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Plant Science HL Red Book Sections: 9.1 to 9.3.

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Presentation on theme: "Plant Science HL Red Book Sections: 9.1 to 9.3."— Presentation transcript:

1 Plant Science HL Red Book Sections: 9.1 to 9.3

2 Dicotyledonous: Stem Tissue
Pith: a storage and support area. Cortex: helps with the support. Epidermis: mostly there for protection, may allow gas exchange. Xylem: carries water and dissolved minerals from the roots to the leaves. Phloem: transports organic nutrients throughout the plant. Cambium: its an area of rapidly dividing cells that differentiate into xylem and phloem.

3 Dicotyledonous: Leaf Tissue
The palisade mesophyll needs to be at the top of the leaf because the most amount of light is available there, and this area of the cell is rich in chloroplast = max photosynthesis. Veins are distributed through out the leaf carrying raw materials for photosynthesis, which is why they’re in the middle so they can be close to all cells. The spongy mesophyll is just above the stroma allowing continuous channels for gas exchange. The stroma are at the bottom of the leaf because of lower temperatures which minimizes water loss.


5 Plant Modifications Modifications occur in: Roots, Stems, and….. Leaves The examples you should recognize: Tubers like Potatoes Tendrils like Twirly Vines BULBS like Onions Storage Roots like Carrots

6 Plants Doing the Limbo Plants show indeterminate growth because of meristematic tissues. Dicot. plants have two types of this tissue : Apical and Lateral Apical meristematic tissue occurs at the tips of roots and stems resulting in primary growth. This allows the roots to extend through the soil. Lateral tissue allows growth in thickness of plants, also known as secondary growth. (mainly woody plants) These plants have two kinds of lateral tissue: Vascular cambium and Cork cambium. Remember LAT = FAT Phototropism is when a plant response to light. Its essential for a plant in crowded areas and seedlings. Auxins is a plant hormone responsible for this, and only work on plants cells with auxin receptors. They seem to increase the plant’s flexibility of the plant cell walls enabling cell elongation on the side of the shoot necessary to cause growth towards the light.

7 Transport in the Angiospermophytes

8 Mineral Movement How The Pump Works
Mineral ions move from the soil to the roots in three ways: diffusion of minerals and mass flow of water, aid provided by fungal hyphae, and active transport. The fungal hyphae create larger surface area, minerals dissolve into water and move into the root because of concentration differences, and active transport using pumps. How The Pump Works Potassium ions move into the root through specialized transport proteins call potassium channels. The proton pump is the most important active transport protein in the plasma membranes of plant cells. First the proton pump uses energy from ATP to pump hydrogen ions out of the cell. Then this results in a higher H+ ion concentration outside the cell than inside creating a negative charge inside the cell. This gradient results in the diffusion of hydrogen ions back into the cell. The voltage difference is called a membrane potential. The hydrogen ion gradient + the membrane potential represent forms of potential energy that can be used to absorb mineral ions.

9 Transpiration Transpiration: the loss of water vapor from leaves and other aerial parts of the plant. Transpirtation is affected be abiotic factors in the environment, these are the ones you need to know. Envi. Factor Effect on Transpiration Light Speeds us transpiration by warming the leaf, opening stomata. Temperature Increasing temperature increases transpiration b/c more water evaporates. Wind Increases the rate of transpiration because humid air is moved away from stomata. Humidity Decrease in humidity = increase in transpiration because of diff. in water concentration

10 Controlling Transpiration
LABEL ME!! Its important to note that guard cells regulate transpiration by opening and closing the stroma, but it is the presence of the hormone abscisic acid that causes the guard cells to close the stroma. Some plants, known as xerophytes have modifications that help reduce transpiration. Four of these modifications include: Small, thick leaves that reduce water loss by reducing surface area. They have a thickened, waxy cuticle. Some plants shed their leaves in dry months and become dormant. Some have a reduced number of stroma decreasing the number of opening water loss can occur at.

