Abstract Detail

Ecology

Understanding trade-offs in vegetative reproduction through bulbils in Globba L. (Zingiberaceae).

Globba L. is the fourth largest genus in Zingiberaceae and is one of three genera in the tribe Globbeae. Currently it comprises at least 120 species that are distributed from Sri Lanka, India, Southeast Asia, to Australia and within India, it is represented by 14 species that are confined only to a few states in the Western Ghats and North East India. Most Globba species show both sexual and asexual (rhizomes and bulbils) reproductive strategies. Although bulbils represent efficient reproductive strategies and an important taxonomic character, very little is known of the nature of its origin and its importance as an ecological trait. Here, we present results from our study on three Globba species: G. sessiliflora, G. marantina and G. orixensis where we investigate the role of bulbils as an efficient reproductive strategy. In this study, we asked the following questions: (i) Do taxa with bulbils show better dispersal abilities (higher geographic range) as well as larger population sizes when compared to taxa without bulbils? (ii) 2. Do bulbil-producing species also resort to sexual reproduction and are there any trade-off between sexual (fruit-set) and asexual (bulbils) mode of reproduction?
Fieldwork was carried out in the months of July to October, which coincides with the flowering time of the three Globba spp. in 28 different locations. Our results show that Globba sessiliflora is a facultative asexual plant in contrast to Globba marantina which dominantly reproduces through bulbils ie asexually. We quantified population densities using fixed quadrats (20*20m2) in the three species and we also quantified the number of flowers, fruit set/seed count, and the number of bulbils, within an individual (n=40 per species), to check if there is any trade-off between sexual and asexual mode of reproduction. Our preliminary results suggest that species that produce bulbils (asexuals) showed higher clumped populations, this may be because bulbils may be resistant to adverse environmental conditions and can establish faster than completely sexual species. The number of bulbils and natural fruit set also varied by geographic location, within a species. This suggests that the formation and number of bulbils are probably dependent on environmental variables. Our correlation analyses show that there is no trade off between the number of fruits and bulbils. We propose that taxa that predominantly reproduce via bulbils will also show higher inbreeding over taxa that are facultatively reproducing through bulbils. However, the inbreeding rates may not directly affect their population sizes, thus confirming that bulbils may offer advantages in population growth, similar to those observed in clonal plants.

1 - Indian Institute Of Science Education And Research Bhopal, Biological Sciences, Lab No -303, Academic Building 3,, Bhauri, Bhopal, MP, 462066, India
2 - IISER Bhopal, Room 223, AB3, Dept. Of Biological Sciences,, IISER- Bhopal, Bhopal Bypass Road, Bhauri,, Bhopal, MP, 462066, India

Keywords:
Globba
Zingiberaceae
asexual reproduction
Bulbils.

Presentation Type: Oral Paper
Number: EC04006
Abstract ID:934
Candidate for Awards:Ecological Section Best Graduate Student Paper