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37.2 Plants Require Essential Elements. By Rommy Obeid. Hypotheses of Plant Growth. Aristotle Thought the plants ate the soil Jan Baptista van Helmont Wanted to test this hypothesis using an experiment
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37.2 Plants Require Essential Elements By Rommy Obeid
Hypotheses of Plant Growth • Aristotle • Thought the plants ate the soil • Jan Baptista van Helmont • Wanted to test this hypothesis using an experiment • He planted a small willow in a pot with a set amount of soil to measure the amount of soil that was uptaken. • Although the plant gained 76.8 kg, only a total of .06 kg disappeared from the soil. • Stephen Hales stated that they received their mass from their air intake. • What was found out is that most of the mass of the plants are organic. • Elements like CARBON, HYDROGEN, and OXYGEN.
Macronutrients and Micronutrients • Essential elements- chemical elements required to complete the life cycle. • Hydroponic culture • Plants are grown in mineral solutions • Used to determine the essential elements
Macronutrients and Micronutrients (Continued) • There are 17 discovered essential elements • 9 are Macronutrients • Macronutrients are the elements needed in large amounts • Carbon, oxygen, hydrogen, nitrogen, phosphorus, sulfur, potassium, calcium, and magnesium • 8 are Micronutrients • Micronutrients are the elements needed in small amounts • Chlorine, iron, manganese, boron, zinc, copper, nickel, molybdenum • http://www.youtube.com/watch?v=wzswABSxm8s
Video • http://www.youtube.com/watch?v=wzswABSxm8s
Symptoms of Mineral Deficiency • The symptoms are different for each type of mineral deficiency. • Mineral deficiencies involving minerals that move constantly affect the older leaves first. • Mineral deficiencies involving minerals that don’t move affect the younger leaves first. • This is because the older leaves have a stored amount of the mineral • Too much minerals can cause poisoning to the plants.
Improving Plant Nutrition • Genetic engineers are trying to tailor plants to make them better fit to the soil conditions. • Resistance to Aluminum Toxicity • Flood tolerance • Smart Plants
Resistance to Aluminum Toxicity • Aluminum reduces plant’s crop yield and damages roots. • To lower aluminum’s toxicity, organic acids bind to the aluminum ions. • To reduce the affects of aluminum toxics, scientist add citric synthase gene.
Flood Tolerance • Plants often die of flooding because of the constant alcohol fermentation build up ofethanol and lack of oxygen. • Submergence 1A-1 • Gene available in anaerobic conditioned plants. • It regulates the breakdown of ethanol • If more is added in plants that are flooding, it can solve the problem of ethanol build up.
Smart Plants • Smart plants is the genetically engineered solution to mineral deficiency. • Engineers use the promoter (a DNA sequence). • It is linked to a gene that will produce a colored tint on the leaf to indicate it is in need of fertilization. • This will occur BEFORE the damage is done to allow for fertilization. • Example: • If the plant is phosphorusdeficient, the promoter will cause the leaf to be tinted blue to indicate to the farmer to use phosphate containing fertilizer.