BIOEXCEL 192 - Roots KEY


____.) Complete the following chart:
In Stems
In Roots
a) Protoderm gives rise to 1.epidermis 1.epidermis
b) Procambium gives rise to 1.xylem
3.vascular cambium
3.vascular cambium
c) Ground Meristem gives rise to 1.cortex
d) Periderm consists of 1.cork cambium
2.cork cells
1.cork cambium
2.cork cells
e) Bark consists of 1.phloem

____.) What is the difference between taproots and fibrous roots?
taproots (gymnosperms and dicots) - primary root grows directly downward, lateral roots grow out from primary
fibrous (monocots, grassroots) - short-lived primary root, several adventitious roots arise from stem base

____.) What is the function of roots?
uptake of water and minerals, anchorage of shoot, storage, hormone synthesis

____.) Draw and label the three zones of root development.

____.) List the mature tissues of the root.
epidermis, cortex, vascular cylinder

____.) Draw and label a mature root cross-section.

____.) Answer TRUE or FALSE. If the answer is FALSE, indicate why.
a) ___ Only young herbaceous plants have an epidermis. False - BOTH young woody and herbaceous plants have an epidermis.
b) ___ Epidermis consists of parenchyma cells. True
c) ___ Living epidermal cells contain both a primary and a secondary cell wall. False - Living epidermal cells contain only a primary cell wall.
d) ___ Guard cells and trichomes are two types of specialized cells of the epidermis. True
e) ___ Stinging nettle and carnivorous plants have glandular hairs. True
f) ___ A root fiber is a type of trichome. False - A root HAIR is a type of trichome.

____.) What are two functions of the root cap?
1.protect root apical meristem (RAM)
2.secrete mucilage for lubrication to ease penetration into soil

a) Root hairs are specializations of the ________epidermis (trichomes)________, are located in the _________region of differentiation___________, and serves the function of _________water absorption ________________________.
b) Secondary or Lateral or Branch roots arise from the __________pericycle __________.

____.) A burgeoning research scientist is performing experiments on various cells extracted from plant roots. In a time-lapse culture assay, the student observes that one group of cells is dividing at a much slower rate than other cell groups. Furthermore, this same group of cells when exposed to toxins showed to be much more resistant than other groups of cells. Based on these observations, where in the plant root did this student extract these cells. Be specific.
the quiescent center of RAM

____.) Give three reasons as to why the pericycle is extremely important to the development and health of a plant.
1.the site where lateral roots appear
2.cells can become cork cambium
3.cells can become vascular cambium

____.) Give three types of modified roots and an example of each. root - sweet potatoes, yams, beets, carrots, turnips
2.pneumatophore root - mangroves
3.buttress root - tropical tall trees in soft wet soil

2002-2003 Kevin Hong