Light micrograph of a sessile secretory gland on the herb sweet marjoram,Origanum majorana. There are two basic types of secretory glands (or trichomes); stalked and unstalked (or sessile). A number of variations of structure exist but generally between 4 and 12 specialised cells form a small cushion over which a membrane develops. Each cell produces and secretes a cocktail of oils which accumulate beneath the membrane causing it to swell. Plants usually secrete extrafloral substances as a defence against bacteria,fungi or predators. Floral secretions attract insects for pollination purposes. Magnification: x400 at 35mm size | |
Lizenzart: | Lizenzpflichtig |
Credit: | Science Photo Library / Power And Syred |
Bildgröße: | 5072 px × 3472 px |
Modell-Rechte: | nicht erforderlich |
Eigentums-Rechte: | nicht erforderlich |
Restrictions: | - |