Effects of Hormone on Callus Induction of White Clover and Histological Observation of Somatic Embryogenesis

The cotyledon and hypocotyl of three varieties of white clover were used as the explants and the effects of different levels of three plant growth regulator 2,4-D、6-BA and KT on white clover callus induction and subculture were studied with orthogonal design,screening the best hormone combinations,and histological observation of somatic embryogenesis was done.The results showed that the best hormone combinations differed with different explants of the same species at the same time,and not consistent between different varieties.The optimum medium for cotyledon of Rivendel varieties seeds was modified SH+2,4-D 2mg/L+6-BA 0.35mg/L+KT 0.5mg/L,for hypocotyl was modified SH+2,4-D 2mg/L+6-BA 0.2mg/L+KT 0.35mg/L;the optimum medium for cotyledon of Prop varieties seeds was modified SH+2,4-D 2mg/L+6-BA 0.5mg/L+KT 0.5mg/L,for hypocotyl was modified SH+2,4-D 5mg/L+6-BA 0.35mg/L+KT 0.5mg/L;the optimum medium for cotyledon of Haifa varieties seeds was modified SH+2,4-D 2mg/L+6-BA 0.2mg/L+KT 0.35mg/L,for hypocotyl was modified SH+2,4-D 5mg/L+6-BA 0.5mg/L+KT 0.5mg/L;The somatic embryos developed through four stages:Globular embryo、Heart-shaped embryo、Torpedo embryo and Cotyledon embryo.