Plants

Plant Characteristics Plants are multi-cellular eukaryotes that produce their food through photosynthesis. (Autotrophs) In addition, many plants have vascular tissue, leaves, roots, and stems.

Vascular Tissue Vascular tissue is an internal system of tube-like structures that carry water, minerals and food. Vascular tissue also helps to support the plant. Plants with vascular tissue are called vascular plants

Nonvascular Plants Nonvascular plants such as mosses do not have vascular tissue. Nonvascular plants can only pass materials from one cell to the next. Because they lack the support that vascular tissue provides, they cannot grow very wide or tall.

Vascular Plants: Seedless Seedless vascular plants have vascular tissue but reproduces by means of spores and must live in moist areas.

Vascular Plants: Seeded These plants have vascular tissue and produce seeds. Seed plants have roots, stems, and leaves. There are two types of seeded plants: –Gymnosperms –Angiosperms

Gymnosperms The seeds of gymnosperms are “naked”; that is, they do not develop within any protective covering. Gymnosperms include conifers, which produce seeds in cones. Most conifers are evergreens that keep their needles all year.

Angiosperms Angiosperms are flowering plants. They produce seeds in structures that develop into fruits. Grasses and apple trees are both examples of angiosperms.

Roots and Stems Vascular plants have roots and stems. Roots are organs that anchor the plants to the ground and absorb water and nutrients from the soil. Stems carry substances back and forth b/w the roots and leaves. Nonvascular plants do not have true roots or stems.

Leaves Leaves are organs that carry out photosynthesis. Leaf cells contain many chloroplasts near the leaf’s upper surface. Plants also need carbon dioxide for photosynthesis. Carbon dioxide enters the leaf through tiny pores called stomata which control the movement of gases into and out of a leaf.

Two stages –Spore Stage Spores are tiny cells that can grow into a new organism. –Reproduction Stage The spore develops into the stage in which undergoes fertilization. –Fertilization occurs when a sperm cell unites with an egg cell. –The fertilized egg is called a zygote –A young organism that develops from a zygote is an embryo.

Cones Most gymnosperms have two types of cones: –Male cones Produce tiny grains of pollen: tiny cells that will later become sperm cells. –Female cones Produce ovules: the structure that contains an egg cell.

Flower Parts Flower: The reproductive organ in some seed plants. Stamens: Male reproductive organs. Pistils: Female reproductive organ. Ovule: A structure that contains the egg cell. Anther: Contains the pollen.

Three Important Parts –Embryo Has the beginnings of roots, stems, and leaves. –Stored Food Helps the embryo survive until it can make its own food. Cotyledons: seed leaves that keep the stored food. –Seed Coat Outer covering of the embryo that keeps the food from drying out.

Fruit As the seed develops, the ovary changes into a fruit, which is the ripened ovary and other structure that encloses one or more seeds.

Tropisms and Hormones Plants respond to stimuli by growing either toward or away from a stimulus. A tropism is the plants growth toward or away from a stimuli. Plants are able to respond to stimuli due to hormones. –Hormones are chemicals produced that affects the organism’s body processes.

Life Spans of Flowering Plants AnnualsAnnuals: live and grow for one year. Ex: Marigolds, Petunias, and Pansies. Biennials:Biennials: flowering plants that live for two years. The 1 st year it grows a root system and leaves. The 2 nd year is the flowers and seed. Ex: Parsley and Celery Perennials:Perennials: live for more than two years. Ex: Honeysuckle