Gholamhossein Davarynejad; Mina Nurzadehnamaghi; Ali Momen
Abstract
Introduction: Pistachio (Pistacia vera L.) is an important horticultural crop that has high economic value. Pistachio trees display some physiological disorders including abscission of inflorescence buds, fruit abscission, blankness, non-splitting, early splitting and deformation of nuts. Unfavorable ...
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Introduction: Pistachio (Pistacia vera L.) is an important horticultural crop that has high economic value. Pistachio trees display some physiological disorders including abscission of inflorescence buds, fruit abscission, blankness, non-splitting, early splitting and deformation of nuts. Unfavorable environmental conditions in most pistachio orchards and inadequate nutrition during the flowering time and after flowering has increased these problems in recent years. Polyamines such as putrescine, spermine and spermidine are some low molecular weight polycationic compounds that have been shown to play an important role as growth regulators in different stages of growth and development of buds, flowers and fruits and resistant plants to abiotic and biotic stress. Therefore, the objective of this study was to investigate the influence of polyamines in water scarcity condition on growth, nut traits and yield of ‘Akbari’ pistachio trees. Materials and Methods: The study was carried out in growing season 2016 in a pistachio orchard (Pistacia vera L. cv Akbari) located in Feyzabad, Mahvelat, Khorasan Province, Iran (34° 40´ N latitude, 58° 25´ E longitude, and around 1253 m above sea level). The climate of the experimental area was arid and semi-arid. The mean annual precipitation was about 171 mm. The irrigation of orchard trees was at 36-day intervals. The experiment was conducted as split plot based on a randomized complete block design with three replications and seven treatments including polyamines spray of Putrescine (Put), Spermine (Spm) and Spermidine (Spd) at concentrations of zero (control), 0.1 and 1 mM on “on” and “off” pistachio trees cultivar Akbari at two-time stages full bloom (FB) and two weeks after full bloom (2WAFB). Leaf chlorophyll index was recorded using the chlorophyll meter (SPAD-502, Konica Minolta, Japan). Leaf area from fully expanded leaves was measured by Digital Leaf Area Meter (LI-3100c). The length and diameter of current-year shoots were measured at harvest time. The percentage of flower bud abscission and fruit abscission were calculated on marked shoots. The yield was calculated by weighting the total dried split nuts separated from each shoot. The data were subjected to analysis of variances (ANOVA) using the SAS software (SAS version 9.1). Difference between means was compared using the least significant difference test (LSD) at 5% level (p ≤ 0.05). Results and Discussion: Results showed that among the treatments, Put (0.1 and 1 mM) and Spm (0.1 mM) applied in the “on” trees significantly increased leaf chlorophyll index. Also, Put spray at two weeks after full bloom indicated better results in increase of length shoot in ‘on’ trees. All of the polyamines reduced fruit abscission in the “on” trees however, Put at 0.1 and 1 mM concentrations with 11.3 and 11.1% was more effective in decreasing the percentage of fruit abscission compared to other treatments. Fruit abscission of pistachio is assumed to be related to improper fertilization, the dominance of fruits in a cluster or abnormalities of reproductive organs. Polyamines have been suggested to improve fertilization, and subsequent embryo and fruit development. It also has been reported that common precursor of S-adenosylmethionine (SAM) needed for synthesizing both of PAs and ethylene. Thus, it seems that polyamines reduce the abscission of fruits by the improvement of embryo growth and development or by antagonism with ethylene, possibly by competing for S-adenosylmethionine (SAM). Our study indicated that all of the polyamines decreased the percentage of blank nuts in the “off” trees especially two weeks after full bloom. The results showed that Put (0.1 and 1 mM) and Spd (0.1 mM) were very effective in increasing number of nuts per cluster. Number of nuts per 100 g, split nuts, and kernel percentage did not differ significantly among treatments. Yield variations were not significantly affected by polyamines in in the “off” trees, but in ‘on’ trees, polyamines of Put, Spm and Spd at 0.1 mM concentration by 46.2, 14.6 and 15.2% and at 1 mM concentration by 38.7, 24.7 and 19.9% increased yield compared to control, respectively. Given to correlation results, the positive effect of polyamines on yield improvement in ‘on’ trees was mainly due to the prevention from fruit abscission and enhancement no. of nuts per cluster. Conclusion: Results showed that application of polyamines treatments in ‘off’ trees only on blank nuts and in ‘on’ trees on leaf chlorophyll index, fruit abscission, No. of nuts per cluster and yield was effected. Foliar application of polyamines was more effective in improving traits of shoot length, leaf area and blank nuts two weeks after full bloom compared to full bloom. The results of this study showed that these plant growth regulators, especially putrescine, had the potential to improve growth, yield and reduce physiological problems of pistachio under unfavorable environmental conditions.
Mina Nurzadeh Namaghi; Gholamhossein Davarynejad; Hossein Ansari; Seyyed Hossein Nemati; Ahmad Zarea Feyzabady
Abstract
Introduction: Mulching is a useful practice with the potential of conserving moisture, reducing evaporation, modifying soil temperature, and improving aeration as well as releasing nutrients in the soil profile. Mulching involves the use of organic materials (e.g. crop residues, straw, grasses, and farmyard ...
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Introduction: Mulching is a useful practice with the potential of conserving moisture, reducing evaporation, modifying soil temperature, and improving aeration as well as releasing nutrients in the soil profile. Mulching involves the use of organic materials (e.g. crop residues, straw, grasses, and farmyard manure) or inorganic and synthetic materials (e.g. polyethylene sheets, and gravels). Application of mulch can notably as a soil management method influence agricultural crop production despite the limited amount of water available in arid and semi-arid areas.
