Growing vegetables
Saeid Khosravi; Maryam Haghighi
Abstract
Introduction: Brassinosteroids promote plant growth by enhancing some metabolic activities such as photosynthesis, nucleic acid biosynthesis, proteins and carbohydrates. Mechanisms of resistance and tolerance in plants have been developed to tolerate water deficit stress. One way to deal with drought ...
Read More
Introduction: Brassinosteroids promote plant growth by enhancing some metabolic activities such as photosynthesis, nucleic acid biosynthesis, proteins and carbohydrates. Mechanisms of resistance and tolerance in plants have been developed to tolerate water deficit stress. One way to deal with drought is to use plant growth regulators. Brassinosteroids were first extracted from the pollen of turnip (Brassica napus) and were considered as the sixth group of plant growth regulators. These compounds stimulate growth and cell division and affect electrical properties, membrane permeability, stability and activity of membrane enzymes. Nowadays, brassinosteroids have been extracted from various plants and their structure and function have been identified.Materials and Methods: This experiment was conducted in a factorial experiment based on a completely randomized design on Capsicum annuum L. Castello cultivar under the average daily temperature of 25 °C and 18 °C at 75% relative humidity in greenhouses. Research conducted by the College of Agriculture, Isfahan University of Technology, with four drought treatments using polyethylene glycol 6000 solutions at four levels of 0, -6, -7, and -8 bar. Brassinosteroids were sprayed in two 1 μM control levels. Pepper seeds planted in transplanting trays containing 1 to 2 volumes perlite and vermiculite substrate. When the actual leaf of seedlings appeared, the root thoroughly rinsed with distilled water and then were transferred to black plastic containers with a diameter of 16 and height 13cm and 1L volume containing Johnson's nutrient solution including four dry treatments using 6000 polyethylene glycol solution and aerated in control for 15 minutes every 5 minutes. At the end of the experiment, vegetative factors such as fresh and dry weight of different parts of the plant, plant length, and volume, and physiological factors such as proline and abscisic acid content and chlorophyll fluorescence changes were measured.Results: The results of the analysis of variance table showed that brassinosteroid had no significant effect on most vegetative traits except root volume and weight and all physiological traits except chlorophyll fluorescence and the mentioned traits increased with the application of 1 mM brassinosteroid. However, the main effects of drought except for amino acid and the interaction of drought and brassinosteroids were significant on all traits. The results of the main drought effects showed that the root fresh weight at -8 bar and dry weight at -7 bar significantly decreased, whereas fresh and dry weight of the shoots at lower than -6 bar. The onset of decline showed that the root length and volume appeared to decrease with the onset of stress by -6 bar and the plant length also reduced with the first stress level. Drought stress at -6 bar level decreased chlorophyll fluorescence, chlorophyll index and Abscisic acid while at -7 bar decreased protein and increased proline. The results also showed that the amount of sulfuric, essential and unnecessary amino acids were significantly reduced by drought stress and brassinosteroid had no effect. Total amino acid content decreased with drought stress but there was no significant difference with control. With increasing drought stress, the fresh and dry weights of shoots decreased and the intensity of shoots decreased. The intensity of shoot growth decreased with the use of brassinosteroids at moderate stress but the mentioned trait showed the same adverse effects at all levels of stress. Brasinosteroid application decreased stress indices such as proline (7%) and abscisic acid (50%) and this decrease was more pronounced in proline, especially in more severe treatments. Amino acid and protein levels decreased with drought stress, and the use of brassinosteroids could not be effectively affected by this reduction, especially for the compounds and the amount of amino acids.The results of biplot analysis showed that the vegetative and protein traits had better mean in stress condition in the presence and absence of stress and in higher stress severity and application of brassinosteroid affected root fresh weight and abscisic acid content more than the other traits. While in mild stress it seemed to be more effectively on the steroid and most of the vegetative and physiological traits than the control.Conclusion: It seems that the application of brassinosteroids on pepper seedling in drought stress at a concentration of 1 μM is effective in maintaining vegetative properties and reducing negative effects of stress and reducing stress indices.
