Leaf Lab Report

Background

Cells and organisms must exchange matter with the environment to grow, reproduce, and maintain organization, and the availability of resources influences response and activities. For example, water and macronutrients are used to synthesize new molecules, and, in plants, water is essential for photosynthesis. Organisms have evolved various mechanisms for accumulating sufficient quantities of water, ions, and other nutrients and for keeping them properly balanced to maintain homeostasis. Plants absorb and transport water, nutrients, and ions from the surrounding soil via osmosis, diffusion, and active transport. Once water and dissolved nutrients have entered the root xylem, they are transported upward to the stems and leaves as part of the process of transpiration, with a subsequent loss of water due to evaporation from the leaf surface. Too much water loss can be detrimental to plants; they can wilt and die. The transport of water upward from roots to shoots in the xylem is governed by differences in water (or osmotic) potential, with water molecules moving from an area of high potential (higher free energy , more water)to an area of low water potential (lower free energy, less water). The movement of the water through a plant is facilitated by osmosis, root pressure, and the physical and chemical properties of water. Transpiration creates a lower osmotic potential in the leaf, and TACT (transpiration, adhesion, cohesion, and tension) mechanism describes the force that move water and dissolved nutrients up the xylem.

Condition | Day 1 | Day 2 | Day 3 | Day 4 | Day 5 | Mass (g) | 78.00 | 79.90 | 71.75 | 67.71 | 46.71 | % change in mass | 0 | 1.9 | 6.25 | 10.29 | 31.29 | % change in mass /surface area | 0 | 0.03 | 0.09 | 0.14 | 0.45 | Surface area (cm2) | 90 | 90 | 90 | 90 | 90 |

Condition | Day 1 | Day 2 |