Characterization of cultivars and low-temperature pollen grain storage in amaryllis (Hippeastrum sp.)

Abstract

The determination of viability and the preservation of pollen grains are useful tools for breeding of ornamentals, especially when the synchronization of flowering between species or cultivars does not occur naturally. Thus, the objective of this study was to characterize the flowering and to evaluate the preservation and maintenance of the viability of pollen grains in cultivars of amaryllis (Hippeastrum sp.) subjected to three storage temperatures. Anthers of five cultivars of amaryllis were collected from 12 to 24 hours after anthesis. One part of the anthers was immediately used for germination tests using in vitro germination in culture medium and the other part was stored at temperatures of 25, 8 and-20 °C. Pollen grains were germinated in culture medium at 0, 20, 75, 125, 165, 205 and 245 days after storage. All cultivars of amaryllis showed an accelerated loss of viability at 25 °C storage temperature. The 'Bull' cultivar showed higher recalcitrance to cold-storage, while 'Intokazie' and 'Pink Panther' cultivars showed higher longevity and higher percentage of germination along storage. The temperature of-20 °C resulted in the best responses for the maintenance of the integrity and preservation of the viability of pollen grains of different cultivars of amaryllis.

Evaluation of the possibility of obtaining viable seeds from the cross-breeding Hippeastrum × chmielii Chm. with selected cultivars of Hippeastrum hybridum Hort.

“…Cross-pollination is the only method of obtaining seeds capable of germination in H. hybridum (Wóycicki, 1966;Almeida et al, 2019). Additionally, the flowers of Hippeastrum are proterandrous, which means that the anthers mature earlier than the stigmas (Almeida et al, 2019;Szlachetka, 2000).…”

“…Cross-pollination is the only method of obtaining seeds capable of germination in H. hybridum (Wóycicki, 1966;Almeida et al, 2019). Additionally, the flowers of Hippeastrum are proterandrous, which means that the anthers mature earlier than the stigmas (Almeida et al, 2019;Szlachetka, 2000). It confirms the necessity In our study, the viability of Hippeastrum pollen grains was evaluated after the opening of the anthers by acetocarmine staining.…”

Viabilidade e conservação de grãos de pólen da carnaúba (Copernicia prunifera (Miller) H.E. More)

“…Entre os constituintes que compõem o meio de cultivo, a concentração de sacarose é um fator fundamental, em que altas concentrações (acima de 30%) podem inibir a germinação dos grãos de pólen. A sacarose tem papel de controlador osmótico e nutricional, sendo que altas concentrações causam desequilíbrio, impedindo a germinação dos grãos de pólen (Almeida et al 2019;Abdelgadir et al 2012). Entretanto, no presente trabalho a menor emissão do tubo polínico no meio M1 provavelmente não está relacionada com a adição em excesso da sacarose no meio de germinação, pois os meios M2 e M3, que proporcionaram maior taxa de germinação do grão de pólen, possuíam a mesma concentração de sacarose que o meio M1.…”

New protocol for storage of viable pollen of Lapageria rosea (Philesiaceae), an endangered plant species endemic to temperate forests of Chile

“…A review of the literature regarding viability of stored pollen indicates that there is a great degree of variability in the response of pollen grains of individual plant species, or even a variety or cultivar, to storage temperature treatments (Almeida, Saziki, & Cardoso, 2019). This has been partially attributed to the temperature‐dependent rates of pollen metabolic activities (Du et al, 2019), the size of the pollen grains (García Cruzatty, Rivero, & Droppelmann, 2015; Koen, Slabbert, Booyse, & Bester, 2020) or the plant genetic background (Beltrán et al, 2019).…”