Effects of various salt-alkaline mixed stresses on Aneurolepidium chinense (Trin.) Kitag.

Abstract

The stress conditions of salt-alkalinized soil were simulated to investigate the features and acting factors of saltalkaline mixed stress, using a natural salt-alkaline tolerant grass Aneurolepidium chinense (Trin.) Kitag. According to the features of salt-alkalinized soil in the northeast of China, various salt-alkali conditions with different salinities and pHs were established by mixing NaCl, NaHCO 3 , Na 2 SO 4 , and Na 2 CO 3 , in various proportions. The treatments included a salt concentration range of 50 to 350 mM and pH values from 7.14 to 10.81. Seedlings of A. chinense were stressed under these salt-alkali conditions. Several physiological indices of seedling stress were determined, including survival rate, tillering rate, number of rhizomes, relative growth rate (RGR), proline content, electrolyte leakage rate, and Na + and K + content, in order to analyze the characteristics of the stresses due to the salt-alkali mixes and their main stress factors.The results showed that the survival rate, tillering rate, number of rhizomes, RGR, and K + content of A. chinense decreased with increasing salinity and pH (or alkalinity). Proline and Na + content and electrolyte leakage rate increased with increasing salinity and pH (or alkalinity). The deleterious effects of a high pH value or salinity alone were significantly less than those of high pH in combination with salinity. This result suggested that for a salt-alkaline mixed stress, a reciprocal enhancement between salt stress and alkali stress was a characteristic feature, and it was most evidently reflected in the survival rate. When salinity was below 125 mM or pH was below 8.8, survival rates were all 100%. However, when salinity was above 125 mM and pH was above 8.8, survival rates sharply declined with the increasing of either salinity or pH.The buffer capacity of the treatment solution was taken as a stress factor in order to simplify the stress factor analysis. The results of the statistical analysis showed that for the stress factors of the salt-alkaline mixed stress, [CO 2− 3 ] and [HCO − 3 ] could be fully represented by the buffer capacity, and [Na + ] could be fully represented by salinity, whereas [SO 2− 4 ] was negligible. Therefore, four factors, salinity, buffer capacity, pH and [Cl − ], could reflect all of the stress factors. Perfect linear correlations were observed between all physiological indices and four or three stress factors by a stepwise regression analysis. However, the effects of the four stress factors on the physiological indices were significantly different in magnitude. Buffer capacity and salinity were dominant factors for all physiological indices. Thus, it is reasonable to consider the sum of salinity plus buffer capacity as the strength value of salt-alkaline mixed stress. Furthermore, the relationships between different physiological indices and various stress factors were shown to be different.Abbreviations: RGR -relative growth rate; DW -dry weight; FW -fresh weight.

Influence of Irrigation Water Discharge Frequency on Soil Salt Removal and Rice Yield in a Semi-Arid and Saline-Sodic Area

“…Liu et al [25] carried out a field experiment to determine the effect of dry saving on rice yield on a salt-affected soil in a yellow river irrigation area of Ningxia and their results showed that dry saving led to a rise in rice production. However, saline-sodic soil dominated by carbonate and bicarbonate salts in Songnen plain becomes alkaline and the combination of salinity and alkalinity may be more harmful than either alone [37]. Thus, dry saving may not be suitable for this soil as it would cause high salt concentration in root zone and then constrain crop growth and bring about yield loss.…”

Effect of increased alkalinity on Na⁺ and K⁺ contents, lipid peroxidation and antioxidative enzymes in two populations of Populus cathayana

“…Plants accumulate cations, such as Na + and K + , and simultaneously accumulate inorganic anions, such as Cl - (Ghoulam et al 2002, Melgar et al 2008, or synthesize organic anions (Sagi et al 1997) to keep ion balance. Previous studies have shown that to maintain pH stability, organic acid accumulation may be an important means for some plants, such as Aneurolepidium chinense (Shi and Wang 2005). Osmotic stress leads to the formation of ROS.…”

“…The 100 cuttings of each population were divided into five groups, and each group (four replications of five cuttings per replication for each population) was exposed to one of the five treatments. Two neutral salts (NaCl and Na 2 SO 4 ) and two alkaline salts (NaHCO 3 and Na 2 CO 3 ) were selected and mixed in various proportions according to Shi and Wang (2005). Plants in one treatment group were watered with Hoagland nutrient solution as control, while plants in the other four groups were watered with nutrient solution containing different salt mixtures which represent the pH 7.9, 8.8, 9.8 and 10.4 treatments.…”

Effects of Na2CO3 on seed germination, seed reserve utilizationand seedling growth in bitter vetch (Vicia ervilia L.)

“…Alkali stress is the stress of alkaline salts (NaHCO 3 and Na 2 CO 3 ) and salt stress can be defined as the stress of neutral salts (NaCl and Na 2 SO 4 ) (Yang et al, 2007). When saline soil contains CO 3 2-and/or HCO 3 -, it causes injury to plants not only through salt stress, but also through alkali stress (Li et al, 2010a and b;Shi and Wang, 2005). The existence of alkali stress has been demonstrated clearly by a number of studies, which have shown it to be more severe than salt stress (Campbell and Nishio, 2000;Brand et al, 2002).…”