Chitosan Oligosaccharides Stimulate the Efficacy of Somatic Embryogenesis in Different Genotypes of the Liriodendron Hybrid

Liriodendron hybrid (L. chinense × L. tulipifera), an essential medium-sized tree generally famous for its timber, is also used as an ornamental and greenery tool in many places around the world. The Liriodendron hybrid (L. hybrid) tree goes through many hurdles to achieve its maximum strength and vigor, such as loss of habitat, vast genetic variation, and low seed setting rate. The establishment of an effective and well-organized somatic embryogenesis (S.E.) system could be used to overcome these obstacles, rather than the old-fashioned seed culture and organogenesis. This study is based on the impact of chitosan oligosaccharide (COS) and its role in the induction of S.E. on the callus of four genotypes of the L. hybrid. The optimal concentration of COS could enhance the momentum and effectiveness in S.E.’s mechanism, which further improves the growth rate of the L. hybrid tree’s plantlets. This study shows that COS has a prominent role in endogenous hormones like indole acetic acid (IAA), zeatin (Z.T.), and gibberellic acid (GA3). Furthermore, COS improves the growth development, growth speed, as well as the development situation of plant germination ability. COS can also regulate branch development and root growth, which could be linked to the antagonistic effect on growth factors to some extent or by affecting auxin synthesis and polar transport.