Dr Carmen Teixeira1, Professor John Hampton2, Assoc. Prof. Dr Notburga Gierlinger3, Professor Derrick Moot1
1Dryland Pastures Research Group, Field Research Centre, Department of Agricultural Sciences, Lincoln University, Lincoln, New Zealand, 2Seed Research Centre, Department of Agricultural Sciences, Lincoln University, New Zealand, Lincoln, New Zealand, 3University of Natural Resources and Life Sciences Institute of Biophysics, Bionami – Boku, Vienna, Austria
Biography:
Dr Carmen completed her PhD and Post-doc at Lincoln University Canterbury, New Zealand where she researched the phenology and hardseededness of subterranean clover cultivars. Areas of expertise include forage pasture growth, subterranean clover phenology, seed health and technology. Currently she is part of the dryland pasture research group engaged on the national database (https://agyields.co.nz) project.
Abstract:
Subterranean clover (Trifolium subterraneum) is an important legume in resilient crop systems in Australia and regenerative pastures in New Zealand. It provides high-quality biomass and nitrogen fixation during late winter and early spring. The hardseeds of subterranean clover have a seed coat which is impermeable and prevents germination even when moisture and temperature conditions are ideal. Ecologically it enables the regeneration and persistence of subterranean clover under a broad range of management and environmental conditions, supplying seeds for germination at the right time of the year and through the development of soil seed banks. Suberin, an extracellular tissue sealing polymer and lignin have been proposed to be the main seed coat biochemical components of hardseeds in subterranean clover. The classic procedures for assessing hardseededness are laborious, costly and involve sample destruction. The Fourier transform infrared microspectroscopy (FTIR) with Attenuated Total Reflectance (ATR) lens, which is a non-destructive, rapid and in situ technique was used to characterise the biochemical profile of the seed coat from six subterranean clover cultivars. The seed coat was composed of different functional groups, mainly of aromatics (1500 -1200 cm-¹) and polysaccharides (1025 cm−¹). In addition, cutin, cellulose and tannins in the coat outer layer were important to confer hardseededness. The maximum percentage of hardseededness (HSmax) was assessed using the top of paper germination test. HSmax was associated (R2= 0.86) with the absorbance of vibrations at 897 cm-¹ ,1337 cm-¹ (cellulose) and 1250 cm-¹ (esters, cutin, suberin). The FTIR-ATR technology can be broadly applied to study the biochemical profile of other important dormant legumes.