Plant Reproduction

• Asexual reproduction lacks the fusion of gametes, resulting in the absence of male and female structures in the reproductive process
• Asexual reproduction through mitosis produces identical offspring from a cell, resulting in clones
• The number of chromosomes in cells varies with the species, e.g. maize plant has 20 chromosomes in all its cells except in the gametes where there are 10 chromosomes
• Vegetative reproduction involves the growth of a new plant part, often a bud or stem, separated from the parent plant
• Perennation is the process of plant survival from year to year
• Artificial methods of vegetative reproduction include cutting, layering, marcotting, budding, and grafting
• Cuttings, layering, and marcotting involve different techniques for propagation
• Budding and grafting involve attaching a scion to a healthy plant called the stock
• Sexual reproduction in flowering plants involves mechanisms like pollination and fertilization
• A complete flower consists of pedicel, receptacle, sepals, petals, stamens, and pistil
• Flowers can be classified as complete or incomplete, bisexual or unisexual, and radially or bilaterally symmetrical
• Cross-pollination has advantages like producing offspring with valuable qualities from both parents and increasing genetic variability
• Plants have special devices favoring cross-pollination, such as dioecious plants and plants with stigmas situated away from anthers
• The structure of an insect-pollinated flower includes calyx, corolla, androecium, and gynoecium
• Wind-pollinated flowers like grasses have specific structures for pollen dispersal
• Fertilization in plants leads to the development of the embryo, endosperm, and fruit
• Fruits and seeds are dispersed by external agents like wind, animals, water, or explosive mechanisms
• Germination of seeds requires sufficient water, suitable temperature, and adequate oxygen supply
• Enzymes play a crucial role in breaking down stored meals during germination
• There are two types of germination: epigeal where cotyledons are above ground and hypogeal where cotyledons remain below the soil