"Flower structure, Ontogeny and Pollen viability of Moringa oleifera Lam."

Abstract

Moringa oleifera Lam. also known as the "miracle tree" or "tree of life", is a small tree up to 12 meters if left unpruned, native of Asia and distriduted in parts of Africa, Asia, and America in tropical and subtropical climates. Moringa is the only genus with 13 species in the flowering plant family Moringaceae and M. oleifera is an evergreen or deciduous tree depending the climate and fast growing, up to 1meter per month (Price, 2007). M. oleifera is very drought-tolerant and can grow on a wide range of well-drained soils, however it is best adapted to a sandy loam with pH range from 5 to 8.5. It can grow up to 1000-1500 m above the sea level and has a rainfall tolerance from 400 mm to 2600 mm (FAO ecocrop, 2013). The plasticity that this species has to adapt to different growing conditions made the chances of crop study in Argentina. Indeed, Falasca and Bernabé (2008) delimited a potential growing area on the basis of thermal and water limits obtained from historical records. They concluded that is possible to cultivate M. oleifera in the great area of Buenos Aires province. In recent years it has shown enormously growing interest on this species due to its multiple benefits and applications in the field of human and livestock nutrition, as a healing of various diseases, in the cosmetics industry. These multiple uses make attractive the cultivation of this species, also because its seeds contain 31-47% of oil. The high tenor of oleic acid of the oil indicates an appropriate way to obtain a good edible oil and biodiesel. Since this species is mainly propagated by seeds, planting material is generally non homogeneous. Hence the selection of superior genotypes is very important and a detailed study of the floral biology is essential in order to improve productivity, to assess the adaptability of Moringa to different growing conditions, and also to widen knowledge about fertility associated to next cross-breeding programmes. The purpose of this thesis is to study more in detail floral biology and pollination of M. oleifera. The specific objectives are the observation of the flower structure and the adaptation of the plant to Moreno (Buenos Aires province) climatic conditions, the study of pollen formation and microsporogenesis, the study of pollination and fertilization and the observation of embryo development.