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.
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.
