Mr. Ramos Plant Organs and Tissues

Introduction to Plants There are over 260,000 different species of flowering plants alone! Plants are multicellular, eukaryotic organisms. Photosynthetic Plants have a cell wall made of cellulose. Plants take up water via capillary action.

Plant Classification Seeds, VascularSeedless, VascularNonvascular AngiospermsFernsMosses GymnospermsHorsetailsLiverworts Whisk fernsHornworts Club mosses Plants are classified as bryophytes and tracheophytes Bryophytes are nonvascular. Tracheophytes are vascular Bryophytes are nonvascular. Tracheophytes are vascular

Bryophytes and Tracheophytes Bryophytes are plants that lack specialized tissues for the transport of water. They absorb substances directly from their surroundings. Mosses, liverworts, & hornworts Tracheophytes are vascular plants. They can be seeded or seedless. Seeded: Flowering & non-flowering plants Seedless: ferns Vascular tissue transports water and nutrients. Phloem transports food from the leaves down to other plant parts Xylem moves water and nutrients from the ground upward in the plant.

Xylem and Phloem

Roots Function of plant roots include Anchoring and supporting the plant Absorbing water & nutrients from the soil Store food and water Root Classification Fibrous roots (monocots) Taproot (dicots)

Stems Stems transport materials between a plant’s root and its leaves and flowers. Trees have hard, rigid stems called a trunk. These plants are called woody plants. Plants with green, flexible stems are called herbaceous plants. These include grasses and garden plants.

Leaves Leaves are the main organs that carry out photosynthesis. Photosynthesis is a process by which plants use sunlight to make food from carbon dioxide and water. Leaves have small openings called stomata where CO 2 and O 2 are exchanged. Guard cells open and close the stomata.

Gymnosperms Gymnosperms are the woody plants. They are vascular plants that contain seeds. One way to determine the age of a gymnosperm is by counting the number of tree rings. The rings are dead xylem.

Angiosperms Angiosperms are the flowering plants. They are vascular and contain seeds. Angiosperms can be further divided into monocots and dicots. Some flowering plants are woody: oak, cherry & walnut. The fruits develop inside the flowers

Seeds A seed is a reproductive structure that contains a plant embryo. In flowering plants, the seed stores food in parts called cotyledon, or seed leaves. Angiosperms may have one or two cotyledons. Monocots contain one seed leaf, or cotyledon. Dicots contain two seed leaves or cotyledons.

Flower Anatomy The male reproductive part is called the stamen. The female reproductive part is called the pistil or carpel. For sexual reproduction, pollen from the stamen must be transferred to the stigma. The wind or animals can carry pollen to the stigma. This is called pollination.

Cones Cones are structures that are adapted for sexual reproduction in conifers. Male cones produce pollen & female cones produce eggs. After fertilization, a seed develops. Unlike the seeds of flowering plants, conifer seeds are not enclosed in protective fruit.

Spores Nonvascular plants, such as mosses, reproduce by making & releasing spores. A spore is a tiny, waterproof reproductive cell that can grow into a new organism if it falls on soil with the right conditions. Seedless vascular plants, such as ferns, also reproduce with spores.

Life Cycle & Reproduction Plants have an alternation of generation. They spend half of their lives as haploids and part of their lives as diploid. A gametophyte is a haploid plant that produces haploid gametes. A sporophyte is a diploid plant that gives rise to haploid spores by meiosis. Spores grow to be gametophytes.

Plant Life Cycle Sporophyte Spores Gametophyte Egg Sperm Fertilization Zygote N N N N N N 2N N N Mitosis Meiosis