The Nature and Composition of Plants PDF

THE NATURE AND COMPOSITION OF PLANTS QUEENEEVI T. QUIJANO, R.A, MSA -The smallest structure in the universe capable of growth and reproduction. Plant Cell -The basic unit of every living organism. -An autonomousliving system capable of independent existence and propagation. -fun...

THE NATURE AND COMPOSITION OF PLANTS QUEENEEVI T. QUIJANO, R.A, MSA -The smallest structure in the universe capable of growth and reproduction. Plant Cell -The basic unit of every living organism. -An autonomousliving system capable of independent existence and propagation. -fundamental morphological unit of plant. Plant cells are the building blocks of plants. Photosynthesis is the major function performed by plant cells. Photosynthesis occurs in the chloroplasts of the plant cell. It is the process of preparing food by the plants, by utilizing sunlight, carbon dioxide and water.  Plant cell has three main components: Cell wall Cytoplasm Nucleus The cell wall surrounds the The cytoplasm is The nucleus controls and plasma membrane of plant responsible for holding the regulates the activities of cells and provides tensile components of the cell and the cell (e.g., growth and strength and protection protects them from metabolism) and carries the against mechanical and damage. It stores the genes, structures that osmotic stress. molecules required for contain the hereditary cellular processes and is information. also responsible for giving the cell its shape. CELL WALL CELL WALL provide structural strength and support, and also provide a semi-permeable surface for molecules to pass in and out of the cell.  CYTOPLASM Responsible for holding the components CYTOPLASM of the cell and protects them from damage. It stores the molecules required for cellular processes and is also responsible for giving the cell its shape.  CYTOPLASM PLASMALEMMA/PLASMA MEMBRANE MITOCHONDRIA In plants, as in all organisms, the plasma a membrane-bound organelle that is the membrane serves two main roles: (1) the site of energy production in cells. transport of solutes, both into and out of each cell, and (2) sensory transduction, i.e., the PLASTID sensing and initiation of the cellular response to changing environmental conditions. double-membrane organelle found in the cells of plants and are the main sites of photosynthesis ENDOPLASMIC RETICULUM a network of membranes inside a cell through which proteins and other molecules move GOLGI APPARATUS responsible for transporting, modifying, and packaging proteins and lipids into vesicles for delivery to targeted destinations.  CYTOPLASM CYTOSKELETON a structure that helps cells maintain their VACUOLES shape and internal organization, and it also crucial for growth and development and provides mechanical support that enables cells has a variety of functions, including to carry out essential functions like division and storage and transport, intracellular movement. environmental stability, and response to injury. Depending on the cell type and growth conditions, the size of vacuoles is MICROBODIES highly dynamic. It participate in numerous cell biochemical processes. The breakdown of lipids, amino acids, alcohol, etc. is made RIBOSOME possible by the enzymes found in Organelles that help in protein synthesis. microbodies. They participate in plants' Protein is required for many cell activities photorespiration. such as damage repair and other chemical processes.  NUCLEUS Store DNA or hereditary information NUCLEUS required for cell division, metabolism and growth. The Anatomical Regions of a Plant Body THE PLANT BODY IS COMPOSED OF THREE PRIMARY ORGANS: Leaf: Primarily responsible for photosynthesis, the process by which plants convert light energy into chemical energy. Stem: Provides support for the plant, facilitating the transport of water, nutrients, and photosynthetic products between roots and leaves. Root: Anchors the plant in the soil and absorbs water and minerals necessary for growth. Angiosperms: The Dominant Plant Group ANGIOSPERMS (FLOWERING PLANTS) Consist of approximately 250,000 species and dominate Earth's Fruit trees, including mango, apple, vegetation. banana, peach, cherry, Orange, and Pear, often show flowers before they Seeds of angiosperms contain an bear fruits, and the pollination process is embryo and cotyledons (seed leaves), generally carried out by agents such as which are nourished by the