Whole Plant Transpiration Lab AP Biology How to

Whole Plant Transpiration Lab AP Biology How to calculate transpiration RATE

STEP ONE: Calculating water loss g/day to ug/sec • Steps for measuring water loss 1. Calculate g of water/day lost then convert to ug/sec • grams x 1 day x 1 hour x 1 minute = ______ gram/sec day 24 hr 60 min 60 sec 2. Now convert your answer to ug/sec Hint: 1 g = 106 ug This answer is the amount of water lost 3. Calculate each day and write out your water LOSS in ug/sec for each day W ______ Th _____ Fr_____ Then do an average of all 3 days _______ug/sec NOW to get the cm 2

STEP TWO: Measuring Leaf Surface Area 1. Gently remove all the leaves on your plant and lay them on the grid to calculate the total number of cm 2 HINT: You may trace around the leaves on the grid and then throw the leaf away. 1 cm x 1 cm grid to use: 4 boxes equal one square centimeter 2. Total the entire surface area in cm 2. ________ cm 2 3. Now take your average water loss divide it by the cm 2 to get your answer for the TRANSPIRATION RATE _____ug/sec/cm 2

Leaf Surface Area Results Fan Plant = ______118_____ cm 2 Control fan group ___172____ cm 2 Dark Plant = ______136. 75___ cm 2 Control dark group __165. 25_ cm 2 Mist Plant = ___208_____ cm 2 Control mist group __123. 5___ cm 2 Bright light plant = ___168____cm 2 Control bright light group _157__cm 2

RAW data for whole plant mass in grams Whole Plant Transpiration Mass in grams (g) Variable Day 1 Day 2 Day 3 Day 4 Fan 304. 4 285. 6 269. 7 251. 8 Dark 233. 7 227. 3 221. 4 215. 9 Mist 253. 9 252. 8 252. 4 Bright Light 286. 2 249. 9 216. 7 183 Control

Calculate the transpiration rate for each variable and your control group Variable Fan Dark Mist Bright Light Control Average Transpiration rate ug/sec/cm 2