Impact of dormancy regulating chemicals on salinity induced dormancy in Lasiurus scindicus and Panicum turgidum: two desert glycophytic grasses

Abstract

The indigenous forage grasses Lasiurus scindicus and Panicum turgidum are candidate species for the restoration of degraded desert rangelands. The impact of five dormancy regulating chemicals on overcoming salinity-induced germination inhibition was assessed under the best germination conditions in the two species. Seeds were germinated in a series of NaCl concentrations: 0-200 mM NaCl for P. turgidum, and 0-300 mM NaCl for L. scindicus. Lasiurus scindicus seeds were more tolerant to salinity than those of P. turgidum. Twenty percent of P. turgidum seeds germinated in 100 mM NaCl and none in the higher levels, but 47.5% and 8.8% of L. scindicus seeds germinated in 100 and 200 mM NaCl, respectively. The five studied chemicals (fusicoccin, GA 3 , kinetin, nitrate and thiourea) did not succeed in improving germination of non-saline treated seeds of the two species, compared to the control, except thiourea in P. turgidum. The salinity-induced germination inhibition in P. turgidum was completely alleviated by the application of gibberellic acid (GA 3 ), partially alleviated by the application of fusicoccin, kinetin and thiourea, but not affected by nitrate. In L. scindicus, the germination inhibition was completely alleviated by fusicoccin, GA 3 , nitrate and thiourea, but partially alleviated by kinetin. For using the two grass species in restoration of degraded rangelands affected by higher salinity, the results suggest using fusicoccin, GA 3 , nitrate and thiourea with L. scindicus and GA 3 with P. turgidum seeds as a preseeding treatment can overcome the problem of reduced germination.

Impacts of dormancy‐regulating chemicals on innate and salinity‐induced dormancy of four forage grasses native to Arabian deserts

“…However, none of the DRCs succeeded in enhancing germination in either C. brevifolium and P. divisum . Similarly, the same concentrations of the DRCs used in the present study failed to improve final germination of the two grasses Lasiurus scindicus and Panicum turgidum growing in the Arabian deserts (El‐Keblawy et al ., ). In other subtropical halophytic plants of Pakistan, the different DRCs used in the present study had no, positive or negative effects on the germination of non‐saline‐treated seeds (Khan and Gul, ).…”

“…In the present study, kinetin inhibited the germination of C. brevifolium . Similarly, the same concentration of kinetin used in the present study (0·5 m m ) inhibited the germination of the Arabian desert Panicum turgidum (El‐Keblawy et al ., ). Khan and Gul () reviewed the impact of kinetin on the germination of non‐saline‐treated seeds of halophytic plants and found contradictory results.…”

“…Concentrations commonly used in other studies that assessed the impact of DRCs on germination of both saline and non‐saline solutions were used in this study (e.g. Khan et al ., ; El‐Keblawy et al ., ; ). These chemicals were dissolved in each of the different saline solutions to assess their impact on germination.…”

“…Adoption of native plants will reduce the use of fresh water, especially if salt‐tolerant plants that could be grown with brackish or salty water are used. However, most of the desert grasses, especially glycophytes, are hard to adopt in salt‐affected lands because of their intolerance to higher salinities during the germination stage (Khan and Ungar, ; El‐Keblawy, ; El‐Keblawy et al ., ; ).…”

“…High salt concentration was found to induce dormancy in seeds of both halophyte (salt‐tolerant) and glycophyte (salt‐sensitive) species (Ungar, ; El‐Keblawy, ; El‐Keblawy and Al‐Rawai, ; El‐Keblawy et al ., ; ; ; ; b). Salinity‐induced germination inhibition could be explained by internal factors in the seeds such as the presence of inhibitors and imbalance of some germination‐regulating substances (Khan, ; Ungar, ).…”