Pollen viability and germination in mango (Mangifera indica L.) cv. Ataulfo.
Gehrke-Vélez M. R., Castillo-Vera A., Ruiz-Bello C., Moreno-Martínez J. L.
Author Affiliation: Kansas State University, Manhattan, Kansas, USA.
Interciencia 36 : 378-385
Abstract : Morphological characteristics of 'Ataulfo' mango pollen are reported at four locations in Chiapas, Mexico. Pollen viability and germination was assessed in vitro and in vivo as well as pollen tube growth rate and velocity within the floral gynaecium, in order to detect possible malfunctions in the pollination process that could explain disorders such as lack of fruit set and excessive nubbin formation. Pollen showed acceptable (70-85%) viability and germination levels of 14.5 and 1.75%, respectively, in hermaphrodite and male flowers. Total pollen content averaged 959 grains per stamen in hermaphrodite flowers and 645 in male flowers. Pollen tube growth rate was initially high (58 µm.h-1) but decreased rapidly 12 h after pollen germination (12.8 µm.h-1). This would indicate that pollen tube growth seems to be hindered by some physiological or atmospheric factor which may be causing deficient ovule fertilization and a consequent embryonic atrophy. Growth velocity decreases drastically from germination to the 12 h interval, increases up to the 24 h stage, and then becomes erratic. Morphological descriptions of pollen growth and development in 'Ataulfo' were not found in the literature, nor were references to pollen tube growth rate and velocity in mango. Results obtained help explain possible malfunctions in the fertilization process and shed light on the causes of a deficient pollination/fertilization observed in Ataulfo mango and a severe crop reduction occurring in this mango cultivar.