Flash flaming is a valid seed enhancement for a diverse range of species and seed morphologies

Abstract

Flash flaming has shown promise as a seed enhancement technology that improves the handling properties of bulky or irregularly shaped seed material, which in turn benefits logistical and ecological aspects of large-scale direct seeding. To date, only a small number of grass species, that possess similar morphological characteristics, have been tested. This paper describes the application of flash flaming to diaspores (i.e. the dispersal unit comprising the seed and any surrounding or attached tissues) of 19 diverse dryland species from the Amaranthaceae, Asteraceae, Chenopodiaceae and Poaceae critical to ecological restoration in the mining intensive Pilbara region of Western Australia. Flash flaming parameters for each species were tested to identify and maximise volume and mass reduction, reduce particle cohesiveness and maximise flow through a mechanical seeding device, whilst maximising germination. Flaming of all species resulted in reductions in batch volume and mass, and improvements to flow characteristics. For 17 species, flaming either benefited or did not impact on germinability. For two species in the Amaranthaceae, flaming with the settings tested here resulted in a reduction in germinability; however, flaming enabled the diaspores to pass through a mechanical seeding device enabling mechanical distribution which is critical if the species are to be used in large scale restoration.

Use of Flash-Flaming Technology to Improve Seed Handling and Delivery of Winterfat (Krascheninnikovia lanata)

“…Many species across the globe possess complex seed morphologies that affect seed flowability (Masarei et al 2019; Ling et al 2022). For this reason, flash flaming was developed to remove these unwanted appendages (Guzzomi et al 2016; Ling et al 2019; Berto et al 2020; Ling et al 2022).…”

“…Many species across the globe possess complex seed morphologies that affect seed flowability (Masarei et al 2019; Ling et al 2022). For this reason, flash flaming was developed to remove these unwanted appendages (Guzzomi et al 2016; Ling et al 2019; Berto et al 2020; Ling et al 2022). In addition to eliminating cumbersome seed appendages, flash flaming in all recorded cases has improved the potential of the seed to be coated with various materials (Guzzomi et al 2016; Erickson et al 2019; Ling et al 2019; Berto et al 2020; Berto et al 2021).…”

“…Before flaming the fruits, but while the fruits were in motion, 10 g of water was added directly to the fruits. While flaming, we added an additional 5 g of water every 60 s. This “flame-softening” approach (Ling et al 2022) was used because our preliminary work indicated that most fruits would com-bust without water, resulting in lower seed viability. This flash-flaming technique was conducted over five flaming durations for 90, 180, 270, 360, and 450 s to determine the maximum duration fruits could be exposed to flash flaming without impacting seed viability.…”

“…After applying the flaming treatment, seeds/fruits can be treated with a polymer seed coating to improve seed flowability and allow for the application of other treatments to enhance seed germination and plant growth (Guzzomi et al 2016; Erickson et al 2019). Flash flaming technology has continued to advance with the scale-up of the size of the apparatus used for treating seeds and has been applied to multiple species in Australia and North America (Erickson et al 2019; Berto et al 2020; Berto et al 2021; Masarei et al 2021; Ling et al 2022).…”

“…Seeds or fruits are flash flamed by placing the material in a rotary seed coater that has a propane torch positioned close to the rotating stream of seeds/fruits to singe off unwanted appendages. A user can precisely singe off appendages without impacting seed viability through experimentation with the flame torch placement and the length of time the fruits or seeds are subject to the treatment ( Ling et al 2022 ). After applying the flaming treatment, seeds/fruits can be treated with a polymer seed coating to improve seed flowability and allow for the application of other treatments to enhance seed germination and plant growth ( Guzzomi et al 2016 ;Erickson et al 2019 ).…”