Essential elements are mineral elements that are necessary to maintain the normal physiological activities of plants. To determine whether various elements are essential for plant growth, it is necessary to use soilless culture methods (solution culture or sand-based culture) to determine this. In recent years, soilless culture has become not only a research tool, but also a new production method, which is used on a large scale in vegetable and flower production. In this experiment, we study the solution culture technique of plants and learn about the necessity of elements such as nitrogen, phosphorus, potassium, calcium, magnesium and iron for the growth and development of plants.
Principle
The basic principle of solution culture of plants and observation of deficiencies is to use essential mineral elements to formulate nutrient solutions to cultivate plants, and the types and amounts of the elements used can be completely controlled artificially. In order to understand the physiological symptoms caused by the deficiency of an element, the element can be subtracted from the nutrient solution and observed in the subsequent growth process, and when the deficiency is observed, the missing element can be added to the nutrient solution, and the deficiency symptoms will gradually disappear again.
This kind of experiment usually use solution culture, in order to manage the convenience, but also often will be added to the solution of clean quartz sand culture plants, is called sand-based culture.
Operation method
Solution culture of plants and observation of deficiency diseases
Principle
The basic principle of solution culture of plants and observation of deficiencies is to use essential mineral elements to formulate nutrient solutions to cultivate plants, and the types and amounts of the elements used can be completely artificially controlled. In order to understand the physiological symptoms caused by the deficiency of an element, the element can be subtracted from the nutrient solution and observed in the subsequent growth process, and when the deficiency is observed, the missing element can be added to the nutrient solution, and the deficiency symptoms will gradually disappear again. This kind of experiment usually use solution culture, in order to manage the convenience, but also often will be added to the solution of clean quartz sand culture plants, is called sand-based culture.
Materials and Instruments
Materials: corn seedlings, tomato seedlings, sunflower seedlings. Move The basic procedure for solution culture of plants and observation of deficiency can be divided into the following steps. 1. Prepare reservoirs of macroelements and Fe: 1. Preparation of reserve solution for macronutrients and Fe: according to Table 8-1, prepare the solution with evaporated water. Trace element stock solution is prepared according to the following formula: 2.86 g of H3BO3, 1.18 g of MnCl2-4H2O, 0.08 g of CuSO4-5H2O, 0.22 g of ZnSO4-7H2O, 0.09 g of H2MoO4-H2O, dissolved in 1 L of evaporated water. 2. Prepare the stock solution for macroelements and Fe according to Table 8-2. 2. Prepare the complete nutrient solution or the deficiency nutrient solution according to Table 8-2 (with distilled water, adjust pH to 5.5-5.8). 3. 3. Add 400 mL of each of the above prepared culture solution into 500 mL culture flasks, fix the young stems of plants with cotton through small holes in the lids, so that the entire root system is immersed in the culture solution, label and write the date. Label and date the vials. Place the vials in a well-lit area at a suitable temperature (20-25°C). Table 8-1 Preparation table for macronutrient reservoirs gl Nutrient Salt Concentration Ca( NO3 ) 2 - 4H2O 236 KNO3 102 MgSO4-7H2O 98 KH2PO4 27 K2SO4 88 CaCl2 111 NaH2PO4 24 NaNO3 170 Na2SO4 21 EDTA-Fe EDTA-Na2 7.45 FeSO4・7H2O 5. 57 Table 8-2 Preparation of deficiency culture solution ml Reserve solution Amount of stock solution per 100 mL of culture solution Completely N-deficient P K Ca Mg Fe Ca( NO3 ) 2 0.5 -Mg 0.5 0.5 -0.5 0.5 0.5 KNO3 0.5 -0.5 0.5 0.5 - 0.5 I 0.5 0.5 MgSO4 0.5 0.5 0.5 0.5 0.5 -0.5 0.5 KH2PO4 0.5 0.5 One one 0.5 0.5 0.5 K2SO4 -K2SO4 0.5 0.5 -0.5 0. 5 I. - I. I CaCl2 One. - One. 0.5 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - I NaH2PO4 NaH2PO4. (SIGHS) - (LAUGHS) One. - One. 0.5 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 0.5-- NaNO3 - - - - NaNO3 - - - - NaNO3 I - - 0.5 0.5 -0.5 0.5 0.5 - Na2SO4 Na2SO4 - One. - One. - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 0.5 - - - - - - - - - - - - - - - - - - - - - - - - - - 0.5 EDTA-Fe 0.5 - EDTA-Fe 0.5 - EDTA-Fe 0.5 - EDTA-Fe 0.5 0.5 0.5 - Trace elements 0.1 0.1 0.1 0.1 0.1 0.1 0. 1 4. Transplanted seedlings can be either corn or tomato. The endosperm should be removed and the root system should be cleaned when transplanting corn seedlings. 5.
Reagents:
Potassium nitrate, magnesium sulfate, potassium dihydrogen phosphate, potassium sulfate, sodium sulfate, sodium dihydrogen phosphate, sodium nitrate, calcium nitrate, calcium chloride, ferrous sulfate, boric acid, abrasive chloride, copper sulfate, zinc sulfate, keyhole acid, hydrochloric acid, disodium ethylenediaminetetraacetic acid (EDTA-Na2).
Equipment:
① 250, 500 mL beaker
② 5, 1 mL graduated pipette
③ 1 000 mL measuring cylinder
④ 500 mL reagent bottle
⑤ 500 mL culture flask
⑥ Skimmed cotton wool
5. After the experiment, observe the seedlings every 2-3 days and record the growth, deficiency symptoms and development of each treatment in Table 8-3, taking care to record the symptoms of essential element deficiency and the site where the symptoms first appeared.
Date/Day | Treatment (growth, deficiency symptoms) | ||||||
Complete | Deficient N | Deficient P | K | Deficient in Ca | Mg | Deficiency Fe | |
| 7 | |||||||
| 14 | |||||||
| 21 | |||||||
| 28 |
Caveat
1. pay attention to keep the pH of the culture solution at 5.5~6.0, test the pH of the culture solution with precision pH paper, if it changes greatly, use dilute acid and alkali to adjust it to 5~6. 2. pay attention to the contamination and mixing of reagents.
2. Pay attention to the contamination and mixing of reagents.
3. Replace the culture solution once every 2 weeks. For good root growth, it is better to keep some space between the cap and the solution to facilitate aeration. Replenish the water loss in the culture flask due to plant transpiration frequently, and take care to add distilled water every week.
4. Record the state of seedling development (root length, stem thickness, leaf size and color, etc.) before the experiment, record plant growth and development and lesions at any time during the experiment, and record the fresh weight, height, and leaf color of the plant at the end. The content of internal plant elements can also be determined.
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