cept ors . ▁High ▁hydro static ▁press ures ▁( H HP s ) ▁of ▁ 2 0 0 – 4 0 0 ▁M Pa ▁also ▁trigger ▁germ ination ▁through ▁the ▁GR s . ▁The ▁germ in ating ▁sp ore ▁initially ▁releases ▁H + , ▁K + , ▁Na + ▁and ▁Ca + 2 , ▁raising ▁the ▁p H ▁of ▁the ▁sp ore ▁core ▁from ▁p H ▁ 6 . 5 ▁to ▁ 7 . 7 . ▁Cor tex ▁l yt ic ▁en zym es ▁are ▁activ ated , ▁and ▁the ▁protect ive ▁sp ore ▁pe pt id og ly can ▁cor tex ▁is ▁de grad ed . ▁Activ ation ▁is ▁a ▁revers ible ▁process ▁that ▁does ▁not ▁necessarily ▁commit ▁the ▁sp ore ▁to ▁germ ination ▁and ▁out g row th ▁( Set low , ▁ 2 0 0 3 , ▁P ared es - S ab ja ▁et ▁al ., ▁ 2 0 1 1 , ▁Stewart ▁and ▁Set low , ▁ 2 0 1 3 ). ▁ ▁Stage ▁II : ▁D PA ▁( py rid ine - 2 , 6 - dic ar box y lic ▁acid ) ▁is ▁de grad ed ▁and ▁released , ▁followed ▁by ▁re h yd r ation ▁of ▁the ▁sp ore ▁core . ▁Re h yd r ation ▁allows ▁the ▁init iation ▁of ▁protein ▁mob ility ▁and ▁react iv ation ▁of ▁bio chem ical ▁processes ▁during ▁out g row th ▁( Z hang ▁et ▁al . ▁ 2 0 1 0 ). ▁ ▁Stage ▁III : ▁Sp