Effects of Inorganic Salt Solutions on Vigour, Viability, Oxidative Metabolism and Germination Enzymes in Aged Cabbage and Lettuce Seeds.

Ademola Emmanuel Adetunji,Norman W Pammenter,Boby Varghese,Sershen Sershen

doi:10.3390/plants9091164

Abstract

This study assessed the potential of pre-hydration treatment with aqueous solutions (electrolysed [cathodic water; CW] and non-electrolysed) prepared from four different inorganic ion combinations: 1 mM CaCl2, 1 µm CaCl2 and 1 mM MgCl2 (CaMg, hereafter), 1 mM MgCl2 and 1 mM NaCl to invigorate controlled deteriorated (CDd) Brassica oleracea (cabbage) and Lactuca sativa (lettuce) seeds by assessing germination, vigour and biochemical markers (electrolyte leakage, lipid peroxidation products, protein carbonylation, and defence and germination associated enzymes) of oxidative stress. Additionally, the possible effects of pH of electrolysed CaMg and NaCl solutions were assessed. The inorganic salt solutions were applied to fresh seeds and seeds deteriorated to 75% viability (P75), 50% viability (P50) and 25% viability (P25); deionised water served as control. The pre-hydration treatment did not enhance normal seedling production in cabbage. However, Ca-containing and CW hydration treatments (CaCl2 CW, CaMg and CaMg CW [6.5], MgCl2 CW, NaCl CW and NaCl CW [6.5]) promoted normal seedling production of CDd lettuce seeds, while seedling vigour was enhanced by CaMg, CaMg CW (6.5), NaCl CW and NaCl CW (6.5) in CDd cabbage seeds, and CaCl2, CaCl2 CW, CaMg, CaMg CW (6.5), MgCl2 CW, NaCl CW and NaCl CW (6.5) in CDd lettuce seeds. The supplementation of Ca, a component of the ionised solutes, and/or the reducing potential of CW contributed to increased normal seedling production in lettuce seeds irrespective of the pH of treatment solutions or degree of deterioration. Overall, the pre-hydration treatments enhanced endogenous antioxidants leading to reduced levels of electrolyte leakage, lipid peroxidation, protein carbonylation, and enhanced germination enzyme activities in lettuce seeds. The study concluded that pre-hydration with selected inorganic salt solutions can invigorate debilitated lettuce seeds.

Highlights

At physiological maturity, characterised by low moisture content in orthodox seeds, germination and vigour are usually at the maximum level [1,2]
The proportion of Abnormal seedling (AS) produced was reduced significantly in P25 cabbage seeds treated with CaCl2 cathodic water (CW), CaMg, CaMg CW, CaMg CW (6.5), MgCl2, NaCl, NaCl CW, NaCl CW (6.5), and in P50 cabbage seeds treated with NaCl CW (6.5) relative to deionised water (DW)-treated seeds
The results of the present study indicated that CaMg CW (6.5) and NaCl CW (6.5) were beneficial in terms of promoting normal seedling production in controlled deteriorated (CDd) lettuce seeds, seedling vigor in CDd cabbage and lettuce seeds, ameliorating oxidative damage and enhancing antioxidative and germination-related enzyme activities in CDd lettuce seeds

Summary

Introduction

At physiological maturity, characterised by low moisture content in orthodox seeds, germination and vigour are usually at the maximum level [1,2]. Plants 2020, 9, 1164 germination, delayed emergence, weak seedling and/or abnormal seedlings and poor field stand, all of which are possible when debilitated seeds are sown [6]. This age-induced physiological deterioration of seeds in storage commonly referred to as ageing is brought about by high seed moisture content, temperature and relative humidity during storage [6,9]

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Discussion

Conclusion