فهرست مطالب

Plant Physiology - Volume:10 Issue:1, 2019
  • Volume:10 Issue:1, 2019
  • تاریخ انتشار: 1398/07/09
  • تعداد عناوین: 8
|
  • Sommart Yoosukyingsataporn *, Somyot Detpiratmongkol Pages 2987-2997

    There is little information about the effects of ethephon ripening hormone on the yield of sweet sorghum in Thailand. Therefore, this study aimed to evaluate the impact of ethephon hormone applied at different growth stages of three cultivars of sweet sorghum on its growth and yield. The experiment was conducted from December 2016 to May 2017 at a research plot of the Faculty of Agricultural Technology, King Mongkut's Institute of Technology Ladkrabang, Bangkok, Thailand. The experiment was designed as a split-plot design with three replications. Three sweet sorghum cultivars (Ethanol 2, KKU 40, and Cowley) were planted in the main plot. Ethephon was applied at five stages of growth of these cultivars: heading stage, panicle stage, milking stage, dough stage, harvesting stage. Ethephon applications at those stages and untreated control were the subplots. Results showed that Ethanol 2 cultivar exhibited a higher growth rate, plant height, stem diameter, grain yield, stem fresh weight, and yield, juice extract yield, and sugar content than those exhibited by KKU 40 and Cowley. Application of ethephon at the heading stage gave the lowest stem diameter, grain yield, stem fresh weight, and yield, whereas applying it at the harvesting stage gave the highest sugar yield. There were no significant correlations between sweet sorghum cultivars and the growth stages at which ethephon was applied. Based on these results, it might be concluded that Ethanol 2 cultivar should be treated with ethephon hormone at its harvesting stage.

    Keywords: sweet sorghum, growth, Yield, ethephon, harvesting stage
  • Behzad Babazadeh Darjazi *, Mozhgan Farzamisepehr, Behrouz Golein Pages 2999-3008

    This study aimed to evaluate the effect of rootstocks on fruit sugars, organic acids, and carotenoids. The contents of sugars and organic acids in fruits were determined by HPLC. Total acidity (TA), total soluble solids (TSS), and pH value of the juice were also evaluated. Total carotenoids and chlorophylls contents were measured using a spectrophotometer. The content of ethylene in fruits was determined by gas chromatography.  HPLC analysis of the juice allowed the detection of 3 sugars and 2 acids. Sucrose was the dominant sugar for all rootstocks. Total sugars ranged from 93.54 (mg/mL) (Flying dragon) to 111.54 (mg/mL) (Swingle citrumelo). Total acids changed from 9.50 (mg/mL) (Trifoliate orange) to 11.45(mg/mL) (Flying dragon). The ascorbic acid content varied from 0.20 (mg/mL) (Flying Dragon) to 0.32 (mg/mL) (Sour orange). The pH value ranged from 3.14 (Flying dragon) to 3.50 (Trifoliate orange), TSS content changed from 10.70 (%) (Flying dragon) to 11.10 (%) (Swingle citrumelo), TSS/TA varied from 11.75 (Flying dragon) to 13.45 (Trifoliate orange). The juice content ranged from 52.18 (%) (Flying Dragon) to 55.63 (%) (Sour orange). The amount of fruit production changed from 15 (Kg /tree) (Flying dragon) to 115 (Kg /tree) (Swingle citrumelo). Total carotenoids varied from 0.09 (Swingle citrumelo) to 0.15 (Sour orange and Flying dragon) (mg/gr DW). Among the four rootstocks evaluated, Swingle citrumelo demonstrated the maximum level of sugars and TSS. The study concluded that the rootstocks can affect sugars, acids, and, carotenoids contents of the fruits.

    Keywords: carotenoids, citrus rootstocks, ethylene, Organic acids, sugars
  • Saeed Rezazadeh, Mohammadnabi Ilkaee *, Fayaz Aghayari, Farzad Paknejad, Mehdi Rezaee Pages 3009-3021

