“…7 ; Supplementary Table S7 ). Importantly, the metabolomics data provide a possible explanation for why oxidative stress-related genes are up-regulated during Arabidopsis leaf development: The polyamines putrescine and spermidine accumulate in response to a range of abiotic stresses to mitigate cellular damage ( Liu et al , 2015 ; Zhang et al , 2015 ), and were shown to reduce ROS abundance and delay the senescence process ( Woo et al , 2013 ; Karimi et al , 2017 ; Chen et al , 2019 ). The amino acids alanine, β-alanine, proline, and glutamate decreased during leaf development and these amino acids and some derivatives thereof have been shown to provide protection against various environmental stresses ( Sharma and Dietz, 2006 ; Martinelli et al , 2007 ; Hayat et al , 2012 ; Majumdar et al , 2016 ; Batista-Silva et al , 2019 ; Parthasarathy et al , 2019 ).…”