Morphology and physiology of pollen grains of Italian Prunus persica (L.) Batsch cultivars grown in Argentina

Abstract

Studies of morphology, viability and quality of reserves of pollen grains are essential in understanding fruit set problems, and the achieved results can be an important tool for choosing breeding strategies. Low fruit production is often associated to microsporogenesis disorders due to genetic causes. The objective of the present work was to study such characteristics in the peach cultivars Maria Aurelia, Maria Emilia, Maria Bianca, Maria Delizia and Maria Serena grown in different areas of Argentina. Measurements of pollen grains depended on humidity content. In swollen pollen, 'Maria Emilia' was larger than 'Maria Aurelia', 'Maria Delizia' and 'Maria Serena'. While on dry grains, 'Maria Delizia' showed a larger diameter with respect to 'Maria Aurelia', 'Maria Emilia' and 'Maria Bianca'. Under the same conditions, the shortest lengths were observed in 'Maria Delizia' and 'Maria Serena' grains. The lowest length/diameter ratio was found in 'Maria Delizia', with a wide percentage of round grains. Nevertheless, Prunus pollen grains are tricolporated. Striated exine ornamentation was observed for all cultivars, apart from 'Maria Emilia' which showed a globular exine structure. Viability on the five studied cultivars was very high, with less than 10% of unviable grains. 'Maria Emilia' and 'Maria Delizia' showed the lowest percentages of viability. Protein and lipids were the main components of reserves.