03 Jul Plant vitamin synthesis under stress
Green leafy vegetables are often one of the most promoted aspects of healthier diets. This is a result of several of their characteristics, including their dietary fibre, phytochemical, and micronutrient content. In a changing climate with increased frequency of extreme weather events, new research has examined what impact adverse growing conditions can have on the nutritional profile of these crops.
Researchers from Germany and Kenya grew three green leafy vegetable crops common in Sub-Saharan Africa under varying water stress and soil fertility conditions. The production of several vitamins or vitamin pre-cursors in plants is a stress reaction, therefore the researchers hypothesised there would be an increase in the concentration of these molecules.
Unsurprisingly, overall crop yield decreased in the crops grown under both poorer soil fertility and increased water stress. However, vitamin concentration showed the opposite trend. Thiamine (vitamin B1) concentration nearly doubled in two of the analysed crops under the highest stress conditions. For pro-vitamin A and vitamin C, the results were more mixed and dependent on the individual crop and the combination of soil fertility and water stress.
Regardless of the change in concentration of the analysed micronutrients, the total micronutrient harvested decreased under the stress conditions due to the reductions in crop yields. For example, although stress conditions could result in more concentrated thiamine in food, the overall thiamine entering the food system would be reduced.
This research advocates for the consideration of micronutrient content in crop trials, particularly those focused on food insecure or climate vulnerable regions. And while micronutrient concentration may increase under these conditions, this will not make up for the >90% decrease in yield observed for some crops.
This SNippet was written by Dr Nick Smith, a Research Officer in the SNi team.