ORIGINAL RESEARCH Ascophyllum nodosum: a Potential Substitute for Synthetic Hormones for Tissue Culture Propagation of Capparis decidua (Forsk) Edgew Jyoti Ahlawat 1 & Anita R. Sehrawat 1 & Ravish Chaudhary 2 & Digvijay Pandey 3 Received: 17 March 2021 /Revised: 2 May 2021 /Accepted: 24 May 2021 # The Regenerative Engineering Society 2021 Abstract Purpose The purpose of the study was to see how seaweed liquid fertiliser (SLF) affected the in vitro regeneration of Capparis decidua explants. The ability of MS (Murrashige Skoog) media preparations containing various concentrations of seaweed without plant growth regulators (PGRs), namely SW1, SW2, SW3, and SW4, and with PGRs, namely SW5, SW6, SW7 and SW8, to promote rooting and shooting was compared. Introduction The media without seaweed served as the control group. Among the group of media without any PGRs, percent rooting of the explants was maximum when cultured on the SW4 medium (93.06%) followed by the SW3 (91.67%), SW2 (87.5%) and SW1 (83.3%) respectively. Methodology Among the group of media with PGRs, percent rooting of the explants was maximum when cultured in the SW6 (100%) medium followed by the SW5 (95.83%), SW7 (90.27%) and SW8 (84.72%) as compared with the control media. The SW6 media led to the formation of maximum number of shoots per callus (Zakaria Asghari et al., Plant Soil Environ. 55(6):252– 25, 2009). Result and conclusion Among the group of media without the PGRs, the SW4 medium supported maximum number of shoots (5.2), followed by the SW3 (4.9), SW2 (3.8) and SW1 (2.9). The present results indicate that seaweed liquid fertilizer (Ascophyllum nodosum) increased the growth parameters of C. decidua, in vitro. Lay Summary The effect of seaweed extracts on Capparis decidua in vitro propagation success was investigated in this report. One of the endangered plants is Capparis decidua. There has been no research into the impact of seaweed extracts on this plant’s in vitro success. Seaweed extracts were found to be useful for mass propagation of this plant. Keywords Ascophyllum nodosum . SLF . Capparis decidua . PGR (Plant growth hormone) Introduction Seaweeds are marine macro algae which form an important component of the marine living resources of the world. Seaweeds represent an alternative to conventional chemical fertilizers. Seaweed extracts have growth-stimulating activities and are used as bio-stimulants in natural crop pro- tection. Seaweeds and their extracts have been used for cen- turies in agriculture to improve the plant growth and impart stress tolerance to the host plants. Seaweed extracts have growth-stimulating properties and are used as bio-stimulants in natural crop protection [1]. The use of extracts obtained from marine algae to promote the plant growth has been ex- tensively studied since the first product was launched into the market in the 1940s [2]. Studies reporting the use of marine algae as fertilizers date back to the history of Ancient Greeks and Vikings. Since, the supplies near the coastlines were plen- tiful, historical records show the long-term use of seaweed as animal fodder and as a soil conditioner [3]. Early references to the use of seaweed as manure can be found in the Oriental history. By the twelfth century the large brown algae were used for manuring on the coastal lands of France, Ireland, * Jyoti Ahlawat J.10dec@gmail.com Digvijay Pandey Digit11011989@gmail.com 1 Maharshi Dayanand University, Rohtak, Haryana, India 2 Division of Seed Science & Technology, IARI, New Delhi, India 3 Department of Technical Education, -2260021, Lucknow, India Regenerative Engineering and Translational Medicine https://doi.org/10.1007/s40883-021-00215-0