THE POTENTIAL FOR EVOLUTION OF SALT (NaCl) TOLERANCE IN SEVEN GRASS SPECIES

Abstract

SUMMARYThe seedling root growth of Agrostis stolonifera L., Agrostis capillaris L., Holcus lanatus L., Loliiim perenne L., Dactylis glomerata L., Festuca rubra L. and PuccineUia distans (L.) Parl. was examined after 14 d of immersion in dilute nutrient solutions containing 0, 150, and 250 mol m-'' NaCl. Root growth of all species was significanfly reduced by increasing NaCl concentration.Samples of 10000 to 20000 seeds of each species were then screened for ability to root in solution cultures at NaCl concentrations which markedly inhibited root growth in the first experiment. Small numbers of individuals of all species rooted in these solutions and high and low selection lines were established based upon root length values.Adult plants from these high and low selected lines were compared with an unselected sample for ability to root in a range of NaCl concentrations. The high line plants had significantly longer roots than the unselected plants in all species, and than the low selected line in all species except Agrostis capillaris. Low selected plants had significantly longer roots than unselected plants in Holcus lanatus, and Dactylis glomerata.The pattern of response to selection showed no consistent relationship to the known ecology of the species examined, and suggests that variability in salt tolerance is widely present in species, but for other reasons salt tolerance does not always evolve in natural situations.

Studies on the sensitivity of some species and cultivars of lawn grasses on salinity with sodium chloride during the seed germination and first year of growth

“…However, the data from literature confirm the fact that within the group of lawn grasses Lolium perenne tolerates salinity relatively well (Ashraf et al 1986, Wysocki 1994, Pawluśkiewicz 2000, Xiaofang et al 2000, Hujun 2001, Yongqin et al 2003, Stawicka et al 2006.…”

“…Horst and Dunning (1989) in the studies on Lolium perenne, and Ashraf et al (1986) in the studies on 7 different grass species found out clear inhibition of the growth of germinal roots under the effect of increasing concentration of NaCl in the environment. On the other hand, in the studies by Ashraf et al (1986), the seedlings of Lolium perenne in the control conditions had longer roots than Festuca rubra roots, but the reduction of their growth under the effect of salinity of 150 and 250 M × m -3 NaCl was also higher than in Festuca rubra. As follows from the studies, salinity inhibits the elongation growth of grass coleoptile the most although in the control conditions those organs grew faster than the roots (Table 2).…”

“…For example, Hujun et al (2001) consider Lolium perenne as a species that is highly tolerant towards salinity, whereas Festuca rubra as fairly or little tolerant, whereas Pawluśkiewicz (2000) found no differences in the germination of Lolium perenne and Festuca rubra with the salinity of 8 mS cm -1 . This indicates considerable differentiation of grass seeds within the species, and even cultivars in tolerating salinity, which is also emphasized by Ashraf et al (1986) and Hanslin and Eggen (2005).…”

“…Hence, the seeds at germination are most susceptible to salinity stress (Horst and Dunning 1989). Studies in this field on the seeds of different grass species were conducted by Ashraf et al (1986), Myers and Couper (1989), Kim et al (1991), Mogsood and Verplancke (1994), Yuying et al (1999), Xiaofang et al (2000), Hujun et al (2001). In Poland, Pawluśkiewicz (2000) dealt with seed germination of 8 species of lawn grasses in the conditions of salinity.…”

Maternal transmission of adaptive modifications in salt‐treated Sorghum bicolor: a first stage in ecotypic differentiation?

“…Ecotype formation seems to be a rapid and successful process (e.g. Al-Hiyaly et al, 1990) which is not always related to any genetic potential for tolerance present in the initial population (Gartside & McNeilly, 1974 ;Ashraf et al, 1986). In Chloris gayana, salinity tolerance was not increased by five successive generations of artificial selection towards the most tolerant individuals (Malkin & Waisel, 1986).…”