    The purpose of the present study was to investigate the effect of plant growth-promoting rhizobacteria(PGPR) on physiological and biochemical properties of maize (Zea mays L.) in different cultivation methods under water stress. The experiment was carried out as split-plot design including water stress (well-watered, mild stress, and severe stress) as main plot and also cultivation (transplanting and direct seeding) and PGPR application (uninoculated and inoculated with Pseudomonas putida) as subplots.Water stress decreased biological and kernel yield. In direct seeding and no Pseudomonas application, severe stress decreased the kernel yield by 37% compared to the well-watered condition. Water stress resulted in significant reduction of chlorophyll content. However, it was increased by Pseudomonas application. In transplanting plants, well-watered and Pseudomonas application increased the chl. a+b by 41% in comparison with severe stress and no Pseudomonas application. Catalase (CAT) and superoxide dismutase (SOD) activities were gradually raised by increasing the water stress. In transplanted plants inoculated with Pseudomonas, severe stress decreased relative water content (RWC) by 23% compared to well-watered plants. In transplanted plants inoculated with Pseudomonas, severe stress increased Malondialdehyde (MAD) by 46% compared to well-watered plants. Total phenolic content (TPC) and total flavonoid content (TFC) increased by mild water stress and decreased by severe water stress. In directly seeded plants inoculated with Pseudomonas, mild water stress increased TPC by 11% compared to well-watered condition. Compared to well-watered treatment, 54% increases were observed in TFC by mild stress in transplanted plants treated with Pseudomonas. Transplanting and Pseudomonas was concluded to alleviate the adverse effects of water stress on physiological and biochemical traits of maize.

    Keywords: cultivation method, Pseudomonas application, Relative water content, Malondialdehyde, phenol
  • Mehri Yousefi, Lotfali Naseri *, Fariborz Zaare, Nahandi Pages 3023-3033
    Nitric oxide (NO), an endogenous signaling molecule, is involved in various physiological processes and stress responses in plants. In the present research, Pyrodwarf pear (Pyrus communis) rootstocks were grown by nutrient solution to investigate the effects of sodium nitroprusside (SNP) application as an NO donor at 0, 0.1, 0.5, and 1 mM levels on plant stress tolerance, content of main polyamines, physiological reactions, and activity of CAT and APX enzymes under NaCl stress condition at 0, 50, 100, and 150 mM concentrations. Exogenous NO significantly increased endogenous NO content of leaves, height of the plants and relative water content (RWC) of leaves while it decreased malondialdehyde (MDA) content. NaCl stress increased the content of putrescine (Put) and spermine (Spm), and exogenous NO resulted in a further increase the content of Spm in plant leaves under NaCl stress. Pyrodwarf pear rootstocks significantly showed higher content of proline and antioxidant activity under NaCl stress, and NO treatment further increased the content of proline and antioxidant activity in plants exposed to NaCl stress. The activity of antioxidant enzymes including catalase (CAT) and peroxidase (POD) increased in plants under NaCl stress, and exogenous NO further induced those antioxidant enzyme activities. Exogenous NO resulted in the enhancement of Spm content and plants with higher Spm content exhibited high levels of antioxidant activity and proline content under NaCl stress, indicating the beneficial effects of exogenous NO under salinity conditions. NO improved the tolerance of Pyrodwarf pear rootstocks under NaCl stress by regulating the content and the ratio of polyamines.
    Keywords: NaCl, nitric oxide, pear, Polyamines, Rootstock
  • Fatemeh Shaikh Abol Hasani, Parto Roshandel * Pages 3035-3045

    In order to evaluate the effects of seed priming with salicylic acid (SA) (0, 2, 10, and 20 mM) to increase salt tolerance (0, 50, 100, 150, and 200 mM NaCl) in medicinal plant Dracocephalum moldavica at seed germination, an experiment was conducted as factorial in a completely randomized design with four replicates. The assessed parameters included germination percentage and rate, length, dry weight, lipid peroxidation, electrolyte leakage, and the activity of catalase, ascorbate peroxidase, and guaiacol peroxidase of the seedlings. Results revealed the values of germination indices significantly decreased with increasing salinity levels. Nevertheless, seed priming with SA (2 mM) significantly mitigated the adverse effects of salinity in D. moldavica. Under salinity and at this level of SA priming, seed germination percentage increased by 24% and 75% at 100 and 150 mM compared to exclusive salt stress. Also, germination rate augmented by SA priming up to 9.2% at 100 mM and 2 folds at 150 mM NaCl. The values of weight (+ 9.1% at 100 mM and +8 folds at 150 mM) and length (+12.5% at 100 mM and + 15.1% at 150 mM NaCl) of seedlings significantlyincreased by SA priming compared to the exclusively salt-stressed ones. SA priming increased antioxidant enzymes activities while it decreased the level of lipid peroxidation and ion leakage in the seedlings of D. moldavica. As a conclusion, SA improved seed performance in D. moldavica under salt stress by reduction of detrimental effects of oxidative stress.

