Response of Phalaenopsis Orchid to Selenium and Bio-Nano-Selenium: In Vitro Rooting and Acclimatization

Abstract

O RCHID plants are considered one of the most valuable and largest flowering plant families, which have a premium position in the global market of cut-flowers. Rooting of orchids is still the main real problem that obstructs its propagation, as roots are hardly to develop.So, Orchid needs to improve its in vitro propagation by enhancing its rooting development. The plant tissue culture of orchids is the most promising field that has been commercially used for getting of virus-free and high-quality rooted plants and representing around 70% of transplants production. In this study the shoots of in vitro plantlets were separated and cultured on half MS medium supplemented with nano-Se (0,10, 20, 30, 40 and 50 mg l-1) or corresponding doses of bulk type selenite; sodium selenite (0, 0.5, 1, 2, 4, 6, 8 and 10 mg l-1) in separates treatments with or without 0.5 mg l-1 NAA (α-naphthalene acetic acid). The two different sources of selenium were selected at mentioned concentrations to improve orchid rooting and acclimatization. Supplementation of half MS medium with 50 mg l-1 nano-Se + 0.5 mg l-1 NAA recorded the highest significant values of rooting percentage and root length as well. Whereas, half MS medium fortified with 40 mg l-1 nano-Se + 0.5 mg l-1 NAA gave the optimum number of roots. On the other hand, this enhancing effect on rooting decreased after augmentation the culture medium with 10 mg l-1 selenite. It could be concluded that in vitro rooting of Phalaenopsis orchid was improved by supplementation of nano-Se up to 50 mg l-1 in presence of 0.5 mg l-1 NAA consequence, acclimatization process was enhanced.

Aplicação de fontes de selenito e selenato na micropropagação de Digitalis mariana Boiss. ssp. Heywoodii

“…Altos níveis de selênio reduziram o número de folhas e provocaram oxidação corroborando com Fargašová (2011), que observou que selênio em altas concentrações inibiu o crescimento de Sinapis alba. Seliem et al (2020) também reportaram que baixas doses de Se (até 6 mg L -1 ) apresentaram efeitos promotores de crescimento, enquanto os níveis mais elevados de Se a 8 e 10 mg L -1 foram associados com toxicidade e anormalidade na folha (apareceu como amarelecimento de folhas) e mau funcionamento do desenvolvimento radicular. Sotoodehnia-Korani et al (2020) reportaram que a incorporação de nanopartículas de selênio (nSe) no meio de cultura causou variações na morfologia e no crescimento de maneira dependente da dose e do tipo de Se em Capsicum annuum.…”

“…Em baixa concentração, o selenato promoveu aumento de biomassa seca de raiz e biomassa seca total, diminuindo em altas concentrações (Tabela 1 e Figura 1). Seliem et al (2020) confirmou que a suplementação no meio MS com Se (até 6 mg L -1 ) e nano-Se (até 50 mg L -1 ) na presença de NAA melhorou o enraizamento e aclimatização da orquídea Phalaenopsis. A essencialidade de Se para plantas não foi estabelecida até hoje, embora tenha havido relatos de efeitos benéficos de Se no crescimento de plantas de hiperacumuladores e, em doses baixas, de plantas não hiperacumuladoras (Hartikainen, 2005).…”

Exploration of Mycobiota in Cypripedium japonicum, an Endangered Species

“…This finding indicates indirect evidence that the larger population in the habitat, the more selenium supplied by the ectomycorrhizal fungi or the higher the selenium concentration. Further research will be needed to clarify, but it was presumed to be associated with the reports that root growth had been promoted when appropriate selenium treatment had been performed on orchids [ 21 ].…”

An Academic and Technical Overview on Plant Micropropagation Challenges

“…External contamination results from the laboratories and used materials (media; glassware; culture vessels, tools, explants), whereas internal contamination is related to the endophytic microbes in mother plants [30]. Several proper methods could be used to exclude and eliminate the contaminants through surface sterilization (Table 1), such as chemical agents (antiseptic agents, liquid detergent, mercuric chloride or sodium hypochlorite), ultraviolet (UV) sterilization, autoclaving of media and instruments, and improvement of cultural practices or handling [20]. Therefore, surface sterilization of the equipment and plant materials should be managed to improve the performance of the laboratories and, thus, acquire aseptic cultures [30].…”

“…These nurseries have huge economic importance for many horticultural production systems, e.g., seedling production for tree-growing programs [17]; availability of high-quality tree planting materials [18]; and disease screening and discovery of new plant pathogens to maintain healthy nurseries [19], with the aim of producing high-quality, productivity as well as pathogenfree plants and/or trees. However, there are many obstacles, which may cause a loss for in vitro cultured plants in nurseries and in vitro culture laboratories, such as contamination of cultures [20], hyperhydricity phenomenon [21], browning of tissues or phenols exudation [22], shoot tip necrosis [23], delay of subculture, somaclonal variations [24,25], root hardening [20], and failure of acclimatization or limited planting [26].…”