Seed germination and salinity tolerance in plant species growing on saline wastelands

Abstract

Seven plant species including three chenopods: Suaeda fruticosa, Kochia indica, Atriplex crassifolia and four grasses: Sporobolus arabicus, Cynodon dacfylon, Polypogon monspeliensis, Desmostachya bipinnata, varied greatly in their seed germination and growth responses to soil moisture or salinity. The germination percentage of each species was significantly lower at soil moisture level of 25 % of water holding capacity than at the levels ranging from 50 to 125 %. Increase in salinity resulted in gradual decrease in seed germination of each species. Growth responses of species to salinity varied widely from significant decrease with slight salinity to stimulation up to salinity levels of 20 dS m -1. Higher K+/Na + ratios in plant shoots of all species compared to that in the root medium indicated selective K + uptake. Higher tolerance in chenopod species seems to be attendant on their ability for internal ion regulation.

The effect of salinity on the growth, water status, and ion content of a leaf succulent perennial halophyte, Suaeda fruticosa (L.) Forssk

“…Suaeda fruticosa shoot biomass production was significantly stimulated at 200 mol m !3 NaCl, which differs from the results of Mahmood et al (1996), where no salt stimulation was found. Similar results have been reported for other halophytes which have optimal growth in the presence of salt (Naidoo & Raghunan, 1990;Ayala & O'Leary, 1995).…”

Germination responses of Sporobolus ioclados: a saline desert grass

“…Sporobolus ioclados populations are distributed in saline wet patches and dry sandy areas on the Karachi University campus where soil-specific conductance varied from 15 to 35 dS m À1 (about 200-400 mM; Khan, 1993) and was found in association with highly salt-tolerant halophytes like Haloxylon stocksii, Suaeda fruticosa and Salsola imbricata in inland communities and with Halopyrum mucronatum, Tamarix indica, Aeluropus lagopoides, Salsola imbricata, Suaeda fruticosa and Heliotropium curassavicum in the coastal communities. Some Sporobolus species are known to be dormant after seed dispersal (Andrews, 1997) and are moderately salt tolerant at germination (Mahmood & Malik, 1996). Grasses vary in their upper limit of salt tolerance and increases in salinity usually delay seed germination .…”

Comparative Salt Tolerance Of Perennial Grasses

“…Similar reports are also available on the salt tolerance of some of the local grasses (Ashraf et al, 1986;Shamsi & Ahmed, 1986;Kumar, 1990;Ashraf & Naqvi, 1991;Bodla et al, 1995;Mahmood et al, 1996;Khan et al, 1999Gulzar et al, 2005). These reports indicate that the salt tolerance of grasses could vary from 300 mM NaCl to 800 mM NaCl (Gulzar et al, 2005).…”

“…Grasses like Aeluropus lagopoides and Urochondra setulosa could survive in up to 1000 mM NaCl (Bodla et al, 1995;Gulzar et al, 2003ab) while a number of them survived salinity (550 to 600 mM NaCl) approaching seawater (Glenn, 1987;Hester et al, 1996Hester et al, , 2001. Some grasses grew in soil salinity ranges between 300 to 500 mM NaCl (Mahmood et al, 1996;Bell & O'Leary, 2003;Peng et al, 2004) while others could not survive in salt concentrations above 300 mM NaCl (Khan et al, 1999;La Peyre & Row, 2003).…”