The reproductive structures and processes in flowering plants involve complex mechanisms that ensure successful pollination and fertilization.
Dicot flowers represent a major group of flowering plants characterized by specific structural features. These flowers typically have parts arranged in groups of four or five, including sepals, petals, stamens, and carpels. Common dicot flower examples include roses, sunflowers, and hibiscus. The dicot flower diagram shows distinct whorls of floral parts, with the outermost whorl consisting of sepals that protect the developing flower bud, followed by colorful petals that attract pollinators. The reproductive structures include the male stamens producing pollen and female carpels containing ovules.
The pollen development process in flowering plants is a crucial aspect of plant reproduction. It begins in the anther's microsporangium, where microspore mother cells undergo meiosis to form haploid microspores. These microspores develop into mature pollen grains through mitosis and cellular differentiation. The mature pollen grain contains two cells: a tube cell and a generative cell, which later divides to form two sperm cells. Plants have evolved two main pollination strategies: wind pollination and insect pollination. Wind-pollinated flowers typically have exposed stamens, light and smooth pollen grains, and reduced or absent petals, while characteristics of insect-pollinated flowers include bright colors, nectar rewards, and sticky pollen. The differences between wind and insect pollinated flowers extend to their structural adaptations - wind-pollinated species often have long, dangling stamens and feathery stigmas to catch airborne pollen, whereas insect-pollinated flowers have various mechanisms to ensure pollen sticks to visiting insects. Some notable examples of wind pollinated and insect-pollinated flowers include grasses and corn (wind-pollinated) and orchids and snapdragons (insect-pollinated).
