Physiological and morphological responses of Leymus chinensis to saline‐alkali stress

Abstract

In this study, soil containing four different concentrations of salt was used to grow Leymus chinensis, which was sampled over 120 days between the beginning of spring and the end of fall. During this time, its physiological and morphological characteristics were analyzed. Maximal superoxide dismutase and betaine content were observed under moderate saline‐alkaline stress treatment (A3), and with increasing saline‐alkaline stress, there was a linear increase in the contents of Na+, proline, malondialdehyde (MDA), organic acids (OAs), catalase, peroxidase, soluble protein and total soluble sugar. However, the K+ content and the K+/Na+ ratio decreased significantly. Under saline‐alkaline stress, the K+, betaine, OA and soluble protein levels in the leaves were higher than those in the rhizomes, whereas the proline, MDA, protective enzyme and total soluble sugar levels in the leaves were lower than those observed in the rhizomes. The node density varied with increases in saline‐alkali stress, and each node index was maximal at A3. Under saline‐alkali stress, the rhizome biomass, leaf biomass and root–shoot ratio first decreased and then increased, whereas the change in root biomass showed a contrary tendency, and the specific root length increased gradually. There was a significant correlation between the root–shoot ratio, specific root length, and the physiological indexes. These results show that under different degrees of saline‐alkali stress, L. chinensis is likely to use a series of adaptive physiological and morphological responses; the physiological responses were primarily related to the allocation of biomass and energy, root length, and the allocation of biomass between the aboveground and belowground organs.

Homeostatic responses and growth of Leymus chinensis under incrementally increasing saline-alkali stress

“…However, the indices were lower under more strongly alkaline conditions (pH > 8.7), indicating that such conditions have toxic effects. This is consistent with previous observations that saline and alkaline stress has both physiological and biochemical effects on roots and leaves of L. chinensis (Liu et al, 2014).…”

“…The dominant species in saline-alkali grassland on the Songnen Plain is Leymus chinensis (L. chinensis) , which can provide high yields of high quality gramineous forage if the salinity and alkalinity are not too severe. It can play an important role in restoring saline-alkali land ( Liu et al, 2014 ), but there is a need to reduce the salinity and alkalinity of affected grassland and improve the species’ yield and stress tolerance. It is therefore important to study the ecological stoichiometric homeostasis of N and P, associated ecological processes, and the effects of saline-alkali stress on the growth rate and survival strategy of L. chinensis .…”

Physiological Effects of Different Stubble Height and Freeze-Thaw Stress on Secale cereale L. Seedlings

“…Soluble protein content was analyzed using method adapted from Liu (Liu et al 2015). Seedling tissue (0.1 g) with 5 ml deionized water was ground into homogenate and then centrifuged at 3000 r/min for 10 min.…”

Photosynthetic response and transcriptomic profiling provide insights into the alkali tolerance of clone halophyte Leymus chinensis

“…L. chinensis can survive for a long time in alkaline grassland with pH above 10 ( Zheng and Li 1999). It is one of the most alkali-tolerant Gramineae halophyte (Liu et al 2015), and it also is close relative of wheat plants. In northern China, L. chinensis is an important forage grass that is used to improve alkaline grassland (Zheng and Li 1999).…”

“…Understanding L. chinensis alkali tolerance would improve the current knowledge of alkali tolerance, and even could provide breeders with candidate alkali tolerance genes. Although some studies on physiological response (Liu et al 2015, microRNAs (Zhai et al 2014), and gene expression profiling (microarray chips) (Jin et al 2008) had been carried out in L. chinensis, these studies only referred to the genome sequence of other species, which inevitably led to imperfection of the gene expression profiling. In this study, we used PacBio platform to constitute a reference full-length transcript sequences (45,037 highquality isoforms) for alkali-stressed L. chinensis, and we subsequently conducted a RNAseq analysis of alkali stress response by mapping Illumina reads to the generated reference transcript sequences.…”