Plant Developmental Biology PDF

PLANT DEVELOPMENTAL BIOLOGY GERALDINE G. VILLANUEVA Faculty Member Department of Environmental Science College of Science Tarlac State University  CHAPTER AT A GLANCE Parts of the Flower Floral Terminologies Life Cycle of Angiosperm...

PLANT DEVELOPMENTAL BIOLOGY GERALDINE G. VILLANUEVA Faculty Member Department of Environmental Science College of Science Tarlac State University  CHAPTER AT A GLANCE Parts of the Flower Floral Terminologies Life Cycle of Angiosperm Embryo Development Fruits Seed Structure and Development ABSORPTION – ROOT  Root underground portion of the plant body Serves as: o anchor of the plant body to the ground o absorb water and inorganic nutrients o conduct water and mineral nutrients.  Classification of the roots according to their origin: Primary root o develop from the hypocotyls (or its lower tip, the radicle) of the embryo. Branch roots (Secondary roots) o develop as branches from the primary root and other roots. Adventitious roots o develop directly from the stems and leaves. Classification of the roots according to their origin: Classification of the roots according to their origin:  Two Basic Root Systems Tap root system o derives directly from the first root that emerge from a seed (the radicle or primary root) that enlarges and forms a prominent central root that is called the taproot. o The taproot is larger in diameter than the lateral roots. o Taproots generally grow more deeply into the soil.  Two Basic Root Systems Fibrous root system o both primary and lateral roots are finely divided and have approximately equal diameters, without evident thickening or an enlarged central root. Two Basic Root Systems Structure of the Root Tip Root cap o tissue at the very tip of the root axis. Meristematic region o region of actively dividing cells, cells divide and increase in number. Structure of the Root Tip Root cap o tissue at the very tip of the root axis. Meristematic region o region of actively dividing cells, cells divide and increase in number. Structure of the Root Tip Region of elongation o root hair zone, cells enlarge and begin to differentiate. Region of maturation o region where primary tissues are completely differentiated. Structure of the Root Tip Region of elongation o root hair zone, cells enlarge and begin to differentiate. Region of maturation o region where primary tissues are completely differentiated.  Anatomy of the Root Epidermis o outer layer of cells, it protects the inner tissues. Cortex o cells between the epidermis and central part of the root. Central cylinder or stele o the cells through the center.  Anatomy of the Root Vascular tissues o conducting tissues composed of the xylem and phloem. Pericycle o a tissue bound externally by the endodermis and internally by the phloem. Anatomy of the Root Anatomy of the Root  Specialized Roots Fleshy or enlarged roots o are specialized to store food and other materials. Cassava Radish Radish Manihot esculenta Raphanus sativus Daucus carota  Specialized Roots Prop roots o add support to the structure of the plant. Pandan Corn Pandanus amaryllifolius Zea mays  Specialized Roots Photosynthetic roots o specialized to manufacture food for they have chlorophyll. Orchids Orchidaceae  Specialized Roots Clinging roots o roots that cling to walls and tree trunks for support. Cadena de Amor Antigonon leptopus  Specialized Roots Pneumatophores o may assist in getting oxygen to the submerged roots. Mangrove Rhizophora stylosa  Specialized Roots Contractile roots o grow into the soil and contract thereby pulling the corm or bulb into the soil. Taro Onion Colocasia esculenta Allium cepa TRANSLOCATION – STEM  Stem an aerial vegetative organ of the plant developed from the epicotyl of a germinating embryo. Functions: o support and translocation of water, minerals and food substances within the plant. Morphology of the Stem Node o portion of the stem where the leaves are attached. Internode o distance or portion between the nodes. Morphology of the Stem Leaf o a lateral outgrowth of the stem. Leaf scar o a mark left when the leaf falls off, usually found below the axillary bud. Morphology of the Stem Leaf axil o the angle formed between the leaf and the stem. Axillary bud or lateral bud o a bud formed between the leaf and the stem. Morphology of the Stem Apical bud