False-colour scanning electron micrograph of pollen grains of the pot marigold Calendula officinalis. The surface of the pollen grains are covered with tiny barbs,which secure them to the body of an insect for transportation and subsequently to the surface of the stigma at the start of fertilization. One of the furrows,visible here along the length of the lower grain,will produce a slender tube,called a pollen tube,which will grow down to the ovary. Inside the pollen tube,two sperms follow its growth. When the egg is reached,the tube bursts,releasing the sperm,one of which will fertilise the egg. Magnification: x700 at 6x4.5cm size | |
Licence : | Droits gérés |
Crédit: | Science Photo Library / Burgess, Dr. Jeremy |
Taille de l’image : | 3472 px × 3543 px |
Model Release : | Non requis |
Property Release : | Non requis |
Restrictions : | - |