Programa de Pós-graduação em Ciências Naturais (PPGCN), Universidade do Estado do Rio Grande do Norte (UERN), Rua Professor Antônio Campos, s/n, CEP: 59600-000, Mossoró-RN, Brazil.
Departamento de Ciências Biológicas, Faculdade de Ciências Exatas e Naturais (FANAT), Universidade do Estado do Rio Grande do Norte (UERN), Brazil.
Ecotoxicol Environ Saf. 2019 Aug 30;178:202-210. doi: 10.1016/j.ecoenv.2019.04.016. Epub 2019 Apr 19.
The objective of this work was to investigate the effects of salinized water on Lippia gracilis by determining the ion accumulation capacity and morphophysiological changes as a function of salinity and time of exposure to stress. L. gracilis was irrigated with water containing different concentrations of salts and electrical conductivities. The analyses were conducted 25 and 50 days after stress (DAS), in leaf, stem/branches, and roots. Plant height (Hplants), basal stem diameter (Φstem), and mean unitary leaf area (ULA) were determined. After that, the plant material was dried, and the total dry biomass (TDB) (in g plant), leaf dry biomass (LDB), stem dry biomass (SDB), and the roots dry biomass (RDB) were determined. Based on these data, the following variables were calculated: total leaf area (TLA) in cm plant; biomass allocation fraction (BAF) obtained by dividing the biomass of the stem, leaves, and roots, separately, with the total plant biomass; relative growth rate (RGR); net assimilation rate (NAR); leaf area ratio (LAR); specific leaf area (SLA); and sclerophylly index (SI). The concentrations of potassium and sodium ions were quantified by atomic absorption spectrophotometry and the chloride ion concentration was determined by argentometric titration. L. gracilis showed a variable response to salt stress as a function of time, having a considerable capacity to withstand an increasing load of toxic ions, while maintaining a positive growth rate, highlighting the potential use of the species in moderately saline environments.
本研究旨在探究盐胁迫对马缨丹（Lippia gracilis）的影响，通过测定离子积累能力和形态生理变化，探讨盐分和胁迫暴露时间对其的影响。将马缨丹用不同盐浓度和电导率的水灌溉。在胁迫后 25 天和 50 天（DAS），分别对叶片、茎/枝和根进行分析。测定植物高度（Hplants）、基径（Φstem）和平均单位叶面积（ULA）。然后，将植物材料干燥，测定总干生物量（TDB）（g 植物）、叶干生物量（LDB）、茎干生物量（SDB）和根干生物量（RDB）。基于这些数据，计算了以下变量：植物总叶面积（TLA）cm 植物；通过将茎、叶和根的生物量分别除以总植物生物量，计算得到的生物量分配分数（BAF）；相对生长率（RGR）；净同化率（NAR）；叶面积比（LAR）；比叶面积（SLA）；和叶质指数（SI）。采用原子吸收分光光度法测定钾离子和钠离子浓度，用银量滴定法测定氯离子浓度。马缨丹对盐胁迫的响应随时间而变化，具有承受不断增加的有毒离子负荷的能力，同时保持正生长速率，突出了该物种在中度盐环境中的潜在用途。
