Fatemeh Nasibi; Khosrow Manouchehri Kalantari; Zahra Manzari Tavakoli
Abstract
One of the major abiotic stresses limiting the productivity and the geographical distribution of many important crops is low temperature. Hydrogen sulfide (H2S) is an important signaling molecule involved in several stress-resistance processes such as drought, salinity and heavy metal stresses in plants. ...
Read More
One of the major abiotic stresses limiting the productivity and the geographical distribution of many important crops is low temperature. Hydrogen sulfide (H2S) is an important signaling molecule involved in several stress-resistance processes such as drought, salinity and heavy metal stresses in plants. The aim of this study was to investigate the effects of exogenous H2S on improving chilling tolerance of cucumber seedlings. The results indicated that seedlings exposed to chilling stress (4 ºC) increased the level of electrolyte leakage, lipid peroxidation, hydrogen peroxide, proline content and guaiacol peroxidase (GPX) activity; while sugar soluble content decreased. Pretreatment with sodium hydrosulfide (NaHS), a hydrogen sulfide donor, slightly reduced the malondialdehyde content, hydrogen peroxide content and electrolyte leakage, which were induced by chilling stress and also elevated the activity of antioxidant enzymes, soluble sugar and proline levels, and reduced glutathione content in plants under chilling stress condition. Pre-treatment with other Na+ and sulfur-containing components including Na2S, Na2SO4, Na2SO3 showed no significant effect on lipid peroxidation and hydrogen peroxide content under chilling stress. It can be concluded that the effect of NaHS pretreatment on alleviation of cold stress damages is probably related to its ability to release H2S because Na+- or sulfur-containing compounds (except NaHS) had no similar effects on alleviation of chilling damages.
Azizolah Khandan-Mirkohi; Mahdieh Khalili Halbi; Seyed Alireza Salami; Hosein Lesani
Abstract
To study effects of salicylic acid (SA) treatments (0, 0.5, 1 and 2 mM) in two forms of seed priming (for 24 h) and spraying on seedling at 4-6 leaf stage an experiment was conducted on periwinkle (Catharanthus roseus Don.) with and without exposure to a mild cold stress of 8 °C (for 32 h). Seeds ...
Read More
To study effects of salicylic acid (SA) treatments (0, 0.5, 1 and 2 mM) in two forms of seed priming (for 24 h) and spraying on seedling at 4-6 leaf stage an experiment was conducted on periwinkle (Catharanthus roseus Don.) with and without exposure to a mild cold stress of 8 °C (for 32 h). Seeds were sown in trays containing peat-based substrate (with 20% sandy loam field soil). Transplants of both groups were treated with mild cold. Seedlings were grown in greenhouse with an average day/night temperature of 25/20± 2°C until their blooming. Seed emergence rate and percentage, activities of catalase (CAT), guaiacol peroxidase (GPX), polyphenol oxidase (PPO), CAT gene expression, height and number of nodes per plant, and days to flowering were evaluated. Results showed that mild cold stress together with salicylic acid at 0.5 mM (as either seed priming or spray on seedling) was the best treatment to accelerate the flowering, and improve growth parameters and antioxidant enzymatic activities. Thus, mild cold stress enhanced the positive effects of SA treatments on cold acclimation of periwinkle (particularly when associated with spraying, which is a simple administration method). Accordingly, it might be recommended for its seedling production and cultivation in temperate climates to prevent late spring frost damages.
Somayeh Esmaeili; Hassan Salehi; Morteza Khosh-Khui
Abstract
Landscape groundcover plants are a diverse group of trailing or spreading species that naturally form continuous soil coverage.Ground cover plants that were used in this study consisted of vegetative propagules of: Vinca minor L. ٬Variegatum’, Vinca minor L. ٬Green’, Oxalis brasiliensis ...
Read More
Landscape groundcover plants are a diverse group of trailing or spreading species that naturally form continuous soil coverage.Ground cover plants that were used in this study consisted of vegetative propagules of: Vinca minor L. ٬Variegatum’, Vinca minor L. ٬Green’, Oxalis brasiliensis G. Lodd, Trifolium repens L., Phyla nodiflora L. and Frankenia thymifolia Desf. The aim of this study was to compare some physiological and biochemical responses of each species used under seasonal changes in Shiraz climatic conditions. Several factors including chlorophyll and relative water content (RWC), electrolyte leakage (EL), proline content, soluble sugars and starch levels and antioxidant enzyme activities of these ground covers were investigated. Results showed that chlorophyll and RWC content were decreased in all ground cover plants during summer time. Furthermore, considerable seasonal variations in antioxidant enzyme activities were detected in all of the studied plants. The highest activity of CAT was obtained in summer, while SOD, POD and APX had their highest activities in autumn and winter seasons. Proline concentration in F. thymifolia was higher than the other species, especially in mid-winter. According to the results of this research, it appears that plants show different mechanisms against natural adverse environmental conditions. It can be concluded that F. thymifolia and P. nodiflora are well-matched with warm season and T. repens and V. minor are well-matched with cool season environmental conditions. Therefore, these plants can be recommended for cultivation in Shiraz green space and the same conditions elsewhere.
Nasser Abbaspour; Lavin Babaee
Abstract
Adaptation and defense responses are the consequences of exposure to drought stress in plants. Salicylic acid (SA) as a natural signaling molecule poses a significant impacts on various aspects of plant growth and development. This study investigates the effects of SA on carotenoids content, lipid peroxidation ...
Read More
Adaptation and defense responses are the consequences of exposure to drought stress in plants. Salicylic acid (SA) as a natural signaling molecule poses a significant impacts on various aspects of plant growth and development. This study investigates the effects of SA on carotenoids content, lipid peroxidation rate and antioxidant enzymes activities. A pot experiment was conducted using a factorial pattern based on a randomized complete block design with three replications under greenhouse conditions. The variables in the experiment included grapevine cultivars (‘Rasheh’ and ‘Bidane Sefid’), irrigation periods (5, 10 and 15 day intervals) and SA concentrations (0, 1 and 2 mM). Results showed that with increasing the drought stress levels, increase in carotenoids, malondialdehyde (MDA) contents, catalase (CAT), ascorbate peroxidase (APX) and guaiacol peroxidase (GPX) enzymes activities were detected. Carotenoids content, catalase (CAT) and ascorbate peroxidase (APX) and guaiacol peroxidase (GPX) enzymes activities were higher in the Rasheh cultivar compared with the ‘Bidane Sefid’ cultivar. Carotenoids content, CAT, APX and GPX enzymes activities increased by application of salicylic acid. . According to the obtained results, the Rasha cultivar showed a greater tolerance to water stress in comparison with Bidane Sefid cultivar, suggesting that SA is capable of inducing drought stress tolerance in plants.
