Manuka is highly valued for its nectar, which gives the unique manuka honey, the basis of a boom in bee keeping around natural manuka stands and extensive new plantings. The leaf chemistry could provide an additional valuable product, and may be important for the growth of this native plant.
The effects of a chemical called grandiflorone are being discovered by primary and intermediate school students investigating the specific traits of their local manuka plants.
Scientists Elaine Burgess from Plant & Food Research and Dr Dave Warren from the Department of Chemistry, University of Otago, are leading the project which has been supported by the new Zealand government ‘Unlocking Curious Minds’ fund.
“Pupils collect foliage from their local manuka, they then prepare a sample voucher, and extracts are made to test for herbicidal (weed killer) activity in a lettuce seedling assay. They then send us sample extracts to analyse in our Plant & Food Research labs in Dunedin,” Burgess says.
Results are being uploaded to the database so that schools can compare the variations within manuka in their own region, plus the differences around wider New Zealand.
The project is already providing new scientific knowledge.
“Students at Musselburgh School in Dunedin have helped us discover quite big chemical differences in varieties of manuka in the local area, so it’s a surprise to learn manuka from a particular region will not necessarily have the same levels of grandiflorone,” explains Dr Warren.
A crucial aspect of the research is testing whether extracts from various manuka plants stop lettuce seeds from growing. Initial results show New Zealand manuka are generally less potent than a related Australian species.
The focus now is to spread the hands-on testing kits around New Zealand to see if there is a manuka variation here equal to, if not better than, the Australian plant.
“We’ve been very excited by the research so far, and look forward to the kits being circulated to places like the East Cape where we know there are significant amounts of manuka,” Burgess says.
So far, around thirty schools have been sent the kits, which include all the equipment and instructions necessary for the students to conduct the scientific investigations themselves. Testing is spread over approximately two weeks, including collecting local manuka, drying and pressing botanical voucher specimens, and extracting and testing on lettuce seeds.
“This is citizen science in action. We want students to not only gain new skills from conducting the experiments themselves, but also to learn about the nature of science, of testing, of researching and of coming to robust scientific conclusions,” Dr Warren says.
Results from the first wave of testing are being collated at Plant & Food Research in Dunedin, meanwhile the next bundle of kits are being distributed to more schools all around New Zealand. The project is expected to be underway for several more years, dependent on further funding for this community science initiative.
Source: Plant & Food Research