Direct Somatic Embryogenesis in Commercial Varieties of Corchorus L.: Morphological, Histo-chemical, and Ultrastructural Aspects Raju Mondal a , Kanti Meena b , and Asit B Mandal c a Mulberry Tissue Culture Lab, Mulberry Division, Central Sericultural Germplasm Resources Centre (CSGRC), Hosur, India; b Biotechnology Unit, ICAR-Central Research Institute For Jute And Allied Fibres, Barrackpore, Kolkata, India; c Biotechnology Unit, ICAR-Central Research Institute For Jute And Allied Fibres, Barrackpore, Kolkata, India ABSTRACT Corchorus L. is an eminent source of industrial fbers. To understand the regeneration capacity, somatic embryogenesis (SEG) has been investigated. In this study, leaf explants are used for induction of the direct somatic embryos (DSEs). Light and scanning electron microscopy (SEM) has been implemented to confrm the DSEs. The infuences of genotypes and plant growth regulators (PGRs) on the SEG have also been evaluated. Among the four studied verities, var. JRC 517 has shown a maximum response aftre one month of dark condition in 0.5 mg l −1 IAA with 0.03 mg l −1 kin fortifed basal medium. The germination rate of the DSEs is obtained about 54.8% in 1 mg l −1 GA 3 fortifed media. The subsequent rate of plantlets conversion has achieved about 31.8% in ½ MS media. The presence of polysaccharide and protein is observed as reserved material upon histochemical study. The unicellular origin of DSE has been confrmed by the cyto-histochemical study. Abbreviations: 2,4-D, 2,4-dichlorophenoxyacetic acid; DAPI, 4′-6-diamidino- 2-phenylindole; DSE, direct somatic embryos; GA3, gibberellic acid; IAA, indole-3-acetic acid; MS medium, Murashige and Skoog medium; NBB, naphthol blue-black; PAS, periodic acid-Schif; PGR, plant growth regulators; PCA, principal component analysis; SEG, somatic embryogenesis; SEM, scan- ning electron microscopy 摘要 Corchorus L.是工业纤维的重要来源. 为了了解再生能力, 首次对体细胞胚胎 发生 (SEG) 进行了研究. 本研究采用叶片外植体诱导直接体细胞胚. 用光镜 和扫描电子显微镜 (SEM) 证实了dse. 研究了基因型和植物生长调节剂 (PGRs) 对SEG的影响. 在四个研究的验证中, JRC 517变种在试管条件下, 在 黑暗条件下一个月后, 在0.5mg l-1IAA和0.03mg l-1 kin强化基础培养基中表 现出最大响应. 在1mgl-1ga3强化培养基中, DSEs的发芽率约为54.8%. 在½MS培养基中, 植株转化率达到31.8%. 在组织化学研究中观察到多糖和 蛋白质作为保留物质. 细胞组织化学研究证实了DSE的单细胞起源. KEYWORDS JRC 517; embryo induction; conversion; principal component analysis (PCA) 关键词 胚胎诱导; 转化; 主成分分 析 (PCA) Introduction Jute is also popular as the “Golden fber.” It is one of the predominant sources of natural lignocellu- losic, biodegradable, nontoxic bast fber that is obtained from the genus Corchorus L. (Famly: Malvaceae). Out of 170 species, only 2 species are considered as valuable (Mojumder et al., 2017). These two species C. capsularis and C. olitorius (2 n = 2X = 14)are widely cultivated. These are annual or short-lived perennial, distributed in tropical, subtropical, and warm temperate regions of the world. CONTACT Kanti Meena rmcrijaf@yahoo.in Mulberry Tissue Culture Lab, Mulberry Division, Central Sericultural Germplasm Resources Centre (CSGRC), Hosur, Tamil Nadu, India. JOURNAL OF NATURAL FIBERS https://doi.org/10.1080/15440478.2020.1848739 © 2020 Taylor & Francis