Materials and Methods: Field studies were conducted in a randomized complete block design with five replications for two years in 2014 and 2015 at Feyzabad city, Iran (34° 40´ N, 58° 25´ E). The aim of the study was to investigate the effects of different mulching treatments on physiological traits of pistachio (Pistaciavera L.) in relation to soil temperature and moisture variations. The treatments were: M1 (whitepolyethylene film mulch covered with two centimeter of soil with width cut), M2 (white polyethylene film mulch covered with two centimeter of soil with circular cut), M3 (green polyethylene film mulch which was as a single layer pulled on water strip so that irrigation water passes under the coverage), M4 (woodchip mulch), M5 (barley residue mulch), and CK (control or no mulching). The measurement (soil moisture and temperature, stomatal conductance and leaf temperature) was carried out periodically on the central trees (4 trees per treatment) every 12, 24 and 36 days after irrigation between 12-15 pm from early-May to late September. The data obtained from the experiment were subjected to an analysis of variance (ANOVA) by using SAS 9.1 software. Difference between means was compared using least significant difference test (LSD) at 5% level (p ≤ 0.05).
Results and Discussion: The results showed that the mean soil moisture percentage in all mulches especially plastic mulches was higher compared to the control over two years of experiment. During the two years of experiment, treatments of M1, M2 and M3 with 35.2, 35 and 38.9 °C and treatments of M4, M5 and CK with 28.8, 29.6 and 32.8 °C indicated the highest and lowest average soil temperature at 20-30 cm soil depth, respectively. Also, similar results were observed at 50-60 cm soil layer. M3 and CK treatments with 47.7 and 41.1 mmol/m-2s-1 had the highest and lowest mean stomatal conductance, respectively. The mean values of leaf temperature during the growing period under M1, M2, M3, M4 and M5 treatments were 2.2, 1.9, 2.4, 1.7 and 1 °C in 2014, and 1.8, 2.2, 2.2, 1.5 and 1.1 °C in 2015 lower than CK (control) treatment, respectively. According to correlation results significant difference was not observed between stomatal conductance and soil moisture, but the relationship of this parameter with soil temperature and relationship between leaf temperature with soil moisture and soil temperature were significant. Thus, this results demonstrate that stomatal conductance and soil temperature weresignificantly affected by soil temperature, so that an increase in soil temperature to 40 °C, canbe improved these traits if other soil and climatic factors werenot limiting. The results also showed that M3 mulch (plastic mulch on soil surface) despite the higher soil water storage due to providing of soil high temperatures, can be leads to moisture stress in heavy cropping year.
Conclusions: The results of thisstudy showed that organic and inorganic mulches improved the soil moisture content throughout the two growing seasons, thus reduced negative effects of water shortage. Mulch treatments indicated smaller fluctuations in soil temperature compared to CK (control) treatment, possibly due to insulating against heat radiation. The results of our study suggested that increase in soil temperature in M3 treatment, despite higher water storage, had limited impacts on improving stomatal conductance and leaf temperature from early July in the second year. Thus, it seems that high soil temperature in this treatment in ON year that trees' water and nutrients requirement is higher than OFF year acts as a limiting factor and restricts absorption of water and nutrients, resulting in the decrease of physiological activity of trees. Generally, it is conclude that white polyethylene films covered with soil especially M2 and organic mulches due to providing optimum soil temperature, preserving soil moisture and lower cost can be better management options to be applied in pistachio orchards especially in arid and semiarid areas, where traditional irrigation methods with high evaporation level are used.
Ghorbanali Asadi; Ali Momen; Mina Nurzadeh Namaghi; Sorur Khorramdel
Abstract
Application of organic manures is one of the most important strategies for plant nutrition compared to chemical fertilizers, especially in organic management of medicinal plants. In order to evaluate the effects of different organic and chemical fertilizers on yield, yield components and qualitative ...
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Application of organic manures is one of the most important strategies for plant nutrition compared to chemical fertilizers, especially in organic management of medicinal plants. In order to evaluate the effects of different organic and chemical fertilizers on yield, yield components and qualitative characteristics of isabgol (Plantago ovata), a field experiment was conducted based on randomized complete block design with three replications at the Agricultural Research Station, College of Agriculture, Ferdowsi University of Mashhad, during growing season of 2011-2012. Treatments included three levels of nitrogen fertilizer (25, 50 and 75 kg.ha-1), three levels of cow manure (5, 10 and 15 t.ha-1) and three levels of vermicompost (2, 4 and 6 t.ha-1) and control.The results showed that the effectof different fertilizers was significant (p≤0.05) on all studied traits except swelling rate of isabgol. The maximum amounts were observed in 6 t.ha-1 vermicompost and 15 t.ha-1 cow manure. The highest seed yield (548.4 kg.ha-1) was observed in 6 t.ha-1 vermicompost that it enhanced up to 26% compared to control. By increasing in organic fertilizers enhanced mucilage content, swelling factor and swelling content of isabgol. The maximum mucilage content and swelling factor were observed in 15 t.ha-1 (with 35.3% and 13.4 ml, respectively). Since, organic matters improved quantitative and qualitative yield of isabgol compared to chemical fertilizer, it concluded that these organic inputs could be regarded as a suitable alternative to enhance the growth and yield of medicinal plants such as isabgol especially in low input systems.
