Matrotrophy

Some flowering plants supplied the developing embryos for the first stages. The ovule has no stocks and the nutrients are provided by the "mother".

In plants, matrotrophy is considered a critical evolutionary development preceding the origin of embryophytes and therefore essential to the evolution of land plants.[1] Matrotrophy is facilitated by cytological and ultrastructural modifications on one or both sides of the generational junction, a region called the placenta.[2] Specialization of the placental cells pertains further to their cytological and ultrastructural characteristics: the cytoplasm is often dense and rich in lipids, the vacuole is typically reduced but large in Sphagnum, the endoplasmic reticulum extensive, mitochondria numerous and large, chloroplasts numerous, often less differentiated, rich in lipid-filled globuli and sometimes filled with starch.[2]

It is associated with live birth (viviparity), in which the embryo of an animal is supplied with additional nutrition from the mother (e.g. through an organ such as placenta or other forms of nutrients providing, e.g. ovatrophy). This can be contrasted with strict lecithotrophy as in oviparity, in which the only source of nutrition for the embryo is the yolk originally contained within the egg.

While commonly associated with vertebrates and especially mammals, matrotrophy is found in 21 of 34 animal phyla, and is fairly common in 11 of those.[3] It has arisen independently in more than 150 clades within Chordata[4] and in more than 140 clades amongst invertebrates.[3]

• Pregnancy (fish)

• Goffinet B, Et al. 2009. Morphology and classification of Bryophyta. In Bryophyte Biology 2nd ed. Cambridge University Press.