Reproductive biology of Tabebuia pallida (Lindl.) Miers. (Bignoniaceae) collection of Purwodadi Botanic Garden

Abstract

Botanic garden play a central role in the ex-situ plants conservation. It is important to maintain the survival life of the living plant collections. Knowledge on the details of reproductive biology of the living collections becomes vital to monitor the success or failure of conservation efforts. Tabebuia pallida (Lindl.) Miers. (Bignoniaceae) is one of the living plants collection in Purwodadi Botanic Garden that need to be monitored. So far information on the reproductive biology of this species is still limited. Based on that, in relation to the conservation effort, the objectives of this study were to provide knowledge about the reproductive biology of T. pallida. The research was conducted at Purwodadi BG, from September 2019 to February 2020. Several important aspects of reproductive biology, including flower biology, pollen viability and stigma receptivity, breeding system (Out-Crossing Index), and pollination biology were investigated. The results showed that T. pallida was monocious, has a pinkish tubular corolla with a yellow throat. There was no spatial separation between the anther and stigma. At the time of anthesis, both pollen and stigma have been receptive. Based on flower biology, pollen ornamentation (reticulate type), and the Out-Crossing Index (OCI=3), the flower showed some characters of entomophily, but self-pollination was possible. There are some insects visitor, but that acts as a pollinating agent was Vespula. The availability of effective pollinators in botanic garden was an obvious requirement for successful plants conservation.