Reza Shabani Fard; Erfan Aghaee Hanjani; Elham Danaee
Abstract
Salinity stress was imposed on Calendula officinalis L. by potassium chloride (KCl) and sodium chloride (NaCl) salts. This study evaluated the ameliorative effects of polyamine foliar application on growth indices and physiological traits of Calendula officinalis L. under salinity stress. A factorial ...
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Salinity stress was imposed on Calendula officinalis L. by potassium chloride (KCl) and sodium chloride (NaCl) salts. This study evaluated the ameliorative effects of polyamine foliar application on growth indices and physiological traits of Calendula officinalis L. under salinity stress. A factorial experiment was arranged in a completely randomized design with three replications. The experiment was conducted in a commercial greenhouse in Pakdasht, Iran (2021). The treatments included salinity stress induced by NaCl and KCl salts (0, 50 and 100 mg L-1) and putrescine and spermine foliar applications (0, 1 and 2 mM). The results showed that the treatments had a significant effect on the measured variables. Increasing NaCl and KCl levels decreased the value of each variable, except for proline and superoxide dismutase activity. Putrescine and spermine foliar applications mitigated the effects of salt stress and improved the evaluated traits. The highest fresh and dry shoot weight (15.59- 3.58 g), plant height (38.70 cm), leaf count (23), and flower count (12.50) were observed in the control. Also, the highest root fresh weight (5.17 g) and root volume (4.60 cm3) were obtained inresponse to NaCl 50 mg L-1 + spermidine 2 mM. The effects of NaCl 50 mg L-1 + putrescine 2 mM caused the highest root dry weight (1.42 g). The highest carotenoid content in petals (0.69 mg g-1 FW) and leaf chlorophyll content (14.54 mg g-1 FW) were obtained in response to KCl 50 mg L-1 + spermidine 2 mM. Also, the highest superoxide dismutase enzyme activity (85.90 unit of enzyme g-1 FW) and proline (8.4 mg g-1 FW) were obtained in response to NaCl 50 and 100 mg L-1, respectively. In summary, this research showed that polyamine foliar application, especially spermine, most significantly increased the growth indices and physiological traits in pot marigold under salinity stress.
Abdulhamid Mohebi
Abstract
Irrigation is an inevitable part of agriculture which determines crop yield and thus food security. In modern era of agriculture, crop yield is determined on the basis of crop production per unit of water-use instead of crop production per land unit area. Deficit irrigation is introduced as a strategy ...
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Irrigation is an inevitable part of agriculture which determines crop yield and thus food security. In modern era of agriculture, crop yield is determined on the basis of crop production per unit of water-use instead of crop production per land unit area. Deficit irrigation is introduced as a strategy for controlling water resources that leads to water resource preservation. Date palm requires regular irrigation after plantation at the primary growth stages. In the present study, the effect of applying superabsorbent polymers on required water for irrigation of date palm seedlings has been evaluated during 2011-2012. Treatments were 60%, 80% and 100% ETc irrigation and 0, 40, 80 and 120 g superabsorbents for each seedling. The experiment was conducted in RCBD and split-split plot experimental designs. Water requirement was calculated based on FAO pan method. Results showed that, percentage of establishment reduced significantly in all irrigation regimes including normal irrigation, mid stress, and severe stress. Moreover, using superabsorbents resulted in an increase in SOD activity under 80% irrigation deficit in comparison to full irrigation. Furthermore, it was demonstrated that superabsorbents significantly affected uptake of mineral nutrients and consequently resulted in a raise in seedling establishment.
Reza Partiya; Reza Fotouhi Ghazvini; Reza Fifaei; Mahmood Ghasemnezhad
Abstract
Hypoxia is a potential threat to various horticultural cropsin lands prone to flooding. Citrus is mostly known as a sub-tropical crop that is often exposed to environmental stresses. In order to evaluate response of six different citrus genotypes, including sour orange, rough lemon, Trifoliate orange, ...
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Hypoxia is a potential threat to various horticultural cropsin lands prone to flooding. Citrus is mostly known as a sub-tropical crop that is often exposed to environmental stresses. In order to evaluate response of six different citrus genotypes, including sour orange, rough lemon, Trifoliate orange, Troyer citrange and two local genotypes labeled; CRC1 and CRC2 to flooding conditions, an experiment was carried out in factorial experiment based on a completely randomized design with two treatments including flooded and control plants and three replications. Flooding stress significantly decreased leaf chlorophyll content, and plant total fresh and dry weights (P≤ 0.05). Flooding caused a significant increase in foliar concentration of proline in CRC1 and CRC2 (P≤ 0.05). Guaiacol peroxidase activity was significantly increased in Trifoliate orange. CRC2 and sour orange showed a significant increase in superoxide dismutase activity (P≤ 0.05). The longest survival period in continuous flooding condition was observed in Troyer citrange and Trifoliate orange (more than 60 days); while sour orange was the most sensitive genotype (less than 30 days). The best thriving genotype at the end of recovery period was Troyer citrange, while sour orange showed the least ability to re-establish. The results suggest that among the studied genotypes, Troyer citrange and Trifoliate orange are able to resist for longer periods of flooding exposure. Troyer citrange had the highest capacity to re-establish after being flooded to their critical surviving point. Furthermore, CRC2 tolerated anoxic condition and recovered more successfully than the other sensitive genotypes.