Niaz Gholi Firozbakht; Mehdi Rezaei
Abstract
Introduction: Size of fruit in Japanese plum has an important role in marketability and fruit quality. In Golestan province, one of the most important areas of plum production in Iran, due to high temperatures in summer that led to unfavorable conditions in fruit ripening stage, final fruit size are ...
Read More
Introduction: Size of fruit in Japanese plum has an important role in marketability and fruit quality. In Golestan province, one of the most important areas of plum production in Iran, due to high temperatures in summer that led to unfavorable conditions in fruit ripening stage, final fruit size are reduced in commercial scale. In this respect, the large financial loss is imposed to plum growers. Today, synthetic auxins are widely applied in the commercial gardens of the world in order to increasing fruit size and improving fruit growth . Auxins can promotes cell division, cell enlargement in fruit growth stages and it also acts as sink for nutrients absorption. In this study, the effects of the foliar application of two synthetic auxins were investigated on fruit qualitative and quantitative of Japanese plums in Golestan province climatic conditions.
Material and Methods: A split-plot factorial experiment based on randomized complete block design with four replications was conducted in a commercial orchard from Run Agri Company in Golestan province, Iran for two years (2015 and 2016). The main factor was considered four plum cultivars including ‘Ghatreh Tala’, ‘Shablon Zodras’, ‘Shablon Mianras’ and ‘Shablon Dirras’ which were spraying by two synthetic auxins: NAA (0, 300 and 400 mg/l) and 2, 4-D (0, 10 and 30 mg/l) along and in combination. Fruit length, diameter, length to diameter ratio and fruit weight, yield, yield efficiency and percentage of first and second fruit grade production characteristics were evaluated. Data analysis was performed by SAS 9.1 software and the comparison of mean values was done by Duncan's multiple range tests at 0.05 of probability level.
Results and Discussion: The results showed that foliar application of auxin significantly increased fruit size and weight. The results showed that the response of plum cultivars to synthetic auxins was different. Fruit length and width of ‘Shablon Dirras’ cultivar were increased with the 2,4-D application at 10 and 30 mg/l , but in the ‘Shablon Mianras’ cultivar, the combination of 2,4-D with NAA improved fruit size. NAA at its highest concentration (400 mg/l) plus 2, 4-D at its highest concentration (30 mg/l) produced the largest fruits and the highest yield in ‘Shablon Mianras’ cultivar. Stern et al. (16) also obtained similar results from NAA and 2, 4-D treatments in plum, which is confirmed our results. The yield (kg/tree) and yield efficiency in plum cultivars increased significantly by synthetic auxin treatments. The average of yield (kg/tree) by 2, 4-D and NAA foliar application increased 30, 60, 28 and 34 percent in ‘Shablon Zodras’, ‘Shablon Mianras’, ‘Shablon Dirras’ and ‘GhatrehTala’ cultivars, respectively. The highest yield efficiency was obtained in ‘Shablon Mianras’ cultivar (0.38 kg/cm2) in 30 mg/L of 2, 4-D plus 400mg/L of NAA, which showed a 120 % increasing in comparison to control trees. Denis (7) reported increases the quantitative characteristics of stone fruits such as fruit size and weight by using synthetic auxin spray. The effect of auxin on increase cell proliferation and cell size are main reason for increasing the length and weight of the fruits (7). The results showed that 2, 4-D and NAA auxins were able to increase the percentage of first grade fruit relative in all plum cultivars in comparison to the control trees, but the concentrations and composition of plant growth regulators that increased the percentage of first grad fruits were not completely same to best treatments on fruit size, weight or yield. It referred to the first-grade fruits selection criteria. In selecting of best marketable fruits, in addition to the size of the fruit, others feature such as fruit appearance, color, physical damage and the absence of symptoms of diseases are also taken into grading. Temperature, water, nutritional and genetic conditions can affect the effect of plant growth regulator treatments (13).
Conclusions: Plum cultivars showed different reactions to synthetic auxin treatments. The largest fruit, highest yield and yield efficiency obtained in 2,4-D (30 mg/l ) with NAA (400 mg/l) in ‘Shablon Mianras’, ‘Shablon Dirras’ and ‘Ghatreh Tala’ cultivars and 2,4-D at 30 mg/l with NAA at 300 mg/l concentration in ‘Shablon Dirras’ and ‘Ghatreh Tala’ Cultivars. The highest degree of first grad-fruit was observed at 10 mg/l 2,4-D in ‘Shablon Zodras’ and ‘Dirrras’ cultivars and 300 mg/l of NAA in ‘Shabolon Mianras’ and ‘Ghatreh Tala’ cultivars.
