Ultrastructure and germination of Vitis vinifera cv. Loureiro pollen

Abstract

The cultivar Loureiro of Vitis vinifera is one of the most economically important, recommended in almost the totality of the Região Demarcada dos Vinhos Verdes. In vineyards, the grape productivity of this cultivar is normal while in others it is extremely low. The aim of this work was to study the morphology and germination of Vitis vinifera cv. Loureiro pollen with high and low productivity. The pollen grain was examined under light, transmission and scanning electron microscopy. Typically V. vinifera pollen present three furrows but in the cultivar Loureiro we found tricolporated and acolporated (without furrows or pores) pollen grains. Both pollen types present generative and vegetative cells with the usual aspect and a dense cytoplasm rich in organelles. In the acolporated pollen a continuous exine layer and an irregular intine layer were observed. Differences were found in the starch accumulation, since only in tricolporated pollen abundant plastids filled with numerous starch granules were observed. To determine the causes of the low productivity of this cultivar we tested pollen viability by the fluorochromatic reaction and pollen germinability by in vitro assays. We observed that the acolporated pollen grain is viable, but no germination was recorded.

Pollen germination, tube growth and longevity in some cultivars of Vitis vinifera L.

“…The results showed that pollen stored at -80°C maintains a good germination during the same season. Abreu et al (2006) investigated the causes of low productivity of V. vinifera cv. 'Loureiro' pollen by studding pollen viability using fluorochromatic reaction and pollen germination ability by in vitro assays and reported that the acolporated pollen grains of mentioned cultivar are viable, but no germination was recorded.…”

“…Pollen viability levels, environmental conditions, and compatibility among cultivars are important for the normal fruit set in all of the fruit trees and grapes (Dantas et al, 2005;Kelen and Demitas, 2003). Different nutrition conditions and germination methods for many plant species and varieties were used by researchers (Abreu et al, 2006;Kelen and Demitas, 2003). Carreño et al (2010) studied the influence of some compounds and temperature on pollen germination capability in some table grape cultivars and reported that optimum temperature for pollen germination depend on the genotype, but in general ranged 25 to 30°C.…”

Reproductive Traits of Hermaphroditic Muscadine Cultivars

“…1G and H). In V. vinifera and Vitis lubruscana pollen, both acolporated and tricolporated pollen stain as viable, but only tricolporated pollen is able to germinate (Abreu et al, 2006;Ahmedullah, 1983). As in muscadine, cultivars only producing acolporated pollen have reflexed stamens ( Fig.…”

“…Tricolporated pollen have plastids filled with numerous starch granules, whereas the plastids in acolporated pollen lack starch grains. Additionally, acolporated pollen plasma membranes presented an irregular shape and in some regions detached from the pollen wall (Abreu et al, 2006). Pollen grains may also differ in size, shape, and exine characteristics that can be used as parameters in cultivar identification of grapes.…”

Fertilization Biology Of Ancient Grape 'Ekşi Kara (Vitis Vinifera L.)

“…There is a big variation in optimum germination conditions of pollen among plant species and cultivars (Kelen and Demirtas 2003). Many researchers have been performed to determine quantitatively and qualitatively the components necessary for the best composition of culture medium in pollen grain germination for different species pollens (Abreu, et al 2006;Dane, et al 2004;Eti 1991;Eti, et al 1998;Kelen and Demirtas 2003;Liu and Zhu 1985;Sharafi 2011).…”