Expression of abscisic acid (ABA) biosynthesis and response genes in Physcomitrella tissues. (a) Reverse transcription (RT)‐PCR of the putative Physcomitrella ABA biosynthesis genes PpABA2 and PpAAO3 (two homologues; Hanada et al., 2011) in Physcomitrella tissues. (b) RT‐PCR of the four putative Physcomitrella ABA receptors (RCARs; Hanada et al., 2011) in Physcomitrella tissues. (c) RT‐PCR of the two putative Physcomitrella ABA signalling kinases (SnRKs; Hanada et al., 2011) in Physcomitrella tissues. (d) RT‐PCR of the Physcomitrella ABI1 ABA‐response genes (Sakata et al., 2009) in Physcomitrella tissues. (e) RT‐PCR of the Physcomitrella ABI3 ABA‐response genes (Khandelwal et al., 2010) in Physcomitrella tissues. All gene expression was compared to a PpTUBULIN control. Dry, dry spores; Imb, imbibed spores; Ger, germinating spores; Prot, protonema; Leaf, Leafy gametophores; W, water control.