or terminal bud o a bud found at the apex or tip of the twig which may develop into a flower or form as extension / elongation of the stem. Morphology of the Stem Bud scale scar o a mark left when the bud scale falls off. Bundle scar o found within the leaf scar that represents the broken ends of veins at leaf fall. Anatomy of the Stem Anatomy of the Stem  Specialized Stems Stolon or runners o are horizontally oriented stems that grow along the soil surface. o Their function is vegetative production. Strawberry Fragaria ananassa  Specialized Stems Tendrils and twining shoots o coil around objects and help support the plant. Chayote / Sayote Sechium edule  Specialized Stems Cladodes or cladophylls o are flat, leaflike stems modified for photosynthesis. Asparagus Asparagus officinalis  Specialized Stems Thorns o are modified stems that protect plants from grazing animals. Bougainvillea Bougainvillea sp.  Specialized Stems Bulbs o are rosette stems surrounded by fleshy leaves that store nutrients. When the nutrients are removed, the leaves collapse. Tulip Tulipa gesneriana  Specialized Stems Rhizomes o are underground stems that grow near the soil surface. o have short internodes and scale leaves o produce roots along their lower surface. o store food for renewing growth of the shoot after periods of stress. Ginger Zingeber officinale  Specialized Stems Corms o are stubby, vertically oriented stems that grow underground, have only a few thin leaves, and store nutrients. Taro Colocasia esculenta  Specialized Stems Tubers o are swollen regions of stems that store food for subsequent growth. Potato Solanum tuberosum TRANSPIRATION – LEAF  Leaf a lateral outgrowth of the stem axis structure of leaves is adapted to carry out two primary functions: o photosynthesis and transpiration. Morphology of the Leaf Apex o the protruding part of the leaf where water droplets accumulate. Morphology of the Leaf Morphology of the Leaf Midrib o a large strengthened vein along the midline of a leaf. Morphology of the Leaf Vein o function of the network of veins in a leaf is to transport water, minerals and food. o it provides support to the leaf. Morphology of the Leaf Morphology of the Leaf Margin o outer edge of a leaf blade is referred to as the leaf margin. Morphology of the Leaf Morphology of the Leaf Base o the slightly expanded area where the leaf attaches to the stem. Morphology of the Leaf Morphology of the Leaf Petiole o the stalk that joins a leaf to a stem. Morphology of the Leaf Leaf blade o main light- collecting structure on a leaf that is large, broad, flat surface. o has many layers that help it store materials and byproducts of photosynthesis.  Types of Leaves Simple Leaves o the leaf is joint to a stem via petiole with no subdivisions. o The true leaf is attached directly to the tree-bud. o Some common plants exhibiting simple leaves are Maples, Oregano, pear plants, Sycamore and many more  Types of Leaves Compound Leaves o has several leaflets attached to the stem via the petiole depicting the complete division of the leaf blade or the lamina along with the midvein.  Types of Leaves Compound Leaves o Palmately Compound Leaf ▪ leaflets emerge from only one point such as a palm. Furthermore, this arrangement can be classified into – unifoliate, bifoliate, trifoliate, and quadrifoliate.  Types of Leaves Compound Leaves o Pinnately Compound leaves ▪ leaflets emerge from both sides of the midrib and are further classified into three pinnate arrangements – unipinnate, bipinnate and tripinnate.  Leaf Arrangement Opposite o leaves and buds are directly across from each other on a stem  Leaf Arrangement Alternate o leaves and buds spaced along a stem in an alternating fashion.  Leaf Arrangement Subopposite o leaves and buds are not spaced far enough apart to be called alternate, but neither are they perfectly opposite.  Leaf Arrangement Whorled o three or more leaves and buds are attached at a node. Leaf Anatomy  Modified Leaves Bracts o modified to have different colors and look like petals. o main function is to attract pollinators. Bougainvillea Bougainvillea sp.  