Influence of Cathodic Water Invigoration on the Emergence and Subsequent Growth of Controlled Deteriorated Pea and Pumpkin Seeds

Abstract

The quality of seeds in gene banks gradually deteriorates during long-term storage, which is probably, at least in part, a result of the progressive development of oxidative stress. Here, we report a greenhouse study that was carried out to test whether a novel approach of seed invigoration using priming with cathodic water (cathodic portion of an electrolysed calcium magnesium solution) could improve seedling emergence and growth in two deteriorated crop seeds. Fresh seeds of Pisum sativum and Cucurbita pepo were subjected to controlled deterioration to 50% viability at 14% seed moisture content (fresh weight basis), 40 °C and 100% relative humidity. The deteriorated seeds were thereafter primed with cathodic water, calcium magnesium solution and deionized water. In addition, to study the mechanism of the impacts of invigoration, the effects of such priming on the lipid peroxidation products malondialdehyde (MDA) and 4-hydroxynonenal (4-HNE) and on the reactive oxygen species (ROS) scavenging enzymes superoxide dismutase and catalase were also determined in the fresh and deteriorated seeds. All priming treatments improved seed emergence parameters, subsequent seedling photosynthesis and growth relative to the unprimed seeds. In general, cathodic water was most effective at invigorating deteriorated seeds. Analysis of the lipid peroxidation products and antioxidant enzyme activities in invigorated seeds provided support for the hypothesis that the effectiveness of cathodic water in invigoration of debilitated orthodox seeds in general and of pea and pumpkin seeds in particular derive from its ability to act as an antioxidant.

Oxidative Stress, Ageing and Methods of Seed Invigoration: An Overview and Perspectives

“…For instance, Singh et al [247] osmoprimed Vigna unguiculata seeds with KNO 3 solution and reported improved germination, plant height, and biomass accumulation compared with unprimed and hydroprimed seeds. Fatokun et al [248] reported enhanced seedling emergence, photosynthetic and growth parameters of Pisum sativum and Cucurbita pepo seeds aged to 50% viability after priming with a mixture of CaCl 2 and MgCl 2 solutions relative to the unprimed seeds. Priming of B. oleracea seeds using varying levels (1%, 2% and 3%) of inorganic salts, such as KCl, KH 2 PO 4 , KNO 3 , MgCl 2 , MgSO 4 , and NaCl, significantly increased germination, seedling vigour, biomass accumulation and reduced mean germination time [249].…”

A Comparison of Water Imbibition and Controlled Deterioration in Five Orthodox Species

“…Testing germination is currently the standard method of assessing the viability of ex situ conserved seeds [23,24]. However, the conventional germination method is destructive, labour-intensive, and time-consuming, especially when large amounts of plant germplasm present in gene banks are considered.…”

Alleviating delayed field curing-induced deterioration in rice seeds by cathodic water invigoration: a comparison of seed and seedling responses in two upland rice species and their interspecific hybrid.

“…Reactive oxygen species such as superoxide ion (O2 • ¯), singlet oxygen ( 1 O2), hydroxyl (•OH) radicals, and hydrogen peroxide (H2O2) molecules accumulate during ageing and damage essential macromolecules such as lipids, proteins, and nucleic acids, resulting in cellular dysfunction (reviewed by Bailly 2004;Bailly et al, 2008;Rajjou and Debeaujon, 2008, and references therein) and cell ultrastructural damage (Powell and Matthews, 2012;Kong et al, 2014;Xia et al, 2015a;. To alleviate the harmful effects of ROS accumulation during ageing and germination will require the exogenous application of antioxidants to scavenge ROS and improve endogenous antioxidant capacity and/or employ treatments that will minimize or inhibit ROS production (Berjak 1978;Basra et al, 1994;Berjak et al, 2011;Gondwe et al, 2016;Adetunji et al, 2020;Fatokun et al, 2020a). In deteriorated or aged seeds, the process of imbibition or rehydration will lead to imbibitional damage (Neya et al, 2004).…”

“…Cathodic water is strongly reducing (Hanaoka, 2001;Hanaoka et al, 2004;Berjak et al, 2011), has strong antioxidant properties (Hanaoka, 2001;Hanaoka et al, 2004), and even protect DNA from ROS damage (Shirahata et al, 1997). Furthermore, depending on the species, CW has been shown to increase DNA quantity and purity (Fatokun et al, 2020a), increase ROS detoxifying antioxidant enzyme activities, and reduce lipid peroxidation products in artificially aged orthodox seeds (Adetunji et al, 2020;Fatokun et al, 2020 b) and enhanced seed germinability and vigour in naturally aged (Gondwe et al, 2016) and artificially aged orthodox seeds (Adetunji et al, 2020(Adetunji et al, , 2021Fatokun et al, 2020a, b).…”

“…Berjak et al, (2011) used CW to reduce oxidative stress in plant tissues exposed to cryopreservation procedures, while studies (Hanaoka, 2001;Hanaoka et al, 2004) have shown that CW has strong antioxidant properties, can scavenge ROS and even protect DNA from ROS damage (Shirahata et al, 1997). Furthermore, seed soaking in CW was shown to enhance DNA quantity and purity (Fatokun et al, 2020a), increase ROS detoxifying antioxidant enzyme activities (e.g. CAT, SOD and glutathione reductase (GR)) (Adetunji et al, 2020;Fatokun et al, 2020b), and reduce lipid peroxidation products, i.e.…”