Agenda 10/26 Plant Nutrition Lecture Plant Nutrition Skits Turn in: Chp 35 notes, video notes Homework 1. Genes Traveling Article 2. Properties of Water Video and Notes

Warm up! In your notes answer the following.. What nutrients do plants need to survive? How do they get those nutrients?

Plants need water! Water and minerals in the soil absorbed by roots Water evaporated through the stomata in the leaves is called transpiration Creates a force within leaves that pulls water upward in xylem

But plants need more than just water…. CO2 and O2 are also exchanged at the stomata for photosynthesis CO2 is absorbed O2 is released Some gas exchange can also happen in the roots

But plants need more than just water…. Sugars are produced by photosynthesis in the leaves They are transport throughout the plant by the phloem Phloem can transport materials in both directions

How does the water get from the roots to the top of the tree? Brainstorm 3 ideas with your partner

Root Pressure As more and more water accumulates in the roots, it creates a pressure in the roots by pushing by on the root cells This pushes water into the xylem and creates pressure in the xylem This pressure creates a force that pushes water up the stem of the plant

Transpiration Root pressure alone isn’t enough to account for water movement in all plants Transpiration is the main pulling force that draws water from the roots to the top of the tree To understand how transpiration works, you have to understand chemical properties of water

Put as many drops of water on your penny as you can! Why does this happen? What is occurring?

TACT Theory (tension-adhesion-cohesion-transpiration theory) Water is a polar molecule It has an uneven distribution of charge When two water molecule approach each other, the form an intermolecular attraction called a hydrogen bond This hydrogen bonds creates cohesion and adhesion in the plant, which allows water to be pulled from the root through the xylem up to the leave

Cohesion and Adhesion Adhesion occurs when water forms hydrogen bonds with xylem cell walls. Cohesion occurs when water molecules hydrogen bond with each other.

Transpiration Water evaporated from the leave When one water molecule is lost, another is pulled along due to the cohesion and adhesion of the water in the xylem Transpiration pull refers to the use of capillary action and surface tension of water This is the primary mechanism of water movement in plants!

Transpiration Pull

Important of the hydrogen bonds Arrange the water molecules at your lab station Use the string to represent the xylem and arrange the molecules accordingly

Importance of Hydrogen Bonds Hydrogen bonds are an intermolecular force- not a physical bond They play an important role in a lot of biological molecules

Stomata regulation transpiration rate When water moves into the guard cells surrounding the stomata they become more turgid The structure of the guard cells’ wall cause them to bend outward opening the pore This allows for an increase of gas exchange, and increase in transpiration

Stomata can regulate transpiration When the guard cells lose water they become less bowed and the pore closes This limits gas exchange and water evaporation/transpiration

Role Of Potassium Ion In Stomatal Opening And Closing The transport of K+ (potassium ions, symbolized here as red dots) across the plasma membrane and vacuolar membrane causes the turgor changes of guard cells. H2O K+ The changes in turgor pressure in guard cells is largely due to the reversible absorption and loss of K+. Stoma open when guard cells actively accumulate K+ from neighboring epidermal cells lowering their water potential.

Teams for today Team 1: Team 2: Del Griselda Daniela Emma Alan Matty Annette Jaz Natalie Martha Leslie Madison

Plant Nutrition Skits In your team, design a skit that outlines how plants get the nutrients they need. Include Overview of how plants get sugars, water, and carbon dioxide into their system Explain how oxygen and water vapor get released Describe how nutrients are transported throughout the plant (xylem/phloem) Explain the role the stomata play in gas exchange/homeostasis Describe three properties of water that contribute to transpiration Show how water moves into the xylem from roots Show how water moves up the plant in the xylem Explain how the stomata can adapt to changing environments