Nutrient conditions and waterlogging
The nutrient solution was after (Cui et al. , 2019a), where the
amount of K+ was varied by changing the amount of KCl.
Two K availability conditions were used here: “low K” (0.2 mM) and
“high K” (4 mM). The amount of nitrate and phosphate (in mM) in the
nutrient solution was kept constant throughout experiments (nutrient
solution composition in Table S1). Nitrate concentration of the nutrient
solution was 15 mM to cover plant N needs and avoid any N-limitation
effects. The amount of Ca2+ (low [0.4 mM], and
high [4 mM]) was adjusted my changing the balance between Ca-nitrate
and Na-nitrate (Table S1). Putrescine was added at a concentration of
0.4 mM. Taken as a whole, there were six nutrient conditions: low K and
high Ca (LK-HCa), high K and high Ca (HK-HCa), low K and low Ca
(LK-LCa), high K and low Ca (HK-LCa), low K and high Ca with putrescine
addition (LK-HCa+P), and high K and high Ca with putrescine addition
(HK-HCa+P). It should be noted that here, the condition low Ca +
putrescine (under either low or high K) has not been used because the
objective was to assess whether putrescine addition can compensate for
the effects of high Ca. In figures, high Ca, low Ca and high Ca +
putrescine conditions are shown with blue, green and pink shades,
respectively.