The effects of salinity and gibberellic acid on blackheart disorder in celery (Apium graveolensL.)

Abstract

SummaryBlackheart of celery is known to be a Ca deficiency-related disorder. The present study shows that blackheart is greatly attenuated in plants adapted to salinity (NaCl) in which the Ca content in young susceptible leaves is significantly reduced. The application of GA3 to untreated plants enhanced blackheart development, but GA3 sprayed on salinized plants has no effect although the Ca level in the young leaves was further reduced by this treatment. GA3 supplied to either untreated or salinity-adapted plants substantially enhanced the elongation of mature leaves but only slightly increased the elongation of young leaves which are the ones most susceptible to blackheart. The same was observed in similarly treated plants the inner leaves of which were covered to encourage blackheart development. GA3 increased electrolyte leakage from sections of petioles from mature and young leaves. However, the most affected sections were those from mature leaves of salinized plants which are not prone to blackhear...