Comparison of growth and mineral accumulation of two solanaceous species,Solanum scabrumMill. (huckleberry) andS. melongenaL. (eggplant), under salinity stress

Abstract

Solanum scabrum Mill. (huckleberry) is widespread in West, East and Central Africa, where it constitutes one of the most important leafy vegetables. However, the salinity tolerance of this crop has not yet been assessed. The objective of this study was to assess the response of huckleberry to salinity stress in comparison with eggplant (S. melongena L.). Four-week-old seedlings of both species were subjected to two levels of salinity stress, 50 mM and 150 mM sodium chloride (NaCl), for 14 d. Leaf water potential of both species decreased with increasing salinity stress. This decrease was lower in huckleberry than in eggplant. Total dry weight and total leaf area were also decreased by salinity, and the reductions of total dry weight and total leaf area under the 50 mM treatment compared with the control were 25 and 18% in huckleberry, while they were 47 and 55% in eggplant, respectively. The increases in leaf sodium (Na) accumulation in the 50 and 150 mM treatments compared with the control were 65 and 66% for eggplant and 18 and 36% for huckleberry, respectively. Na accumulation in stem and root in huckleberry was higher than that of leaf, whereas it was the reverse in eggplant under both salinity treatments. Huckleberry accumulated less Na in the leaves than eggplant, suggesting that huckleberry might reduce the transport of Na to its leaves more effectively than eggplant. The decrease of potassium (K) accumulation and the increase of Na in leaves by salinity resulted in a higher Na/K ratio in leaves, but this trend was greater in eggplant than in huckleberry. The calcium (Ca) concentration in leaves of huckleberry was also increased by salinity, whereas that of eggplant was decreased. These results indicate that huckleberry is more tolerant to salinity than eggplant, and less decrease in leaf area associated with lower leaf Na and increased Ca concentrations may be important in enhancing quality and sustaining productivity of the crop under this stress.

Effect of Salt Stress on Na Accumulation, Antioxidant Enzyme Activities and Activity of Cell Wall Peroxidase of Huckleberry (Solanum scabrum) and Eggplant (Solanum melongena)

“…2). This pattern offers further support to the existence of a mechanism of Na + exclusion to the leaf blade in huckleberry (Assaha et al, 2013). The present study further revealed that in addition to stem and root, the petiole also appears to be a potential control point for Na + delivery to the leaf blade.…”

“…The huckleberry and eggplant used in this study were the same as described in Assaha et al (2013). Seeds of both plants were sown in seed beds, transferred 4 weeks after germination to 2 L pots, filled with a mixture of regosol soil, perlite and peat moss (2: 1: 1, v/v) and irrigated with ¼ nutrient solution for 10 d. Thereafter, the plants were arranged in a randomized complete block design with 4 groups of 4 replicates each and irrigated with ½ strength nutrient solution, supplemented with 0 (for control) and 150 (stressed) mM NaCl to induce salinity stress.…”

“…Seeds of both plants were sown in seed beds, transferred 4 weeks after germination to 2 L pots, filled with a mixture of regosol soil, perlite and peat moss (2: 1: 1, v/v) and irrigated with ¼ nutrient solution for 10 d. Thereafter, the plants were arranged in a randomized complete block design with 4 groups of 4 replicates each and irrigated with ½ strength nutrient solution, supplemented with 0 (for control) and 150 (stressed) mM NaCl to induce salinity stress. The composition of the nutrient solution was as described by Assaha et al (2013). The NaCl solution was applied at 50 mM increments every day until the maximum concentration (150 mM) was reached, at which point start of treatment was considered.…”

“…Huckleberry accumulates very low Na + in leaf and more in root and stem, while eggplant accumulates more in leaf and less in root and stem. It is this uncontrolled accumulation of Na + in eggplant that is thought to be responsible for its growth reduction under salt stress (Shaheen et al, 2012;Assaha et al, 2013). Excess accumulation of Na + in the leaf of the eggplant cultivar, New Nobel, was shown to correlate with increased H2O2 and MDA production, indicating Na + -induced oxidative damage (Shaheen et al, 2012).…”

“…and eggplant (Solanum melongena L.) are two solanaceous vegetables that differ in the pattern of Na + accumulation (Assaha et al, 2013). Huckleberry accumulates very low Na + in leaf and more in root and stem, while eggplant accumulates more in leaf and less in root and stem.…”