PLANTS n n n Parts Clasification Reproduction Parts

PLANTS n n n Parts Clasification Reproduction

Parts of a Vascular Plant n vertical axis n n Underground: root to absorb water and ions and anchor above ground: shoot: n n n stem serves as a framework for positioning the leaves Leaves: photosynthesis takes place growth zones: unspecialized cells called meristems

Tissue Types 1. Dermal: n n 2. outer protective covering covered by a waxy layer called the cuticle, effective barrier against water loss Vascular: 2 types n Xylem n n water and minerals pass from the roots to the shoots, when water reaches the leaves, most exits through the stomata Phloem n principal food-conducting tissue

1. Roots n Main Roots have: n n n central column of xylem alternating are strands of phloem surrounding the central column, a cylinder of cells called pericycle: branch or lateral roots form from

A root cross section

2. Stems n Growth: n n n Primary: leaves appear while the apical meristem elongates Secondary: differentiation of the vascular tissue types: n n dicots, vascular bundles (xylem and phloem) are around the outside of the stem monocots, vascular bundles are scattered throughout

n n places of the stem where leaves form are called nodes portions of the stem between these leaf attachment points are called internodes

n source of economically important product: wood n n n is accumulated xylem displays rings based on the growth rate differences: cambium divides more actively in the spring and summer bark (periderm): all of the tissues of a mature stem outside of the vascular cambium including the cork

3. Leaves n n Growth: marginal meristems which grow outward and ultimately form the blade (the flattened portion) of the leaf veins, comprised of xylem and phloem, run through the leaf n n dicots, the veins have a net or reticulate venation monocots, the veins are parallel

Water Movement n factors: 1. initial movement of water into the roots: osmosis 1. 2. 3. 4. 5. fluid in the xylem contains more solutes than the surroundings capillary action adds “pull” to the movement of water up A final “pull” is transpiration, water evaporating from the top (leaf) of the tube pulls the column of water up the column of water does not collapse because water molecules are attracted to each other the narrower the diameter of the tube, the more tensile strength, or resistance to separation, of the water column

Plant Classification n n complex multicellular organisms Autotrophs, feed themselves by photosynthesis almost exclusively on land dominant organisms on the surface of the earth

Plant Evolution n n ancestor probably: green algae Four key evolutionary advances: 1. 2. 3. 4. alternation of generations, vascular tissue, transports water and nutrients and provides support Seeds, provide nutrients and protection for the plant embryo until it encounters favorable growing conditions flowers and fruits, facilitated fertilization and dispersal of their seeds

1. Nonvascular Plants n n n size limited materials transported by osmosis and diffusion mosses

2. Seedless Vascular Plants n ferns n sporophyte generation is much larger and complex

Vascular Tissue n specialized cylindrical or elongated cells that form a network throughout a plant

3. Vascular, Seed Plants n n Seed: crucial adaptation to land to protect the embryonic plant produce two kinds of gametophytes: n develop within the sporophyte n n n gymnosperms n n male: pollen grains female: egg within an ovules are not completely enclosed angiosperms n ovules are completely enclosed

Gymnosperms n Conifers, n n n Cycads, n n seeds in cones most needle-like leaves palmlike leaves Ginkgo, n fan-shaped leaves

Angiosperms: flowers n n 90% all living plants Embryos store food reserves in seed leaves or cotyledons n n monocots have one cotyledon dicots have two cotyledons

Angiosperm Reproduction 1. 2. sexual Asexual

n Asexual, vegetative reproduction n n new individuals are cloned from parts of the parent Samples: n n Runners, stems growing along the soil Rhizomes, underground horizontal stems

n Sexual reproduction: alternation of generations n n male gametophytes: pollen grains female gametophyte: embryo sac

Flowers n n Base: receptacle four concentric circles: 1. Sepals, protect 2. Petals, attract pollinators 3. male parts: stamens, anther with the pollen grains 4. female parts: ovules in the bulging base called ovary, a stalk style, sticky tip stigma to receive the pollen

n different kinds of flowers: because insects and plants coevolved insects specialize in visiting particular kinds of flowers n Birds also pollinate some flowers, especially red ones n

Formation of pollen and egg n n Eggs develop in the ovules each ovule contains a megaspore mother cell that undergoes meiosis to produce four haploid megaspores, only one survives to undergo repeated mitotic divisions that produce eight haploid nuclei

Pollination n process by which pollen is transferred from the anther to the stigma n n gymnosperms, pollen is dispersed by wind; species must grow close, flowers are small, green, and odorless angiosperms use animals to carry pollen from flower to flower and are rewarded with food; e. g. , nectar

n n Pollen grains adhere to the surface of the stigma and begin to grow a pollen tube until it reaches the ovule in the ovary, entry to the embryo sac it releases two sperm cells: double fertilization one sperm fertilizes the egg n the other sperm goes on to form endosperm n

Seed three parts n 1. 2. 3. embryo endosperm, a source for food for the developing embryo (cotyledons) a drought-resistant protective cover

n Seeds improved the adaptation of plants to living in land: 1. 2. 3. Dispersal into new habitats Dormancy and Germination, plants postpone development until conditions are favorable Nourishment; provisions the seed during the critical period just after germination

Fruits n n Is a mature ripened ovary containing fertilized seeds angiosperms use fruits to have animals aid in the dispersal of seeds; although eaten the seeds are resistant to chewing and digestion passing out with the feces and ready to germinate

Types of fruits and common modes of dispersion

Practice questions 1. Growth in vascular plants is regulated and coordinated by: A) photosynthetic tissue B) root tissue C) meristematic tissue 2. In vascular plants, phloem tissue transports _______ 3. In stems, the tissue responsible for secondary growth is the: A) Collenchyma B) Pith C) Cambium D) cortex

4. One difference between monocot/dicot plant stems is the: A) absence of buds in monocots B) organization of vascular tissue C) presence of guard cells 5. Which of the following is not a process that directly assists in water movement from the roots to the leaves? A) photosynthesis B) root osmotic pressure C) capillary action D) transpiration 6. Sexual reproduction in angiosperms requires male _______

7. The flower shape, scent, color, nectar in the flowers of some angiosperms are related to the plant's __ 9. Fruit forms from a flower's: A) Ovary B) sepals C) carpels D) stigma 10. Which of the following structures does not give the plants an evolutionary advantage? A)chloroplasts B)vascular tissue C)seeds D)flowers 11. Mosses do not reach a large size because ------12. One characteristic that separates ferns from more complex vascular plants is that ferns do not have -----

13. What separates the gymnosperms from the rest of the vascular plants is: A) a vascular system B) ovules completely covered C) ovules not completely covered D) fruits and flowers 14. What separates the angiosperms from the rest of the vascular plants is: A) a vascular system B) ovules completely covered C) ovules not completely covered by the sporophyte D) fruits and flowers 15. Flower shape and color can be linked to the process of ------16. If the seeds of a plant are encased in a fleshy fruit, then the most likely form of dispersal is: A) to attach to an animal's fur or skin B) Wind C) an animal's digestive system and processes D) water