Ahmad Noroozi; Abdolreza Bagheri; Nasrin Moshtaghi; Ahmad Sharifi
Abstract
Introduction: Anthurium is a popular genus of the Araceae (order Spathiflorae).The flower consists of a protruding spadix containing numerous florets, subtended by a brightly colored modified leaf, the spathe. Anthuriums are bisexual and protogynous.Anthuriumscherzerianum as the most important species ...
Read More
Introduction: Anthurium is a popular genus of the Araceae (order Spathiflorae).The flower consists of a protruding spadix containing numerous florets, subtended by a brightly colored modified leaf, the spathe. Anthuriums are bisexual and protogynous.Anthuriumscherzerianum as the most important species ofAnthurium genus is a potted perennial plant. Due to having beautiful, attractive and long-life flowers, A. scherzerianum can be used for the production of pot and cut flowers. Tissue culture is suggested as the most commonly method in order to rapid propagation and removing disease in a short period of time. This method also recommended for Anthuriumbecause of problems in classical propagation method of this flower..The three basic propagation methods for Anthuriumare propagation by seed, traditional vegetative and tissue culture.Micropropagation of Anthurium is using forcommercial production.
Materials and Methods: In this study, the effect of plant growth regulators and explants on indirect regeneration of A. scherzerianumdetermined in separate experiments. In the first experiment, callogenesis was done by leaf explants on MS medium containing growth regulators, BA in three concentrations (0.5, 1.25 and 2 mg/l) in combination with
2, 4-D (0.5, 1.25 and 2 mg/l) or NAA (0.5, 1.25 and 2 mg/l) and the combinations of TDZ (0.5, 1.25 and 2 mg/l) with
2, 4-D (0, 0.5 mg/l). In the second experiment, regeneration was done on MS medium containing 0.75 mg/l BA with 0.05 mg/l 2, 4-D and 0.1 mg/l NAA and also in combination with TDZ (0.75mg/l). For rooting, MS medium containing different concentrations of IBA and IAA (0, 0.2 and 1 mg/l) were used. Callus induction, regeneration and rooting experiments were done based on completely randomized design, with 12, 6 and 6 replications, respectively.Data from all the schemes used in this study were analyzed with SAS statistical software. The comparison of means using Duncan's multiple range test was evaluated at the 5% level.
Results and Discussion: Analysis of variance showed that the effect of explant type and hormone combinations was significant on the percentage of callogenesis, callus volume and survival percentage. The interaction effect of explant type and combination of hormones was also significant on percentage of callogenesisand the volume of callus. Means comparisons showed that the highest callogenesis, viability and callus volume were achieved on MS medium containing 2 mg/l of BA and 0.5 mg/l of 2, 4-D. Petiole explants, also produced the highest percentage of callus (95%), survival rate (96%) and callus with dimensions of 6 mm2. Callus formation in leaf vein explants was higher than others. The effect of explant type and hormone combinations on regeneration, number of branches, number of leaves and leaf length was significant.The interaction of explant and hormone combinations on regeneration, number of branches, number of leaves and leaf length was also significant. Moreover, results of regeneration experiment indicated that the maximum number of shoots (6.9) and the maximum shoot length (5 cm), number of leaves (18) and the leaf length (2.8 mm) were achieved in 0.75 mg/l BA mg/l of and 0.05 mg/l 2, 4-D. In this study, petiole explants were also regenerated earlier than leaf explants.The effect of hormone combinations and concentrations was significant on rooting specially on the number of roots and root length.Furthermore, results of rooting experiment revealed that the highest rooting percentage (95%), the maximum number of roots (4.5 per plantlet) and the longest roots (3.5 cm) were produced in the medium containing 0.2 mg/l of IBA. Finally, the rooted plantlets were adapted (90%) in vivo condition by placing them on a mixture of cocopeat and perlite (2:1) substrate.
