School of Environmental and Life Sciences, The University of Newcastle, Callaghan, NSW 2308, Australia; Department of Aquaculture, Patuakhali Science and Technology University, Dumki, Patuakhali, 8602, Bangladesh.
Global Centre for Environmental Remediation, The University of Newcastle, Callaghan, NSW 2308, Australia.
Environ Pollut. 2023 Apr 15;323:121333. doi: 10.1016/j.envpol.2023.121333. Epub 2023 Feb 21.
Halophytes residing in metal-contaminated saltmarsh habitats may employ strategies to enhance fitness of the next generation. We aimed to test the hypothesis that Juncus acutus individuals inhabiting metal-contaminated locations would experience elevated tolerance of offspring to metals compared to plants residing in locations with no metal contamination history. J. acutus seeds (F generation) were collected from F parent plants residing at eight locations of a contemporary sediment metal gradient (contaminated to uncontaminated) across the coast of NSW, Australia (Hunter river, Lake Macquarie and Georges River). Seeds were exposed in the laboratory to incremental Zn (0.0-1.6 mM) and Pb (0.0-0.50 mM) for nine (9) days, and % germination, germination rate, root elongation and vigour index were assessed for the determination of tolerance. Greater root accumulation (BCF = 1.01) of Zn and subsequent translocation to aerial parts (culm BCF = 0.58 and capsule BCF = 0.85) were exhibited in parents plants, whereas Pb was excluded from roots (BCF = 0.60) and very little translocation to aerial portions of the plant was observed (culm BCF = 0.02 and capsule BCF = 0.05). F offspring exhibited tolerance to Zn with EC (% germination) significantly correlated with their parents' culm (R = 0.93, p = 0.00) and capsule (R = 0.57; p = 0.03) Zn. No correlations were observed between offspring Pb tolerance and Pb in parents' plant tissues. Enhanced tolerance to the essential metal Zn may be because Zn is very mobile in the parent plant and seeds experience greater Zn load as a significant portion of sediment Zn reaches capsules (85%). Thus, Zn tolerance in J. acutus seeds is likely attributable to acclimation via maternal transfer of Zn; however, further manipulative experiments are required to disentangle potential acclimation, adaptation or epigenetic effects in explaining the tolerance observed.
生活在受金属污染盐沼生境中的盐生植物可能会采用策略来提高下一代的适应性。我们旨在检验以下假设，即在受金属污染的位置生长的芦苇（Juncus acutus）个体比在没有金属污染历史的位置生长的植物，其后代对金属的耐受性更高。我们从澳大利亚新南威尔士州海岸的一个当代沉积物金属梯度（污染到无污染）的八个位置采集了生活在金属污染环境中的 F 代植物的 J. acutus 种子（F 代）（亨特河、麦夸里湖和乔治河）。在实验室中，将种子暴露于递增的 Zn（0.0-1.6 mM）和 Pb（0.0-0.50 mM）中 9 天，并评估发芽率、发芽率、根伸长和活力指数，以确定耐受性。亲代植物表现出对 Zn 的更大的根系积累（BCF=1.01）和随后向地上部分的转运（茎 BCF=0.58 和蒴果 BCF=0.85），而 Pb 则被根系排斥（BCF=0.60），很少观察到向植物地上部分转运（茎 BCF=0.02 和蒴果 BCF=0.05）。F 代后代对 Zn 表现出耐受性，EC（发芽率）与亲代的茎（R=0.93，p=0.00）和蒴果（R=0.57；p=0.03）Zn 显著相关。在后代对 Pb 的耐受性和亲代植物组织中的 Pb 之间没有观察到相关性。对必需金属 Zn 的耐受性增强可能是因为 Zn 在亲代植物中非常易移动，并且由于大量的沉积物 Zn 到达蒴果（85%），种子经历了更大的 Zn 负荷。因此，J. acutus 种子对 Zn 的耐受性可能归因于通过母体转移 Zn 来适应；然而，需要进一步的操纵实验来阐明潜在的适应、适应或表观遗传效应，以解释所观察到的耐受性。
