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Native-Invasive Plants vs. Halophytes in Mediterranean Salt Marshes: Stress Tolerance Mechanisms in Two Related Species.

Al Hassan M, Chaura J, López-Gresa MP, Borsai O, Daniso E, Donat-Torres MP, Mayoral O, Vicente O, Boscaiu M - Front Plant Sci (2016)

Bottom Line: This explains the (slightly) higher stress tolerance of I. crithmoides, as compared to D. viscosa, established from growth inhibition measurements and their distribution in nature.Oxidative stress level-estimated from malondialdehyde accumulation-was higher in the less tolerant D. viscosa, which consequently activated antioxidant responses as a defense mechanism against stress; these responses were weaker or absent in the more tolerant I. crithmoides.Based on these results, we concluded that although D. viscosa cannot directly compete with true halophytes in highly saline environments, it is nevertheless quite stress tolerant and therefore represents a threat for the vegetation located on the salt marshes borders, where several endemic and threatened species are found in the area of study.

View Article: PubMed Central - PubMed

Affiliation: Instituto de Biología Molecular y Celular de Plantas, (UPV-CSIC), Universitat Politècnica de València Valencia, Spain.

ABSTRACT
Dittrichia viscosa is a Mediterranean ruderal species that over the last decades has expanded into new habitats, including coastal salt marshes, ecosystems that are per se fragile and threatened by human activities. To assess the potential risk that this native-invasive species represents for the genuine salt marsh vegetation, we compared its distribution with that of Inula crithmoides, a taxonomically related halophyte, in three salt marshes located in "La Albufera" Natural Park, near the city of Valencia (East Spain). The presence of D. viscosa was restricted to areas of low and moderate salinity, while I. crithmoides was also present in the most saline zones of the salt marshes. Analyses of the responses of the two species to salt and water stress treatments in controlled experiments revealed that both activate the same physiological stress tolerance mechanisms, based essentially on the transport of toxic ions to the leaves-where they are presumably compartmentalized in vacuoles-and the accumulation of specific osmolytes for osmotic adjustment. The two species differ in the efficiency of those mechanisms: salt-induced increases in Na(+) and Cl(-) contents were higher in I. crithmoides than in D. viscosa, and the osmolytes (especially glycine betaine, but also arabinose, fructose and glucose) accumulated at higher levels in the former species. This explains the (slightly) higher stress tolerance of I. crithmoides, as compared to D. viscosa, established from growth inhibition measurements and their distribution in nature. The possible activation of K(+) transport to the leaves under high salinity conditions may also contribute to salt tolerance in I. crithmoides. Oxidative stress level-estimated from malondialdehyde accumulation-was higher in the less tolerant D. viscosa, which consequently activated antioxidant responses as a defense mechanism against stress; these responses were weaker or absent in the more tolerant I. crithmoides. Based on these results, we concluded that although D. viscosa cannot directly compete with true halophytes in highly saline environments, it is nevertheless quite stress tolerant and therefore represents a threat for the vegetation located on the salt marshes borders, where several endemic and threatened species are found in the area of study.

No MeSH data available.


Related in: MedlinePlus

Stress-induced growth inhibition in Dittrichia viscosa and Inula crithmoides. Leaf fresh weight [FW(%)] (A–C) and water content [WC(%)] (D–F) after 3 (A,D) and 6 (B,E) weeks of treatment with the indicated NaCl concentrations, or after 3 weeks of water stress (C,F). For each treatment, FW is expressed as percentage of the absolute weight of the corresponding non-treated control, taken as 100%: 10.85 and 24.40 g for D. viscosa and 11.11 and 19.99 g for I. crithmoides, at 3 and 6 weeks of growth, respectively. Values shown are means ± SD (n = 5). Different letters (lowercase for D. viscosa and capital letters for I. crithmoides) over the bars indicate significant differences between treatments for each species according to Tukey test (α = 0.05). Asterisks (*) indicate significant differences between the two species for the same treatment.
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Figure 3: Stress-induced growth inhibition in Dittrichia viscosa and Inula crithmoides. Leaf fresh weight [FW(%)] (A–C) and water content [WC(%)] (D–F) after 3 (A,D) and 6 (B,E) weeks of treatment with the indicated NaCl concentrations, or after 3 weeks of water stress (C,F). For each treatment, FW is expressed as percentage of the absolute weight of the corresponding non-treated control, taken as 100%: 10.85 and 24.40 g for D. viscosa and 11.11 and 19.99 g for I. crithmoides, at 3 and 6 weeks of growth, respectively. Values shown are means ± SD (n = 5). Different letters (lowercase for D. viscosa and capital letters for I. crithmoides) over the bars indicate significant differences between treatments for each species according to Tukey test (α = 0.05). Asterisks (*) indicate significant differences between the two species for the same treatment.

Mentions: The leaf FW of both, D. viscosa and I. crithmoides salt-treated plants strongly decreased in parallel with increasing external NaCl concentrations, as compared to the corresponding non-treated controls. After 3 weeks of treatment, the relative FW reductions were slightly greater in D. viscosa than in I. crithmoides, but the differences were statistically significant only in the presence of 450 mM NaCl: 77% decrease in the former species, as compared to 57% in the latter (Figure 3A). When the salt treatment was prolonged for 6 weeks, these differences became clearer (Figure 3B), indicating that I. crithmoides is more resistant to salt stress than D. viscosa, in terms of inhibition of biomass accumulation. Similarly, after 3 weeks of water stress treatments—not all plants survived 6 weeks without watering—the relative FW reduction was again significantly higher in D. viscosa than in I. crithmoides (Figure 3C).