endosperm bees. and protected by a seed coat. Grains, including rice, corn, and wheat, are also examples of Angiosperm. Seed Germination and Growth Seeds germinate under favorable conditions, including adequate moisture, appropriate temperature, sufficient oxygen, and sometimes light. During germination, the root (radicle) and shoot (plumule) emerge from the embryo. Seedling growth is driven by cell division Germination is specifically the process a in meristematic tissues, which are seed goes through as it breaks regions of active cell division. dormancy and initiates growth. Growth is an irreversible increase in size. Plant Development As the seedling matures through the juvenile stage, it eventually produces flowers and fruits following pollination and fertilization. Fruits develop from the fertilized flowers and contain seeds, thereby completing the plant’s life cycle.  Plant Tissues SIMPLE TISSUES COMPLEX TISSUES The simple tissues (tissues with uniform cells) are complex tissues (tissues with more than one type composed of the same type of cells. of cells) are composed of more than one type of cell, these are unique to plants. Parenchyma, Collenchyma, and Sclerenchyma are the three types of simple permanent tissues. Xylem and Phloem are types of complex tissues.  PLANT ORGANS Organs: Structures composed of several PLANT SYSTEMS tissues that perform distinct functions. Examples include leaves, stems, and Systems: Groups of interacting organs roots. that work together as a functional unit in the life of the plant. For instance, the vascular system includes both xylem and SIMPLE TISSUES phloem tissues, which transport water, This structure allows plants to efficiently nutrients, and food throughout the perform essential functions such as plant. photosynthesis, nutrient transport, support, and reproduction, ensuring their growth, survival, and propagation.  MERISTEMATIC TISSUES These tissues consist of actively dividing cells that contribute to plant growth. They are found in regions of the plant where growth can take place. Apical Meristems: Located at the tips of roots and shoots, responsible for primary growth (lengthening of the plant). Lateral Meristems: Found in the vascular and cork cambium, responsible for secondary growth (increase in thickness or girth of the plant). Intercalary Meristems: Located at the base of leaves or internodes, particularly in grasses, and contribute to regrowth.  PERMANENT TISSUES Group of cells that have lost the ability to divide and have reached a stable and mature state. These cells are specialized for specific functions and can be further classified into various types based on their structure and role. Permanent tissues are crucial for the functioning, growth, and support of the plant.  TYPES OF PERMANENT TISSUES Simple Permanent Tissue: Composed of similar types of Complex Permanent Tissue: Composed of different types cells, these tissues perform basic functions. of cells that work together to perform a specific function. Parenchyma: These are living cells with thin cell walls Xylem: Responsible for the transport of water and and large central vacuoles. They are involved in storage, minerals from the roots to the rest of the plant. Xylem is photosynthesis, and wound repair. composed of tracheids, vessel elements, xylem fibers, and xylem parenchyma. Collenchyma: These cells have thicker cell walls and provide flexible support to the plant. They are often found in regions of the plant that are still growing. Phloem: Transports the products of photosynthesis, such as sugars, from the leaves to other parts of the plant. Sclerenchyma: These cells have thick, lignified walls and Phloem consists of sieve tube elements, companion cells, are usually dead at maturity. They provide rigid support phloem fibers, and phloem parenchyma. and strength to the plant. Sclerenchyma can be further divided into fibers and sclereids. Functions of Permanent Tissues Parenchyma: Functions include storage of nutrients and water, photosynthesis in chlorenchyma cells (a type of parenchyma containing chlorophyll), and healing and repair of plant tissues. Collenchyma: Provides flexible structural support to growing parts of the plant such as young stems and leaves. Sclerenchyma: Provides mechanical strength and rigidity to mature parts of the plant, such as the bark and seed coats. Xylem: Facilitates the upward movement of water and dissolved