Temperature and Light Effects on Germination of Papaver bracteatum Lindl., P. orientale L., and P. somniferum L.

Abstract

The germination requirements of Papaver bracteatum, a potentially new medicinal crop, were determined. Seeds of P. bracteatum, P. orientale, and P. somniferum were germinated on ther–mogradient plates with isotherms from 6° to 35° C in total darkness. Maximum germination was from 18° to 26° C and maximum rate of germination was from 21° to 26° C for P. bracteatum seeds. Maximum germination and maximum rate of germination was from 18° to 30° C and from 13° to 33° C for P. orientale and P. somniferum, respectively. When dormancy was induced by holding imbibed seeds of P. bracteatum at 35° C for 1 to 3 days, a single brief FR irradiance promoted germination at 20° C to the same level as R. When the seeds were pretreated at 35° C for 7 days, intermittent FR was required to promote germination to the same level as R. Continuous and intermittent FR inhibited the germination of non–pre–treated P. bracteatum seeds. The FR inhibition was reversed by R when intermittent R followed each intermittent FR treatment. Thus, the reversible phytochrome reaction was demonstrated in these seeds.