The paper presents the phenomenon of implantation. Discussed the mechanisms of its individual stages: apposition, adhesion and invasion. It explains the mechanisms of hormonal regulation and paracrine these phenomena. Attention is paid to the interaction of the embryo and the endometrium. The complexity and complexity of the mechanisms controlling the implantation mean that even a slight disturbance of homeostasis of the organism leads to a reduction of fertility.

The phenomenon of genomic imprinting occurs in both animals ( mammals ) and plants ( flowering plants ), and consists of seemingly nierównocennej expression of imprinted genes derived from the father and mother in offspring ; alleles derived from one of the parents are muted. This article presents the Issues of imprintingiem genomowynm associated with plants . In flowering plants the embryo and endosperm are the result of double fertilization, a characteristic only for this group of plants.