in your botanical knowledge, and happy exploring!