Salicylic acid, better known as aspirin, really is a wonder drug. Although most of us use it primarily for minor aches and pains, aspirin can also prevent blood clots leading to heart attack and stroke, and may be protective against certain cancers. Helping farmers drought-proof their crops, on the other hand, is a new one, but scientists at the State University of Paraiba have shown it can do just that.
The cowpea (Vigna unguiculata), known to North Americans as the black-eyed pea, is a staple crop in parts of Brazil. When drought comes, failure of the cowpea crop can bring suffering to millions. Like all plants, the cowpea has mechanisms for coping when conditions are not quite ideal. It produces three enzymes, superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APX), that help it survive dry conditions.
Dr Alberto Soares de Melo and Dr Wellison Filgueiras Dutra experimented with boosting these enzymes through the application of salicylic acid to seeds laid on moistened paper. Six varieties of cowpea were used, and in each case compared with two controls; soaking the paper in purified water and not soaking at all. In turn, each of these variety/treatment combinations was grown using five different water allocations in early growth.
The authors reveal in Agronomy Journal there were differences in the cowpea responses depending on variety, but BRS Itaim cultivar, in particular, responded to the aspirin with increased production of all three enzymes. The increased drought tolerance was large enough that it may be worth the cost of processing seeds in this way, although the researchers say more work needs to be done to see how much water irrigators can save in the field.
"The acid could minimize production and productivity losses of cowpea, and other crops, when cultivated under conditions of low or irregular rainfall, such as the Brazilian Northeast,” Soares de Melo said in a statement.
Many scientists have argued that aspirin is greatly under-researched. It is so widely available that patenting any new applications is effectively meaningless. Consequently, pharmaceutical companies don't spend the money to conduct trials on its many suspected benefits. Research, therefore, is restricted to government funded institutions, like universities, and to what can be covered by charitable donations.
Given the enormous costs of clinical trials, such work is generally beyond these institutions. Fortunately, however, it is a lot cheaper to study plants than humans – they grow faster and don't insist on getting paid to take part in trials – allowing the cowpea study to be done.