Calcium oxalate crystals are commonly found in cortical cells and parenchymal cells of
phloem and xylem parenchyma. Calcium oxalate crystals are formed when oxalic acid which
is toxic to plants is metabolized with calcium ions resulting in precipitation. These
precipitates then form crystals, hereinafter called calcium oxalate crystals.
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Properties of calcium oxalate crystals, when added vinegar acid and slightly heated, it will
form bubbles of carbon dioxide gas. In addition to using vinegar, it can also be used
hydrochloric acid and sulfuric acid.
One interesting ergastic object to observe in the anatomical field of plants is the crystalline
calcium oxalate (Ca oxalate). Calcium oxalate crystals have various forms, depending on the
type of plant. Here are some forms of calcium oxalate crystals that can be found in certain
plant cells: a
1. Druse form, is a gland-shaped crystals or globusic masses or druse. This form is only
present in certain cells. The shape is often irregular, can be similar stars, round, or other
shapes. This form of calcium oxalate crystals can be found in papaya stalk fiber cells (Carica
papaya), and their presence often meets the cell lumen.
2. A regular prism shape, usually present in cells under the epidermis of citrus leaves (Citrus
sp.).
3. Needle shape, can be found on the leaves at four flowers (Mirabilis jalapa).
4. The shape of small grains, often called sand crystals. This form of calcium oxalate crystals
can be found on the spin leaf (Amaranthus sp.).
5. Form rafida, or needle shape arranged parallel. Rafida can be found on the skin of the palm
fruit (Arenga pinnata), which is on the cells of the parenchyma tissue.
Calcium oxalate crystals are the end product of the exchange of substances that occur in the
cytoplasm. It is suspected that free oxalic acid is toxic to plants deposited in the form of Ca-
oxalate salts. These crystals are not soluble in vinegar, but are soluble in strong acids. The
forms of crystalline Ca-oxalate:
1) Crystals: small pyramid shaped, usually found in large quantities. For example in spinach
leaves (Amaranthus sp.), Tobacco leaf stalk (Nicotiana tabacum) and Begonia (Begonias sp.).
2) Large single crystals: shaped prismoa / poliedris, for example on orange leaves (Citrus).
3) Rafida: shaped like a needle / broom stick, contained on the leaves of the flower at four
(Mirabilis jalapa), aloe vera root and rod (Aloe sp.), Pineapple leaves (Annanas squomosus).
4) Spheritite crystals: crystalline composed of radially arranged portions, are present on
Phyllococcus stems.
5) Compound crystals: shaped like a host / rosette and are called drussen crystals that are only
present in certain cells with irregular shapes (can be stars or other). These crystals are found
in the cortex of melinjo stem (Gnetum gnemon), amethyst leaf (Datura metel), begonia leaf,
pomegranate cortex (Punica granatum) and stem distance (Riccinus communis).
Calcium oxalate crystals found in vegetables can affect taste in vegetables, such as raffida
can cause itching. In certain disease patients is recommended to megurangi consumption of
vegetables containing calcium oxalt with high density because it is likely to cause a
recurrence of the disease. This study aims to obtain information on calcium oxalate crystal
content in some vegetables consumed leaves, especially about the shape, density and
distribution. The form of crystal obtained in general form roset as in papaya leaves, spinach,
kangkung, cassava, belinjo, cassava ramen, kelor, katu, kenikir, crystal prism terdaapat
shades on mauve and lettuce, while the needle shape on the puke. White mustard and green
mustard that does not contain calcium oxalate crystals The highest density found in papaya
leaves is followed by mauve, spinach, cassava, angkung rambat, kenikir, basil, kelor lettuce.
