The composition of pollenkitt and its role in the progamic phase of reproduction are poorly understood. With the aim of extending knowledge on these topics, we chose to study two monocotyledons rich in pollenkitt, with bi-celled and long-lived pollen and dry-type stigma: Crocus vernus Hill subsp. vernus and Narcissus poeticus L. Fatty acids of pollenkitt were assayed with gas chromatography. Germination tests were performed in vivo by pollinating the stigmas with a beard hair under a stereomicroscope, and in vitro in liquid culture medium using pollen, either treated or not, with carbon disulphide to remove pollenkitt. The pollen tube percentages were evaluated using fluorescence microscopy techniques. Scanning electron microscopy was used to examine pollen and to follow the early post-pollination stages. Pollenkitt forms bridges between pollen grains but not between grains and stigma papillae. It consists of a mixture of 25 fatty acids, most with long and unsaturated chains, among which are some omega acids. The same acids with different percentages persist on the peritapetal membrane. After its removal, the pollen loses adhesiveness and dries quickly, but retains full capacity for germination on the papillae and can even trigger germination in contiguous pollen grains that do not touch the papillae. The results, while confirming the key role of pollenkitt in protecting pollen and favouring pollination, suggest secondary roles in the progamic phase, and highlight the interactive ability of the pollen regardless of lipid shell. The predominance of fatty acids with 18:3 and 16:0, as already noted in Brassica napus pollenkitt, suggests their hierarchy independent of plant species.

Pollenkitt of some monocotyledons: lipid composition and implications for pollen germination

Chichiricco G.
;
2019

Abstract

The composition of pollenkitt and its role in the progamic phase of reproduction are poorly understood. With the aim of extending knowledge on these topics, we chose to study two monocotyledons rich in pollenkitt, with bi-celled and long-lived pollen and dry-type stigma: Crocus vernus Hill subsp. vernus and Narcissus poeticus L. Fatty acids of pollenkitt were assayed with gas chromatography. Germination tests were performed in vivo by pollinating the stigmas with a beard hair under a stereomicroscope, and in vitro in liquid culture medium using pollen, either treated or not, with carbon disulphide to remove pollenkitt. The pollen tube percentages were evaluated using fluorescence microscopy techniques. Scanning electron microscopy was used to examine pollen and to follow the early post-pollination stages. Pollenkitt forms bridges between pollen grains but not between grains and stigma papillae. It consists of a mixture of 25 fatty acids, most with long and unsaturated chains, among which are some omega acids. The same acids with different percentages persist on the peritapetal membrane. After its removal, the pollen loses adhesiveness and dries quickly, but retains full capacity for germination on the papillae and can even trigger germination in contiguous pollen grains that do not touch the papillae. The results, while confirming the key role of pollenkitt in protecting pollen and favouring pollination, suggest secondary roles in the progamic phase, and highlight the interactive ability of the pollen regardless of lipid shell. The predominance of fatty acids with 18:3 and 16:0, as already noted in Brassica napus pollenkitt, suggests their hierarchy independent of plant species.
File in questo prodotto:
File Dimensione Formato  
pollenkitt 2019.pdf

solo utenti autorizzati

Tipologia: Documento in Versione Editoriale
Licenza: Dominio pubblico
Dimensione 737.04 kB
Formato Adobe PDF
737.04 kB Adobe PDF   Visualizza/Apri   Richiedi una copia

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11697/136069
Citazioni
  • ???jsp.display-item.citation.pmc??? 2
  • Scopus 9
  • ???jsp.display-item.citation.isi??? 8
social impact