Plant Conducting Tissues, Water Movement & Mineral Nutrition

34 vocabulary flashcards summarizing the structure and function of plant conducting tissues, water movement mechanisms, transpiration, and essential mineral nutrients.

Conducting (Transporting) Tissues

Plant tissues—xylem and phloem—that form continuous tubes for moving water, minerals and food throughout the plant body.

Xylem

Vascular tissue that transports water and mineral salts upward from roots to aerial parts; also provides mechanical support.

Phloem

Vascular tissue that transports manufactured food (phloem sap) from leaves to all parts of the plant.

Tracheids

Elongated, dead xylem cells with tapering ends and thickened walls that conduct water and give mechanical strength.

Xylem Vessels

Tube-like, dead xylem elements aligned end-to-end, forming continuous channels for rapid upward water conduction and support.

Xylem Parenchyma (Wood Parenchyma)

Living, thick-walled cells in xylem that store food and assist in water and mineral conduction.

Xylem Fibres (Wood Fibres)

Thick-walled, narrow, dead sclerenchyma cells in xylem that provide mechanical support only.

Sieve Tubes

Cylindrical, enucleated phloem cells arranged vertically; end walls form sieve plates through which food passes cell to cell.

Companion Cells

Living, thin-walled cells intimately associated with sieve tubes; help in food conduction and metabolic control.

Phloem Parenchyma

Living parenchymatous cells in phloem that store food reserves.

Phloem Fibres

Dead, elongated sclerenchyma fibres in phloem that impart mechanical strength to the plant.

Ascent of Sap

Upward movement of water and dissolved minerals through xylem from roots to leaves.

Root Pressure

Hydrostatic pressure developed in roots by continuous osmotic water inflow, pushing xylem sap upwards.

Capillarity

Upward movement of liquid in narrow tubes; narrower xylem vessels enhance water rise by this force.

Cohesion

Attraction between water molecules that helps maintain a continuous water column inside xylem.

Adhesion

Attraction of water molecules to xylem vessel walls, aiding their upward pull during transpiration.

Root Hair

Fine, tubular extension of a root epidermal cell that greatly increases surface area for water and mineral absorption.

Osmosis

Movement of water molecules from a dilute solution to a concentrated one across a semi-permeable membrane.

Diffusion

Passive movement of molecules from a region of higher to lower concentration when in direct contact.

Active Transport

Energy-requiring movement of substances across membranes from lower to higher concentration.

Semi-permeable Membrane

Membrane that allows water molecules to pass but restricts larger solute molecules.

Endosmosis

Osmotic entry of water into a cell or structure, causing it to swell (e.g., raisins in water).

Exosmosis

Osmotic exit of water from a cell or structure, causing shrinkage (e.g., grapes in sugar solution).

Transpiration

Loss of water vapour from aerial parts, mainly through stomata in leaves.

Factors Affecting Transpiration

Sunlight, temperature, wind speed and humidity respectively increase or decrease the rate of water loss.

Cooling Effect (of Transpiration)

Evaporation of water during transpiration removes latent heat, lowering plant temperature.

Macro-nutrients

Mineral elements required in relatively large amounts—chiefly nitrogen, phosphorus and potassium.

Micro-nutrients

Mineral elements needed in trace amounts—e.g., iron, manganese and zinc.

Nitrogen (N)

Macro-nutrient; major constituent of all proteins and promotes overall growth.

Phosphorus (P)

Macro-nutrient; component of cell membranes and certain proteins, vital for energy transfer.

Potassium (K)

Macro-nutrient; abundant in growing tissues, regulates stomatal opening and closing.

Iron (Fe)

Micro-nutrient; component of some proteins, essential for chlorophyll synthesis.

Manganese (Mn)

Micro-nutrient; constituent of several enzymes involved in photosynthesis and respiration.

Zinc (Zn)

Micro-nutrient; part of plant hormones and enzyme activator, important for growth regulation.