Re ECF Project: ECF 2015-41

Project Title: Conserving Hong Kong’s endemic and endangered flora: pollination ecology, seed dispersal, population genetics and conservation biology of Thismia species

Applicant: Professor Richard MK SAUNDERS, School of Biological Sciences, The University of Hong Kong

Total Approved Grant: $472,000

Duration: 1/5/2016 to 30/4/2018

Project Status/Remarks: Completed

This project aims to:

(1) further our knowledge of the reproductive biology of Thismia species, including pollination ecology and seed dispersal;
(2) develop local conservation priorities; and
(3) using these highly charismatic species to raise public awareness of biodiversity research and the importance of conservation biology.

Summary of the Findings/Outcomes:
The research team assessed the floral biology of both local Thismia species in detail, with emphasis on T. tentaculata. Anthesis extends over ~16 days, with the stigma and stamens functional throughout. The flowers are pollinated by fungus gnats (Corynoptera, Sciaridae), which are constrained within the floral tube before departing via apertures between the anthers. The fungus gnats are attracted by yellow pigmentation and floral scents that include dipteran pheromones. Although controlled pollination experiments revealed that the plants are self-compatible, self-pollination is largely avoided by stamen appendages that prevent pollen deposition on the stigma of the same flower. Pollen transfer is therefore dependent on pollinators, and limited seedset under natural conditions suggests pollinator limitation. Seeds are dispersed by rain-splash, effective over short distances of up to 80 cm. The symbiosis between Thismia and their arbuscular mycorrhizal partners is highly specific, implying that any attempt at ex situ cultivation is extremely unlikely to be successful. The research team does not advocate any attempt at cultivating Thismia species in botanical gardens or transplanting to new localities in the wild, and hence there is an urgent need for in situ conservation.