Module 1 Plant Structure and Function PDF

Southern Luzon State University College of Teacher Education Laboratory School Lucban, Quezon MODULE 1: PLANT STRUCTURE AND FUNCTION INTRODUCTION: Plants are essential to l...

Southern Luzon State University College of Teacher Education Laboratory School Lucban, Quezon MODULE 1: PLANT STRUCTURE AND FUNCTION INTRODUCTION: Plants are essential to life on Earth, providing food, oxygen, and many other benefits. Let's explore their fascinating structures and functions. The plant is divided into two systems: the root system and the shoot system. Plant Structures: The Root System Roots perform essential functions: Anchorage: Roots keep the plant grounded. Absorption: They take in water and nutrients from the soil. Storage: Roots can store nutrients and energy for the plant. Transport: They move water and nutrients to different parts of the plant. Root systems also adapt to their environment. For instance, plants in dry areas might develop deeper root systems to reach water stored deep in the ground, while plants in nutrient-rich areas might have shallower roots. TYPES OF ROOTS 1. Taproot System: This system features a primary root that grows directly downward. It's common in dicots (plants with two seed leaves). Taproots can go quite deep to access water and nutrients, like carrots and dandelions. 2. Fibrous Root System: This system consists of many small roots spreading out from the base of the plant. Monocots (plants with one seed leaf) typically have fibrous roots. These roots are usually shallow but spread widely, improving soil stability and helping plants like grasses and wheat. Plant Structures: The Shoot System A plant's shoot system is just as crucial as its root system. The shoot system positions leave to capture sunlight effectively. It produces flowers and fruits, enabling reproduction and the generation of offspring. The vascular system within the stems (comprising xylem and phloem) is essential for transporting water, nutrients, and photosynthetic products. Some stems and leaves store nutrients and water. Examples include tubers (like potatoes) and succulent leaves. In summary, the shoot system is integral to a plant's ability to grow, reproduce, and interact with its environment. In addition, it includes everything above ground: stems, leaves, flowers, and fruits. Each part plays a vital role in the plant's growth, reproduction, and survival. Here's a breakdown of the main components: Components of the Shoot System 1. Stems: Structure & Support: Stems provide support for leaves and flowers and keep the plant upright. Transport: They contain vascular tissues (xylem and phloem) that transport water, nutrients, and sugars throughout the plant. Growth: Stems contain nodes (points where leaves are attached) and internodes (the space between nodes). New growth can occur at these points. 2. Leaves: Photosynthesis: Leaves are the primary site for photosynthesis, the process by which plants convert sunlight into energy. Gas Exchange: They have structures called stomata, which open and close to allow for gas exchange (CO₂ in, O₂ out) and transpiration (release of water vapor). 3. Flowers (if the plant is a flowering plant, or angiosperm): Reproduction: Flowers are the reproductive structures of angiosperms. They contain male (stamens) and female (pistils) reproductive organs. Pollination: The shape, color, and scent of flowers attract pollinators, which help in transferring pollen from one flower to another. Flowers can be classified as complete flower or perfect flower. A complete flower has four main parts: Sepals: These are the outermost part of the flower, usually green, and protect the bud before it opens, Petals: These are often colorful and attract pollinators, Stamens: The male parts of the flower, consisting of anthers and filaments, which produce pollen, and Pistils (or Carpels): The female parts of the flower, consisting of the stigma, style, and ovary, which produce ovules.  A flower that has all four of these parts is called a “complete flower.” Examples of complete flowers include lilies, roses, and tulips. A perfect flower, also known as a bisexual or hermaphroditic flower, contains both male and female reproductive organs. Specifically, a perfect flower has stamens (male parts) and pistils (female parts) but doesn't necessarily have sepals or petals. The key feature is the presence of both reproductive structures. Examples of perfect flowers include roses, lilies, and tomatoes. Notice that some flowers can be both perfect and complete, meaning they have all four main parts and both reproductive organs. 4. Fruits (in fruiting plants): Seed Protection & Dispersal: Fruits develop from fertilized flowers and protect the seeds. They also aid in seed dispersal, often by attracting animals who eat the fruit and later excrete the seeds. PLANT REPRODUCTION INTRODUCTION Reproduction is one of the important aspects and functions of an organism for the existence of its species. Organisms, plants, and animals reproduce by means of gametes or without the gametes. In this chapter, we will learn how organisms reproduce for the continuance of their species. Plants reproduce in two ways, asexual and sexual reproduction. Asexual reproduction does not need the fertilization or union of two gametes. Gametes are sperm and egg. The offspring from only one parent are identical with each other. These are known as clones. Sexual reproduction, on the other hand, requires gametes for fertilization to occur. Some examples of asexual reproduction in plants are the following: 1. VEGETATIVE PROPAGATION a. Budding – method wherein a bud outgrows from the parent organism and detaches itself later to become a new and same organism as the parent. (Watch this to better understand budding: https://youtu.be/d5-hPkcQDrU) b. Marcotting – method wherein roots are developed in stem of a parent plant for several days after putting soil in it. (Watch this to better understand marcotting: https://youtu.be/Q19EDIqGDdA) c. Grafting – it is made possible when a scion (shoot of one plant) is inserted into the stem of another plant (same species or closely related). (Watch this to better understand grafting: https://youtu.be/BzAKedZgqfM) d. Kalanchoe stem and leaf cutting – a method wherein the cut stem and leaf are placed in loose, moist soil, the cutting readily grow adventitious roots and develop new shoots. (Watch this to better understand leaf cutting: https://youtu.be/NIGHnESAk10) e. Plantlets (e.g. kalanchoe) – tiny new plants which develop in the notches along the leaf margins. When these tiny new plants drop from a leaf and fall to the ground, they begin to grow but removing and potting is the fastest way to propagate new maternity kalanchoe plant. 2. TISSUE CULTURE It is a tool or technique for growing species of living tissues in artificial media. It was first demonstrated by the botanist F.C. Steward in 1958. It is commonly used now in propagating orchids. (Watch this to better understand tissue culture: https://youtu.be/Y9Ot_2YK8-A)