minerals from the roots to the aerial parts of the plant. It also provides structural support. Phloem: Distributes the products of photosynthesis from the leaves to other parts of the plant, supporting growth and development. Plant tissue systems are organized into three major types, each responsible for different aspects of the plant's structure and function. These tissue systems are: Dermal Tissue System: Function: The dermal tissue system forms the outer protective covering of the plant. It serves to protect the plant from mechanical injury, pathogens, and water loss. Components: Epidermis: A single layer of cells covering the younger parts of the plant, often coated with a waxy cuticle to reduce water loss. Periderm: Found in woody plants, it replaces the epidermis in older regions. The periderm includes the cork, cork cambium, and phelloderm. Specialized Structures: Stomata: Pores flanked by guard cells that control gas exchange. Trichomes: Hair-like structures that can reduce water loss and provide protection against herbivores. Ground Tissue System: Function: The ground tissue system makes up the bulk of the plant body and is involved in photosynthesis, storage, and support. Components: Parenchyma: The most common type of ground tissue, these cells are involved in photosynthesis, storage, and tissue repair. They have thin cell walls and large vacuoles. Collenchyma: These cells provide flexible support for growing parts of the plant. They have thicker cell walls compared to parenchyma. Sclerenchyma: These cells provide rigid support and strength to the plant. They have thick, lignified cell walls and can be found as fibers. Vascular Tissue System: Function: The vascular tissue system is responsible for the transport of water, nutrients, and food throughout the plant. Components: Xylem: Transports water and dissolved minerals from the roots to the rest of the plant. It consists of tracheids, vessel elements, fibers, and parenchyma cells. Phloem: Transports the products of photosynthesis (sugars) from the leaves to other parts of the plant. It consists of sieve tube elements, companion cells, fibers, and parenchyma cells. Each of these tissue systems is integral to the plant's growth, development, and survival, contributing to its overall function and adaptation to its environment. ROOTS Regions of the Root: Root cap – protects the tender apex (absent in aquatic plants). Region of cell division – 1 to few mm above the root cap; have small cells with thin walls, dense with protoplasm; undergo repeated cell division (meristematic region). Region of elongation – lies above meristematic region; extends to 1-5 mm; undergo rapid elongation and enlargement; responsible for growth in length of the root. Region of maturation – lies above the meristematic region of elongation, this region produces root hairs. Types of Roots: 1. Tap root system primary root grows vertical downward. branches grow downward or horizontally outwards Functions. Functions: absorb water, mineral, salts from soil, anchorage. 2. Adventitious root system Roots that grow from any part of the plant body other than radicle. 3. Fibrous root system In monocots (with all adventitious roots). 4. Foliar root system From leaves mainly petiole or vein (spontaneous or due to injury). Types of stems: a. bulb - short, erect underground stem. b. culm - flowering stem of grasses and sedges. c. Offset - like runner originates from leaf axil as a short and thickened branch away from the mother plant. d. rhizome - horizontal underground stem. e. runner or stolon - indeterminate aboveground stem with internodes and new plantlet at the tip. f. sucker - shoot arising below the ground from old stem. g. tendril - slender coiling branch for climbing. h. tiller - shoot produced from the base of the stem or culm. i. tuber - thick storage underground stem. j. corm - enlarged solid fleshy base Leaves are indeed fascinating structures essential for the survival of plants. Functions of Leaves: Food manufacture (Photosynthesis): Leaves contain chlorophyll, which captures sunlight to convert carbon dioxide and water into glucose, providing energy for the plant. Exchange of gases: Leaves facilitate the exchange of oxygen and carbon dioxide with the atmosphere, crucial for both photosynthesis and respiration. Evaporation of water (Transpiration): Through tiny pores called stomata on the leaf surface, water evaporates, helping