Special symposium: In vitro plant recalcitrance do free radicals have a role in plant tissue culture recalcitrance?

Abstract

Free radicals have an important role in the metabolism and development of aerobic organisms; however, their uncontrolled production leads to oxidative stress. This paper explores the possibility that free radical-mediated stress has a role in tissue culture recalcitrance. In the context of this paper, recalcitrance is considered to be the inability of plant tissue cultures to respond to culture manipulations; in its broadest terms, this study also concerns the time-related decline (i.e. in vitro aging) and loss of morphogenetic competence and totipotent capacity. Studies on a diverse range of in vitro plant systems have shown that tissue cultures produce free radicals, lipid peroxides and toxic, aldehydic lipid peroxidation products. Levels of these compounds vary in response to different tissue culture manipulations, but their production is enhanced during dedifferentation and antioxidant profiles also vary throughout different phases of culture. A hypothesis is presented which suggests that tissue culture manipulations cause major metabolic and developmental changes, some of which may predispose in vitro cultures to increased free radical formation. If antioxidant protection is compromised, oxidative stress ensues and free radicals and their reaction products react with macromolecules such as DNA, proteins and enzymes, causing cellular dysfuction and, as a result, the cultures become recalcitrant.

Ethylene synthesis inhibition effects on oxidative stress and in vitro conservation of Lippia filifolia (Verbenaceae)

“…Senescence is a natural phenomenon resulting from both the increase of oxidative metabolism and the decrease of antioxidant enzyme activity, and ethylene is particularly associated to these processes (Kumar et al, 1998;Benson, 2000;Ievinsh et al, 2000;Mittler, 2002;Arora et al, 2002;Wang et al, 2002;Meratan et al, 2009). Our study showed that EDTA, STS and mainly Co have protective effects against lipid peroxidation on in vitro L. filifolia explants.…”

“…Plant tissue culture involves manipulations, and the explants respond to environmental, physiological and metabolic changes. As a consequence, there is an increase in the demand for antioxidant protection to compensate for the pro-oxidative changes that occur in parallel to metabolic and developmental transitions (Benson, 2000).…”

In Vitro Mass Propagation of Ornamentally and Medicinally Important Coelogyne flaccida Lindl. through Pseudobulb Segments

“…The different NO3 -: NH4 + levels effect indirectly to pH changes, which control cation absorption and eventually morphogenesis (Cousson and Tran Thanh Van 1993). Ions such as Ca2 + , Mg2 + , K + , (SO4)2 -, H2PO4 -, Cl -are also correlated with initiation of the morphogenetic activity in the tissues (Benson 2000, Pinto et al 2008. In the present study, it is clear that higher content of nitrogenous elements and appropriate proportion of NO3 -and NH4 + ions in the medium favoured higher regeneration percentage in C. flaccida pseudobulb segments in MS.…”

Improvement in androgenic response of borage (Borago officinalis L.) cultured anthers using antibrowning agents and picloram

“…This phenomenon leads to a decrease in culture competence (Benson, 2000). In our previous report (Chardoli Eshaghi et al, 2015), we first reported an anther culture protocol for borage under the influence of temperature pretreatments and some hormone treatments.…”