Essential Nutrients for Plant Development The water culture technique (hydroponics) is a way of maintaining plants in a solution that contains the elements (in the form of mineral salts) that plants need. This method has been developed for a long time, and is widely used to study the symptoms of nutrient deficiencies in various types of agricultural plants, determine the essentiality of an element for plants, and determine the amount of nutrient requirements for plants. Of the many mineral elements found in nature, only a few (± 15 elements) only the important (essential) things needed by plants. If one of these elements is missing, the plant will show deficiency symptoms. According to the magnitude of the need for elements nutrients, then essential nutrients are classified into two groups, namely: (1)macro elements which are needed in large quantities, include: C, H, O (obtained by plants in the form of CO2, H2 and O2), N, P, K, Ca, S, and Mg; and (2)micro elementswhich are needed in small quantities, include: Fe (sometimes included in the macro element group), Mo, B, Cu, Mn and Zn. To facilitate the preparation of nutrient solutions, salts containing macro elements are usually provided in the form of a single salt solution as a standard solution. Meanwhile, micro elements (except Fe) are provided in the form of a mixture consisting of salts containing macro elements. The Fe element is provided separately in a standard solution of FeEDTA salt (EDTA: Ethylene Diamine Tetra Acetic Acid) or FeCl salt3. Experiment a. Effect of Essential Nutrients on Plant Growth Objective: Examining the effects of lack of nutrients needed by plants Materials and Tools: Plant material : kale sprouts (Ipomoea aquatic ) which is approximately 7 days old which is grown on wet cotton media or other aquatic plants under which there is water. Chemical material : standard solution of nutrient elements, distilled water Tools : 11 jam bottles covered with black paper measuring 250 mL, 11 bottle stopper made of three-hole cork, tweezers, measuring cup, pH-meter, cotton wool and label paper Ways of working: 1. Wash the jam bottles until clean and then rinse 2 or 3 times with distilled water. 2. Make a stock solution 3. Mark the bottles for testing with the label: Complete. –N, -P, -K, -Ca, -Mg, -S, - Fe1, -Fe2, -Micronutrients. 4. Fill the bottles with stock solution according to the code that has been made on the stock solution and match the code to the treatment given 5. After all the stock solutions have been pipetted according to the table, increase the solution to 1 liter by adding distilled water. Because all the solutions in the table are calculated in 1 liter, if in practice a solution of 250 mL is used, pipetting is done a quarter of the amount pipetted in the table and the amount is added with distilled water to make 250 mL. 6. Place the green bean sprouts in the cap of the selei bottle. Follow these steps: a. Carefully insert the sprout roots through the plug hole b. Strengthen the position of the sprout by wrapping cotton into the plug hole around the sprout's hypocotyl c. Try not to let the cotton come into contact with the solution, to avoid the growth of algae or fungus around the hypocotyl 7. When finished, ask an assistant to check whether each treatment is complete and check the pH of the nutrient solution in each bottle. 8. Check every day and add distilled water if there is not enough water in the bottle. 9. After 1 week, check the condition of the sprouts, note any abnormal symptoms. Discard any sprouts that are dead or whose growth is very stunted and leave 2 sprouts in each bottle. Check the pH of the nutrient solution and note any changes. 10. In the second week, measure the average length of the roots and stems, note the symptoms of nutrient deficiency for each plant. 11. At the end of the fourth week, measure the average length of the roots and stems again. Then also measure the pH of the nutrient solution. Note if there is a difference in pH. 12. At the sixth week, measure the average length of the roots and stem again. Then also measure the pH of the nutrient solution. Note if there is a difference in pH. 13. The practicum ends in the eighth week, throw away all the nutrient solution and plant material and then wash the bottles. 14. Report the results of your observations accompanied by photographs of the results of each observation carried out. Experiment b. Effect of Salt Concentration on Plant Growth Objective: Observing the effect of different salt levels on plant growth Materials and tools: Plant material : PlantVigna sinensis orPhaseolus radiatus Chemical material : CaCl solution2or NaCl with various concentrations Tools : Clean bottle, ruler, cotton wool and cover Ways of working: 1. Make a solution with a concentration of 0.00; 0.01; 0.03; 0.05; 0.1 and 0.2 M. 2. Fill the solution into the bottles provided, 200 ml each. 3. Take the plant seeds provided, measure the length of the stem above the cotyledons, then put it in the bottle until the roots are submerged in the solution and the seed is held in place with cotton and a cardboard cover. 4. Mark the top surface of the solution in the bottle, and observe every 2 days. If the solution decreases, add distilled water so that the surface of the solution returns to its original position. Note the amount of distilled water added. Do the same thing until the 10th day and note the morphological condition of the plant.