Plant Vascular System: Xylem and Phloem

Flashcards covering major concepts related to the vascular system in plants, focusing on xylem and phloem transport mechanisms.

Xylem

Transport tissue in plants responsible for moving water and minerals from the roots to the leaves.

Phloem

Transport tissue in plants that moves a variety of dissolved substances, including sugars and amino acids, throughout the plant.

Transpiration

The evaporation of water from plant leaves, creating tension in the xylem that helps draw water upward.

Pressure flow model

A model that explains how sucrose concentrations determine the direction of flow in the phloem.

Source cells

Cells that produce sucrose and load it into the phloem; typically found in photosynthetic leaf cells.

Sink cells

Cells that unload sucrose from the phloem; commonly found in roots, developing fruits, and shoot tips.

Osmosis

The movement of water across a semipermeable membrane from a region of lower solute concentration to a region of higher solute concentration.

Turgor pressure

The pressure that builds within a sieve tube as water enters, forcing the sugar solution to flow toward sink cells.

Sieve tubes

The structures within the phloem through which the sugar solution flows.

Differentially permeable membranes

Membranes that allow certain substances, like water, to cross while preventing others, such as sucrose.