Lecture 4 Flashcards
(21 cards)
Crown of a tiller does not elongate. T or F?
True
Under stress….which tillers die first?
Youngest
What does the Root Cap do?
protects root meristem from abrasive effects of soil particles as growth proceeds through the soil.
upward movement of substances (from root to base of plant) -xylem
Basipetal transport
downward movement of photoassimilates from leaves to roots (from base of plant to roots) - phloem
Acropetal transport
What do Root Hairs do?
increase surface area of roots to absorb water and nutrients
The amount of shoot growth is directly related to the amount of _______ ?
Root Growth
Root growth is dependent of what?
the Photosynthetic capability of the plant
What is the Inflorescence?
The flowering portion of the grass shoot that includes the spikelets and the supporting axis or branch system.
What is the stem called that bears the inflorescence?
Flowering Culm
Formation of the grass inflorescence occurs in 4 distinct stages. What are they? 1 - 4….
- Maturation of the plant
- Induction of the flowering stimulus
- Initiation of the stem apex
- Development of the flowers
in the second stage of grass inflorescence…Induction of the Flowering stimulus. What major change is going on in the plant? What causes that change?
apical meristem changes from vegetative to reproductive.
- Vernalization - plant is exposed to cold temperatures
- Photoperiod Induction - “length of day”
Cool season grasses have a Vernalization requirement as the First prerequisite for flowering. What is the most effective temperature range?
32 - 50 degrees F.
Vernalization Requirements for Perennial Ryegrass:
- –Low Requirement—
- Short period, a few weeks with Temperature 45 - 50 degrees
- Only need ONE vernalized tiller for WHOLE plant to flower
Vernalization Requirements for Creeping Bentgrass:
—High Requirement—
-Longer period or 2 - 3 weeks with temperatures at 40 degrees.
Only the tillers that are vernalized will flower
Where does the Photoperiod induction take place?
In the leaves
In the Third stage of grass inflorescence production, Initiation of the Stem Apex…..What is the major change that is going on?
Transformation of the stem apex from a vegetative to a flowering axis.
Define: Lodicules
function to open the grass flower for pollination
the Male reproductive structure of the flower is called what? How many are there? and what do they consist of?
It’s called a Stamen and there are three on each flower They have pollen bearing anthers and their filaments. (see diagram in notes)
What is the Female reproductive structure of the flower called? what does it consist of?
The female portion is called Pistil and it consists of a single ovary and usually two feathery stigmas and styles.
During egg pertilization…describe that the 2 different sperm do…
one fertilizes the the egg (embryo) and one fertilizes the polar nuclei (endosperm)
