No abstract

To study the effects of salt stress and plant growth regulators (kinetin, gibberellic acid, potassium) on growth, yield, glycine betaine content, phosphoenolpyruvate carboxylase (PEPC) and ribulose biphosphate carboxylase (RBC) gene expression of two Libyan bread wheat varieties, a factorial design of greenhouse experiment with three replications was conducted. Results revealed that salt stress significantly reduced plant growth and productivity of both varieties. Moreover, the addition of kinetin + potassium and gibberellic acid + potassium had improved the performance of the morpho-metric parameters of both genotypes under salt stress; but the performance was more effective for kinetin treatment than for gibberellic acid. At the biochemical level, the results showed that salt stress increased glycine betaine contents in both varieties with different proportions. This increase is more elevated in the presence of kinetin + potassium than the treatment with gibberellic acid+ potassium, which showed an almost similar result as in only salt stress. At the molecular level, the effects of salt stress and plant growth regulators on the PEPC and RBC gene expression showed that the increase was significantly higher for kinetin, gibberellic acid, and salt stress when compared to the control.

Several enzymes play an important role in the biosynthesis of osmolyte in plants. The main objective of this work is to study the effects of salt stress, kinetin+potassium and giberellic acid+potassium on calcium-dependent protein kinases (CDPKs) and delta-1-pyrroline-5- carboxylate synthase (P5CS) genes expression of two bread wheat varieties. The results shodwe that, salts stress reduced the plant growth of the two wheat germplasms. Moreover, the addition of kinetin+ potassium improved the performance of morphometric parameters while the addition of giberellic acid +potassium has less effect. On the biochemical level, results indicated that salt stress increased the proline contents compared with control plants. Extra increase in proline contents was recorded by kinetin+ potassium, while the treatment of giberellic acid +potassium showed almost similar results as in salt stress only. On the molecular level, salt stress, kinetin and giberellic acid significantly increased the two genes expression of CDPKs and P5CS with more effect in presence of kinetin+ potassium.