Optimization of induction conditions for embryogenic callus of somatic embryogenesis in Cunninghamia lanceolata

ObjectiveThis paper aims to optimize the induction culture of embryogenic callus in the somatic embryogenesis process of Cunninghamia lanceolata and explore the effects of basic medium, maternal genotype and exogenous additives on the induction of Cunninghamia lanceolata somatic embryo.

MethodFemale gametophyte (the immature zygotic embryo is in the multi-embryo stage) of three parental genotypes (Z1, Z2, Z3) were used as explants, and used six basic media, different concentrations of exogenous additives of TDZ and MeJA, cytological observation during the induction culture.

ResultWith DCR as the basic medium, the induction culture was best, the callus induction rate was 70.74%, and the induction rate of embryogenic callus was 17.36%, which was the best choice for the induction of immature embryo culture of Cunninghamia lanceolata; the maternal genotype had a greater impact on embryogenic callus induction, and the female gametophyte of the Z1 genotype tree was most suitable for inducing embryogenic callus; with DCR as the basic medium, adding sucrose 30 g/L, activated carbon 1 g/L, plant gel 5 g/L and adding plant growth regulator 2,4-D 1.5 mg/L, KT 0.4 mg/L, MeJA 1.2 μmol/L and TDZ 0.004 mg/L, for the embryogenic callus of Cunninghamia lanceolata, the induction rate was the highest, reaching 19.83%; embryogenic callus can be induced in only 4 days, and the structure and polarity characteristics of the proembryogenic masses in different stages were significantly different.

ConclusionThe basic medium, maternal genotype and exogenous additives all significantly affected the induction culture of Cunninghamia lanceolata somatic embryos. Female gametophyte with Z1 donor parental genotype as explants, DCR as the basic medium and adding MeJA and TDZ in combination can significantly improve the somatic embryos induction rate of Cunninghamia lanceolata.