Olive floral biology and climatic elements: twenty-eight years of observations

S. Bartolini, R. Viti
In these last years, the complex relationship between climatic elements and plant phenology has been examined in temperate fruit species in order to analyze the effects of the underway climate change. The increase in air temperature and declining rainfall are affecting the biology of plants which may show a shift of phenological phases. Addressing particular attention to and providing information about the influence of meteorological variables on floral biology may be crucial for the coming years, in a context of global warming. Accordingly, in this work we report the floral biology of several olive clones ('Leccino') grown in Tuscany (Italy), over a long period of observations. The influence of climatic elements, such as temperature and rainfall, on the main phenological phases was studied. Biological and morphological analyses were conducted to assay: quality traits of floral organs and pollen grains, and pollination and fertilization processes. In particular, the pollen-pistil relationship was tested by self- and open-pollination. Meteorological data, concerning daily temperatures and rainfall from autumn to summer were acquired. The post dormancy conditions influenced inflorescence and pollen traits. A positive and significant correlation was found between rainfall and inflorescence length, and between pistil abortion and mean-maximum temperatures. As regards pollen, vitality and rainfall were correlated, while the germination capacity was related to mean temperatures of the blooming month. As concerns results on the pollen-pistil relationship assessed in vivo, no self-incompatibility reaction was observed and pollen tubes were able to reach the ovary and ovules when flowers were self-pollinated. Maximum temperatures were significantly-inversely correlated with pollen tubes reaching the ovary and fruit set obtained by self-pollination.
Bartolini, S. and Viti, R. (2018). Olive floral biology and climatic elements: twenty-eight years of observations. Acta Hortic. 1229, 299-304
DOI: 10.17660/ActaHortic.2018.1229.45
Olea eropaea L., phenology, temperature, rainfall, self-compatibility

Acta Horticulturae