Morphophysiological Traits of Gray Mangrove (Avicennia marina (Forsk.) Vierh.) at Different Levels of Soil Salinity

Kholoud Abou Seedo,Mohammad S Abido,Asma Abahussain,Ahmed Salih

doi:10.1155/2018/7404907

Kholoud Abou Seedo, Mohammad S Abido + Show 2 more

Open Access

https://doi.org/10.1155/2018/7404907

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Abstract

The traits of gray mangrove (Avicennia marina (Forsk.) Vierh.) at different levels of soil salinity were assessed at three sites along the Tubli Bay coastline of Bahrain. Morphophysiological traits include rates of photosynthesis and transpiration, leaf morphology, and leaf pigment content. Results showed that the rates of photosynthesis and transpiration, the intercellular CO2 concentration, and stomatal conductance were significantly lower (p ≤ 0.05) in the trees of a low salinity site compared to those of high salinity sites. Pairwise correlation between soil electrical conductivity levels and photosynthesis and transpiration rates was very low, implying an adverse effect of low salinity on both processes. However, the dimensions of leaf area and the sclerophylly index were significantly higher (p ≤ 0.05) in the trees grown in low salinity site compared to those in more saline conditions. On the other hand, pigments were significantly lower in leaves of trees grown in low salinity site compared to the other two sites. The pairwise correlation between electrical conductivity values and chlorophyll a, b, and carotenoid was 0.51, 0.52, and 0.57 consecutively at (p <0.0001), implying moderate effect of salinity on leaf pigments. This study illustrates the adverse and positive effects of soil salinity on some traits of gray mangrove in Bahrain, which might be considered in ecosystem rehabilitation along other coastlines of the country.

Highlights

Gray mangrove (Avicennia marina (Forsk.) Vierh.) grows principally in tropical areas
A tall, dense growth of mangroves is found in high rainfall areas across the tropics; dwarf forms of the species typify its physiognomy in the Arabian Peninsula
At each study site and along a transect line placed in a seaward landward direction, three soil cores were taken in summer and winter at three different depths: 0-5 cm, 10-15 cm, and 15-30 cm

Summary

Introduction

Gray mangrove (Avicennia marina (Forsk.) Vierh.) grows principally in tropical areas. The shrubby form of mangroves reflects the aridity of the environment, the high seawater salinity, and other local site conditions [4, 5]. An increase was reported in CO2 assimilation rates in mangroves at low salinity levels [11]. A negative correlation was reported between high salinity levels and chlorophyll content of mangroves [16, 17]. Some plant adaptations have emerged as a response to environmental conditions, yielding site-specific phenotypes Knowing these characteristics is essential for evaluating species performance in harsh environments [20].

Material and Methods

Methods

Results and Discussion