Modified Leaves Spines o modified leaves used for protection against herbivores. o evolved as a water-saving strategy in some plants. Dragon fruit Selenicereus undatus  Modified Leaves Reproductive leaves o produce plantlets along the margins of their leaves. o new plants fall off and become separate from the main plant. Kataka-taka Bryophyllum daigremontianum  Modified Leaves Tendrils o modified leaves used for climbing or support. Cucumber Cucumis sativus  Modified Leaves Storage leaves o modified to store water and/or nutrients for the plant. Aloe vera Aloe vera  Modified Leaves Trap leaves o modified to trap insects. o evolved due to low nutrient availability in the soil where they grow, so plants with these leaves can gather nitrogen and other nutrients from the bodies of the insects they trap. Venus fly trap Dionaea muscipula  PLANT REPRODUCTION – FLOWER AND FRUIT  Flower the reproductive shoot of the plant which is responsible for sexual reproduction Composed of four parts: o petals o sepals o carpels o stamens  Flower Two division of floral parts: o Essential parts ▪ are those that are directly involved in sexual reproduction o Non-essential parts ▪ are not directly involved in sexual reproduction.  Parts of a Flower – Essential Parts Carpel/Pistil o the female reproductive structures. o All the carpels of the flowers are called gymnoecium. o Composed of: 1. Ovary ▪ the enlarged basal part of the carpel that contains one or more ovule. 2. Style ▪ a necklike structure that holds the stigma.  Parts of a Flower – Essential Parts Carpel/Pistil o Composed of: 3. Stigma ▪ located at the top of the carpel. ▪ usually, sticky due to the sugary liquid where the pollen grains adhere during pollination. Parts of a Flower  Parts of a Flower – Essential Parts Stamen o the male reproductive structure. o All the stamens of the flowers are called androecium. o Divided into: 5. Anther ▪ the terminal sacs where the pollens is produced. 6. Filaments ▪ the thin stalk that elevates the anther in the flower. Parts of a Flower Parts of a Flower – Non Essential Parts 8. Petal o are usually colored and the most attractive part of the flower and usually aid in attracting potential pollinators. o are collectively known as the corolla. 9. Sepal o are usually green and leaf like and protect the flower bud. o collection of sepals is called calyx. o The calyx and the corolla are collectively called perianth. Parts of a Flower – Non Essential Parts 11.Receptacle o a part of the floral stalk where the floral parts are attached. Peduncle o sometimes pedicel o the flower stalk to which the receptacle is attached. Parts of a Flower  Floral Terminologies Complete Flower o A flower is said to be complete when all floral parts (sepals, petals, carpels and stamens) are present. Incomplete Flower o Flower that lacks one or more flower parts. Floral Terminologies  Floral Terminologies Perfect Flower o Both stamens and carpels are present on the same flower. Imperfect Flower o Flower contains the stamen or carpel but not both. o Staminate flower ▪ flower containing stamen only. o Carpellate flower ▪ flower containing carpel only. Floral Terminologies  Floral Terminologies Inferior Ovary o Flower in which the ovary is situated below the attachment of other floral parts. Superior Ovary o The ovary is situated above the attachment of other floral parts. Floral Terminologies  Floral Terminologies Monoecious Plant o Plant with staminate and carpellate flowers. Corn is an example of monoecious plant. Dioecious Plant o A plant that produces just carpellate or staminate flower. Floral Terminologies  Embryo Development The embryo begins to develop from zygote within the ovule soon after fertilization. As the ovule matures into a seed, the embryo forms the major plant axis with shoot and root apical meristem, the embryo represents the sporophyte (2n) stage of the next generation.  Fruits a ripened or matured ovary. protects the seeds and help in the dispersal of seeds by wind or animals.  Classification of Fruits A. Simple fruit o are fruits derived from a single ovary. a. Simple fleshy fruit o succulent when ripe. 1. Berry o entire pericarp is fleshy, although skin is sometimes tough; may be one or many seeded. o Ex: tomato (Lycopersicon lycopersicum)  Classification of Fruits A. Simple fruit a. Simple fleshy fruit 2. Drupe o fleshy fruit in which the inner layer (endocarp or stone) of the fruit is hard and stony. o Ex: mango (Mangifera indica) and coconut (Cocos nucifera) 3. Hesperidium o berry with leathery rind. o Ex: suha (Citrus sinensis)  Classification of Fruits A. Simple fruit a. Simple fleshy fruit 4. Pepo o berry with thick hard rind. o Ex: cucumber (Cucumis sativus) 5. Pome o berry like, fleshy receptacle adnate to pericarp; endocarp cartilaginous. o Ex: apple (Malus sylvestris)  Classification of Fruits A. Simple fruit b. Simple dry dehiscent o Fruits that split open at maturity. 