Indirect somatic embryogenesis of purple coneflower (Echinacea purpurea (L.) Moench): a medicinal-ornamental plant: evaluation of antioxidant enzymes activity and histological study

Abstract

Purple coneflower (Echinacea purpurea (L.) Moench) is a widely used medicinal and ornamental plant. In the present study, the callus embryogenesis was examined using benzyl adenine (BA) at three levels (3, 4, 5 mg L−1), 1-Naphthalene acetic acid (NAA) at three levels (0.1, 0.2 and 0.5 mg L−1) with or without activated charcoal (1 g L−1), coconut milk (50 ml L−1) and casein hydrolysate (50 mg L−1) in the MS (Murashige and Skoog 1962) medium. The embryogenesis indirectly occurred with the production of callus. The calli were observed in three forms: undifferentiated, embryogenic and organogenic. The embryogenic calli were dark green and coherent with a faster growth rate. The highest embryogenesis (100%) and embryonic regeneration (plantlet production) were obtained in the combined BA + NAA treatments with the activated charcoal, coconut milk and casein hydrolysate. However, the combined treatments of growth regulators failed to produce somatic embryos without the use of coconut milk and casein hydrolysate. The maximum amount of protein, peroxidase and catalase activity of embryogenic calli (2.02, 1.79 and 6.62ΔOD/Min/mg.protein, respectively), and highest percentage of acclimatization success (29.3% of plants) were obtained in the combined treatment of 5 mg L−1 BA + 0.5 mg L−1 NAA + activated charcoal + coconut milk + casein hydrolysate. The highest amount of chlorophyll content (33.3 SPAD value) and growth characteristics of acclimatized plantlets were observed in the media containing 3 mg L−1 BA + 0.1 and 0.2 mg L−1 NAA + 1 g. L−1 combined activated charcoal, coconut milk, casein hydrolysate. The histological studies confirmed the somatic embryogenesis in purple coneflower. Generally, it was found that the somatic embryogenesis of E. purpurea occurs at high levels of BA and low levels of NAA with the addition of coconut milk and casein hydrolysate.

Biochars as culture medium additives influence organogenic potential of plant explants through changes in endogenous phytohormone and carbohydrate contents in Daphne species

“…It facilitates acclimatization and increases survival rate in in vitro cultured plants (de Paiva Neto et al 2013). Stimulation of chlorophyll accumulation in the presence of activated charcoal was observed in in vitro cultures of orchids (Dehestani-Ardakani et al 2020). Chlorophyll content increased also in mung bean and sweet basil treated with biochar (Torabian et al 2018;Ding et al 2020).…”

“…Biochars could be also applied in experiments on somatic embryogenesis. Phytohormonal changes induced by charcoal and biochar in explants, particularly decreased level of auxins and increased concentration of cytokinins, may stimulate induction of somatic embryogenesis as well as accelerate embryo maturation and conversion, as revealed in hybrid larch (Von Aderkas et al 2002), grapevine (López-Pérez et al 2005) and purple coneflower (Echinacea purpurea) (Dehestani-Ardakani et al 2020).…”

Transcriptome analysis revealed enrichment pathways and regulation of gene expression associated with somatic embryogenesis in Camellia sinensis

“…Therefore, the high frequency and stable somatic embryogenesis system of tea plants has not been established so far, which greatly affects and limits the development of cell engineering and genetic engineering of tea plants and other related researches. At present, more studies on somatic embryogenesis in horticultural plants have been conducted, and the technical methods are more mature 31 – 33 , but the researches on somatic embryogenesis in tea were less systematic. The majority of current studies have focused on determining the optimal conditions for somatic embryogenesis, including the ratio of plant growth regulators and the combination of basal medium 34 – 36 .…”