Double coating nurtures seeds

Abstract

Extreme climate events mean crops are increasingly stressed by drought—especially during the crucial stages of seed germination. Inspired by chia seeds’ natural coating, which swells into a gel when wet, researchers have developed a new seed coating that helps seeds retain moisture while capturing nutrients from the soil during germination ( Nat. Food 2021, DOI: 10.1038/s43016-021-00315-8). Seeds are commonly coated with nutrients or fertilizers. For semiarid regions, which make up about 15% of global land, farmers and seed producers can apply superabsorbent polymers to seeds or soil to protect against drought. These practices can contaminate the soil with excess fertilizer and polymer residue. Benedetto Marelli, a biomedical engineer at the Massachusetts Institute of Technology who led the research, wanted to create a more environmentally friendly coating. He started with silk, which is an emerging coating for drug delivery because its unique proteins stabilize biomolecules and because it degrades over time.