Seed germination, seedling survival, and physiological response of sunflowers under saline and alkaline conditions

Abstract

Salinization and alkalization of soil are widespread environmental problem and the alkali stress is more destructive than the effects caused by salt stress. To compare the mechanism of salt and alkali stresses, a sunflower variety (Helianthus annuus L. cv. Baikuiza 6) was tested under saline or alkaline conditions by mixing two neutral salts (NaCl and Na 2 SO 4 ) or two alkaline salts (NaHCO 3 and Na 2 CO 3 ). The results showed that saline conditions differed greatly from alkaline conditions in their threshold intensities where sunflower can germinate, survive and grow. Under saline conditions, the emergence time was delayed, and the emergence rate and seedling survival rate also decreased with increasing salinity. However, under alkaline conditions, the rate of seedling survival decreased sharply but the emergence time and emergence rate did not change. In addition, the damaging effects of alkali stress on growth and photosynthesis were more severe than those of saline. In shoots, the main inorganic osmolyte and cation was K + rather than Na + ; the primary organic osmolytes were organic acid and soluble sugar rather than proline. Organic acid, NO 3 -, and Cl -(only under saline condition) were the main source of anion. In addition, the osmotic adjustment and ion balance differed among sunflower roots, stems, and leaves. In conclusion, saline and alkaline conditions are two different stress conditions and there are special responses to two stress conditions for sunflower.

Seed Germination and Physiological Response of Sunflower (Helianthus annuus L.) Cultivars under Saline Conditions

“…Our results are consistent with the other studies and shows that under saline conditions, the emergence time was delayed, and the emergence rate and seedling survival rate also decreased with increasing salinity (Liu, et al, 2010, El Midaoui et.al., 2002, Ma et al, 2016.…”

Monitoring cotton (Gossypium hirsutum L.) leaf ion content and leaf water content in saline soil with hyperspectral reflectance

“…For the determination of Cl -and SO 4 2-contents, leaf samples of 0.1 g were extracted in 10 ml of distilled water by heating at 80 C for 3 h [Ashraf and Orooj, 2006]. The Cl -and SO 4 2-contents in the extracts were analyzed with ion chromatography (DX-300, Sunnyvale, CA, USA) [Liu et al, 2010].…”

Effect of salinity and sodicity stresses on physiological response and productivity inHelianthus annuus

“…Soil salinity is mainly due to the accumulation of NaCl and alkaline soil which latter is mainly caused by the accumulation of NaHCO 3 and Na 2 CO 3 [12]. Salt-affected soils have been categorized into three different types: saline, saline-alkali, and alkaline soils depending on the total concentration of soluble salts they possess, pH of the soil solution, and exchangeable sodium percentage of the soil [26].…”