1. Capsule o splits open along three or more sutures or pores to release its seeds. o Ex: cotton (Gossypium sp.) 2. Pod or Legume o splits open along two sutures to release its seeds. o Ex: peanut (Arachis hypogea)  Classification of Fruits A. Simple fruit b. Simple dry dehiscent 3. Follicle o split open along one suture to release its seeds. o Ex: pandakaqui 4. Silique o from two or more carpels separated by a hard partition wall of septum, splits open along two sides; seeds attached to the dividing wall. o Ex: garlic vine  Classification of Fruits A. Simple fruit b. Simple dry indehiscent o Fruits that do not split open when mature. 1. Achene o the fruit wall is separate from the seed coat. o Ex: sunflower (Helianthus annuus) 2. Grain or caryopsis o the fruit wall is fused to the seed coat. o Ex: corn (Zea mays) and rice (Oryza sativa)  Classification of Fruits A. Simple fruit b. Simple dry indehiscent 3. Nut o with stony wall and does not split open at maturity. o Ex: cashew (Anacardium occidentale) 4. Samara o with pericarp extended into papery appendages or wings. o Ex: narra (Pterocarpus indicus)  Classification of Fruits B. Aggregate Fruits o Are those that are derived from a single flower with separate carpels. o Ex: strawberry C. Multiple Fruits o Are fruits derived from inflorescence or separate tightly clustered flowers. o Ex: pineapple Classification of Fruits Seed Structure and Development Following the fertilizations in the embryo sac, the zygote divides repeatedly by mitosis and differentiates into an embryo. The endosperm nucleus also divides by mitosis and forms the endosperm tissue, which provide food for the developing embryo.  Parts of the Seed Hilum o Scar formed on the seed coat after detached from funiculus.  Parts of the Seed Micropyle o Small opening located in the hilum  Parts of the Seed Seed Coat or Testa o Develops from the integuments and protects the embryo as the seed develops until germination.  Parts of the Seed Endosperm o Which develops from the fertilized central cell. The endosperm nourishes the developing embryo.  Parts of the Seed Embryo o Which develops from the zygote. o Cotyledon – one or two seed leaves.  Parts of the Seed Embryo o Hypocotyl – the axis below the cotyledon, at the tip which is the radicle that gives rise to the primary root of the seedling.  Parts of the Seed Embryo o Epicotyl – the axis above the attachment of the cotyledons, which ends in an apical meristem.  DIFFERENCE BETWEEN MONOCOTYLEDON AND DICOTYLEDON  Difference Between Monocotyledon and Dicotyledon Cotyledon refers to the ‘first seed leaf’, present in the embryo. If it is a single seed leaf, then it is categorized as monocots and if it is a pair of leaves then it is categorized as dicots.  Difference Between Monocotyledon and Dicotyledon Monocotyledon Dicotyledon The monocotyledonous The dicotyledonous embryos have a single embryos have a pair of cotyledon cotyledons They have a fibrous root They have a tap root system system Leaves in monocots Leaves in dicots have have parallel venation reticulate or net venation In monocot flowers, the The count of parts in a count of parts of the dicot flower is a multiple flower is a multiple of of four or five or equal to three or equal to three four or five  Difference Between Monocotyledon and Dicotyledon Monocotyledon Dicotyledon The roots and stems of The roots and stems of monocotyledons do not dicotyledons possess a possess a cambium and cambium and have the cannot increase in ability to increase in diameter diameter A few examples of A few examples of monocotyledons are dicots are beans, garlic, onions, wheat, cauliflower, apples and corn and grass, etc. pear, etc.  Difference Between Monocotyledon and Dicotyledon  Angiosperm The Life Cycle of an Angiosperm Diversity of Angiosperms https://courses.lumenlearning.com/wm- biology2/chapter/angiosperms/  Gymnosperm Life Cycle of a Conifer Diversity of Gymnosperms https://courses.lumenlearning.com/wm- biology2/chapter/gymnosperms/