How do xylem and phloem differ in their structure and function within vascular tissue?
Xylem conducts water unidirectionally from roots to shoots using tracheids and vessel elements, while phloem transports sugars and other molecules bidirectionally using sieve tube elements and companion cells.
Describe the three main types of ground tissue cells and their functions.
Parenchyma cells are involved in healing, nutrient transport, and storage; collenchyma cells provide flexible support in growing regions; sclerenchyma cells offer rigid support in mature areas and are often dead at maturity.
What is the main function of xylem in vascular tissue?
Xylem conducts water and dissolved nutrients unidirectionally from the roots to the shoots.
How do vessel elements differ from tracheids in the xylem?
Vessel elements are shorter, wider, and have perforations for more efficient water conduction, while tracheids are long, thin, and have pits for water flow.
What is the primary role of phloem in plants?
Phloem transports sugars, amino acids, and signaling molecules bidirectionally between roots and shoots.
What are sieve tube elements and companion cells, and how do they function together in phloem?
Sieve tube elements transport sugars and other molecules, while companion cells support them metabolically and physically, as sieve tube elements lack certain organelles.
What is the function of the plant epidermis and its cuticle?
The epidermis protects the plant from pathogens and water loss, while the cuticle is a waxy film that further reduces water loss.
Describe the function of trichomes found on the plant epidermis.
Trichomes are hair-like structures that can reduce water loss, defend against herbivores, reflect sunlight, or even trap insects.
What are the three main types of ground tissue cells and their primary functions?
Parenchyma cells are involved in healing, nutrient transport, and storage; collenchyma cells provide flexible support in growing regions; sclerenchyma cells offer rigid support in mature areas and are often dead at maturity.
Where are the pith and cortex located in a plant stem, and what is their general function?
The pith is the inner region of ground tissue surrounded by vascular bundles, while the cortex is the ground tissue outside the vascular bundles; both are involved in storage and support.