Abscission zone A region near the base of petiole of leaf which contains abscission layer.
Absorption Spectrum A curve obtained by plotting the amount of absorption of different wavelengths of light by a pigment is called its absorption spectrum.
Action Spectrum A graphic representation showing the rate of photosynthesis at different wavelengths of light is called action spectrum
Aeroponics A technique of growing plants suspended over the nutrient solution in a mist chamber. Nutrient sprayed by motor driven rotor on the roots.
Agar Jelly-like substance, derived from red algae
Allelopathy The chemical substances released by one plant species which affect or benefit another plant
Amphicribal/ Hadrocentric Xylem in the centre with phloem surrounding it. Example:Ferns ( Polypodium)
Amphivasal /Leptocentric Phloem in the centre with xylem surrounding it. Example: Dragon plant – Dracena and Yucca
Anabolic It is an enzyme catalyzed reaction in a cell that involves synthesis of complex molecules from simple molecules which uses energy.
Apical cell theory Single apical cell growing into whole plant Axil Parenchyma Parenchyma arranged longitudinally along the axis
Callose Sieve pores are blocked by substances called callose
Carbonic acid A weak acidic solution of carbon-di-oxide dissolved in water
Catabolic It is an enzyme catalyzed reaction in a cell that involves degradation of molecules into simple subunits which release energy.
Chelating agents A chelate is the soluble product formed when certain atoms in an organic ligand donate electrons to the cation.
Chlorosis Breakdown of chlorophylls leads to yellowing of leaves
Closed vascular bundle Cambium absent between xylem and phloem Example:Monocot stem
Coenzyme A non-protein molecule involved in enzyme catalyzed reactions serves as transfer of protons or electrons between various molecules
Colloidal An evenly distributed mixture of two different particles in a system without losing its own properties.
Deamination The enzymatic removal of an amino group from an amino acid to form its corresponding keto acid.
Desiccation tolerance Ability of plants which can tolerate extreme water stress without being killed.
Drought resistance Capacity of a plant to limit and control consequences of water deficit.
EDTA Ethylene Diamine Tetra Acetic acid, chelating agent makes iron uptake possible by forming soluble complex in an alkaline soil.
Endergonic A chemical reaction with a positive free energy charge or ATP utilizing reactions.
Exergonic A chemical reaction with a negative free energy charge or ATP producing reactions.
Extra stellar ground tissue Tissues outside the stele
Fibre-Tracheids Transitional form between fibre and tracheids
Fluorescence Emission of light by a substance that has absorbed light in the form luminescence.
Gelatin An animal-based product used as a gelling agent.
Granum A stack of thylakoid in a stroma of chloroplast
Hadrome Xylem-by Haberlandt
Halophytes Plants native to saline soils and complete their life cycle
Heliophytes Plants which are adapted to light
Histogenesis Differentiate tissues from undifferentiated cells of meristem
Indeterminate growth Plants grow throughout their life
Intrastelar ground tissue Tissues within the stele
Isomerisation Rearrangement of atomic groups within the same molecule without any loss or gain of atoms.
Leptome Phloem – by Haberlandt
Lumen Space inside the tracheid/vessel/fibres
Malate Shuttle mechanism It is a biochemical system for translocating electrons produced from glycolysis across inner membrane of mitochondrion for oxidative phosphorylation.
Mass meristem Meristem which divides in all planes
Necrosis Death of tissue Non heme iron An iron porphyrin prosthetic group of heme proteins from plant origin
Nutation The growing stems of twiner and tendrils show automatic movement
Open vascular bundle Cambium present between xylem and phloem Example: Dicot stem
Oxidation Water is oxidised into Oxygen (loss of electrons)
PAR The wavelength at which the rate of photosynthesis is more is called ‘Photosynthetically Active Radiations’ which falls between 400 to 700 nm.
Phosphorescence Phosphorescence is the delayed emission of absorbed radiations.
Photolysis Splitting of water molecules by light which generate protons, electrons and oxygen.
Photon Light is electromagnetic radiant energy and travels as tiny particles called photons. A discrete Physical unit of light energy.
Photoperiodism The response of plants to the photoperiod expressed in the form of flowering.
Phytochrome A photo reversible proteinaceous plant pigment in very low concentration that absorbs red and far red light which controls flowering.
Pitted thickening Uniformly thick except at their pits
Preparatory phase First half of glycolysis comprising five enzymatic reactions in which one molecule of glucose splitting into two molecules of glyceraldehyde 3 phosphate with consumption of two ATP molecules.
Prickles Stiff and sharp outgrowth
Quantasome Morphological expression of physiological photosynthetic units, located on the inner membrane of thylakoid lamellae. Act as photosynthetic unit contains 200 to 300 chlorophyll molecules.
Quantum The energy contained in a photon is represented as quantum
Quantum requirement The number of photons or quanta required to release one molecule of oxygen during photosynthesis
Quantum yield The number of oxygen molecules produced per quantum of light absorbed.
Quiescent centre concept Inactive region of root meristem
Radial vascular bundles Xylem and phloem present on different radii
Ray Parenchyma Parenchyma cells arranged in radial rows
Redox reactions Oxidation (loss of electrons) and Reduction (gain of electrons) reactions are called redox reactions.
Reduction CO2 is reduced into Carbohydrates (gain of electrons)
Rib-meristem Meristem which divides anticlinally in two planes
RUBISCO Enzyme responsible for fixation of Carbon dioxide, the most abundant protein (Ribulose 1,5 bisphosphate Carboxylase Oxygenase)
Salt stress Adverse effects of excess mineral salts on plants
Sap It is a fluid consist of water and dissolved minerals
Slime body A special protein (Phloem Protein) in sieve tubes
Stellate hairs Star shaped hairs
Stratification A process of breaking the dormancy of some plants resulting from chilling requirements
Subsidiary cells Surrounding guard cells in the leaf epidermis
Sucrose Non-reducing disaccharide composed of glucose and fructose
Trichoblasts One type of epidermal cells that is also called short cell
Trichomes Unicellular or multicellular appendages
Tunica-carpus theory Two zones of apical meristem Tunica and Carpus
Xylos Wood
