Putrescine metabolism modulates the biphasic effects of brassinosteroids on canola and Arabidopsis salt tolerance

Brassinosteroids (BRs) are known to improve salt tolerance of plants, but not in all situations. Here, we show that a certain concentration of 24‐epibrassinolide (EBL), an active BR, can promote the tolerance of canola under high‐salt stress, but the same concentration is disadvantageous under low‐salt stress. We define this phenomenon as hormonal stress‐level‐dependent biphasic (SLDB) effects. The SLDB effects of EBL on salt tolerance in canola...