نوع مقاله : مقاله پژوهشی
نویسندگان
گروه علوم باغبانی، دانشکده کشاورزی، دانشگاه تهران، کرج. ایران
چکیده
کلیدواژهها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
In order to investigate the effect of sodium nitroprusside on reducing the negative effect of salinity stress on four grape rootstocks and cultivars, a research was carried out in a factorial based on a completely randomized block design with three replications. Two-year-old rooted cuttings of all four cultivars and rootstocks (Bidaneh Sefid, Yaghouti, 140Ru and 1103P), were subjected to three levels of salinity (salinity in Cramer's nutrient solution) zero, 25 and 50 mM sodium chloride (1.3, 4.50 and 6.80 ds/m) and three levels of sodium nitroprusside (SNP) zero, 0.5 and 1 mM. The results showed that increasing salinity levels, reduced the indices of leaf relative water content and contents of chlorophyll a and b and carotenoid. Furthermore, proline, glycine betaine, soluble sugars, total phenolic, ion leakage, malondialdehyde and hydrogen peroxide increased along with increasing salinity levels. Based on the results, application of SNP, especially at a concentration of 1 mM under salt stress conditions, increased the leaf relative water content, the content of photosynthetic pigments, total phenolic, proline, glycine betaine and soluble sugars, and reduced ion leakage, malondialdehyde and hydrogen peroxide in grape cultivars and rootstocks. Use of SNP caused greater effects on ‘Bidaneh Sefid’ and ‘Yaghouti’ cultivars than the rootstocks. The results showed that ‘Bidaneh Sefid’ cultivar was sensitive to salinity, while 140Ru rootstock was more tolerant to salinity than ‘Bidaneh Sefid’ and ‘Yaghouti’ cultivars, as well as 1103P rootstock.
کلیدواژهها [English]
Extended Abstract
Introduction
Soil and irrigation water salinity has been regarded as one of the major challenges in most of the Iran vineyards and is one of the most important environmental stresses that severely reduces the quantity and quality of economic products. To cope with this threat, selecting and producing salinity-tolerant cultivars for direct use or as rootstocks for commercial cultivars through various experiments is one of the important solutions that can be useful in the future. Tolerant cultivars and rootstocks that show good efficiency under salinity stress conditions can be used in the establishment of new gardens or as suitable parents in crossbreeding programs and controlled crossings. Other solutions include the use of compounds such as sodium nitroprusside (as a nitric oxide releaser). Nitric oxide is a biologically active molecule that plays a role in regulating many cellular functions in the plant, ranging from root growth to compensatory responses to biotic and abiotic stresses. Therefore, it seems necessary to conduct a research to investigate the mechanism of the sodium nitroprusside (SNP) effect in alleviating the negative effects of salinity stress on the growth and yield of grapes.
Materials and Methods
This study was conducted as a factorial in a randomized complete block design with three replications in Karaj, Iran, during 2019-2020. Treatments included four grape cultivars and rootstocks (Bidaneh Sefid, Yaghouti (native cultivars), 140Ru and 1103P), salinity stress at three levels (0, 25 and 50 mM sodium chloride) and SNP spraying at three levels (0, 0.5 and 1 mM). One-year-old rooted cuttings were transferred to 10-liter pots containing cocopeat and perlite (1:3). When plants reached the 10-leaf stage, the salinity treatments (0, 25 and 50 mM sodium chloride) were applied to the pots twice a week along with Cramer's nutrient solution (Cramer et al., 2007) through irrigation water. Simultaneous with salinity treatment, SNP treatment was applied in the form of foliar application at three levels (0, 0.5 and 1 mM SNP as nitric oxide releasing compound) one week before the onset of salinity treatment and again in another two stages with one week interval after the start of salinity treatment. Six weeks after the beginning of salinity treatment, leaves were sampled for measuring physiological and biochemical traits.
Results and Discussion
The results of means comparison showed that the amounts of chlorophyll a, b and carotenoid in the leaves decreased under the influence of different salinity levels. According to the obtained results, SNP increased the amounts of chlorophyll a and b and total carotenoid in the studied genotypes of grape under salinity conditions. The amount of ionic leakage of the membrane of leaf cells, at different levels of salinity, was higher in Bidaneh Sefid cultivar than the other evaluated grape genotypes, so that this increase in Bidaneh Sefid cultivar increased from 25.14% (Bidaneh Sefid control) to 80.69% (50 mM sodium chloride). Furthermore, the application of SNP had a good effect on reducing the amount of malondialdehyde at both salinity levels. The effect of 1 mM SNP compared to 0.5 mM concentration had the greatest effect in reducing the amount of malondialdehyde, especially at the salinity level of 50 mM for all evaluated genotypes. The results of this research showed that salinity treatment significantly increased the amount of hydrogen peroxide. In this study, along with the increase of salinity, the amount of free oxygen radicals increased and caused lipid peroxidation of the membrane, which in turn increased the amount of ion leakage and malondialdehyde, which is consistent with the findings of other researchers (Khan et al., 2020; Hasanuzzaman et al., 2020). In this study, the amount of proline increased with the increase of salinity levels, and this increase was higher in the salinity-tolerant genotype, including 140Ru rootstock. In addition, in this study, the simultaneous application of salt stress and SNP increased the proline content of grape leaves compared to the application of salt stress alone. In this study, salinity stress significantly increased the amount of glycine-betaine in grape leaves, which has also been observed in the results of other researchers in Summer Black grape variety (Haider et al., 2019). The effect of SNP use on increasing glycine-betaine amount was more pronounced in 140Ru and 1103P rootstocks and Yaghouti cultivar than Bidaneh Sefid at different salinity levels. Interaction of salinity and SNP resulted in a significant increase in the amount of soluble sugars, so that maximum soluble sugars were observed at high salinity level and one mM SNP. According to the results of this research, SNP and salinity treatments increased the amounts of total phenolic compounds in the evaluated grape genotypes, especially in 140Ru rootstock, which is in line with the results reported by Mohammadkhani and Abbaspour (2017).
Conclusion
According to the obtained results, 140Ru and 1103P rootstocks with the least decrease in photosynthetic pigments and leaf relative water content, and the most increase in the amount of compatible osmolytes and total phenolic, as well as the least increase in the amount of electrolyte leakage, malondialdehyde and hydrogen peroxide, respectively, were more tolerant to salinity. By contrast, Bidaneh Sefid cultivar was sensitive to salinity with the highest increase in the amount of ion leakage, malondialdehyde and hydrogen peroxide, as well as the highest decrease in the amount of photosynthetic pigments and leaf relative water content. Use of SNP at different levels of salinity had the best effect compared to the control treatment. In addition to being affected by different salinity levels, SNP was also influenced by the studied cultivars and rootstocks. So that the effect of 1 mM SNP was more than 0.5 mM at both salinity levels, especially 50 mM. Bidaneh Sefid and Yaghouti cultivars were more affected by SNP concentrations than the rootstocks 140Ru and 1103P.
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