Pea Seed Abscission Mutant Study

The four lines of pea (P. sativum L.) seeds (JI 116, JI 2822, JI 1184, and JI 3020) in this study were selected based on the presence of specific alleles at the Def locus, which control the detachment of the seed from the funiculus (Ayeh et al., 2009 (link), 2011 (link)). Two wild types (WT) with the Def locus and two def mutant pea seeds were kindly supplied from the John Innes Pisum Collection Ayeh et al. (2009 (link)). Tall wild type (JI 116) and dwarf wild type (JI 2822) develop normal abscission events and therefore abscise the seed from the funiculus through the intervening hilum region. The tall def mutant (JI 1184) and the dwarf def mutant (JI 3020) both lack the abscission event and therefore fail to abscise the seed from the funiculus. These lines have a deficient abscission zone, which we have given the name abscission-zone-less (AZL; Ayeh, 2008 ). Seeds of each line were sown in pots with fertilized peat and grown under greenhouse conditions at 22°C and 16/8 h photoperiod with a photon flux of 110 μmol m⁻² s⁻¹ [400–700 nm Photosynthetic Active Radiation (PAR)] and a daylength extending light provided from incandescent lamps (OSRAM, Germany).