Native-Invasive Plants vs. Halophytes in Mediterranean Salt Marshes: Stress Tolerance Mechanisms in Two Related Species.

Al Hassan M, Chaura J, López-Gresa MP, Borsai O, Daniso E, Donat-Torres MP, Mayoral O, Vicente O, Boscaiu M - Front Plant Sci (2016)

Stress-induced growth inhibition in Dittrichia viscosa and Inula crithmoides. Leaf fresh weight [FW(%)] (A–C) and water content [WC(%)] (D–F) after 3 (A,D) and 6 (B,E) weeks of treatment with the indicated NaCl concentrations, or after 3 weeks of water stress (C,F). For each treatment, FW is expressed as percentage of the absolute weight of the corresponding non-treated control, taken as 100%: 10.85 and 24.40 g for D. viscosa and 11.11 and 19.99 g for I. crithmoides, at 3 and 6 weeks of growth, respectively. Values shown are means ± SD (n = 5). Different letters (lowercase for D. viscosa and capital letters for I. crithmoides) over the bars indicate significant differences between treatments for each species according to Tukey test (α = 0.05). Asterisks (*) indicate significant differences between the two species for the same treatment.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4834351&req=5

Figure 3: Stress-induced growth inhibition in Dittrichia viscosa and Inula crithmoides. Leaf fresh weight [FW(%)] (A–C) and water content [WC(%)] (D–F) after 3 (A,D) and 6 (B,E) weeks of treatment with the indicated NaCl concentrations, or after 3 weeks of water stress (C,F). For each treatment, FW is expressed as percentage of the absolute weight of the corresponding non-treated control, taken as 100%: 10.85 and 24.40 g for D. viscosa and 11.11 and 19.99 g for I. crithmoides, at 3 and 6 weeks of growth, respectively. Values shown are means ± SD (n = 5). Different letters (lowercase for D. viscosa and capital letters for I. crithmoides) over the bars indicate significant differences between treatments for each species according to Tukey test (α = 0.05). Asterisks (*) indicate significant differences between the two species for the same treatment.
Mentions: The leaf FW of both, D. viscosa and I. crithmoides salt-treated plants strongly decreased in parallel with increasing external NaCl concentrations, as compared to the corresponding non-treated controls. After 3 weeks of treatment, the relative FW reductions were slightly greater in D. viscosa than in I. crithmoides, but the differences were statistically significant only in the presence of 450 mM NaCl: 77% decrease in the former species, as compared to 57% in the latter (Figure 3A). When the salt treatment was prolonged for 6 weeks, these differences became clearer (Figure 3B), indicating that I. crithmoides is more resistant to salt stress than D. viscosa, in terms of inhibition of biomass accumulation. Similarly, after 3 weeks of water stress treatments—not all plants survived 6 weeks without watering—the relative FW reduction was again significantly higher in D. viscosa than in I. crithmoides (Figure 3C).

Bottom Line: This explains the (slightly) higher stress tolerance of I. crithmoides, as compared to D. viscosa, established from growth inhibition measurements and their distribution in nature.Oxidative stress level-estimated from malondialdehyde accumulation-was higher in the less tolerant D. viscosa, which consequently activated antioxidant responses as a defense mechanism against stress; these responses were weaker or absent in the more tolerant I. crithmoides.Based on these results, we concluded that although D. viscosa cannot directly compete with true halophytes in highly saline environments, it is nevertheless quite stress tolerant and therefore represents a threat for the vegetation located on the salt marshes borders, where several endemic and threatened species are found in the area of study.

View Article: PubMed Central - PubMed

Affiliation: Instituto de Biología Molecular y Celular de Plantas, (UPV-CSIC), Universitat Politècnica de València Valencia, Spain.

ABSTRACT
Dittrichia viscosa is a Mediterranean ruderal species that over the last decades has expanded into new habitats, including coastal salt marshes, ecosystems that are per se fragile and threatened by human activities. To assess the potential risk that this native-invasive species represents for the genuine salt marsh vegetation, we compared its distribution with that of Inula crithmoides, a taxonomically related halophyte, in three salt marshes located in "La Albufera" Natural Park, near the city of Valencia (East Spain). The presence of D. viscosa was restricted to areas of low and moderate salinity, while I. crithmoides was also present in the most saline zones of the salt marshes. Analyses of the responses of the two species to salt and water stress treatments in controlled experiments revealed that both activate the same physiological stress tolerance mechanisms, based essentially on the transport of toxic ions to the leaves-where they are presumably compartmentalized in vacuoles-and the accumulation of specific osmolytes for osmotic adjustment. The two species differ in the efficiency of those mechanisms: salt-induced increases in Na(+) and Cl(-) contents were higher in I. crithmoides than in D. viscosa, and the osmolytes (especially glycine betaine, but also arabinose, fructose and glucose) accumulated at higher levels in the former species. This explains the (slightly) higher stress tolerance of I. crithmoides, as compared to D. viscosa, established from growth inhibition measurements and their distribution in nature. The possible activation of K(+) transport to the leaves under high salinity conditions may also contribute to salt tolerance in I. crithmoides. Oxidative stress level-estimated from malondialdehyde accumulation-was higher in the less tolerant D. viscosa, which consequently activated antioxidant responses as a defense mechanism against stress; these responses were weaker or absent in the more tolerant I. crithmoides. Based on these results, we concluded that although D. viscosa cannot directly compete with true halophytes in highly saline environments, it is nevertheless quite stress tolerant and therefore represents a threat for the vegetation located on the salt marshes borders, where several endemic and threatened species are found in the area of study.

No MeSH data available.


Related in: MedlinePlus