Decode the hidden long-term growth limitation in wheat caused by low temperature stress: Insights from leaf functional traits, anatomical bases, resource efficiency, and biochemical capacity

Low temperature events can induce lasting growth limitations in wheat, impacting the final grain yield, but trade-offs of leaf functional traits in this process remain unclear. To address this issue, we investigated the relative biomass accumulation rate and leaf functional traits throughout the ‘low temperature stress-short recovery-long recovery’ process in wheat. Key leaf functional traits, including leaf dry mass per area, leaf nitrogen, and photosynthetic rate per unit mass were increased under low temperature. Their network relationships contribute to enhanced growth responses during short-term recovery. However, decreased leaf nitrogen and phosphorus, photosynthetic rate per unit mass_, and increased dark respiration per unit mass at the 6-leaf stage, coupled with subsequent lower growth responses during long-term recovery, indicate that the irreversible detrimental impact of low temperature becomes apparent after a long recovery stage post the cession of low temperature stress. Changes in photosynthesis capacity during low temperature and the recovery period are influenced by leaf nutrients, CO₂ fractionation, and photosynthesis biochemistry. These factors are closely related to the coordination of leaf anatomy, thylakoid electron transport, and enzyme activities in wheat. Quantifying key leaf functional traits and understanding their network relationships provide important insights for evaluating crop responses to environmental temperature alterations.