Salt tolerance of selected halophytes at the two initial growth stages for future management options

Abstract

Scarcity of water and the small area of the agricultural land are considered as the crucial environmental issues challenged the Arabian Gulf countries. In this study, experiments were conducted to identify the salt tolerance during the germination and the seedling stages of some native halophytes in the State of Qatar. Seeds of eight native species (Salsola setifera, Halopeplis perfoliata, Caroxylon imbricatum, Suaeda aegyptiaca, Acacia tortilis, Limonium axillare, Tetraena qatarensis and Aeluropus lagopoides) were investigated. Except for Tetraena qatarensis, Acacia tortilis and Suaeda aegyptiaca, all achieved ≥ 30% of seed germination at a concentration of 200 mM NaCl. Around 30% of Salsola setifera seeds were able to germinate in a salt concentration of 400 mM. Germination recovery of seeds that have been treated with 800 mM NaCl for 3 weeks was the greatest for Halopeplis perfoliata (94%) and the lowest for Aeluropus lagopoides (22%). Five halophytes were investigated for seedling growth under saline irrigation ranged from 0 to 600 mM NaCl. No significant differences obtained in growth biomass of seedlings of each of Caroxylon imbricatum, Suaeda aegyptiaca and Tetraena qatarensis between saline and non-saline treatments.

Figure 1

Pictures of seeds of species used in the present study: (A) Acacia tortilis, (B) Halopeplis perfoliata, (C) Salsola setifera, (D) Suaeda aegyptiaca, (E) Tetraena qatarensis, (F) Caroxylon imbricatum, (G) Limonium axillare, (H) Aeluropus lagopoides.

Figure 2

Cumulative percentage of seed germination of halophytes as dependent on NaCl concentration. Values shown are means ± SE. Values in a figure with a common letter are not significantly different according to Tukey's test at p ≤ 0.05.

Figure 3

Percentage of seeds that able to recover germination when subjected to distilled water after three weeks of NaCl treatments. Values shown are means ± S.E. Values in a figure with a common letter are not significantly different according to Tukey's test at p ≤ 0.05. The absence of letters in a graph means no significance among treatments.

Figure 4

Dry weight of seedling under the influence of different NaCl concentrations. Values shown are means ± S.E). Values in a figure with a common letter (small for aboveground, capital for belowground biomass) are not significantly different according to Tukey's test at (p ≤ 0.05). Group-1 refers to plants that had more than 50% germination at concentration equal or less than 200 mM NaCl while Group-2 represents plants that had more than 50% germination at concentration of equal or less than 50 mM NaCl. The absence of letters in a graph means no significance among treatments.

Figure 5

Percent of growth change in height of seedling under the influence of different NaCl concentrations. Values shown are means ± SE. Values in a figure with a common letter are not significantly different according to Tukey's test at (p ≤ 0.05). Group-1 refers to plants that had more than 50% germination at concentration equal or less than 200 mM NaCl while Group-2 represents plants that had more than 50% germination at concentration of equal or less than 50 mM NaCl. The absence of letters in a graph means no significance among treatments.