For Exam 2 Flashcards
Shoot system components
Stems, buds, leaves, and flowers
Phyllotaxis def
Refers to the arrangements of leaves on a stem or a branch
Alternate phyllotaxis
Single leaf grows from each node, each successive leaf positioned 180 degrees apart
Opposite phyllotaxis
Two leaves grow on each node on opposite sides of the stem, each succcessive pair rotated 90 degrees
Whorled phyllotaxis
Three or more leaves grow at a single node, forming a circular arrangement around the stem
Spiral phyllotaxis
One leaf per node, arrange in a spiral around the stem
Why does phyllotaxis matter?
Reduces leaf overlap to maximize light interception
Helps with water runoff and gas exchange
Primary growth - dicot stems
Vascular bundles are found in rings
Primary growth - monocot stems
Vascular bundles are scattered throughout the stem
Primary meritstems - procambium
Made of primary xylem and phloem
Angiosperms are __________ and gynosperms are ___________
Hardwood, softwoods
Components of bark
Secondary phloem and periderm (which is cork cambium, cork, and phelloderm)
What are rhizomes
Underground stems
gymnosperm wood has and doesn’t have
Has - resin ducts
Doesn’t have - vessels elements
How can you identify earlywood from latewood?
Early wood is the darker part of the ring and latewood is the lighter part
Sapwood vs heartwood
Sapwood - lighter wood near the edges
Heartwood - darker near the center
Secondary growth results from activity in the
Cambium and cork cambium
Secondary growth is responsible for this type of growth
Width
Can secondary growth occur simultaneously with primary growth?
Yes
Do herbaceous plants undergo secondary growth?
Not usually
Are pinopsida gymnosperms or angiosperms
Gymnosperms
In stems, phloem differentiates towards the ______
Outside
In woody stems, Xylem differentiates toward the _____
Center
