Reproductive biology of Echinodorus grandiflorus (Alismataceae): evidence of self-sterility in populations of the state of São Paulo

Emerson R Pansarin,Ludmila M Pansarin

doi:10.1590/2175-7860201162114

Emerson R Pansarin, Ludmila M Pansarin

Open Access

https://doi.org/10.1590/2175-7860201162114

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Abstract

Abstract The reproductive biology and the pollination of Echinodorus grandiflorus (Cham. & Schltdl.) Micheli were studied in populations native to interior of the State of São Paulo, Brazil. This species blossoms in summer and its flowers offer both nectar and pollen as rewards to pollinators. Nectar is produced in nectaries located at the base of the marginal carpels, opposite the petals. However, the effective pollinators (social and solitary bees), were recorded collecting pollen only. Visits, which can last from one or a few seconds to more than one minute, occur during the whole flower lifespan. Each flower opens at about 5:30 a.m. and lasts circa eight hours. All plants in the studied populations produce only hermaphrodite flowers. Percentage of pollen viability is 75%. The studied populations are self-incompatible and, as a consequence, pollinators are needed to transfer pollen among individuals. In natural conditions and after hand cross-pollinations, all receptacles presented mature achenes. Based on the analyses of pollen tube growth from hand self-pollinated flowers, and as a consequence of achenes abortion circa 30 days after self-pollinations, the populations of E. grandiflorus studied apparently presents a mechanism of late-acting self-sterility.

Highlights

Alismataceae is subcosmopolitan and it is represented in the temperate, subtropical and tropical regions of both hemispheres (Haynes & Holm-Nielsen 1994)
Among the genera of Alismataceae growing in Brazil (Echinodorus Rich., Sagittaria L. and Helanthium (Benth. & Hook. f.) Engelm. ex J.G
Sm.), the production of hermaphrodite flowers is the main characteristic used to distinguish Echinodorus from Sagittaria (Haynes & Holm-Nielsen 1986, 1994; Pansarin & Amaral 2005)

Summary

Introduction

Alismataceae is subcosmopolitan and it is represented in the temperate, subtropical and tropical regions of both hemispheres (Haynes & Holm-Nielsen 1994) This family includes circa 80 species distributed in approximately 11 genera, three of which occur in Brazil: Echinodorus Rich., Sagittaria L. and Helanthium According to the classification by Haynes & Holm-Nielsen (1994), E. grandiflorus present two subspecies Both occur in the State of Minas Gerais and present different reproductive systems: E. grandiflorus When studies involving widely distributed species are carried out in more than one area, differences are observed with regard to their pollination systems (Smith & Snow 1976; Cole & Firmage 1984) Based on these assertions, the present work investigated the reproductive system of E. grandiflorus in populations native to the rural area of Ribeirão Preto, State of São Paulo, through studies on floral morphology, pollinators and pollination.

Material and methods

Discussion