Evolution of Vascular Tissue Lab - Coggle Diagram
Evolution of Vascular Tissue Lab
Water-conducting parenchyma cells start with simple water conducting cells then to specialized hydroids, true tracheids and vessel elements
Water-conducting hydroids lack lignin and secondary wall thickenings.
Hydroids lack the helices and other thickenings typical of tracheids. They also lack secondary wall patterns, they collapse during water stress which makes them highly resistant to cavitation.
Simple parenchyma specializes into leptoids
At maturity, the nucleus degenerates but protoplasm remains
Similar to phloem sieve cells and nearly identical to protophloem cells of certain tracheophytes. they, along with parenchyma cells account for the leptome.
An elongate shape and slightly oblique end walls.
No true vascular tissue. Contains hydroids and leptoids
Hydroid cells undergo structural modifications to the cell wall and are dead at maturity. In some cases the wall thickens
Leptoids present in forms that are transitional between the parenchyma cells and the fully differentiated leptoid cells within the seta.
Stereids add support to the stem and are arranged in a cylinder around the hydrome. These cells are elongate, thick-walled, primary in nature, and lack lignon.
be able to locate the hydroid, leptoid, stereid, cortex, parchyma, and epidermis
Lycophytes (aka spike mosses or quillworts)
Most extant species are tropical.
Earliest group with true vascular tissue.
Has a dominant free living sporophyte stage
Be able to locate the cortex, epidermis, phloem, stele, and xylem
includes whisk ferns, horsetails, and ferns.
Has well developed vascular tissue throughout the monilophytes
Be able to locate the phloem tissue, xylem tissue, parenchyma cell, and sclerenchyma cell
Nonvascular to Vascular Tissue
True vascular tissue majorly impacted the evolution of terrestrial biology.
It facilitated the development of plants with increased stature, photosynthetic output, and ability to colonize.
3 essential functions are performed by the vascular system
1) Delivery of resources such as water, essential nutrients, sugars, and amino acids to various plant organs.
2) Mechanical support
3) Communication within the plant
The degree of modifications of transport cells increases from the nonvascular plants to the vascular cryptogams through to seed plants