Part 4

Parts of a Flower ( A.K.A. Pistil )

Structure & Function of Flowers Flowers are the reproductive organs of many angiosperms and vary greatly in shape, color and size. A typical flower has both male & female gametes.

Structure & Function of Flowers Flowers typically are composed of four types of specialized leaves:  pistil (carpel)  stamen  petals  Sepals Listed from inner most to outer most layer

Structure & Function of Flowers The outermost layer, or whorl, of a flower is called the sepals, which in many plants are green and closely resemble regular leaves.

Structure & Function of Flowers Petals are the often brightly colored structures that are found just inside the sepals and are used to attract pollinators like insects and birds.

Structure & Function of Flowers The male part of the flower is called the stamen, which consists of the anther and the filament. The anther of a flower is where pollen is located. Pollen is basically plant sperm. Stamen

Structure & Function of Flowers The female part of a flower is called the carpel (or pistil), which consists of 3 parts: the stigma, the style and the ovary. The ovary contains the female eggs that pollen travel to after landing on the stigma.

After fertilization, the ovules develop into seeds, while the ovary enlarges into the fruit. If a flower has only one ovule, the fruit will contain one seed, as in a peach. The fruit of a flower with many ovules, such as a tomato, will have many seeds. Structure & Function of Flowers

Flower Pollination and Fertilization

Pollen Grains A pollen grain contains a sperm cell that fertilizes an egg. If fertilization is successful, a seed is produced. The pollen grains of each species are unique. The pollen grains shown here are about 1000 times their actual size.

Plant Responses & Adaptations There are many ways that plants have adapted to their various environments and have developed to assist in their growth and development. Plants have hormones, which are chemical substances that control a plant’s pattern of growth and development, as well as its’ response to environmental conditions.

Plant Responses & Adaptations Many plants lay dormant when cold weather approaches and turn off their photosynthetic pathways until warmer weather returns. Other plants have adapted to living in aquatic environments, extremely salty environments or very dry environments.

Plant Responses & Adaptations Some plants that have specialized structures for obtaining nutrients include carnivorous plants and parasitic plants. Many plants defend themselves against insect attack by making compounds that ward off potential predators. Poison ivy Venus fly trap

Plants As Food Many plants are used as food sources in many countries. Cereals such as rice, wheat, and corn are important sources of food. Cereals produce dry fruits calls grains, which contain a single seed that is paced with energy-rich endosperm.

Plants As Food Though wheat’s primary use is to make flour, it is also used in brewing & distilling, for livestock feed and even as a coffee substitute. Rice, corn & wheat are the 3 most important & widely used cereal crops.

Legumes Legumes, such as beans and peas, are important foods because they provide essential amino acids that grains lack.

Root crops Root crops, like potatoes & yams, are a major source of calories. They are used to inexpensively fill stomachs in poor countries (cassava).

Other uses of Plants While many plants are consumed primarily for food, other plants are utilized for other reasons.

Wood Wood, an important plant resource, is found in thousands of products, from lumber used to build houses, to wood that is ground into pulp to make fabrics (rayon) and paper.

Besides rayon, plants are also used to make other textiles like cotton, rubber and latex. Other uses of Plants

Plants as Medicine Plants are the sources of many important medicines that are used to treat diseases and other ailments. Some examples: Aspirin, cancer treatment drugs & cortisone.

Impact of Plants Though the first plants appeared on land only about half a billion years ago, today they account for, by far, the largest proportion of the Earth's biomass. Plants provide life on Earth with oxygen and shelter, as well as serving as the foundation of the food web. Plants frequently determine the appearance of other organisms that depend on them in a variety of different habitats.

Impact of Plants Plants have laid the foundation that provides power for industrial society. Plants have supplied sufficient oxygen to the atmosphere to support the evolution of higher animals.

Impact of Plants Plants have modified the terrain of the Earth, making its’ surface habitable to maintain many different life forms.

Impact of Plants From towering redwood trees to the microscopic duckweed plant, Kingdom Plantae is an extraordinarily diverse and long-lived group that makes the life of animals, fungi and other organisms possible.

PLANT TEST COMING SOON!! You will be tested over what you have learned about plants on: A  Friday 5/13 B  Wednesday 5/18