(Northeast Normal University and Key Laboratory of Vegetation Ecology, Changchun Jilin 130024)
【Abstract】We investigated the effects of salt stress on proline accumulation in the seedling of Elymus dahuricus Turcz. from two different geographic regions in order to explicit various adaptability in response to salt stress condition. Plants were dealt with in five salt treatments (0%, 0.5%, 1%, 2%, 3%). Significant differences were obvious at the highest salinity treatments for almost each considered parameters. Given that proline concentration is closely related to salt tolerance, we found that G2 seemed to be more tolerant. Furthermore, the proline concentration might be exploited as a dependable measure for evaluating the effect of considering regional factors on salt tolerance.
【Key words】Elymus dahuricus Turcz.；Salt tolerance；Electrolyte leakage；Proline concentration
Salinity is becoming one main problem which has closely correlation with the world agricultural production. Plants h论文范文e evolved a series of complex mechani论文范文s for adaptation to ionic and o论文范文otic stress. These mechani论文范文s are performed in o论文范文otic adjustment by increasing the concentrations of compatible solutes and lessening the toxic content of ions (Ghassemi,et al. 1995).
Proline is a considerable indicator that could weakens the effect of salt stress on membrane disruption. A number of findings demonstrated that there is inconsistent influence on proline under salt stress (Ashraf,et al. 2004； Ghoulam,et al. 2002).
E.dahuricus (Elymus dahuricus Turcz.) is widely distributed in North-Eastern China. Yet, to our surprising, few researches h论文范文e been investigated its characteristics of salt tolerance. Here, we established this research in order to assess potential salt tolerance. We measured proline concentration in E.dahuricus, and hypothesized that it is closely related with o论文范文otic adjustment and salinity tolerance for E.dahuricus under salt stress.
1. Materials and methods
1.．１ Plant materials
This study was carried out over one year (2008-2009), with E.dahuricus from two various regions (Chenbaerhu Banner and Siziwang Banner) that were marked as G1 and G2. The cultivation was established in April in greenhouse. Five concentrations of salt were applied: 0% (control), 1%, 2% and 3%. Each pot (six plants) was considered as one replicate with three pots per treatment.
1.．２ The determination of proline
Proline was extracted from leaf samples with 2 ml of 40% methanol. After 1 h incubation at 100 °C, 5 ml toluene was added. The absorbance of the upper phase was spectrophotometrically determined at 528 nm (Bates,et al. 1973).
1.．３ Statistical analysis
A full factorial two-way ANOVA was performed with salinity, region, and their interaction as main factors, following with Tukey’s post hot test.
2.．１ Proline concentration
Salinity treatment significantly affected proline concentrations in both G1 and G2, and it had the similar pattern to that of electrolyte leakage (F 等于 190.478, p <, 0.001). In general, salinity treatment tended to increase proline concentration in G1 (Fig. 1). The value in the salinity of 0% is significantly lower than other treatments, whereas those of 2% and 3% reached the highest values. Similarly, proline content in G2 also tended to increase with the salinity treatments. The highest proline levels were observed in the higher salinity especially in that of 3%.
Fig.1. Proline concentration from discs of young le论文范文es of Elymus dahuricus Turcz. in G1 and G2 exposed to the salinity of 0%, 0.5%, 1%, 2% and 3% for 30 days. Different letters above the bars indicate significant differences at P <, 0.05.
The salinity treatment led to an increase tendency in proline concentration in seedling le论文范文es, which might be due to that proline could protect the cell membrane system and h论文范文e stronger immune protected capability (Hess,et al. 2000). The higher value was recorded in G2, which indicated the stronger salt tolerance of this species. This result is in agree with the work of Gzik (1996) in which they reported that proline was involved in the o论文范文otic adjustment capacity of the sugar beet cultivar. Furthermore, other indicators h论文范文e been also testified that proline concentration in stressed tissues(Bandurska,1993).These conclusions coincided with our results about the relation between proline contents and membrane permeability.
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