Developmental Biology and Plant Reproductive Development Flashcards

Comprehensive vocabulary flashcards covering key concepts from developmental biology, plant reproduction, gametogenesis, embryogenesis, leaf and stomatal development, organogenesis, and root anatomy.

Developmental Biology

The field of study aimed at understanding how an organism grows and develops from a single cell into a complex, organized grouping of specialized cells.

Genomic Equivalence

The principle that somatic cells within an organism contain identical genomes, allowing cells to change phenotype without altering genotype.

Differential Gene Expression

The selective activation of specific genes in a cell, defining its structure, function, and cell type specialization.

Alternative Splicing

An RNA processing mechanism where an RNA molecule containing multiple exons is spliced in various ways to allow a single gene to encode multiple distinct protein variants.

Promoters and Enhancers

Promoters are DNA sequences near the transcription start site where RNA polymerase binds; enhancers are distant DNA sequences that boost gene transcription.

Tapetum

A specialized cell layer surrounding the anther locule that synthesizes pollen wall components, supplies nutrients, and produces enzymes for microspore release.

Stomium

The specific region where adjacent anther walls join, serving as the final breakage site during anther dehiscence.

Secretory Tapetum

A type of tapetum that stays in its original location within the anther locule, secreting pollen wall materials before undergoing breakdown.

Plasmodial Tapetum

A type of tapetum whose cell walls break down, releasing protoplasts that fuse together to form a multinucleate plasmodium.

Microsporogenesis

The developmental process wherein diploid microspore mother cells undergo meiosis within the microsporangium to produce haploid microspores.

Callase

An enzyme secreted by the tapetum that breaks down the surrounding callose wall of a microspore tetrad to release individual free microspores.

Microgametogenesis

The development of a haploid microspore into a mature pollen grain via asymmetrical mitotic division, forming a vegetative cell and a generative cell.

Post-Fertilization Structure Transformation

The transformation of floral and ovule structures following fertilization into seed parts, where the ovule becomes the seed, egg cell becomes embryo, central cell becomes endosperm, and integuments become the seed coat layers.

Megasporogenesis

The formation of megaspores from a diploid megasporocyte through meiosis, typically leaving one functional chalazal megaspore while three micropylar megaspores degenerate.

Megagametogenesis

The development of the female gametophyte (embryo sac) from a functional megaspore through three mitotic divisions, forming a mature 7-cell, 8-nucleate structure.

Autogamy

A form of self-pollination occurring within a single bisexual flower where male and female organs mature simultaneously without requiring external pollinators.

Geitonogamy

A form of self-pollination occurring between different flowers on the same plant, often involving external pollination agents.

Xenogamy

Cross-pollination involving the transfer of pollen grains from the anther of a flower on one plant to the stigma of a flower on a distinct plant.

Double Fertilization

A process unique to angiosperms in which one sperm nucleus fertilizes the egg cell to form the zygote (embryo) and a second sperm nucleus fertilizes the central cell to form the endosperm.

Hypophysis

A developmental boundary region between the suspensor and the embryo proper that contributes to the formation of root apical meristem cells.

Suspensor

A filamentous or spherical embryonic structure derived from the basal cell that transfers nutrients to the developing embryo proper and positions it toward food reserves.

Scutellum

The single modified cotyledon found in monocot embryos that acts as conductive tissue for nutrient absorption from the endosperm.

Coleoptile and Coleorhiza

Specialized protective sheath structures in monocot embryos covering the emerging shoot (plumule) and embryonic root (radicle), respectively.

Central Zone (CZ)

The central domain of the Shoot Apical Meristem containing slowly dividing pluripotent stem cells that replenish the meristem.

Peripheral Zone (PZ)

The region surrounding the Central Zone in the Shoot Apical Meristem where founder cells undergo rapid division to give rise to leaf and floral primordia.

SPEECHLESS (SPCH)

A basic helix-loop-helix (bHLH) transcription factor in Arabidopsis that initiates stomatal development by directing the first asymmetric division of meristemoid mother cells.

MUTE

A bHLH transcription factor in Arabidopsis that drives the differentiation of a meristemoid into a Guard Mother Cell (GMC).

FAMA

A bHLH transcription factor in Arabidopsis that controls the terminal symmetric division of a Guard Mother Cell (GMC) into two paired mature guard cells.

Trichomes

Unicellular or branched epidermal appendages on leaf surfaces that provide physical protection and produce defensive chemicals against herbivores.

MADS-box Transcription Factors

A family of master regulatory genes that control floral organ identity and structural patterning across successive floral whorls.

Quiescent Center (QC)

A distinct group of slowly dividing cells within the Root Apical Meristem that preserves surrounding stem cells and prevents their premature differentiation.

Columella

A specialized group of cells in the root tip cap responsible for gravity sensing and directing downward root growth.

SCARECROW (SCR) and SHORT-ROOT (SHR)

Transcription factors essential for regulating cell identity, asymmetric cell divisions, and radial tissue layer patterning in the root.