Department of Biodiversity and Conservation Biology

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https://hdl.handle.net/10566/34

The department of Biodiversity and Conservation Biology is active in the following research areas: jelly fish; education studies; endangered species conservation; landscape ecology and GIS; marine biology; plant ecophysiology; restoration ecology; sustainable livelihoods; taxonomy and systematics; traditional plant use.

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Browsing by Author "Adetunji, Ademola Emmanuel"

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    Effects of inorganic salt solutions on vigour, viability, oxidative metabolism and germination enzymes in aged cabbage and lettuce seeds
    (MDPI, 2020) Adetunji, Ademola Emmanuel; Sershen, Naidoo; Pammenter, Norman William
    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 m 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 e ects 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, CaMgCW(6.5), MgCl2 CW, NaClCWand NaClCW(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.
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    Exogenous antioxidants enhance seedling growth and yield of artificially aged cabbage and lettuce seeds
    (MPDI, 2021) Adetunji, Ademola Emmanuel; Sershen; Varghese, Boby
    Aged seeds exhibit compromised vigour in terms of germination, seedling emergence and growth, but this can to some extent be alleviated by invigoration treatments before sowing. This study aimed to investigate ageing rates and patterns in cabbage (Brassica oleraceae) and lettuce (Lactuca sativa) seeds and whether the beneficial effects of invigorating aged seeds with exogenous antioxidants translate to enhanced seedling performance. Seeds were artificially aged to 25% viability before soaking in 0.4 mM glycerol, 0.6 mM GSH and 0.2 mM trolox for cabbage, and 0.6 mM glycerol, GSH and trolox for lettuce; deionised water served as a control. After 14 days of sowing, seedling emergence percentage, mean emergence time, mean daily emergence, and time taken to 25% emergence were computed. Seedling vigour index, root and shoot dry weight, root:shoot ratio, leaf area, leaf area ratio, and leaf chlorophyll content were assessed 6 weeks after sowing. Furthermore, the photosynthetic rate (Pn), stomatal conductance (Gs), transpiration rate (E), and chlorophyll fluorescence were measured 6 weeks after sowing. Notably, ageing resulted in the loss of seed vigour and viability at higher rates in lettuce than cabbage. Seed pretreatment with glycerol promoted seedling growth in both species and shoot dry weight in lettuce, while glycerol and GSH enhanced Pn, Gs and E in lettuce.