Maryam Jabbarzadeh, Ali Tehranifar, Jafar Amiri, Bahram Abedy,
Volume 6, Issue 19 (3-2018)
Abstract
Salinity is one of the environmental factors that has a critical influence on plant growth and development. Researchers have shown that some plant growth regulators such as nitric oxide improves the plants resistance to environmental stresses such as salinity, heat, cold and drought. Sodium nitroprusside (SNP) commonly was used as a nitric oxide (NO) donor in plants. The aim of this research was to evaluate the role of SNP on salt tolerance of Zinnia elegans and its effects on some morphological, physiological and biochemical characteristics of this plant. A factorial experiment based on completely randomized design was conducted with five levels of salinity 0 (control), 25, 50, 75 and 100 mM NaCl and four levels of sodium nitroprusside (SNP) (foliar spray) 0.0 (control), 0.25, 0.50 and 0.75 mM with 3 replications. In salinity level of 50 mM, the length of stem and root was reduced 41.22 and 29.63 percent in compared to control. In salinity level of 50 mM, application of 0.5 mM sodium nitroprusside, increased total antioxidant capacity, glycine betain and proline 1.93, 3.98 and 2.12 times respectively compared to control. It also increased ascorbate peroxidase, catalase and guaiacol peroxidase 5.15, 4.69 and 2.78 times respectively compared to control. The application of SNP (especially at salt concentrations lower than 50 mM) ameliorated the adverse effects of salt stress, in Zinnia elegans plant.
Mehri Mahdavifard, Abdolhossein Rezaei Nejad, Sadegh Mousaviafard,
Volume 9, Issue 35 (4-2020)
Abstract
The aim of this study was to investigate the effect of different light intensities and ascorbic acid on some physiological and biochemical characteristics of Zinnia elegans L. The experiment was designed as a completely randomized design in a form of split-plot with three replications. The treatments were consisted of three light intensity levels (600, 1200 and 1800 μmol m-2 s-1) as the main factor using shade net and spraying three ascorbic acid concentrations weekly (0, 1, 2 mM) as sub-plots. Analysis of variance showed that light intensity had a significant effect on all studied traits, except for the guard cell width. As light intensity increased, proline content, catalase, and ascorbate peroxidase activity increased. The lower light intensity increased chlorophyll a and b, carotenoids, total chlorophyll, and peroxidase enzyme activity. Further, with increasing light intensity, stomatal density and index, and epidermal cells density increased, so that stomatal density of plants grown under 1800 μmol m-2 s-1 light intensity was twice of that under 600 μmol m-2 s-1 light intensity. Moreover, application of ascorbic acid increased ascorbate peroxidase enzyme activity, stomatal density, guard cell length, while, it reduced proline content, catalase and peroxidase enzyme activities. Overall, the results showed that increasing light intensity induced stress in Zinnia and weekly application of ascorbic acid alleviated the stress effects.
