Plants & Civilization

Special Project: PLANT MINERAL NUTRITION

Plant Mineral Nutrition • Plants need CO2 & H2O (and sunlight) to live. • Plants also use a variety of nutrients – Macronutrients = major minerals required by plants include: » Nitrogen (N), Phosphorus (P), Potassium (K), Calcium (Ca), Magesium (Mg), and Sulfur (S). – Micronutrients = smaller amounts utilized by plants. » Iron (Fe), Manganese (Mn), Copper (Cu), and Zinc (Zn).

• These mineral components of soil are used rapidly by plants…therefore, typically these minerals are common in fertilizers.

Nutrient Effect on Plant Growth • Macro & micronutrients affect plant growth. • Each mineral is absorbed by plant roots to serve a specific purpose: • Nitrogen- component of amino acids, proteins, nucleic acids, chlorophyll, & hormones. • Iron- needed for energy transfer in respiration & photosynthesis; also involved in chlorophyll synthesis. • Calcium- component of cell walls & of middle lamella. • Magnesium- component of chlorophyll; involved in enzymatic reactions.

Nutrient Effect on Plant Growth, continued

Without these necessary minerals, plants will suffer certain deficiencies in growth.

Hydroponics • Hydroponics – method of growing plants without the use of soil. • Instead, plants are placed in a liquid medium where roots can absorb minerals directly.

Setting Up this Experiment: Employing the concept of hydroponics to grow sunflower plants, you will experiment with the effects of each mineral nutrient on plant growth. [i.e. What is the purpose of each mineral? How does each mineral affect plant growth, specifically?]

Setting Up this Experiment, continued • You will work in groups of 4, by table. • Each table will be assigned a specific “treatment”: » Complete media – contains all necessary macro/miconutrients. » Nitrogen deficient – lacks N » Iron deficient – lacks Fe » Calcium deficient – lacks Ca » Magnesium deficient – lacks Mg

• 3 sunflower seedlings will be grown hydroponically in the greenhouse for a

period of 6 weeks.

Setting Up this Experiment, continued Before beginning: 1. Set-up your growth chambers with appropriate hydroponic liquid medium. 2. Make initial observations of your 3 sunflower seedlings – be sure to keep track of seedling #1, #2, and #3 throughout the experiment!

3. Take initial masses (‘weigh’) of each of the seedlings. 4. RECORD all initial factors & make HYPOTHESES based on your ‘treatment’.

Setting Up this Experiment, continued • You must monitor the growth of your seedlings (3) by making observations each week noting: – Stem height, # of leaves, color of young/old leaves, root condition, & areas of necrosis. – BE CONSISTENT WITH YOUR ‘MEASUREMENTS’.

• Make sure your plants are receiving adequate light & have a full container of hydroponic medium…each week. – This will help ensure that no outside factors are affecting the growth, or lack of growth, of your sunflower plants.

Hydroponic Chamber Set-Up

Photos by: J. Jamison

Concluding this Experiment • After the 6 week experimental trial you will be able to answer the question: » How does each macro/micro-nutrient studied effect plant growth, specifically?

• Each group (with a different treatment) will provide their results to the instructor who will combine them. • You will INDIVIDUALLY answer questions based on the combined CLASS TOTALS.

Concluding this Experiment This experiment, complete with all observations, hypotheses, results, conclusions, etc. will form the basis of an

INDIVIDUALLY WRITTEN LAB REPORT! (worth 50 lab points total) Due in lecture on April 20, 2006 at 10:00am SHARP! Late papers (that is, after 10:00am) will be deducted 5 points per day. No Exceptions!

TODAY’S PLAN: • Work SLOWLY & CAREFULLY to set-up your Mineral Nutrient Seedlings. 9The seedlings are very delicate. Handle with care to avoid breaking stem. 9If you destroy your plant(s), you will not have any to work with!

• Make initial observations & record as directed by your lab manual. • Afterwards, you will move onto Lab #5: “The Root & the Apical Meristem”