Light-Sensitivity in Seed Germination of Ficus benjamina var.nuda (Moraceae) and Its Ecological Significance

In this paper,Ficus benjamina L.var.nuda seeds were used as experimental materials,and effects of temperature,light,phytohormone (gibberellin,6-benzyladenine and ethylene),nitrogenous compounds (sodium nitroprusside,nitrate,and nitrite) on seed germination were studied,and ecological significance of light in seed germination was discussed.Under alternating photoperiod (14?h light,10?h dark,12?μmol m -2 s -1 ),final germination percentage of seeds was 87.5%,100%,100%,100%,98%,89% and 100%,respectively,at 15℃,20℃,25℃,30℃,35℃,40℃ and 30℃/20℃,and mean germination time of seeds was 34.7?d,16.3?d,5.6?d,4.8?d,6.4?d,9?d and 6.3?d,respectively.Germination percentage of seeds which were incubated for 35?d at 15℃,20℃,25℃,30℃,35℃,40℃,30℃/20℃ and dark was zero,and these seeds rapidly germinated after addition of alternating photoperiod.Light intensity of 0.5-20?μmol m -2 s -1 markedly increased final germination rate of seeds.However,different light intensity influenced hardly final germination percentage of seeds,but altered germination rate of seeds.Under photoperiod of 24?h,final germination percentage of seeds notably increased with increasing length of light duration.The seeds treated for 24?h,36?h,and 48?h by continuous light could germinate at subsequent dark.Different concentrations of exogenous gibberellin,6-benzyladenine,ethylene,sodium nitroprusside,nitrate and nitrite could not replace light and not accelerate seed germination,and these seeds rapidly gained germinablity after addition of alternating photoperiod.Germination behavior of F.enjamina L.var.nuda seeds was closely related to long-term adaptation to tropical forests.