Effects of saline and alkaline stresses on the germination, growth, photosynthesis, ionic balance and anti-oxidant system in an alkali-tolerant leguminous forageLathyrus quinquenervius

Abstract

We compared the effects of saline stress (9:1 molar ratio of NaCl : Na 2 SO 4 , pH 6.44-6.65) and alkaline stress (9:1 molar ratio of NaHCO 3 : Na 2 CO 3 , pH 8.71-8.89) on the germination, growth, photosynthesis, ionic balance and activity of anti-oxidant enzymes of Lathyrus quinquenervius to elucidate the physiological adaptive mechanism of plants to alkaline stress (high pH). The results showed that, at a low stress intensity, the effects of saline stress and alkaline stress on L. quinquenervius were similar. Compared with saline stress, high alkaline stress intensity clearly inhibited germination, growth, photosynthesis and root system activity, and led to a sharp increase in Na + and an ion imbalance in the shoots, as well as enhanced H 2 O 2 and malondialdehyde content, resulting in severe intracellular oxidative stress. The results indicated that the accumulation of organic acid was a central adaptive mechanism by which L. quinquenervius maintained intracellular ionic balance under alkaline stress. Lathyrus quinquenervius may enhance organic acid synthesis to remedy the shortage of negative charge resulting from the massive influx of Na + and decreased inorganic anions. In addition, saline stress and low alkaline stress slightly enhanced the activities of superoxide dismutase (SOD) and ascorbate peroxidase (APX), but did not affect catalase (CAT) activity. However, strong alkaline stress significantly enhanced the activities of SOD and APX, and reduced CAT activity. We propose that enhancing the activities of SOD and APX may be a vital mechanism by which L. quinquenervius resists oxidative stress caused by alkaline stress.

Photosynthetic Responses of Tomato Leaves to Salt and Cadmium Stresses: Growth and Chlorophyll a Fluorescence Kinetic Analyses

“…1b) contents. It was shown that NaCl and Cd bring ionic toxicity by elevated levels of Na + [28][29][30] and Cd 2+ [32][33] in plant tissues, which disturbs nutrient uptake and stomatal opening, inhibits some of the enzymes of the Calvin cycle, and affects plant biomass [62].…”

“…Environmental stresses such as salt [28][29][30][31] and cadmium [32][33][34][35] can also affect photosynthetic pigments and inhibit photosynthesis. It was shown that PSII efficiency depends on pigment concentration and structure [36].…”

The Effect of Temperature, Light and Calcium Carbonate on Seed Germination and Radicle Growth of the Polycarpic Perennial Galium cracoviense (Rubiaceae), a Narrow Endemic Species From Southern Poland

“…Most studies examining the effects of salinity on seed germination were carried out with individual salts, especially NaCl solution (Bliss et al, 1986;Tobe et al, 1999Tobe et al, , 2000Huang et al, 2003;Zia and Khan, 2004;Li, 2008;Qu et al, 2008;Ahmed and Khan, 2010), but little information exists concerning the effect of Ca 2+ ions on seed germination (see Shaikh et al, 2007 and references therein). Calcium has been shown to inhibit Na + uptake and thereby reduce its adverse effect on seed germination (Marcar, 1986;Rengel, 1992;Ebert et al, 2002;Bonilla et al, 2004;Yang et al, 2007;Zehra et al 2012), increase plant growth (Colmer et al, 1996;Kinraide, 1999;Tobe et al, 2003;Hirschi, 2004;Joshi et al, 2012) and alleviate the toxic effects of Na + , Mg 2+ (Tobe et al, 2002(Tobe et al, , 2004Probert, 2000;Bonilla et al, 2004;Zhang and Mu, 2009) and various sulphate salts on germination or seedling growth (Tobe et al, 2002(Tobe et al, , 2004. Alkaline salts have a more severe effect on plant growth than neutral salts (Shi and Yin, 1993;Tang and Turner, 1999).…”

Defense Induced by Jasmonic Acid: A Review

“…The steady-state levels of two key enzymes in JA biosynthesis, lipoxygenase (LOX) and allene oxide synthase (AOS), and the content of JA are higher in salt-tolerant tomato cultivars9. The salt hypersensitivity of the lox3 mutant can be complemented by MeJA10 (Zhang et al, 2009). …”