Seed Structure and Germination PDF
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This document provides a detailed description of seed structure, germination process, and factors that affect germination. It includes information about external factors such as water, oxygen, and temperature, as well as internal factors such as seed viability and dormancy. The text also covers different types of seed germination, such as epigeal and hypogeal.
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**:The Seed.1**.A ripened, fertilized ovule *.Functions: Perennation (survival), dispersal, and reproduction *.In angiosperms (flowering plants), seeds are enclosed within fruits *.In gymnosperms (conifers), seeds are exposed *...
**:The Seed.1**.A ripened, fertilized ovule *.Functions: Perennation (survival), dispersal, and reproduction *.In angiosperms (flowering plants), seeds are enclosed within fruits *.In gymnosperms (conifers), seeds are exposed * **:Seed Structure.2** Seed Coat (Testa):** Protective outer covering. Protects the seed from fungi, bacteria,** * and insects. Attached to the fruit via the hilum (a scar). Contains a micropyle (tiny pore) for.water uptake Embryo:** A young plant enclosed within the seed coat. Consists of an embryo axis and** *.cotyledons Embryo Axis:** Includes the plumule (develops into the shoot system), epicotyl** * (part of the axis between the plumule and cotyledonary node), cotyledonary node, hypocotyl (part of the axis between the cotyledonary node and radicle), and radicle (develops into the.)root system Cotyledons:** One or two, store food, protect the embryo, and function as** *.photosynthetic organs after germination in some cases **:Seed Germination.3**.The process by which an embryo grows from a seed, resulting in a seedling * :Three processes *.)Water absorption (swelling and splitting of the seed coat.1.Increased enzymatic activity and respiration.2.)Cell enlargement and division (growth of the radicle and plumule.3 **:Factors Affecting Germination.4** **:External** * Water:** Essential for seed activation and softening the seed coat to allow for nutrient** *.uptake.Oxygen:** Required for respiration** * Temperature:** Optimal range exists; too high or too low can damage seeds or cause** *.dormancy Light:** Some seeds require light; others need darkness; many are not sensitive to** *.light **:Internal** *.Seed Viability:** The seed's capacity to germinate** * Dormancy:** A period where a viable seed does not germinate even with adequate** *.conditions. Reasons include immature embryos or hard seed coats **:Types of Germination.5**.Epigeal:** Cotyledons emerge above the soil surface and become photosynthetic** *.Hypogeal:** Cotyledons remain below the soil surface and do not photosynthesize** *
