Plant Biology Lecture PDF

**PLANT BIOLOGY** **BOTANY** - **Plant Science** - Deals with the **[study of plants,]** including their structure, properties, biochemical processes, and interactions with the environment. **THEOPHRASTUS** - **[Father of Botany]** - Systematically document on how plants grow;...

**PLANT BIOLOGY** **BOTANY** - **Plant Science** - Deals with the **[study of plants,]** including their structure, properties, biochemical processes, and interactions with the environment. **THEOPHRASTUS** - **[Father of Botany]** - Systematically document on how plants grow; he **[categorized them.]** - His works lay the **[groundwork for the taxonomic system]** of plants. ***WHAT ARE PLANTS?*** **THE PLANT** - Living organisms in **Kingdom Plantae** - Multicellular organisms that **make their own food *(autotroph)*** **CHARACTERISTICS OF PLANTS** 1. **Eukaryotic** - Plant cells have defined nucleus (enclosed in a nuclear membrane) and other membrane-bound organelles. 2. **Multicellular** - made up of many cells 3. **Producer** - **autotrophs;** utilize energy from the sun to convert light energy to chemical energy 4. **Photosynthesis** - process of making their own food 5. **Cell Wall** - give structural support; cellulose 6. **Vascular system, seed** a. **Xylem** (malalim) - **water;** upward b. **Phloem** (pagkain) - **food;** upward and downward 7. **Medicinal, food source** - herbal plants have medicinal properties 8. **Alternation of Generation** - In the course of their life cycle, plants alternate between two separate life stages or generations. 9. **Pollination/Fertilization** - The transfer of pollen from the anther to the stigma of a flower. **Key Terms:** - **Haploid:** Having a single set of chromosomes **(n).** - **Diploid:** Having two sets of chromosomes **(2n).** **Reproductive Structures:** - **Gametangia:** Reproductive structures that produce **gametes.** - **Antheridia:** **Male** reproductive structures; **sperm cells** - **Archegonia: Female** reproductive structures; **egg cells** **Reproductive Cells:** - **Gametes:** Sex cells (sperm and egg). **Life Cycle Stages:** - **Spores:** **Haploid cells** produced by sporophytes. They can develop into new gametophytes. - **Zygote:** A fertilized egg, the first cell of a new diploid organism. **Cell Division:** - **Mitosis:** **two (2) identical diploid** cells. - **Meiosis: four (4) haploid c**ells (spores or gametes). **Plant Generations:** - **Gametophyte (sexual phase):** The **haploid phase.** It produces **gametes (sex cells) through mitosis.** - **Sporophyte** **(asexual phase):** The **diploid phase. It develops from the zygote and produces spores through meiosis.** **ALTERNATIONS OF GENERATION** 1. **Sporophyte Stage:** This is the part of the plant's life where it **makes spores.** The sporophyte is **[diploid,]** which means it has **two sets of chromosomes.** It creates **[haploid spores]** (one set of chromosomes) through a process called **meiosis.** 2. **Gametophyte Stage:** The spores grow into the **gametophyte.** This stage is **[haploid,]** and it **makes** the plant's sex cells, or **gametes** (sperm and egg), through **mitosis.** 3. **Fertilization:** When the sperm and egg meet, they **form a zygote, which is [diploid.] This zygote grows into a new sporophyte, and the cycle starts over.** ***In other words...*** **1. Sporophyte Stage (spores)** - **Diploid** (2 sets of chromosomes) - Produces **haploid spores** (1 set of chromosomes) through **meiosis** *Spores grow into\...* **2. Gametophyte Stage (gametes)** - **Haploid** (1 set of chromosomes) - Produces **gametes** (sperm and egg) through **mitosis** - Sperm + Egg = Fertilization **3. Zygote Formation** - **Diploid zygote** is formed - Grows into a **new sporophyte** *Cycle continues again....