Phosphate starvation during the transition phase increases the sex ratio and 12-oxo-phytodienoic acid contents in females of Urtica dioica

•Phosphate starvation shifts the sex ratio towards females in stinging nettle (Urtica dioica L.).•Chemical defences, in terms of 12-oxo-phytodienoic acid accumulation, increases more in females than in males.•Changes in the sex ratio and chemical defences may compensate the negative impact of nutrient limitation in this dimorphic species.