to regulate the plant's temperature and transport nutrients. PARTS OF A LEAF PARTS OF A FLOWER Complete Flower - has all four parts of the flower (sepals, petals, pistil and stamen). Incomplete Flower - A flower lacking sepals, petals, pistil or stamen  SEEDS a ripened ovule which when shed from the parent plant consist of embryo and stored food supply both of which are enclosed in a seed coat or covering. Sexual propagation involves the union of the pollen (male) with the egg (female) to produce a seed. The seed is made up of three parts: the outer seed coat, which protects the seed; the endosperm, which is a food reserve; the embryo, which is the young plant itself. When a seed is mature and put in a favorable environment, it will germinate (begin active growth).  SEEDS Dicotyledon - embryo lies within an axis of two cotyledons. Monocotyledon - consist of seed coat, endosperm and embryo.  SEEDS PARTS OF A SEED  SEEDS PARTS OF A SEED  SEEDS TYPES OF A SEED Seeds can be classified based on their storage behavior into three main categories: orthodox, intermediate, and recalcitrant seeds. Each type has specific characteristics that affect how they are stored and their longevity. 1. Orthodox Seeds Orthodox seeds can be dried to low moisture contents (typically around 5-7%) and stored at low temperatures for extended periods without losing viability. These seeds enter a state of dormancy and can withstand adverse conditions, making them suitable for long-term storage in seed banks. Characteristics: Low moisture tolerance: Can be dried to low moisture levels. Long-term viability: Remain viable for many years when stored correctly. Storage conditions: Prefer cool and dry environments. Examples: Cereal grains: Wheat, rice, maize. Legumes: Beans, peas. Vegetables: Tomato, lettuce, cabbage.  SEEDS TYPES OF A SEED 2. Intermediate Seeds Intermediate seeds fall between orthodox and recalcitrant seeds in terms of their storage behavior. They can tolerate some drying but not to the extent of orthodox seeds, and they are somewhat sensitive to low temperatures. These seeds require careful handling to maintain their viability over time. Characteristics: Moderate moisture tolerance: Can be dried, but not to very low levels. Shorter viability: Do not store as long as orthodox seeds. Sensitive to low temperatures: Cannot withstand freezing conditions well. Examples: Coffee Citrus Papaya  SEEDS TYPES OF A SEED 3. Recalcitrant Seeds Recalcitrant seeds cannot withstand drying below relatively high moisture levels and are very sensitive to low temperatures. They must be kept moist and warm to remain viable, making them challenging to store for long periods. These seeds often germinate quickly and have short-lived viability. Characteristics: High moisture requirement: Cannot be dried below certain moisture levels. Sensitive to drying and cold: Lose viability quickly if dried or exposed to low temperatures. Short viability period: Must be planted soon after harvest. Examples: Tropical fruits: Mango, lychee, avocado. Some nuts: Chestnut, coconut. Certain trees: Oak, willow.  SEEDS TYPES OF A SEED Summary of Storage Recommendations: Orthodox Seeds: Store in cool, dry conditions; ideal for seed banks. Intermediate Seeds: Store at moderate moisture levels and avoid freezing; moderate storage lifespan. Recalcitrant Seeds: Keep moist and warm; plant soon after harvest. Understanding the type of seed is crucial for proper storage and ensuring their viability for future planting.  Fruits It is a mature, ripened ovary. Contain the seed (ripened ovules) and pericarp (the tissue that surrounds the seed) Simple Fruits Simple fruits develop from a single ovary of a single flower. They can be either fleshy or dry. Aggregate Fruits Aggregate fruits develop from a single flower with multiple ovaries (multiple carpels). Each ovary matures into a small fruitlet, and together they form a cluster on a single receptacle. Examples include: Raspberry Blackberry Strawberry (note: in strawberries, the actual fruits are the tiny seeds on the surface, each originating from a separate ovary). Multiple Fruits Multiple fruits develop from an inflorescence, a group of flowers. Each flower in the inflorescence produces a fruit, and these mature into a single mass. Examples include: Pineapple Fig Mulberry Summary Simple fruits: Develop from a single ovary of a single flower (e.g., tomatoes, peas). Aggregate fruits: Develop from a single flower with multiple ovaries (e.g., raspberries, blackberries). Multiple fruits: Develop from multiple flowers in an inflorescence (e.g., pineapples, figs). These classifications help in understanding the development and structure of different types of fruits.  