Effects of salt and alkali stresses on growth and ion balance in rice (Oryza sativa L.)

Abstract

Rice seedlings were stressed with salt stress or alkali stress. The growth, organic acids (OAs) and inorganic ions in stressed seedlings were measured to investigate the physiological adaptive mechanism by which rice tolerates alkali stress. The results showed that the injury effect of alkali stress on rice was stronger than salt stress. Under salt stress, inorganic anions were dominant in maintaining intracellular ionic equilibrium; however, under alkali stress, the contents of inorganic anions decreased, which caused a severe deficit of negative charge. The deficit of negative charge was remedied by greatly accumulated OAs, especially malate and citrate, and OAs were the dominant components and contributed to 61–81% of total negative charge, indicating that OA accumulation might be necessary for intracellular ion balance in rice. In addition, the OA metabolism adjustment of rice differed from that of other plant species, implying that rice may have a special alkali-tolerance mechanism.

Crucial variations in growth and ion homeostasis of Glycine gracilis seedlings under two types of salt stresses

“…However, the fact that the RGR decrease under AS was greater than under NS, implies not only that NS and AS stresses are distinct, but also the resistance of G. gracilis to NS stress is stronger than to SA stress. The injurious effect caused by AS was greater than that of NS at the same salinity concentration, consistent with previous reports (Shi and Sheng, 2005;Yang et al, 2007;Wang et al, 2011).…”

“…A high-pH environment surrounding the roots can cause metal ions and phosphorus to precipitate (Shi and Wang, 2005;.With the loss of the normal physiological root functions and destruction of the root cell structure (Li et al, 2009) , would be greatly affected, and thus disrupt the ionic balance (Yang et al, 2007Chen et al, 2009). Thus, plants in alkaline soil must cope with both physiological drought and ion toxicity, and also maintain the intracellular ionic balance (Wang et al, 2011). A systematic analysis of ion contents and ratios in different plant organs are important parameters for plant growth assessment, and approaches to the study of the stress physiology.…”

Effect of sodium carbonate-induced salinity–alkalinity on some key osmoprotectants, protein profile, antioxidant enzymes, and lipid peroxidation in two mulberry (Morus alba L.) cultivars

“…However, alkali stress added the influence of high pH which inhibits ion uptake and disrupts ionic balance of plant cells. Alkalinity stress is more harmful than salinity stress and is reported by many researchers (Guo et al 2010;Wang et al 2011;Javid et al 2012;Lin et al 2012). Maximum papers are published on salinity stress on plants and the research on alkalinity stress is very less.…”

“…Although NaCl is the dominant salt in most salt affected soils, other salts such as Na 2 SO 4 , MgCl 2 , KCl, NaHCO 3 are also frequently found in considerable amounts in such soils (Bie et al 2004). High levels of alkalinity in soil or irrigation waters adversely affect seed germination and crop growth and productivity (Wang et al 2011;Lin et al 2012;Zhang et al 2012). Much work has been done on the salinity tolerance of various crops using NaCl, whereas pH of the root-growing medium has been maintained close to neutral.…”

Germination, Growth, Chlorophyll Fluorescence and Ionic Balance in Linseed Seedlings Subjected to Saline and Alkaline Stresses

“…The response of linseed growth to AS differed from that of wheat (Triticum aestivum) and rice (Oryza sativa L.). As low as 30 mM Na + concentration under AS significantly inhibited wheat and rice growth; however, only severe AS (Na + > 90 mM) inhibited the growth of linseed, indicating that linseed was stronger alkali-tolerant than other crops (Guo et al, 2011;Wang et al, 2011).…”