Plant Diversity F. Y. B. Sc. Prof. Ms. Vrushali S Plant Diversity F. Y. B. Sc. Prof. Ms. Vrushali S. Dighe Department Of Botany S. M. Joshi College, Hadapsar, Pune.

What is a Plant? Plants are the base for the food chain on land. Provide shade, shelter and oxygen Evolved more than 470 million years ago Multicellular, Eukaryotes Cell walls made of cellulose Photosynthesis using chlorophyll a and b Most are autotrophs; few parasites + saprobes Ex. Trees, shrubs, grasses, mosses and ferns

Life Cycle Haploid (N)-Gametophyte; gamete-producing Diploid (2N)-Sporophyte; spore-producing Produce a new individual by mitosis All plants have both phases, but in different forms Can reproduce independently of water Some also reproduce asexually (vegetative)

Generalized Plant Life Cycle Section 22-1 Haploid Diploid MEIOSIS Spores (N) Sperm (N) Eggs (N) FERTILIZATION Go to Section:

Plant Survival Sunlight Water and Minerals Movement of Water/Nutrients Taken up through the roots Movement of Water/Nutrients Make food in their leaves Water and nutrients carried upward through tissue from soil Gas Exchange

Early Plants Evolved from multicellular green algae First plants were dependent on water Similar to today’s mosses in structure and growth close to the ground Evolved different adaptations for terrestrial environments

Cladogram of Plant Groups Section 22-1 Cone-bearing plants Ferns and their relatives Seeds Water-Conducting (Vascular) Tissue Go to Section:

Overview of the Plant Kingdom Divided into four groups based on water- conducting tissues, seeds and flowers Reproductive structures and body plan are also considered Compare DNA sequences of various species Deep Green (1994)-Evidence that first plants evolved from green algae that lived in fresh water

The Diversity of Plants Section 22-1 Cone-bearing plants 760 species Flowering plants 235,000 species Ferns and their relatives 11,000 species Mosses and their relatives 15,600 species Go to Section:

Bryophytes Nonvascular plants 1) Mosses (in swamps) Can live in harsh environments Rhizoid-long, thin cells absorb water and minerals and anchor them to the ground 2) Liverworts and 3) hornworts Use osmosis to draw up water Water needed for reproduction Act as natural sponge and form peat moss

Bryophytes Mosses Liverworts Hornworts http://www.ghettodriveby.com/hornworts/

Seedless Vascular Plants Vascular tissue-Specialized to conduct water and nutrients thought he body of the plant Xylem-form of vascular tissue that carries water upward from the roots to every part of the plant Phloem-transports solutions of nutrients and carbohydrates from photosynthesis Tree rings in the lower trunk indicate the tree age Formed by cell division in thin layers inside bark Width of the bands indicate environmental conditions for each year (Ex. Drought conditions)

Ferns Evolved 350 million years ago Roots-Underground organs to absorb water and minerals with water-conducting tissue Leaves-Photosynthetic organ that contain bundles of vascular tissue Veins-Made of xylem and phloem Stems-Connect roots and leaves

Seed Plants Gymnosperms-Seeds on cone surfaces Conifers, Cycads, Ginkgoes and gnetophytes Angiosperms-Flowering plants with seeds in tissue layers Flowers or cones transfer sperm by pollination and protect embryos in seeds Life cycle alternates between gametophytes and sporophyte

The Structure of a Seed Seed coat Seed Embryo B Stored food supply A Section 22-4 Seed coat Embryo Stored food supply Seed B A Go to Section:

Reproduction without Water Cones-sporophyte structures which are seeding bearing for gymnosperms Flowers-Seed-bearing structure of angiosperms Pollen Grains-Contain male gametophytes Seeds-Embryo of seed plant with seed coat and food supply Eaten and dispersed by animals or stick to their fur Fossils from 30 million years ago

A Bee With Pollen On It’s Leg

Gymnosperms Cone Bearers / “naked seed” Gnetophytes: a) Ex. Welwitschia-Namibian desert with large, leathery leaves; spread across the ground Cycads- (Cycadophyta): a) Palm-link plants with large cones b) Appeared during Triassic Period (225 million years ago) c) Grow in tropical and subtropical places

Welwitschia mirabilis, a Gnetophyte Welwitschia mirabilis, a Gnetophyte. And Zamia pseudoparasitica, a Cycad.

Gymnosperms Ginkgoes-Only Ginkgo biloba currently exists One of the oldest seed plant species alive today Cultivated in China and planted around temples Often planted in urban settings in U.S. due to resistance to air pollution Conifers-(Coniferophyta) Ex. Pines, spruces, firs, cedars, sequoias, redwoods Long, thin leaves (Ex. Pine needles)-reduces surface area, waxy layer Most are “evergreens” with cycling of needles

Ginkgo and Pseudotsuga menziesii, a Conifer.

Angiosperms Phylum Anthophyta “enclosed seed” Cretaceous Period (135 million years ago) arrival Dominate Earth’s plant life Reproduce with flowers or fruits Ovary develops into fruits to protect seed and for dispersal Fruit-thick wall of tissue surrounding the seed

Seed Dispersal By Wind And General Flower Structure

Monocots and Dicots Cotyledons-Seed leaves in the plant embryo Monocots-One seed leaf, parallel veins, multiples of 3 floral parts, vascular bundles scattered and fibrous roots Dicots-Two seed leaves, branched veins, multiples of 4 or 5 floral parts, vascular bundles in a ring and a taproot

Comparison of Monocots and Dicots Section 22-5 Monocots Dicots Single cotyledon Parallel veins Floral parts often in multiples of 3 Vascular bundles scattered throughout stem Fibrous roots Two cotyledons Branched veins Floral parts often in multiples of 4 or 5 Vascular bundles arranged in a ring Taproot Seeds Leaves Flowers Stems Roots Go to Section:

Monocots and Dicots http://www. emc. maricopa

Diversity of Angiosperms Wood plants made of cells with thick cell walls (Trees, shrubs and vines) (Ex. Grapes and Ivy vines) (Ex. Blueberries and rose bushes) Herbaceous plants-No wood production as they grow (Ex. Dandelions, zinnias, sunflowers and petunias)

Rose Bush, Grape Vine, Zinnias and Petunias http://www. flowers

Diversity of Angiosperms Annuals-Complete a life-cycle within one growing season (Ex. Marigolds, petunias, pansies, zinnias, wheat and cucumbers) Biennials-Complete their life cycle in 2 years Year 1-germinate and grow roots & very short stems Year 2-Grow new stems and leaves and produce flowers and seeds (Ex. Primrose, parsley, celery) Perennials-Live for more than 2 years (Ex. Asparagus, grasses-herbaceous stems) (Ex. Maple trees-wood stem)

Primrose, Marigolds, Ornamental Grasses