The glands of plants are single cells, tissues, or intercellular ones that secrete secretions . The endoplasmic reticulum , the Golgi apparatus and the cell nucleus are often strongly developed in the gland cells.
Functions of the secretions
The secretions formed in the cytoplasm perform various functions:
- Milky sap, gum and resins seal wounds.
- Essential oils, fragrances and nectar are used to attract animals.
- Alkaloids and steroid glycosides contained in secretions deter herbivores .
- In salty locations, plants secrete excess salts via salt glands.
- Carnivorous plants, such as the sundew family , form sticky secretions with which they catch insects and then digest them with exoenzymes from digestive glands.
The shape of glands is just as diverse as their functions:
- When intercellular spaces take on a glandular function, they are surrounded by chlorophyll-free cells. Examples are the glands in the leaves of St. John's wort , which appear as small bright spots, and the glands in the peel of lemons and bitter oranges.
- Superficial glands like the nectaries contain cylindrical or prismatic cells. The cuticle above it is lifted by the secretions and later perforated.
- Other forms of plant glands are glandular hairs and water-separating hydathodes .