JOURNAL HIGHLIGHTS BY STEVE RANGER
Researchers have looked at the potential to use seed nutripriming to enhance the nutritional quality of microgreens as part of efforts to tackle the widespread problem of selenium deficiency.
Crops cultivated in selenium-poor soils will contain low levels of the micronutrient, and projections under moderate climate change scenarios suggest soil selenium losses of up to 8.7% in two-thirds of croplands, which could make this problem even worse, according to a paper published in SCI’s Journal of the Science of Food and Agriculture by the researchers from Portugal. They point to agronomic biofortification as a sustainable and effective strategy to improve food quality at the source.
‘Unlike supplementation, it allows micronutrients to be naturally incorporated into plant tissues and speciated into biomolecules during growth, thereby enhancing their dietary availability,’ says José Pinela, one of the team involved in the research.
‘Microgreens are particularly attractive in this context because they are fast-growing, nutrient-dense, and highly responsive to controlled cultivation strategies, making them ideal candidates for rapid nutritional enhancement,’ he adds.
Seed priming involves controlled seed hydration to activate pre-germinative metabolic processes without radicle protrusion; the more advanced nutripriming uses nutrient-enriched solutions for hydration which can improve germination performance as well as the nutritional value of the resulting plants.
The researchers said nutripriming holds promise when applied to high-value, nutrient-dense crops such as microgreens. In particular, pea (Pisum sativum L.) microgreens are widely consumed, and their rapid growth cycle and responsiveness to nutrient inputs make them useful models for testing these types of biofortification strategies.
The study evaluated the effects of nutripriming pea seeds with different selenium concentrations and soaking durations. The pea seeds were soaked in freshly prepared sodium selenate solutions at different selenium concentrations, for either 6 or 12 hours in the dark, with a batch of non-primed seeds serving as the untreated control.
The researchers found that nutripriming significantly increased seed selenium content, with the 100 μm – 12-hour selenium treatment resulting in a four-fold accumulation compared with controls, at the same time as preserving membrane integrity. However, this 12-hour duration significantly reduced the emergence rate and aerial biomass yield.
Selenium nutripriming enhanced the nutritional quality of pea microgreens but ‘revealed a critical trade-off’ the researchers said. Although 12-hour priming maximised selenium uptake and antioxidant properties, it reduced agronomic production, the paper said.
It noted that six-hour priming promoted better biomass yield, although germination remained lower than in the non-primed control. ‘Therefore, optimising priming duration is essential to balance the biofortification benefits with overall crop productivity,’ they said.
‘One of the most striking findings was the clear trade-off between nutritional enhancement and agronomic performance,’ says Pinela. ‘While more intense or prolonged treatments increased selenium accumulation and improved antioxidant properties, they also reduced germination rates and biomass production.’
Another notable result was that selenium originating from primed seeds in the sodium selenate form was translocated to the aerial parts much more efficiently (77–91%) than the selenium possibly present in the cultivation substrate (66% in the non-primed control).
‘This suggested that biofortification is not simply a matter of increasing nutrient supply – it requires careful optimisation of concentration, treatment duration, and even the source of selenium exposure,’ he says.
Pinela says that the study showed that a single 35 g serving of biofortified pea microgreens can provide approximately 100% of the adult daily reference intake for selenium (55 µg), as established by EU regulation. ‘These findings reinforce their potential as functional foods for modern diets, particularly in regions where selenium deficiency is endemic,’ he says.
He said future work will focus on optimising both selenium accumulation and its speciation while maintaining or improving agronomic performance, as the health benefits depend strongly on the formation of organic compounds such as selenomethionine, selenocysteine, and methylselenocysteine.
‘We are particularly interested in understanding the mechanisms of selenium speciation within plants. We also plan to extend this approach to other crops, such as spinach and Swiss chard, and to explore combined biofortification strategies,’ he says.
Another key direction is the use of controlled environment agriculture, particularly indoor vertical farming, as these systems allow precise control over environmental factors such as light, temperature and humidity, enabling year-round production of microgreens with enhanced nutritional quality, he notes.
Selenium biofortification of pea (Pisum sativum L.) microgreens through seed priming: Effects on agronomic performance and nutritional quality
Cátia Magalhães, Matilde Rodrigues, José Pinela
Journal of the Science of Food and Agriculture
doi.org/10.1002/jsfa.70595
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