SEED GERMINATION OF -AMYGDALUS ARABICA OLIV.- AS INFLUENCED BY STRATIFICATION AND CERTAIN PLANT BIOREGULATORS

In one experiment-Amygdalus arabica Oliv.-seeds with their endocarps (intact seed) were stratified for 0,15,30, 45 and 60 days at 5°C. Significantly highest germination percentage (G%) (63% and 67%) was obtained from intact seeds stratified for 45 or 60 days while the nonstratified ones did not germinate. During the stratification periods, seed content of free and bound ABA gradually declined, while for endocarps no distinct pattern was observed. Excised seeds contained free and bound ABA 7 to 8 and 12 to 13 folds more than in endocarps. Stratification for 45 or 60 days was associated with least free ABA content in seeds (0.179 and 0.142 μg/g fresh weight) and in endocarps (0.0208 and 0.0193 μg/g fresh weight). In another experiment, seeds were stratified for the same durations and soaked separately in 1500 ppm GA₃. Stratification for 30 days plus soaking resulted in highest G% (37%). Stratifying seeds for 45 or 60 days plus soaking in 1500 ppm GA₃ was deleterious to germination. In a third experiment, stratified seeds for 30 days and soaked for 24 hrs in either 750 or 1000 ppm GA₃ significantly raised G% to 50 and 40 over those soaked in several GA₃ concentrations (0,250 and 500 ppm). In a fourth experiment soaking separately non stratified intact seeds alone in GA₃ at 250, 500 and 750 ppm for 24 hrs significantly raised G% over those soaked in BA (250,500, 750 ppm) alone, GA₃ 500 ppm combined with 500 ppm BA and nontreated seeds. Nonchilled excised embryos germinated at 20°C showed various features of abnormality when compared with chilled ones.