* **POLLINATION (FERTILIZATION)** - Process of transferring pollen grains from the male anther of a flower to the female stigma **TYPES OF POLLINATION** *Anther (male) to stigma (female)* - **Autogamy (1)** - self-pollination; same plant - **Geitonogamy (2)** - different flowers; same plant (pollinating a 'neighbor') - **Xenogamy (11)** - cross pollination; different plants  +-----------------------------------------------------------------------+ | A. **THE PLANT CELL: MAIN STRUCTURES** | +-----------------------------------------------------------------------+ **Cell Wall** - **First** cell **structure discovered** by **Robert Hooke** in **** - Defines the **shape** of the cell - Contains the **cellulose** A. **Primary cell wall** - Allows for **cell expansion** during growth B. **Secondary cell wall** - Lignified **(woody)** - Once a secondary cell wall **forms,** a ***cell cannot grow anymore*** **Cell Membrane** - **Selectively permeable membrane** that controls what's going in and out of the cell - Serves as a **gate** - Composed of **phospholipid bilayer** a. **One [hydrophilic head]** (phosphate) b. **Two [hydrophobic tails]** (fatty acids) **Vacuoles** - **Most prominent** structure; central large vacuole - It **fills much of plant cells** - Serves as a **storage and waste area** - Some of the plants contains **poison** **(tannin)** to scare away animals **Vacuole and Turgor Pressure**  **Plant cells** prefer a **[hypotonic solution,]** where the **[concentration of solute inside]** the cell **[is greater]** than the concentration outside the cell. This causes **water to move into the cell** through **[osmosis.]** - *In a hypotonic solution, water flows into the cell, **making it turgid**, which is the **[desired state]** for **[plant cells.]*** **Cytoplasm** - **Everything within the cell** membrane which is not the nucleus is the cytoplasm. - Contains **cytosol** - *organelles are suspended here* - **cytosol + organelles - nucleus** **= cytoplasm** - **Protoplasm** - nucleus is embedded here **Chloroplast (and other plastids)** - Presence of plastids that make or store food - Most **common plastid** is **chlorophyll** - the **site of photosynthesis** - Each chloroplast encloses a system of **flattened, membranous sac** called **[thylakoids,]** which **contain [chlorophyll.]** - The **space** between the grana is filled with cytoplasm-like **[stroma.]** - **Thylakoids** - site of **light** dependent **reaction** of photosynthesis - **Stroma** - site of **dark reaction** of photosynthesis **Why does chloroplast have its own DNA?** - Chloroplasts have their own DNA because they were **once free-living bacteria.** - **Endosymbiosis theory by Lyn Margulis.** **Nucleus** - Carries the **genetic material** of a plant - **Control center** - Nucleus is **[normally the largest]** organelle within a **eukaryotic cell** **Ribosome** - The **[site of protein synthesis]** - They are **not surrounded by a membrane.** - **[Most common organelles]** in almost all cells. - They exist in **[two sizes:]** a. **70s** - found in **[prokaryotes],** chloroplasts, and mitochondria, **[free-floating;]** [Endosymbiosis Theory by Lyn Margulis.] b. **80s** - found in **[eukaryotes,]** **attached** to **rough ER,** **[larger]** i. **Polysomes** - **group of 80s** working together. +-----------------------------------------------------------------------+ | A. **THE PLANT CELL: MAIN STRUCTURES** | +-----------------------------------------------------------------------+ **Endoplasmic Reticulum** - **System** of **membranous tubules** and **sacs.** - It acts as an [**internal transport system**,] allowing molecules to move from one part of the cell to another. **Types of Endoplasmic Reticulum** a. **Rough ER** - Studded with 80s ribosomes - **Site of protein synthesis** b. **Smooth ER** - Do not have ribosomes - Polypeptides are converted into functional proteins. - Proteins are prepared for secretion. - **Site of lipid and steroid synthesis.** - **Associated with the Golgi complex.** **Dictyosomes** - **Golgi bodies in plants.** - **Process, package, and secretes organelles** - Common in **glandular cells.** - System of membranes; made of flattened sac-like structures called **cisternae.** - **Works closely with the smooth ER** to **[modify proteins for exports by the cell.]** **Mitochondria** - **Powerhouse of the cell** - Organelle responsible for breaking down glucose into simpler units - **Carbon dioxide, water, ATP** **(by-products)** - **ATP** is the **[energy currency]** of the body. ---------------------- **B. PLANT TISSUES** ---------------------- **Types of Plant Tissue** 1. Meristematic tissue 2. Dermal tissue 3. Vascular tissue 4. Ground tissue A. **MERISTEMATIC TISSUE** - ***"Meritos"*** - to **divide** - Cells **[remain forever young.]** - **Undergo cell division.