    Keywords: antioxidative system, hormonal priming, Moldavian balm, Oxidative stress, seed priming
  • Zohre Rohi Vishekaii, Ali Soleimani *, Mahmood Ghasemnezhad, Akbar Hasani Pages 3047-3058

    Nitrogen is an important element in the life of a plant. A wide range of nitrogen-containing compounds is available in the world market, with different formulations and efficiencies. Urea is present in most fertilizer applications; however, nano-nitrogen products are becoming popular although there is only limited information on their field efficiency. Thus, this paper studied the foliar application with two sources of nitrogen (urea and nano-chelated nitrogen fertilizer) on 15-year-old ‘Zard’ olive trees. Fertilizers were used during the bud-swelling stage, before blooming, pit hardening stage, and shortly after harvest of table olive, at the concentration of 2.21 (U1) and 2.95 (U2) g urea, 6 (nano-N1) and 8 (nano-N2) g nano-chelated nitrogen, corresponding to 1.02 g (U1 and nano-U1) and 1.36 g (U2 and nano-N2) pure nitrogen per liter. Results revealed that the nano-N1 treatment increased the fruit set. However, fruit yield efficiency increased using U1 in both years. Fruit consuming-quality attributes were affected mainly by U1 treatment. Mineral elements, chlorophyll and carbohydrate contents of leaves were affected during summer and fall by nitrogen treatments. The maximum oil percentage was achieved by nano-N2 treatment. However, oil yield increased with increasing fruit load as a result of applying U1. It seems that urea, due to rapid absorption compared with slow-released nano-nitrogen, provided requiring assimilates in the growing season so that especially in the first year the yield and mineral composition improved. However, in the second year, both types of fertilizers led to improved nutrient status. Further research is recommended for application of nano-chelated nitrogen fertilizer in olive orchards.

    Keywords: Foliar application, mineral elements, nanotechnology, Olea europeae L
  • Sian Fallah *, Zahra Alimohammadi, Zohrab Adavi, Mojtaba Karimi Pages 3059-3071
    Allelopathic effects of plant residues is an important research avenue regarding optimization of rotation systems in agronomy. The aim of this study was to investigate the allelopathic effects of four plant residues, namely, black cumin, dragonhead, dill, and soybean on the germination and growth of wheat (Triticum aestivum) in different cropping systems. Results showed that application of organic manure for previous crops reduced the residue phytotoxicity and consequently alleviated the adverse effect of plant residues on the leaf area, length, and dry weight of the wheat root, affecting chlorophyll a, chlorophyll b, and carotenoids of wheat seedling leaves. In the presence of plant residue, the length and dry weight of the wheat roots were more negatively affected in comparison with shoots. The greatest allelopathic inhibition was observed for the wheat cultivated in the residue of black cumin, but soybean, dill, and dragonhead residues also potentially showed inhibition effects. It can be concluded that agroecosystems in which autumn wheat is in the rotation should be avoided where there are residues of soybean, black cumin, dragonhead, and dill. The tillage system in the same condition may not be agronomically suitable because of the allelopathic effects of previous crops.
    Keywords: Allelopathy, Medicinal plant, photosynthetic pigment, phytotoxicity
  • Leila Aalam, Mohammad Sedghi *, Omid Sofalian Pages 3073-3077
    The present study investigated the effect of salicylic acid (SA) and sodium nitroprusside (SNP) on germination and activity of antioxidant enzymes in soybean under oxidative stress using a factorial experiment based on completely randomized design with three replications. Treatments included SA (0 and 1 mM), SNP (0, 30, and 60 µM), and H2O2 (0, 50, and 100 µM). Results showed that the highest germination percentage (97%) was related to 1 mM SA without SNP and H2O2 which was 6% greater than the control and the highest germination rate (0.72) was related to 1 mM SA and 60 µM SNP without H2O2 (6.63% greater than the control). The highest activity for superoxide dismutase (89.17 units mg -1 protein) was achieved by application of 100 µM H2O2 without SNP. In conclusion, oxidative stress increased all antioxidant enzymes while SNP application decreased the enzyme activity and stress severity.
    Keywords: soybean, germination, hydrogen peroxide, Oxidative stress, Catalase