Topic 2: Plant Structures and Adaptations

1. Topic 2: Plant Structures and Adaptations • Plants have specific structures to help them adapt to their environments • Plants are made of three main systems  parts with multiple smaller parts. They are the systems. Roots • Found underground • Main roles are to absorb minerals and nutrients in the soil, absorb water in the soil, anchors the plants from being blown or washed away, store food in case of scarcity • Have tiny, fine whose main role is to increase the root system’s surface area for better absorption of water and nutrients. a.  some plants have a single, prominent taproot that often dig deep into the ground. Ex) carrots, dandelions, large desert plants

2.  a network of similar-sized roots that can quickly soak up moisture. Ex) cacti to absorb water quickly before the water drains away in the desert sands. •  some plants where the main parts eaten are the roots where much of the nutrients are found. Ex)carrots, beets, turnips, radishes, parsnips. **Potatoes are not roots. They are (special type of underground stems)

3. One of the most important function of roots is absorption of nutrients and water. Roots absorb water and nutrients through: •  tendency for particles to become evenly distributed by moving from areas of high concentration to an area of lower concentration •  is one type of diffusion where only certain types of particles such as water and specific nutrients are allowed to pass through a barrier that is (also called semi-permeable). Other particles not needed by the plant is kept out. Water inside plant cells is what keeps them firm and maintains their shapes. Without water, plants go limp, soft and eventually die. Water also dissolves minerals in the soil for osmosis into the roots.

4. Shoot • The visible parts of plants USUALLY above the ground • consists of the (parts of some stems are underground) and • Woody tree stems (the tree trunk) consist of • dead wood in the centre. The oldest part and also gives the tree its strength • carries water and nutrients up from roots to leaves •  growing part of tree that makes new xylem and phloem cells. They form the tree rings • cells that carry the sugars made in the leaves downwards to the roots and stem. •  rough, outer woody skin that prevents dehydration, the environment, pests, and insulates the tree Memorize the layers of the tree and their functions on page 108! Mr. Dang standing inside the tree trunk of the Big Hollow Tree in Stanley Park, Vancouver. It’s a giant cedar tree.

5. Roles of the stem: • Transport nutrients and water up the , sugars down the cells • Support the plant so it doesn’t fall over and also it reaches up high for light • Food storage- many plants store extra food in specialized stems, some of which is underground. But they are NOT roots! Ex) potatoesand yams are tubers. Sugar canes store sugars in their stems. • Types of stems: • – roots and new baby plants grow at the end of horizontal runners. Ex) strawberryand spider plants • - special bulbs like tulips, gladioli, daffodil flowers, onions, garlic • -horizontal stems that allow the plant to spread under ground. Ex) cattails, raspberry • - prickly pear cactus have special flat stems so that one side faces the sun for maximum light, the other side is in shade to stay cool.

6. Roles of leaves: • Some are specially shaped to prevent water loss. Ex) coniferous tree needles • Most important role is to make food by  the process of making sugars by combining water with CO2 (g) and using light. Memorize this equation. Note how each part is written: carbon dioxide gas is absorbed into the leaves through tiny holes called (singular –stoma) and reacts with the water (that was absorbed in the roots and carried up by the xylem) inside the special structures called , a pigment (a chemical that absorbs and reflects certain colors) called reacts with light to break apart H20 and CO2 and forms (a type of sugar that plants use for energy) and O2. O2 is released into the air through the stomata. Plant cells with clearly visible chloroplasts containing chlorophyll for photosynthesis

7. on each side of the stomata control the opening and closing of the stomata. • During dry times, the guard cells tighten the stomata opening to prevent water loss • is the reverse of photosynthesis. All animal cells and plant cells (only at night) undergo respiration. Memorize this equation too. A single stoma opening with 2 guard cells on each side Guard cells