The Effect of Simulated Seawater on Two Ornamental Plant Species At Benghazi City

Abstract

Salinity affects about one third of irrigated land, causing a significant reduction in crop productivity. For this reason researchers have paid considerable attention to this important environmental problem over the last decades. Few studies, however, have dealt specifically with ornamental plants used in landscapes, despite the fact that salt stress causes serious damage in these species. This study was carried out in Benghazi/ Libya. This study was conducted during spring-summer 2020, to determine the response of different ornamental like (Albizia Lebbeck and Acacia cyanophyla) plant species to different concentrations of simulated seawater and determine the resistant of plant species for different levels of salinity, the effect of simulated seawater on the morphological characteristics and growth rate of plant species also to access to the best mixing between fresh water and sea water and used it to irrigate ornamental plants and how to take advantage of the sea water under Libyan environmental conditions, the experiments was conducted at Benghazi university laboratory, five dilutions of simulated seawater were prepared 1%, 2%, 5%, 10%, 20% , the experiment of both plants is including the same steps, with differences in number of days, both plants treated with the same procedures where seeds were surface-sterilized with 2% sodium hypochlorite solution for 12 minutes and rinsed with sterile distilled water several times then blotted using sterile paper towels. The experiment was repeated using different treatments including (potable water, sulfuric acid, boiled water and mechanical scarification method). 10 Seeds were plated on Petri dishes under aseptic conditions, incubated and maintained in the dark at 22±0.5°C, this process was in 3 replicates for each concentration, plates were watered as needed with 5 ml of each concentration, the number of germinated seeds was determined. Germinated seeds were counted daily for the calculations of daily and final germination percentages (G%), mean germination time (MGT) seedling xxi vigor index (SVI) was calculated, Obtained data were summarized in SPSS, and analyzed by ANOVA test to estimate the differences in the response to verities of sea water dilutions, followed by post hoc multiple comparison test, significance was accepted at P-values below 0.05 the confidence interval was set at 95%. The results of the study revealed that, mean germination time of both plants was slightly delayed with increased seawater concentrations ranging between (7-10 days) for Lebbeck and (12-18 days) for Acaica. Germination percentage of both plants decreased with increased seawater concentrations, at concentrations of (10% and 20%) no germination percentages which revealed that both plants not tolerate seawater concentrations. Seedling vigor index showed significant reduction at increased sea water concentration in both plants. This study revealed that both fresh and dry lengths of shoot and root were negatively affected by seawater concentrations, shoot were more sensitive to seawater concentrations than roots. Both fresh and dry weights of Lebbeck shoot systems were decreased with increased seawater concentrations and this decrease was significant. Both fresh and dry weights of Acacia root systems were decreased with increased seawater concentrations level, but this reduction was not significant compared with the control treatment. Decreased dry weights of roots revealed that did not tolerate seawater concentrations. Sulfuric acid pretreatment enhance germination of seeds of both plants even at higher concentrations (10% and 20%).