Effects of drought stress on quantitative and qualitative yield and antioxidative activity of Bunium persicum

The response of chlorophyll fluorescence, photosynthetic CO 2 assimilation (PN), stomatal conductance (gs), electrolyte leakage, and transpiration (E) was observed in Jatropha curcas seedlings subjected to soil flooding. A strong reduction in growth, leafarea expansion (64%), and stomatal conductance (45%) impaired photosynthetic CO 2 assimilation (66%), which eventually reduced biomass yield. The ratio between variable-to-initial chlorophyll fluorescence (Fv/Fo) and the maximum quantum yield efficiency of the photosystem II (Fv/Fm) was used to explore damage associated with the functioning of the photosynthetic apparatus. A strong, nonlinear correlation between physiological parameters and soil flooding duration was found. Our study primarily revealed consequences of epigenetics, i.e. stagnant soil flooding, which affected growth, development, and performance of Jatropha curcas significantly. The activities of catalase (CAT), ascorbate peroxidase (APx), glutathione reductase (GR), and glutathione peroxidase (GPx) in leaves increased, implying an integrated pathway involving CAT, APx, GR, and GPx for protection against the detrimental effects of reactive oxygen species (ROS) during soil flooding.

Section: Introductionmentioning

confidence: 99%

Photosynthetic gas exchange, chlorophyll fluorescence, antioxidant enzymes, and growth responses of Jatropha curcas during soil flooding

Verma¹,

Singh²,

Gupta³

et al. 2014

“…The increasing number of salt-induced free radicals decomposes protein, lipids, and nucleic acids (Mittler et al, 2011). In order to cope with this problem, the most effective alternative pathway in scavenging/ eliminating of excess ROS is enzymatic or nonenzymatic antioxidant resistance mechanisms (Munns, 2005;Saeidnejad et al, 2013). Enzymatic antioxidants include superoxide dismutase (SOD; EC 1.15.1.1), catalase (CAT; EC 1.11.1.6), peroxidase (POX; EC 1.11.1.7), ascorbate peroxidase (APX; EC 1.11.1.1), and glutathione reductase (GR; EC 1.6.4.2) (Meloni et al, 2003;Zhang et al, 2013).…”

Section: +mentioning

confidence: 99%

Modulation of osmotic adjustment and enzymatic antioxidant profiling in Apera intermedia exposed to salt stress

Yıldıztugay

Konakci²,

Küçüködük³

et al. 2014

IntroductionOne of the environmental stresses leading to the reduction of plant growth and productivity is soil salinity, a problem that has been increased by improper irrigation practices (Munns and Tester, 2008). The survival of plants under stress conditions may vary depending on cultivars, developmental stage of the plant, application period, and severity of salinity. In general, plants can be grouped as halophytes and glycophytes in terms of salt tolerance. The plants known as glycophytes cannot tolerate extreme salt concentrations (25 mM NaCl can be toxic), but halophytes have adapted to grow in saline soils and can tolerate salt concentrations as high as 500-1000 mM NaCl (Flowers et al., 2010). However, high salt concentrations negatively affect plant metabolism even in halophytes. Understanding the salinity tolerance mechanisms of halophytes can provide useful information about their adaptation strategies. Some protection mechanisms have evolved at the cellular, tissue, or whole plant level. Most of the halophytes utilize certain basic adaptation strategies for reestablishing cellular homeostasis under salinity: 1) preferring high ratios of K + /Na + and Ca 2+ /Na + in stomatal response of plants to salinity to achieve normal turgor regulation; 2) exclusion of salt from the inner tissues by means of a permeable membrane or salt glands, known as avoidance; and 3) accumulating various compatible osmolytes so as to continue water absorption from saline soil and to maintain osmotic balance under high salinity conditions (Mittler et al., 2011). As these processes are not entirely sufficient or effective against the stress, reactive oxygen species (ROS) generated by the disturbance to the electron transport system leads to the reduction of O 2 (Meloni et al., 2003). On the other hand, recent reports show that nontoxic ROS content can play a role in signaling pathways under stress (Jiang and Zhang, 2002) and can also be produced in plants growing under nonstressed conditions. The increasing number of salt-induced free radicals decomposes protein, lipids, and nucleic acids (Mittler et al., 2011). In order to cope with this problem, the most effective alternative pathway in scavenging/ eliminating of excess ROS is enzymatic or nonenzymatic antioxidant resistance mechanisms (Munns, 2005;

“…Due to a limited number of studies related to the antioxidative system of these mutant lines of A. thaliana, this study investigates the expression patterns of some of the antioxidant enzymes in this plant. The role of antioxidative defense systems in plant responses to other abiotic stresses, such as drought, have been comprehensively documented (Sekmen et al, 2012;Saeidnejad et al, 2013). The reason for taking this approach is the phenotype of the mutant plants under chilling stress, namely, the yellow color of the aerial parts.…”

Section: Introductionmentioning

confidence: 99%

The role of Mn-SOD and Fe-SOD genes in the response to low temperature in chs mutants of Arabidopsis

Gharari¹,

Nejad²,

Band³

et al. 2014

To determine whether the expression of iron superoxide dismutase (Fe-SOD) and manganese superoxide dismutase (Mn-SOD) increase superoxide-scavenging capacity, and thereby improve the survival rate of chilling sensitive (chs) mutants of Arabidopsis, 4 chs mutant (chs1-1, chs1-2, chs2-1, and chs2-2) and wild-type plants were grown under low (chilling, 13 °C; cold, 4 °C) and normal growth (23 °C) temperatures. Photosynthetic parameters were investigated following treatment with chilling, cold, and normal growth conditions. Chlorophyll content and maximum quantum efficiency of PSII primary photochemistry (Fv/Fm) were reduced in plants grown at chilling stress. The degree of chilling sensitivity of chs1 mutant plants was significantly greater than that of wild-type and chs2 mutants, as measured by chlorophyll fluorescence value and chlorophyll content. MSD1 was expressed during chilling stress in chs mutant and WT plants, while expression of FSD2 and FSD3 SODs in chs mutants was not detected during any of the treatments. Our results suggest that MSD1 expression in chs1-chilled plants responds to chilling, and that the lack of expression of FSD2 and FSD3 genes in chs mutants grown at chilling temperature supports the hypothesis that chloroplasts might be damaged, due to the chs mutation, when they are chilled.