** - Plant has **four (4) kinds** of meristems. **(ALI)**  **Kinds of Meristem** **A. Apical Meristem** - **[elongation;]** **tips** of roots and shoots**; [produces primary meristems]** a. ***Protoderm*** b. ***Ground meristem*** c. ***Procambium*** **B. Lateral Meristem** - **[secondary growth]** of the plant; **[thickness]** a. **Vascular cambium** b. **Cork cambium** **C. Intercalary Meristem** - **[monocots,]** **[internodes]** and leaf bases; **[regrowth]** **[Re: A. Apical Meristem]** A. **Protoderm** - This is the **[outermost layer]** of a young plant. - It **develops** into **[dermal tissue,]** which becomes the **plant's protective "skin"** B. **Ground Meristem** - This is the **[middle layer]** of a young plant. - It develops into **[ground tissue,]** which **makes up most of the plant** and **[helps]** with **[support, storage, and photosynthesis.]** C. **Procambium** - This is the **[innermost layer]** of a young plant. - It develops into **[vascular tissue,]** which forms the plant's **"transport system"** **(xylem and phloem)** to move water, nutrients, and food. ***In short...*** - **Protoderm** **([dermal tissue])** = becomes the plant's **"skin"** - **Ground Meristem ([ground tissue])** = becomes the **"filler"** tissue for support and food **storage** - **Procambium ([vascular tissue])** = becomes the plant's **"pipes"** for transport; develops into the vascular tissue: **xylem and phloem** **[Re: B. Lateral Meristem]** **Lateral Meristem** - Also known as **[cambium]** - Occurs at the **lateral areas** *(stem, leaves, roots)* - Facilitate **[growth in thickness]** or **[girth]** in a maturing plant - **Two main types** lateral meristematic tissue: a. **Vascular cambium** - **[secondary growth]** in stems and roots; **produces new xylem** (wood cells) outside, phloem - inside b. **Cork cambium** - **[bark layer]** outside of stems **[Re: C. Intercalary Meristem]** - Occur only in **[monocots,]** at the bases of leaf blades and nodes (areas where leaves are attached to a stem) - Enables the **[monocot leaf blade]** to **[increase in length from the leaf base. ]** ***In other words...*** **Apical Meristem** - Found at the **[tips of roots]** and [**shoots**] (the ends of the plant). - Helps the plant **[grow taller]** **or** **[longer.]** **Vascular Cambium** (a type of **Lateral Meristem**) - Found **[between the wood]** (xylem) and bark (phloem). - Helps the plant **[grow thicker or wider (secondary growth)]** - Also **produces new xylem** **Cork Cambium** (also a **Lateral Meristem**) - Found near the **outer part** of stems and roots. - Produces the outer protective layer, like **[bark.]** **Intercalary Meristem** - Found at the **[base of leaves]** or where leaves and stems meet (common in **grasses**). - Helps the **[plant grow quickly]** **after being [cut or grazed.]** **C. DERMAL TISSUE** - **"Derma", "skin"** - **Protects the outer part** of the plant - **Begin** as **[parenchyma cells]**, **which are then modified** to form various type of cells **[for protection ]** A. **Epidermis** - Secretes **[cuticle,]** a waxy substance that **protects** the plant **from water loss** B. **Stomata** - **[Openings]** of the **epidermis** - **[Regulates exchange of gases]** in and out of the plant C. **Trichomes** - **Extension of the epidermis** that **[controls or regulates heat and water balance]** in the leaf D. **Root hairs** - **Outgrowth of epidermis** - **[Keeps]** the **[plant root in contact with the soil]** for stronger attachment  **In other words...** - The **dermal tissue** is the **plant's protective covering.** - The **epidermis** is the **[outermost]** layer; **[secretes cuticle]** - **Stomata (singular: stoma)** are like **[pores]** for breathing and water control by **[closing and opening.]** - **Trichomes** are **[small hair-like]** structures **on leaves and stems;** **[protect the plant]** from pests, reduce water loss, or help keep it cool by reflecting sunlight. - **Root hairs** help the **plant absorb more water and nutrients;** **[increases surface area ]** **D. VASCULAR TISSUE** - Transport food and water internally throughout the plant **Two Types of Vascular Tissue** A. Phloem - food/sugar, up and down; two-way B. Xylem - water, one-way **D. GROUND TISSUE** - Also called as a fundamental tissue system - Consist of all the tissues other than the vascular and dermal tissue system - Usually formed between the dermal and vascular tissue were they are known as the cortex A. Parenchyma - Living tissue - Soft tissue - For repair, photosynthesis, and storage B. Collenchyma - Living tissue - Flexible support for growing parts C. Sclerenchyma - Dead tissue - Mechanical support and aids in food and water transport.  --------------------- **C. PLANT ORGANS** --------------------- Plant Organs 1. Roots 2. Stem 3. Leaf 4. Flower 5. Fruits 1. **Roots** - Essential plant structures - Grow underground and serve several crucial functions Root Functions: - Absorbs water and dissolved materials from the soil. - Anchors the plant to the soil. - Aids in the conduction of water. - It is for reproduction. **Root Parts** - Root Cap - Root Hair - Secondary root Root Cap - Tip of the root - Regulate the primary growth of the root at the tip Root Hair - Tiny, hair-like projections that emerge from the surface of young root cells Secondary Root - Also known as lateral root; branches off from the primary root Summary: - Root cap = protects the tip of the root. - Root hair = absorbs water and nutrients; increases surface area - Secondary root = supports the primary root **Regions of Roots** - Region of root cap - Region of cell division - Region of elongation - Region of maturation 1. **Region of Root Cap** - This is the **tip of the root**. - It protects the root as it pushes through the soil and guides its direction of growth. - Secretes mucilage - Involved in gravitropism 2. **Region of Cell Division** - Located just below the root cap. - This is where new cells are produced (like a \"growth factory\"). - Contains the apical meristem; actively dividing cells 3. **Region of Elongation (Undifferentiated)** - Above the cell division zone. - This is where the new cells **grow longer**, making the root extend deeper into the soil. 4. **Region of Maturation (Differentiated)** - The uppermost part of the root. - This is where cells fully develop into their specific roles, like absorbing water, providing support, or forming root hairs. a. Epidermis - outermost; covers the root b. Cortex - contains the parenchyma c. Endodermis - single layer of cell connecting the vascular cylinder In short: Regions of.... - **Root Cap**: tip of the root, protection. - **Cell Division**: New cells are made. - **Elongation**: Cells grow longer to lengthen the root; undifferentiated - **Maturation**: Cells develop to perform specific tasks (differentiated) **Types of Roots** - Primary roots - Adventitious roots - Taproot - Fibrous roots - Modified roots ### **1. Primary Root (radicle)** - The first organ to appear when a seed germinates. - It develops from the primary root of the seedling into either taproot or a fibrous root system. - The **first root** that grows from a seed. ### **2. Adventitious Root** - Roots that grow from **unexpected places**, like stems or leaves. - They provide extra support or help with reproduction. - Example: Roots of a corn plant or banyan tree. ### **3. Taproot** - A **single, thick main root** that grows deep into the soil. - Smaller side roots grow from it. - Example: Carrots, radishes, or mango trees. ### **4. Fibrous Root** - A network of **thin, shallow, branching roots** that spread out close to the soil surface. - Helps prevent soil erosion. - Example: Grasses, rice, wheat. ### **5. Modified Roots** - Specialized roots with unique functions: - **Storage Roots**: Store food or water (e.g., sweet potatoes). - **Aerial Roots**: Grow above ground for support or breathing (e.g., mangroves). - **Climbing Roots**: Help plants climb (e.g., vines). - **Prop Roots**: Extra support for heavy plants (e.g., corn). *In short:* - **Primary Root**: First root from the seed. - **Adventitious Root**: Grows from different plants of the plants like the stem or leaves - **Taproot**: A deep, main root; mango - **Fibrous Root**: Thin, branching roots near the surface; weeds - **Modified Roots**: Roots with special functions like storage, support, or climbing. **TYPES OF MODIFIED ROOTS** - Stilt roots - Aerial roots - Floating roots - Storage roots - **Stilt Roots**: Large, above ground roots, typically in rainforest, lower part of the stem; For extra support (e.g., maize) - **Aerial Roots**: Air; above ground for support or moisture (e.g., orchids). - **Floating Roots**: In water plants for oxygen (e.g., water hyacinth). - **Storage Roots**: Store food or water (e.g., carrots). 2\. STEM STEM - continuation of the root system that normally grows above the ground - Shoot consists of a stem with branches and leaves. Functions: - Conduction of materials from roots to leaves and vice-versa - Storage of food - For reproduction - For photosynthesis; and - Supports the leaves, branches, even flowers