Respon Fisiologis dan Anatomis Mangrove terhadap paparan Logam Berat Timbal (PB) di kawasan Mangrove Wonorejo Kecamatan Rungkut, Kota Surabaya, Jawa Timur

ABSTRACT

Mangroves are coastal plants capable of adapting to extreme environmental conditions and possess physiological and anatomical characteristics that are sensitive to changes in environmental quality, making them suitable as bioindicators of heavy metal pollution. This study aimed to determine the physiological and anatomical responses of four mangrove species, namely A. marina, A. alba, R. mucronata, and R. stylosa, as biomarkers of Pb contamination. This research was a quantitative descriptive study conducted from September to November 2025. The study was carried out in the Wonorejo Mangrove Area, Surabaya, using three research stations. Root, leaf, and fruit samples were collected in triplicate using purposive sampling by selecting research stations and individual mangrove plants that represented different environmental conditions and had relatively uniform morphological characteristics.The measured parameters included Pb concentrations in sediment, water, roots, leaves, and fruits using Atomic Absorption Spectrophotometry (AAS). Physiological parameters consisted of transpiration rate, photosynthetic rate, and chlorophyll content. Anatomical parameters were observed in root and leaf tissues, along with the calculation of the Bioconcentration Factor and Translocation Factor. Data analysis included Analysis of Variance (ANOVA) followed by Duncan’s Multiple Range Test (DMRT), as well as Canonical Correspondence Analysis (CCA) to identify significant differences among species and stations and to assess the relationships between physicochemical factors and Pb concentrations. The results showed that Pb concentrations in sediments ranged from 1.48 to 7.93 ppm, in water from 0.111 to 0.176 ppm, and in plant tissues from 0.87 to 4.07 ppm in roots, 0.39 to 1.40 ppm in leaves, and 0.11 to 0.85 ppm in fruits. Physiological responses indicated transpiration rates ranging from 0.88 to 1.75 mmol H₂O m⁻² s⁻¹, photosynthetic rates from 1.91 to 3.91 µmol CO₂ m⁻² s⁻¹, and chlorophyll content from 31.7 to 33.1 SPAD units. Furthermore, BCF and TF values, all of which were < 1, confirmed that the four mangrove species function as excluder-type plants and phytostabilizers. Anatomical responses revealed alterations in root and leaf tissue structures, as well as a reduction in stomatal density and size in leaves as an adaptive response to Pb exposure. Physicochemical factors were within ranges that support mangrove growth and facilitate Pb accumulation. CCA results indicated that variations in physicochemical factors influenced differences in Pb concentrations across stations.