Metabolic and film antitranspirants both reduce drought damage to wheat yield despite having contrasting effects on leaf ABA

Film antitranspirants (e.g. di-1-p-menthene) and metabolic exogenous ABA) can be used to protect grain crops from drought, particularly during reproductive development. Here, we compared effects of di-1-p-menthene (1.0 L/ha) ABA (100 µM) on well-watered droughted spring wheat in two glasshouse experiments. Progressive drought was imposed the first experiment, controlled second, both flag leaf emergence. Antitranspirants were applied at emergence, except experiment where additional applications made four further stages up anthesis-complete. Measurements taken for endogenous ABA, stomatal conductance photosynthesis development, yield components maturity. Both progressive elevated less so di-1-p-menthene-treated plants, whereas ABA-treated plants further. Overall, improved under reproductive-stage more drought. Grain negatively associated with concentration that raising multiple high yield. In conclusion, generally reduced despite having contrary ABA.