LaMotte AST Series Professional Soil Test Outfits - Manual (Page 38)

GREEN PLANT TISSUE TESTS
Nutrient deficiencies during plant growth can be verified by using an
extract prepared from fresh plant tissue. A procedure for testing nitrate
nitrogen, phosphorus, and potassium in plant tissue is described below.
Additional information on plant tissue testing is discussed in the
LaMotte Soil Handbook (Code 1504).
These tests are meant to be used in a comparative manner. When testing
plant tissue, it is important to compare tissue from healthy plants to
tissue from the problem plants. Plants of the same species, the same age
and grown in the same environment should be compared. Since test
reactions vary from species to species, and even from environment to
environment within a species, it is not possible to accurately quantify
results. Relative values from very deficient to abundant have been
assigned to the range of possible test reactions under each factor below.
PREPARATION OF TISSUE EXTRACT
1.
Select a small lot of the leaf petioles or succulent portions of the
stem. When testing problem plants, collect tissues from those areas
where the abnormality is most visible.
2. Use a clean, sharp knife or razor blade to cut the material into small
pieces, not more than 1/8" to 1/16" in length and thickness.
3. Fill a extraction vial (0701) half way with plant material.
NOTE: Do not pack material into vial.
4. Use a 1 mL pipet (0354) to add 1 mL of *Acid Extracting Solution
(6361).
5. Dilute to line with deionized water. Cap and shake for 5 minutes.
6. Use filter paper (0465) and a funnel (0459) to filter sample (see
How to Use a Funnel and Filter Paper, page 10). Collect filtrate in a
second vial. Use tissue extract in test procedures instead of soil
extract.
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