PBIO 004 Lecture 6: Meristems and Plant Growth
31 Jan 2019
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Department
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Professor
Meristems and Plant Growth
January 30th
− Shoot apical meristem is a small number of cells at the tip of a growing shoot, covered by
leaf primordia
• Cells are undifferentiated and undergo mitosis
• The continued division results in increased plant height
− Root apical meristem is a population of growing cells within the root tip, covered by a group
of cells called the root cap
• Continued cell division results in increased root length
− Lateral meristems give rise to cells that increase the width of the stem
− Primary meristems are derived from apical meristems, they are a continuation that grows off
of them
• They are more differentiated as they serve to give rise to all other tissues in the plant
(1) Protoderm: a type of primary meristem that gives rise to the epidermis, which is
composed of dermal tissue
(2) Ground meristem: a type of primary meristem that gives rise to ground tissues
(such is the cortex)
(3) Procambium: a type of primary meristem that gives rise to the vascular system,
which is composed of vascular tissue
Details on the three types of tissue can be found in the Lab 1 notes
− The three types of tissue (ground, dermal and vascular), exist and function in each area of the
plant
• In the leaf:
Dermal tissue is the outer cell layer of the leaf and is responsible for diffusion of gas
and water into the plant
Ground tissue carries out photosynthesis
Vascular tissue conducts water and solutes throughout the plant
• In the stem:
Dermal tissue is the outer cell layer of the stem
Ground tissue helps support the plant against the force of gravity
Vascular tissue conducts water and solutes throughout the plant
• In the roots:
Dermal tissue is the outer cell layer of the root
Ground tissue helps support the plant and provides a selective barrier against
unwanted mineral ions in the soil from entering the xylem
Vascular tissue conducts water and solutes throughout the plant
− Secondary meristem makes roots and stems wider
• Responsible for lateral roots, those that grow off of the sides of mature roots and are not a
result of apical meristem growth
Outgrowth of cells that initiate in the cortex layer in response to hormones
The lateral roots will form apical meristem to contribute to growth
• Lateral growth and stems in trees and woody bushes is due to types of secondary
meristem:
Document Summary
Shoot apical meristem is a small number of cells at the tip of a growing shoot, covered by leaf primordia: cells are undifferentiated and undergo mitosis, the continued division results in increased plant height. Root apical meristem is a population of growing cells within the root tip, covered by a group of cells called the root cap: continued cell division results in increased root length. Lateral meristems give rise to cells that increase the width of the stem. Details on the three types of tissue can be found in the lab 1 notes. The three types of tissue (ground, dermal and vascular), exist and function in each area of the plant. Dermal tissue is the outer cell layer of the leaf and is responsible for diffusion of gas and water into the plant. Dermal tissue is the outer cell layer of the stem. Ground tissue helps support the plant against the force of gravity.
