Chapter 31 Flashcards
A discrete population of actively dividing, totipotent cells; apical meristems are located at the tip of stems and roots and produce cells that allow plants to grow in length, while lateral meristems surround stems and roots and produce cells that allow growth in diameter.
meristem
In phylogenetic trees, the point where a branch splits, representing the common ancestor from which the descendant species diverged. In plants, the point on a shoot where one or more leaves are attached.
node
The segment between two nodes on a shoot.
internode
A group of totipotent cells near the tip of a stem or branch that gives rise to new shoot tissues in plants.
shoot apical meristem
A gene that contributes to meristem stability and function.
meristem identity gene
A meristem that forms at the base of each leaf.
axillary bud
An organ in its earliest stage of development; leaf primordia form near the tips of shoot apical meristems and develop into leaves.
primordia
One of many like structures formed from leaf primordia that, together, protect shoot apical meristems from desiccation and damage due to cold.
bud scale
A cell that retains the capacity for cell division and gives rise to both xylem and phloem
procambial cell
In a stem, the region between the epidermis and the vascular bundles, composed of parenchyma cells. In the mammalian brain, the highly folded outer layer of gray matter, about 4 mm thick, made up of densely packed neuron cell bodies and their dendrites. In the mammalian renal system, the outer layer of the kidney.
cortex
In a stem, the region inside the ring of vascular bundles.
pith
A plant hormone that stimulates the elongation of stems.
gibberellic acid
The increase in plant length made possible by apical meristems.
primary growth
The increase in plant diameter resulting from meristems that surround stems and roots.
secondary growth
The source of new cells that allows plants to grow in diameter.
lateral meristem
Lateral meristem that is the source of new xylem and phloem.
vascular cambium
Lateral meristem that renews and maintains an outer layer that protects the stem against herbivores, mechanical damage, desiccation, and fire.
cork cambium
New xylem cells produced by vascular cambium, which are located to the inside of the vascular cambium.
secondary xylem
New phloem cells produced by the vascular cambium, which are located to the outside of the vascular cambium.
secondary phloem
In long-lived trees, the layer adjacent to the vascular cambium that contains the functional xylem.
sapwood
The center of the stem in long-lived trees, which does not conduct water.
heartwood
One of the many rings apparent in the cross section of the trunk of a tree, produced by decreases in the size of secondary xylem cells at the end of the growing season, that make it possible to determine the tree’s age.
growth ring
In angiosperms, a narrow cell with thick walls that provides mechanical support in wood. In animals, a term for a muscle cell, which produces forces within an animal’s body and exerts forces on the environment.
fiber
An individual cell that is part of a xylem vessel for water transport in plants.
vessel element
In roots, a single layer of cells just to the inside of the endodermis from which new root apical meristems are formed, allowing roots to branch.
pericycle
A plant hormone that triggers stomatal closure, stimulates root elongation, and maintains seed dormancy.
abscisic acid
The effect of the photoperiod, or day length, on flowering.
photoperiodism
A plant that flowers only when the day length is less than a critical value.
short-day plant
A plant that flowers only when the light period exceeds a critical value.
long-day plant
A plant that flowers independently of any change in day length.
day-neutral plant
A prolonged period of exposure to cold temperatures necessary to induce flowering.
vernalization
(of an immature or stem cell) capable of giving rise to any cell type or (of a blastomere) a complete embryo.
totipotent
Any member of a class of signaling molecules produced by glands in multicellular organisms that are transported by the circulatory system to target distant organs to regulate physiology and behaviour.
hormone
Is the phenomenon whereby the main, central stem of the plant is dominant over (i.e., grows more strongly than) other side stems; on a branch the main stem of the branch is further dominant over its own side branchlets.
apical dominance
The turning of all or part of an organism in a particular direction in response to an external stimulus.
tropism
What are the five major plant hormones, where are they produced, and how are they transported?
Auxin, gibberellin, cytokinin, ethylene, and abscisic acid.
How do auxin and cytokinin interact to explain plant growth patterns?
They help with plant growth dealing with height and width making sure it is balanced
What, developmentally, is a flower (i.e., what organ(s) is/are modified into flowers)? What are the parts of the flower? See figure.
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