Leaf functional trait variation associated with salt tolerance in perennial ryegrass

Abstract

Salinity is one of major environmental stresses that dramatically threaten plant growth, and variations in genetic structure and functional traits have important effects on the salt tolerance of perennial ryegrass (Lolium perenne L.). The objectives of this study were to: (i) assess the inter-clonal variation of functional traits of accessions among geographic groups or between wild and commercial groups in response to salt stress; (ii) develop a mathematical model to effectively assess salt tolerance of perennial ryegrass accessions originating from different geographic populations; and (iii) determine the relation between spatial genetic structure and salt tolerance in perennial ryegrass. Wide variations were found among the accessions for seven functional traits. One regression model (F = 0.49 × F1 + 0.303 × F2 + 0.207 × F3) was established to ascertain salt tolerance of each accession. The highest variation of the traits and salt tolerance were obtained for accessions from the European group. Wild accessions exhibited more variation in functional traits and salt tolerance than commercial cultivars. Both molecular marker techniques and functional traits were used to conduct phylogenetic analysis, and the majority of accessions from the same or adjacent regions were clustered into the same group or subgroup. The perennial ryegrass accessions with similar salt tolerance had a close phylogenetic background. The patterns in functional trait variations associated with salt tolerance might allow acceleration of the process for improving salt stress resistance in perennial ryegrass.

Expression profiles of Pr5CS1 and Pr5CS2 genes and proline accumulation under salinity stress in perennial ryegrass (Lolium perenne L.)

“…The salt tolerance of both cultivars has been identified in our previous study (Hu et al. ). The pots were watered daily and fertilized weekly with half‐strength Hoagland's solution (Hoagland and Arnon ).…”

Plant Growth and Morphophysiological Modifications in Perennial Ryegrass under Environmental Stress

“…The other research reported that the effect on parameters of photosynthetic efficiency in perennial ryegrass "Roadrunner" was less than that in "Nira" under salt stress condition [6]. Moreover, the highest salt tolerance accessions were from the European group, wild accessions and exhibited more variation in functional traits and salt tolerance than commercial cultivars [90]. Some other strategies can also improve the salt-tolerance in perennial ryegrass.…”

“…Responses of plants to salinity stress occur mainly through two distinct phases over time: osmotic-changing and ion specific phases [87][88][89]. Like other turfgrasses, salt stress caused morphology, physiology, molecular changes in growth and development of perennial ryegrass, such as TQ LFW, LED, and RWC of perennial ryegrass decreasing after exposure to salinity [89,90]. The alterations of morphological characteristics of turfgrass under salt stress are derived from the changes of physiological traits such as cell membrane stability [14].…”

Evaluation of Salt Tolerance in Italian Ryegrass at Different Developmental Stages

“…u(xj) is the subordinate function value of the jth evaluation index. D indicates the integrated values for salt tolerance in Italian ryegrass [Equation (13)]. The lower the value of D, the higher the salt tolerance.…”

“…In addition to rapid growth, high dry matter production and high forage quality are desirable characteristics for promising forage varieties. In grass species, saline environments induce adaptive changes in morphological, physiological, and biochemical traits of plants, including changes in growth rate, osmotic adjustment, photosynthesis efficiency, and nutrition value [12][13][14]. Plant adaptation to salt is a complex phenomenon.…”