Seeds, Meristems, and PCR Lecture Notes

Exam 2

Seed Functions

Provide maximum protection to young plants, supply energy reserves, adapted for dispersal, and can maintain dormancy.

Seed Dormancy

Prevents germination until growth conditions are favorable, can last for days to years, and dormancy breaks vary by habitat.

Dormancy Break Conditions (Desert Plants)

Occurs after heavy rainfall.

Dormancy Break Conditions (Chaparral Regions)

Occurs after exposure to fire (smoke).

Seed Germination Events

Imbibing causes swelling and rupturing of the seed coat, metabolic changes restart growth, storage materials are broken down and transferred, and the radicle emerges.

Indeterminate Program

Growth and development are not genetically limited and continue as long as environmental conditions and resources permit.

Determinate Program

Growth and development are fixed or limited by genetic parameters.

Meristem

A region of undifferentiated cells from which new cells arise, characterized by self-renewal and the ability to produce cells that can differentiate.

Totipotent

The ability of nucleated plant cells to differentiate into any other cell type or, with help, develop into an entire plant.

Apical Meristems

Responsible for elongation growth. Types include Shoot Apical Meristem (SAM) and Root Apical Meristem (RAM).

Primary Meristems (from Apical Meristems)

Protoderm, Procambium, and Ground Meristem.

Lateral Meristems

Responsible for diameter growth (girth). Types include Vascular Cambium and Cork Cambium.

Protoderm

A primary meristem that gives rise to the epidermis.

Ground Meristem

A primary meristem that gives rise to ground tissue.

Procambium

A primary meristem that gives rise to primary vascular tissue.

Vascular Cambium

A lateral meristem that gives rise to secondary vascular tissue.

Cork Cambium

A lateral meristem that gives rise to periderm.

Quiescent Center (RAM)

A relatively inactive region of the Root Apical Meristem (RAM) containing initials.

Central Zone (CZ) (SAM)

A part of the Shoot Apical Meristem (SAM) that has large, slow-dividing cells and provides new cells.

Peripheral Zone (PZ) (SAM)

A part of the Shoot Apical Meristem (SAM) that has small, fast-dividing cells and forms leaves and flowers.

Rib Zone (RZ) (SAM)

A part of the Shoot Apical Meristem (SAM) where cells divide and push the meristem up, forming ground and vascular tissue.

stm (shoot meristemless) mutant

A plant mutant that fails to produce any meristem-derived tissues, resulting in no leaves, stem, or flowers.

PCR (Polymerase Chain Reaction)

A method to amplify (copy) DNA from a single strand to generate billions of copies, revolutionizing molecular biology.

Kary Mullis

Awarded the Nobel Prize for originating PCR in 1983.

Components needed for PCR

Template DNA, dNTPs (nucleotides), DNA Polymerase (Taq), Primers, a tube, and a thermocycler (PCR machine).

Taq Polymerase

A heat-stable DNA Polymerase derived from Thermus aquaticus, essential for PCR.

Steps of PCR

Denaturation (~950C), Annealing (~600C), and Extension/Elongation (~720C).

35S CMV Promoter

A standard viral promoter often used to express transgenes in most plant cells, detectable via PCR in genetically modified organisms.

Agarose Gel Electrophoresis

A method used to visualize PCR products by separating amplified DNA fragments based on size.