Lecture 1 - Plant Physiology - Primer

Vacuole

A large organelle in plant cells that provides support through turgor pressure and stores ions, water, and chemicals.

Plastids

Organelles involved in metabolism that produce and/or store carbohydrates, fats, and amino acids, surrounded by a double membrane and containing DNA and RNA.

Chloroplasts

A type of plastid that contains chlorophyll and other pigments essential for photosynthesis, found in all green tissues of plants.

Chromoplasts

Plastids that contain carotenoids, responsible for the yellow, orange, and red pigments in flowers and fruits, attracting pollinators and seed dispersers.

Amyloplasts

Non-pigmented plastids responsible for the synthesis and storage of starch grains, converting them to sugar for energy.

Plant Cell Wall

A rigid structure surrounding plant cells, composed of cellulose, hemicellulose, pectins, and proteins, providing support and protection.

Lignin

A complex organic polymer found in the secondary cell wall of plants, adding strength and making the walls inflexible and impervious to water.

Plasmodesmata

Occur in cytoplasm/plasma membrane and mediate direct cell-to-cell communication and transport of molecules between neighboring cells.

Parenchyma

Characterized by thin primary cell walls and no secondary cell walls, involved in various functions including storage and photosynthesis. Single celled, 5 different types.

Collenchyma

Plant cells with unevenly thickened primary cell walls, providing flexible support to growing tissues, typically found in stems and leaves.

Sclerenchyma

Plant cells with thick lignified secondary cell walls, providing structural support and protection, characterized by pits for gas exchange.

2 general categories of sclerenchyma

1. Conducting sclerenchyma (xylem)

2. Non-conducting sclerenchyma (fiibers & sclereids)

Astrosclereids

A type of sclereid found in leaves, more specifically water lilies, providing structural support in tissues with air spaces for buoyancy and gas exchange.

Brachysclereids

Tough sclereids with exceptionally thick walls, found in fruit flesh and contributing to the gritty texture in pears.

Pits

Channels in the secondary cell wall that facilitate water and mineral transport between adjacent cells.

5 types of Parenchyma

1. Synthetic

2. Structural

3. Boundary

4. Transport (transfer cells)

5. Storage