Presowing Seed Treatment with Cytokinins and Its Effect on Growth, Photosynthetic Rate, Ionic Levels and Yield of Two Wheat Cultivars Differing in Salt Tolerance

Abstract

The effects of presowing seed treatment with different concentrations of cytokinins (kinetin and benzylaminopurine; 100, 150, and 200 mg/L) on growth, photosynthetic capacity, and ion homeostasis were investigated in two spring wheat (Triticum aestivum L.) cultivars, namely MH-97 (salt sensitive) and Inqlab-91 (salt tolerant). Primed and non-primed seeds were sown in a field in which NaCl salinity of 15 dS/m was developed. Of the different concentrations of priming agents tested, the effect of a moderate concentration of kinetin (150 mg/L) was very pronounced, particularly in improving growth and grain yield, in both cultivars. In addition, priming with kinetin alleviated the adverse effect of salt stress on gaseous exchange characteristics (net CO 2 assimilation rate and water use efficiency) in both cultivars. Seed priming with a moderate concentration of kinetin also altered the pattern of accumulation of Na + and Cl -in the shoots, irrespective of the wheat cultivar, under conditions of salt stress. However, all other priming agents at the different concentrations tested did not show any consistent effect on ion levels, except hydropriming, which increased K + levels in the shoots of both cultivars under salt stress. In conclusion, a moderate concentration of kinetin showed a consistent effect in altering the growth and grain yield of both wheat cultivars, which was related to the beneficial effects of kinetin priming on water use efficiency and photosynthetic rate under conditions of salt stress.

Seed enhancement with cytokinins: changes in growth and grain yield in salt stressed wheat plants

“…Therefore, the exogenous application of kinetin is likely to diminish the effects of salt stress on the growth and grain yield of wheat cultivars. These results are in agreement with those of some other studies that have shown the kinetin-induced salt tolerance in wheat (Roth 1987;Iqbal and Ashraf 2005b). The effectiveness of kinetin-priming to promote later growth and development in the present studies suggested its application to the soils where plants are irrigated with saline water that affects later plant growth and hence yield severely.…”

“…Seed enhancement with PGRs has been successfully applied to counteract the deleterious effects of salinity on germination and plant growth (Debez et al 2001;Angrish et al 2001;Iqbal and Ashraf 2005b). Cytokinins are important signalling molecules in plants (Rashotte et al 2005) and interact with other plant hormones in the regulation of plant growth and development (Schmü lling et al 1997;Brault and Maldiney 1999).…”

“…As priming agents, plant growth regulators (PGRs) have been successfully applied to counteract the deleterious effects of salinity on germination and growth of a number of species (Gadallah 1999;Debez et al 2001;Ashraf 2005a, 2006). Among PGRs, seed priming with optimal concentrations of cytokinins has been shown to have beneficial effects on germination, growth, and yield of wheat when grown under saline conditions (Gadallah 1999;Angrish et al 2001;Iqbal and Ashraf 2005b). However, there is a lack of knowledge about factors contributing to the priming-induced alleviatory effects under stressful environments.…”

Two Rice Authentic Histidine Phosphotransfer Proteins, OsAHP1 and OsAHP2, Mediate Cytokinin Signaling and Stress Responses in Rice

“…6), in contrast to the enhanced salt tolerance of Arabidopsis ahp mutants (Nishiyama et al, 2013). In Arabidopsis, cytokinin appears to have both positive (Elkeltawi and Croteau, 1987;Gadallah, 1999;Iqbal and Ashraf, 2005;Iqbal et al, 2006) and negative (Tran et al, 2007) effects on salt tolerance, suggesting that the role of cytokinin is complex and that its influence depends on a variety of factors. The salt overly sensitive (SOS) signaling system increases plant salt tolerance by activating Na + -extrusion antiporters (Shi et al, 2002;Martínez-Atienza et al, 2007); the high-affinity K + transporter1;1 (OsHKT1;1), which mediates inward Na + transport (Jabnoune et al, 2009), protects young leaves from ion toxicity by the accumulation of Na + and Cl 2 in old leaves (Wang et al, 2012); and Na + /H + antiporter genes (OsNHXs) play roles in the compartmentalization of Na + into vacuoles (Fukuda et al, 2011).…”

Growth and photosynthetic characteristics of Nigella sativa L. as affected by presowing seed treatment with kinetin

“…With regard to presowing seed treatment, CYT have been demonstrated to promote germination, yield, and fiber properties of cotton (Sawan et al 2000), besides enhancing nitrogen metabolism and productivity of chickpea (Fatima et al 2008). Moreover, seed priming with kinetin has also been shown to counteract the adverse effects of salinity on germination of lettuce (Khan and Huang 1988), wheat (Afzal et al 2005), and sorghum (Ismail 2003), as well as growth, photosynthetic activity, ion contents and yield of wheat (Iqbal and Ashraf 2005). In this milieu, it is foreseeable that further elucidation of the effects of KIN pretreatment per se, especially on key enzyme activities, concurrent to photosynthetic and yield attributes, would provide valuable comparative information for tolerance-enhancing strategies focusing on presowing hormone supplementation.…”