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ARS Home » Southeast Area » Poplarville, Mississippi » Southern Horticultural Research Unit » Research » Publications at this Location » Publication #243751
Title: Pollen Biology of Ornamental Ginger (Hedychium spp. J. Koenig)

Author
item Sakhanokho, Hamidou
item Rajasekaran, Kanniah - Rajah

Submitted to: Scientia Horticulturae
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/13/2009
Publication Date: 12/22/2009
Citation: Sakhanokho, H.F., Rajasekaran, K. 2009. Pollen Biology of Ornamental Ginger (Hedychium spp. J. Koenig). Scientia Horticultureae pgs 129-135.

Interpretive Summary: The genus Hedychium (ornamental ginger) consists of about 80 species characterized by beautiful foliage as well as diverse, showy, and fragrant flowers. Despite the potential ornamental, medicinal, and industrial values of the Hedychium genus, very little work has been done to understand the pollen biology such as germinability, storage, viability, nuclear status, and pollen/ovule ratio. Knowledge about in vitro germination, tube growth, storage, nucleus status, ultrastructure of Hedychium pollen as well as pollen: ovule ratio can be of the utmost importance for understanding not only the basic characteristics of Hedychium pollen but also its pollination biology, which could ultimately lead to better breeding strategies for the Hedychium genus. An improved in vitro pollen germination assay was developed to assess the viability of stored Hedychium pollen. The effect of polyethylene glycol (PEG) (10, 15, and 20% w/v) on pollen germination and tube growth was evaluated for H. longicornutum and two commercial Hedychium cultivars, ‘Orange Brush’ and ‘Filigree’. Overall, the inclusion of PEG 4000 in the medium improved both pollen germination and tube growth for the three different genotypes tested and the results varied depending on genotype. Two viability tests, in vitro germination and acetocarmine staining, were used to assess the viability of Hedychium pollen stored up to two months. Of the two viability tests, only the in vitro germination test was found to be a good indicator of the viability of stored Hedychium pollen. Pollen nucleus status was determined for four Hedychium cultivars, ‘Orange Brush’, ‘Anne Bishop’, ‘Filigree’, and ‘Daniel Weeks’. Pollens of ‘Orange Brush’ ‘Anne Bishop’, and ‘Daniel Weeks’ were found to be binucleate but ‘Filigree’ was shown to possess both binucleate (two nuclei) and trinucleate (three nuclei) pollens. High pollen: ovule ratio values were obtained in several Hedychium species, suggesting that Hedychium plants are mostly cross-pollinated. The results obtained on the nuclear pollen status and pollen: ovule ratios will further our understanding of the pollination biology and help clarify the taxonomy of Hedychium species.

Technical Abstract: An improved in vitro pollen germination assay was developed to assess the viability of stored Hedychium pollen. The effect of polyethylene glycol (PEG) (10, 15, and 20% w/v) on pollen germination and tube growth was evaluated for H. longicornutum and two commercial Hedychium cultivars, ‘Orange Brush’ and ‘Filigree’. Overall, the inclusion of PEG 4000 in the medium improved both pollen germination and tube growth for the three different genotypes tested and the results varied depending on genotype. Two viability tests, in vitro germination and acetocarmine staining, were used to assess the viability of Hedychium pollen stored up to two months. Of the two viability tests, only the in vitro germination test was found to be a good indicator of the viability of stored Hedychium pollen. Pollen nucleus status was determined for four Hedychium cultivars, ‘Orange Brush’, ‘Anne Bishop’, ‘Filigree’, and ‘Daniel Weeks’. Pollens of ‘Orange Brush’ ‘Anne Bishop’, and ‘Daniel Weeks’ were found to be binucleate but ‘Filigree’ was shown to possess both binucleate and trinucleate pollens. High pollen: ovule ratio values were obtained in several Hedychium taxa, confirming the high degree of self-incompatibility in Hedychium genus. The results obtained on the nuclear pollen status and pollen: ovule ratios will further our understanding of the pollination biology and help clarify the taxonomy and phylogeny of Hedychium species.