Leaf primordia are
groups of cells that will form into new leaves
. These new leaves form near the top of the shoot and resemble knobby outgrowths or inverted cones.
How does a leaf primordium become a leaf?
When very young leaf primordia (P2) are excised from the shoot apex in tobacco and explanted to a medium containing inorganic salts and sugar
, they develop into leaves. This indicates that cells within the primordium are determined at this very early stage (Steeves and Sussex, 1989).
How does a leaf Primordium differ from a mature leaf?
Leaf primordia are
groups of cells that will form into new leaves
. These new leaves form near the top of the shoot and resemble knobby outgrowths or inverted cones.
What is leaf initiation?
Initiation.
The formation of a leaf primordium at the flanks of the shoot apical meristem
. Leaf maturation. The gradual process of the acquisition of leaf shape and size, from leaf initiation to a mature functional leaf to senescence.
What is primordium formation?
Primordium formation starts
from the fast and anisotropic growth at the periphery of the shoot apical meristem
, with the maximum extension in the meridional direction. … The bulge is formed from the shallow crease due to slower and less anisotropic growth than at the onset of primordium formation.
What causes leaf growth?
If a plant finds itself in competition with others
, it will direct growth into leaf growth and away from reproductive growth (flowers, fruits, tubers or other storage organs). The plant can detect the presence of other plants within a metre of it by the spectrum of the light landing on its leaves.
What is responsible for leaf growth?
The term auxin is derived from the Greek word auxein, which means “to grow.”
Auxins
are the main hormones responsible for cell elongation in phototropism and gravitropism. They also control the differentiation of meristem into vascular tissue, and promote leaf development and arrangement.
What is petiole function?
A petiole
attaches the leaf to the stem
and contains vascular tissue that provides a connection from the stem to permit sap to enter the leaf and the products of photosynthesis (carbohydrates) to be transported from the leaf to the rest of the plant.
How does a leaf interact with the environment?
Leaves are the primary way plants interact with the atmosphere and
take care of their basic needs
. Food: Plants don’t eat food (heterotrophic)—they make it (autotrophic) by taking atmospheric CO
2
, water from the soil, and energy from light to make simple sugars in a process called photosynthesis.
What is the leaf structure?
All leaves have the same basic structure –
a midrib, an edge, veins and a petiole
. The main function of a leaf is to carry out photosynthesis, which provides the plant with the food it needs to survive. Plants provide food for all life on the planet.
What determines leaf shape?
Genetic basis of leaf shape:
genetic interactions, gene expression patterns, microRNAs, and active hormonal regulations
.
What is a petiole on a leaf?
A plant leaf is generally composed of a petiole and a leaf blade. The petiole
connects the leaf blade to the plant stem
and, from a structural viewpoint, it resembles a cantilever beam.
What are the main events in the initiation and development of the leaf?
The early events in leaf development have been divided into three main processes (Foster, 1936, Steeves and Sussex, 1989, Smith and Hake, 1992), namely,
the initiation of the leaf primordium, the establishment of dorsiventrality
, and the development of a marginal meristem.
What are the steps of leaf development?
Afterward, the transformation of the small leaf primordium to a mature leaf is controlled by at least six distinct processes: cytoplasmic growth (4), cell division (5), endoreduplication (6),
transition between division and expansion (7), cell expansion (8) and cell differentiation (9) into stomata (9a), vascular
…
What is the primordium of the brain?
The neural tube
is the primordium of the brain and spinal cord, and the process of its formation is called neurulation.
Where are leaf primordia found?
The shoot apical meristem (SAM), at the tip of the plant stem
, has two roles; it is the source of the new cells that are needed for stem growth, and it is the site of small cellular outgrowths, called leaf primordia (LP), that develop into the leaves (1).