11 Riding along the Transpiration Stream
Water moves along the transpiration stream through the xylem vessels. The two major cell types used in the vessels include Vessel Elements and Tracheid. They are both made of dead cells that have thick lignified walls for support. They are also attached end to end to keep the flow of water continuous. In the picture label where transpiration pull, cohesion, adhesion, and evaporation are occurring.

12 Angiospermophytes Getting Busy
Pollination: transfer of pollen grains from anther to carpel (think of bees ). Fertilization: fusion of male and female gametes to form new organism. Seed Dispersal: moving seeds away from parent plant (reduces competition) fertilized ovules form seeds.

13 Baby Seed’s Parts and Needs
There are general conditions that all baby seeds need to germinate: Water is need to rehydrate the dried seed tissues. Oxygen is needed to allow aerobic respiration to produce ATP. An appropriate temperature for the seed in necessary (import. for enzyme action).

14 How the Baby Seed Grows First things first IT HAS TO ABSORB WATER!
Then metabolic changes occur. Gibberellin, or gibberellic acid, is released once the water is absorbed. This is a growth substance and it triggers the production of amylase. The amylase causes hydrolysis of starch into maltose. (The starch is already there as a food reserve in the endosperm). Maltose then further hydrolyses into glucose that can be used for cellular respiration or converted into cellulose by condensation reactions. The cellulose is necessary to produce the cell walls of new cells being produced.

15 Flower Control Photoperiodism is the plant’s response to light involving the relative lengths of day and night, which is an important factor in the control of flowering. To ensure continued existence in an area, a plant must flower when pollinators are available and when necessary resources are plentiful. Plant Type: Flowering and Light: Examples Long-day Plants Bloom when days are longest and nights are shortest. (midsummer) Lettuce, Spinach Short-day Plants Bloom in spring, late summer, + autumn when days are shorter. Asters, Poinsettias Day-neutral Plants Flower without regard to day length Roses, Dandelions

16 PLANTO TIME!!!!! Guard Cells Abscisic Acid Transpiration Xylem Phloem
Cambium Epidermis Pith Cortex Cuticle Palisade Mesophyll Spongy Mesophyll Stamen Carpel Short-day Plants Apical Meristems Lateral Meristems Auxin Pollination Fertilization Seed Dispersal Bulbs Stem Tubers Storage Roots Tendrils Phototropism Monocot. Plant Dicot. Plant Day-neutral Plants Long-day Plants

17 A twirly stem modification.
The tissue that produces primary growth, allows roots to grow. Happens when male and female sex cells unite to make a gamete. The loss of water vapor from leaves and other openings. The outer most layer that protects against water loss and insect invasion. The three female part of an angiosperm. Plants that flower without regard to day length. The central region of a root used for storage and support. A plant’s growth in response to light. Open and close the stomata. A plants that produces flowers with petals in multiples of threes. The transfer of yellow grains from anther to carpel. Buzz Buzz. Surround the vascular tissue in roots and stems. Bloom when the days are at their longest. Horizontally growing stems below ground. Potatoe. The tissue that produces secondary growth. FAT. Just above stomata allowing continuous channels for gas exchange.

18 Carries water and dissolved minerals from the roots to the leaves.
The hormone that causes positive phototropism. Bloom when the days are shorter. Has vascular tissue usually arranged in a ring. Specialized cell within the root that store large quantities of carbs and water. Carrot. The substance that causes guard cells to close stomata. The two male parts of an angiosperm. Moving fertilized seeds away from the parent. The area of rapidly dividing cells that differentiate into xylem and phloem. Located in a leave where the most light is avaliable, rich with chloroplast to allow maximum photosynthesis. Surround the pith and helps with support. Vertical, underground stems consisting of enlarged bases of leaves that store food. Onions. The one thing I haven’t mentioned yet if we have still made it this far: transports organic nutrients throughout the plant.


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