FLESHY FRUITS fruits with a soft, thick pericarp (fruit wall) at maturity. They are typically classified based on the structure and development of their pericarp. The five main types of fleshy fruits are: Berry: A berry is a simple, fleshy fruit in which the entire pericarp is soft and edible. Examples include tomatoes, grapes, bananas, and blueberries. Drupe: Also known as a stone fruit, a drupe has a thin exocarp (skin), a fleshy mesocarp, and a hard, stony endocarp (pit) that encloses a single seed. Examples include peaches, cherries, olives, and plums.  FLESHY FRUITS Pome: Pomes are fruits produced by flowering plants in the subtribe Malinae of the family Rosaceae. They have a core containing several small seeds, surrounded by a fleshy edible layer. Examples include apples and pears. Hesperidium: This is a type of berry with a leathery rind and partitions between the sections of fleshy fruit. Examples include citrus fruits such as oranges, lemons, limes, and grapefruits. Pepo: A pepo is a type of berry with a hard, thick rind, typically found in the gourd family (Cucurbitaceae). Examples include cucumbers, pumpkins, watermelons, and squashes.  DRY FRUITS Dehiscent Fruits Fruits that split open at the time of maturity are referred to as dehiscent fruits. They open naturally along their line of weakness to shed their seeds. There are three types of dehiscent fruits: Follicle: A dry dehiscent fruit formed from 1 carpel that opens only at one side. E.g, peony and milkweed Legume: A dry dehiscent fruit formed from 1 carpel that opens on both the sides. E.g, beans and peas Capsule: It is a dry dehiscent fruit that is formed from several carpels. E.g, orchid  DRY FRUITS Indehiscent Fruits Fruits that do not split open to release their seeds are referred to as indehiscent fruits. They do not have a natural line of weakness to split apart. They are of five major types: Achene: It is a dry indehiscent fruit that contains a single seed. The single seed is attached only at one point to the fruit wall. E.g, sunflower Nut: A dry indehiscent fruit that has a thick and hard fruit wall. E.g, hazel, walnut  DRY FRUITS Samara: A dry indehiscent fruit in which part of the fruit wall grows out into a wing. It can be single or double seeded. E.g, maple Grain: A one seeded dry indehiscent fruit in which the fruit wall and the seed coat are fused. E.g, corn, wheat Schizocarp: It is a fruit that is formed from several carpels, and at maturity each carpel separates to form a distinct indehiscent fruit. E.g, dill  Pericarp Definition: The pericarp is the entire fruit wall that develops from the ovary wall after fertilization. It surrounds the seed(s) and is composed of three layers: the exocarp, mesocarp, and endocarp. Function: Protects the seed(s) and aids in their dispersal. Exocarp Definition: The exocarp is the outermost layer of the pericarp. Characteristics: It forms the skin or peel of the fruit. In some fruits, the exocarp is thin and delicate (e.g., grapes, tomatoes), while in others, it is thick and tough (e.g., watermelon, oranges). Function: Provides protection and may contribute to the fruit's color and texture.  Mesocarp Definition: The mesocarp is the middle layer of the pericarp. Characteristics: This layer is typically fleshy and juicy, but it can also be fibrous or dry depending on the type of fruit. The mesocarp is often the edible part of the fruit. Function: Stores nutrients and water, contributing to the fruit's flavor, texture, and overall appeal. Endocarp Definition: The endocarp is the innermost layer of the pericarp. Characteristics: The endocarp can be hard and stony (as in drupes like peaches and cherries), or it can be papery or membranous (as in pomes like apples and pears). Function: Encloses and protects the seed(s). In some fruits, the endocarp helps facilitate seed dispersal. Summary Pericarp: The entire fruit wall, consisting of the exocarp, mesocarp, and endocarp. Exocarp: The outer skin or peel of the fruit. Mesocarp: The middle, often fleshy and edible layer. Endocarp: The inner layer that directly surrounds the seed(s). THANK YOU AND GOD BLESS