Conclusion: In this study callugensis, regeneration and rooting of A.scherzerianum’s petiole and leaf explants were studied and different levels of plant growth regulators used for callugensis and regeneration. In this study petiole explants showed the highest callugenesis and regeneration. MS medium containing BA (2 mg/l) and 2, 4-D (0.5 mg/l), was the best for callugenesis. Also the highest percentage of regeneration was observed in medium containing BA (0.75 mg/l) and 2, 4-D (0.05 mg/l). Moreover low concentration (0.2 mg/l) of auxin has a better effect on rooting than high levels (1mg/l) so that the highest rooting percentage was produced in medium containing IBA (0.2 mg/l) and the lowest rooting percentage was produced in medium containing IAA (1 mg/l). Anthurium plantlets acclimized is cocopeat and perlite substrate (2: 1) with 90% acclimation.
Mohamad Hossein Sheikh Mohammadi; Nematollah Etemadi; Ali Nikbakht
Abstract
Introduction: Drought is one of the most detrimental abiotic stresses for turfgrass growth across a wide range of geographic locations. Most cool-season grass species are not well adapted to extended periods of drought, particularly during summer months. Decline in turf quality caused by drought stress ...
Read More
Introduction: Drought is one of the most detrimental abiotic stresses for turfgrass growth across a wide range of geographic locations. Most cool-season grass species are not well adapted to extended periods of drought, particularly during summer months. Decline in turf quality caused by drought stress is a major concern in turfgrass culture. Therefore, developing management practices for improving drought resistance of turfgrasses has become essential in arid and semi-arid regions, especially during water use restriction. One strategy to improve plant drought resistance is to promote drought avoidance by reducing water loss during drought, which may be achieved by slowing growth rate of shoots and lowering leaf area canopy to reduce demand for water. Application of growth regulators is one of the methods for increasing resistance of plants to biotic and abiotic stresses. Trinexapac-ethyl (TE) is one of the most widely used PGRs in the management of cool-season and warm-season turfgrass species. TE absorbed quickly by foliage and slow cell elongation through inhibiting of converting one form of gibberellic acid (GA20) to another (GA1). Most studies conducted under non-stressed conditions found that TE application increased chlorophyll content, turf quality, turf density and reduced shoot extension rate. We hypothesized that TE may influence plant tolerance to drought stress. Limited available data─ as reported in the above referred studies─ suggest that TE application may be beneficial for plant tolerance to stresses, but the effectiveness varies with turfgrass species, dose and duration of TE treatment, and type of stress. The main aim of this research is to evaluate the effect of Trinexapac-ethyl on increased resistance to drought stress in wheatgrass.
Materials and Methods: Wheatgrass (Agropyron desertorum L.) was used in this study. This study was conducted in field conditions at Isfahan University of Technology, Isfahan, Iran.. Wheatgrass native seeds (Agropyron desertorum L.), collected from the turfgrass research farm at Fereydan, Isfahan, which were cultivated hand broadcast in plots (3m × 2m) with seeding rates of 30 gm–2. A factorial experiment based on randomized complete block design (RCBD) with three replications was conducted for TE (Primo Maxx; Syngenta Crop Protection, Inc., Greensboro, NC) and drought stress. Treatments involved three levels of Trinexapac-ethyl growth regulator (0, 0.25 and 0.5 kg/h) and two levels of drought stress (with irrigation and without irrigation). After planting, the plots were irrigated to maintain soil moisture at 80% field capacity or higher. Irrigation was applied as required to prevent any drought stress during grass establishment. Turfgrass species were maintained at cutting height of 4 cm and were mowed once a week using a reel-type mower. All data were subjected to analysis of variance using SAS 9.1 (SAS Institute Inc., Cary, NC) and Fisher’s protected LSD test was employed at the 5% probability level..
