Transport of food and minerals in plants Cheat Sheet (DRAFT) by Shanayak

Definition Elements necessary for healthy plant growth. Total = 16 essential elements Macron­utr­ients Needed in large amounts. Carbon (C) Hydrogen (H) Oxygen (O) Nitrogen (N) Phosphorus (P) Potassium (K) Sulphur (S) Calcium (Ca) Magnesium (Mg) Micron­utr­ients (Trace Elements) Needed in small amounts. Chlorine (Cl) Iron (Fe) Copper (Cu) Boron (B) Molybdenum (Mo) Zinc (Zn) Manganese (Mn)

Definition Elements necessary for healthy plant growth. Total = 16 essential elements Macron­utr­ients Needed in large amounts. Carbon (C) Hydrogen (H) Oxygen (O) Nitrogen (N) Phosphorus (P) Potassium (K) Sulphur (S) Calcium (Ca) Magnesium (Mg) Micron­utr­ients (Trace Elements) Needed in small amounts. Chlorine (Cl) Iron (Fe) Copper (Cu) Boron (B) Molybdenum (Mo) Zinc (Zn) Manganese (Mn)

xylem and phloem usually occur together :) in the roots, stems and leaves and they both form vascular bundles.

Complex tissue → Parenc­hym­atous + sclere­nch­ymatous cells. Contains living & non-living cells. 4 elements: Sieve tubes, Companion cells, Phloem parenc­hyma, Phloem fibres.

companion cells- Associated with sieve tubes. Smaller cells. Dense cytoplasm. Prominent nucleus. Help in food conduc­tion.

Aim Show transport of food in plants. Girdling Removal of phloem (bark) from the wood. Procedure 1. Select a small tree. 2. Remove 1 cm ring of bark using a razor blade. 3. Leave for 1 week. Observ­ation Above girdled area → Swells. Below girdled area → No swelling. Reason Phloem removed → Food transport blocked. Food accumu­lates above the cut. Conclusion Phloem transports food. Xylem remains intact → Water transport continues.

Definition Pressure causing water to move from living root cells into xylem. Cause Accumu­lation of absorbed water in roots. Function * Helps transport water stem → leaves.

Definition Membrane that allows certain substances to pass but blocks others. Thin membrane with small pores. Allows Solvent (water) molecules. Does NOT Allow Solute molecules. Examples Plasma membrane Egg membrane Cellophane paper SCIS-BITS Cell wall is freely permeable → allows almost all substances to pass.

Diffusion is the method of transport of materials in single celled and simple multic­ell­ular** plants

Definition Loss of water as water vapour from leaves to the atmosp­here. Occurs through stomata by diffusion. Why does it occur? Plants absorb more water than required. Excess water is lost by transp­ira­tion. Some water is used for: Photos­ynt­hesis Keeping plant erect Preventing wilting Transp­iration Pull Evapor­ation of water from leaves creates suction pull. Pulls water roots → stem → branches → leaves. Water moves through xylem. Importance Transports water & minerals to leaves. Supplies water for photos­ynt­hesis. Produces cooling effect. Prevents damage due to strong sunlight. Cools surrou­ndings.

Ascent of Sap Definition * Upward movement of water through xylem due to transp­ira­tion. Process 1. Cell membrane = Partially permeable. 2. Cell sap in vacuole has high solute concen­tra­tion. 3. Soil has higher water concen­tration than root hairs. 4. Water enters root hair by osmosis. 5. Cell sap becomes diluted. 6. Water moves cell → cell by osmosis. 7. Water reaches xylem. 8. Xylem carries water upwards against gravity due to transp­ira­tion.

Sources Atmosphere Water Soil Minerals return to soil by death & decay of plants and animals.

1. Intensity of Light Day: Stomata open → More transp­iration Night: Stomata close → Less transp­iration 2. Temper­ature Higher temper­ature → Higher transp­iration 3. Wind Higher wind speed → Higher transp­iration 4. Humidity Higher humidity → Lower transp­iration 5. Soil Water Dry soil → Less available water → Lower transp­iration ⸻ SCI-BITS Root Pressure Theory proposed in the early 18th century. Cannot alone explain water rise in tall trees.

Definition Movement of water molecules through a partially permeable (semip­erm­eable) membrane. Water moves from higher water concen­tration → lower water concen­tra­tion. A special type of diffusion involving water only. Requir­ements Two solutions. * Partially permeable membrane.

Aim Show upward movement of water in a plant shoot. Procedure 1. Take a balsam shoot. 2. Place in dilute red dye (eosin­/sa­fra­nin). 3. Leave for some time. 4. Cut stem sections. 5. Observe under low-power micros­cope. Observ­ation Only certain parts become red. Stained region = Xylem. Conclusion Xylem transports water upward through the plant.

In tall plants diffusion occurs slowly, it cannot move materials enough in sufficient quantities.

movement of water and minerals takes place from the roots to other plant parts , through stem. The upward movement of water and minerals occurs through channels called xylem elements.

movement of food materials in the leaves transport through another channel called phloem. It transports the food from leaves to all other parts of the plant body

Aim Demons­trate osmosis. Procedure 1. Take 2 bowls. 2. Bowl A: Put raisins in water. 3. Bowl B: Put grapes in sugar solution. 4. Leave for a few hours. Observ­ation Bowl A: Raisins swell. Bowl B: Grapes in sugar solution do not swell (may shrink if observed longer). Conclusion Water enters raisins by osmosis, causing them to swell.

Aim Demons­trate transp­ira­tion. Materials 2 flasks Water Plant twig Oil Cotton plug Procedure 1. Fill flasks half with water. 2. Mark water level. 3. Add oil layer (prevents evapor­ation). 4. Place plant twig in Flask A. 5. Close both flasks with cotton plugs. 6. Leave for 24 hours. Observ­ation Flask A: Water level decreases. Flask B: Water level unchanged. Conclusion * Water lost through transp­iration from leaves.

Functions of Roots Anchor (fix) plant to soil. Absorb water & mineral salts.

Definition Movement of molecules against concen­tration gradient. Requires energy. Occurs across a semipe­rmeable membrane. In Plants Root hairs absorb minerals by active transport. Root hair cells have higher mineral concen­tration than soil. Passive Absorption Water absorbed by transp­iration pull. * No energy required.

Xylem is a complex tissue as it consists of both parenc­hym­atous ( living thin wall cells) and sclere­nch­ymatous ( dead thick walled cells)

1. Tracheid- It is a non-living, elongated cell with tapering ends. The wall is highly thickned with lignin except at certain circular spots called pits.

Tracheids and vessels are main conducting elements in the xylem. they also provide mechanical support tho...

4. xylem fibers- They are non living and thick walled cells which provide mechanical support.