Results Discussion: Results indicated that Trinexapac-ethyl and drought reduced growth, fresh weight and dried above ground organs significantly. Wheatgrass growth in concentrations 0.25 and 0.5 kg/h were 19.20 and 26.90%, respectively. Previous studies reported plants that have slow-growing shoots may survive more extended periods than faster-growing plants in drought conditions. Slow growth may reduce the adverse impact of drought by conserving water and carbon energy, and plants can use limited water to survive drought for an extended period of time. Unlike drought stress, Trinexapac-ethyl improved the quality of plant tissues and their color. Increase in turf quality under TE treatment might occur as a result of improved canopy photosynthesis capacity and single-leaf photochemical efficiency. Drought stress reduced relative water and chlorophyll content, increased proline level and finally led to electrolyte leakage. Trinexapac-ethyl improved wheatgrass in drought stress conditions by increasing relative water content, prolin, chlorophyll and decreasing electrolyte leakage and increased wheatgrass to drought stress resistance. Proline acts as an osmotic regulator in cytoplasm and vacuoles, protects proteins against dehydration, adjusts osmosis; detoxify radical active oxygen species, keeping more stable antioxidant enzymes. Proline immediate increase under drought stress is associated with decreasing leaf water content, in turn, induced drought tolerance. Under drought stress conditions, penetration of root depth and effective root depth has been increased, while Trinexapac-ethyl did not affect root traits significantly. The results of the present study indicated that TE decreased damages on drought stress probably via improving turf quality, chlorophyll concentration, leaf water content, proline content and less electrolyte leakage in Wheatgrass.
Mohammad Gerdakaneh
Abstract
The present investigation was conducted to study the effects of type and concentration of auxin and cytokinin on callus induction of three strawberry (Kurdistan, Parose and Camarosa) cultivars. For this purpose, leaf blade, nodal, petiole, receptacle, stamen and flower bud explants were cultured on Murashige ...
Read More
The present investigation was conducted to study the effects of type and concentration of auxin and cytokinin on callus induction of three strawberry (Kurdistan, Parose and Camarosa) cultivars. For this purpose, leaf blade, nodal, petiole, receptacle, stamen and flower bud explants were cultured on Murashige and Skoog (MS) medium at three separate experiments included 2, 4 dichlorophenoxyacetic acid (2,4-D) at 2, 3, 4, 5 and 6 mg/L, naphthalene acetic acid (NAA) at 2, 3, 4, 5 and 6 mg/L and different concentrations (0, 0.5, 1.0, and 2.0 mg/L) of benzyl adenine (BA) combination with 4 mg/L NAA. The concentration and type of growth regulators, cultivar and explant type were found critical to the callus induction and callus physical appearance. All explants exception of receptacle incubated on medium formed callus. The leaf and nodal were the most responsive explant to produce callus. MS medium supplemented with combination of auxin and cytokinin were evidently higher than those in the single auxin treatments. 4.0 mg/L NAA + 1 mg/L BA yielded the highest percentage of callus in all types of explants. In this medium, the highest callus induction (98.50%) was recorded in nodal explants of Kurdistan cultivar.
M. Gerdakaneh; A.A. Mozafari; A.M. Hadji Amiri
Abstract
Present study was conducted to consider the effects of different concentrations of 2,4-D and BA on somatic embryogenesis induction, development and maturation of three strawberry cultivars (Kurdistan, Parose and Camarosa). For this purpose, leaf blade, nodal, petiole, stamen and flower bud calli were ...
Read More
Present study was conducted to consider the effects of different concentrations of 2,4-D and BA on somatic embryogenesis induction, development and maturation of three strawberry cultivars (Kurdistan, Parose and Camarosa). For this purpose, leaf blade, nodal, petiole, stamen and flower bud calli were cultured on Murashige and Skoog (MS) medium supplemented with 2, 4 dichlorophenoxyacetic acid (2,4-D at 0.25, 0.5, 1 and 2 mg/l ) as well as the combination with different concentrations (0.0, 0.25, 0.5, and 1 mg/l) of benzyl adenine (BA). The concentration and kind of growth regulators, cultivar and explant had great importants on strawberry somatic embryogenesis induction, development and maturation. Results obtained from the studies revealed that all explants with the exception of petiole and stamen incubated on medium formed embryonic calli. MS medium supplemented with combination of auxin and cytokinins were evidently higher than those in the single auxin treatments. 1 mg/l 2,4-D + 0.25 mg/l BA yielded the highest percentage of embryonic calli and number of globular embryo stage and 0.5 mg/l 2,4-D + 0.25 mg/l BA yielded the highest number of embryo cotyledonary in all types explants. The leaf explant calli and Parose cultivar were the most responsive to produce to somatic embryogenesis induction, development and maturation.
