Pomology
Seyyedeh Fatemeh Motevalian; Bahram Abedy; Yahya Selahvarzi; Ali Tehranifar
Abstract
Introduction Major problems of pomegranate production, which is common in almost all of the world's pomegranate growing areas, especially in warm and dry regions, is the splitting of fruit, which is the most damaging to gardeners after pomegranate fruit moth. On the other hand, different studies ...
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Introduction Major problems of pomegranate production, which is common in almost all of the world's pomegranate growing areas, especially in warm and dry regions, is the splitting of fruit, which is the most damaging to gardeners after pomegranate fruit moth. On the other hand, different studies indicate that girdling affects the quantitative and qualitative characteristics of different fruit trees. In the gird, the trunk skin must be completely removed so that the upper to lower skin relationship is completely cut off. The raw material that is absorbed by the root and rising through the xylem is transformed into a sap in the leaf, and in the return path through the phloem, it hits the barrier and accumulated above the wound site. Due to this process, sugar and plant hormones and starch reach the upper part of the wound girdling in trees for various purposes, such as raising the percentage of fruition of the plant, increasing size and increasing the quality and accelerating the fruition is done.Material and Methods An experiment was conducted to investigate the effect of girdling time on quantitative and qualitative properties of two red peel sweet and tart varieties in the Mahdi Shahr city, Semnan province. The girdling was taken at three full bloom days, two months after full bloom and four months after full bloom. To do a girdling, a double-edged knife was plunged into the trunk, and the ring-like cutting was done around the trunk. So that the layer of bark was cut from the trunk with a diameter of less than 2 to 3 mm continuously and separated from the trunk completely, so that the relationship between the top and the bottom was cut off. To evaluate qualitative and quantitative traits, 3 fruits were selected from the northern, southern and middle parts of each tree and transferred to the laboratory for measuring morphological and physiological traits. Physiochemical traits including pH, titratable acidity content, total soluble solids and morphological traits including weight, volume, average weight of 100 aryls and percentage of fruit juice, Ariel seed weight percentage, and split percentage were investigated.Results and Discussion The results indicated that girdling at full bloom and two months after full bloom significantly reduced the percentage of fruit blooming in both cultivars compared to the control (non-girdling) treatment. Also, among the studied cultivars, percentage of splitting in red peel was higher than that of sour-sweet. In addition, girdling at full bloom and four months after bloom was able to increase weight, volume, and average weight of 100 aryls. Among two studied cultivars, sour-sweet showed higher soluble solids content and titratable acid percentage than red peel. It can be stated that photosynthetic materials in the crown of the tree are blocked by conducting a loop on the branch of the plant and prevent the transfer of these materials to the root. This allows the carbohydrates from photosynthesis to be transferred to fruits that are growing. As a result, the fruit grows more and subsequently increases its weight, volume, and number of aryls. In addition, the growth of root is reduced as a result of girdling and water, mineral salts, as well as growth regulators to the canopy and terminal meristem of the plant are slowed down, thereby significantly decreasing vegetative growth to be seen in the tree. Subsequently, with decreasing vegetative growth in the tree, the carbohydrate which is produced in the leaves is allocated to the growing fruits. This also increases the weight and volume of fruit in the tree. Since the girdling treatments are associated with meiosis (in full blooming stage) and in the stage of the growing of fruits cells (4 months after full bloom), it can be justified to enhancement of the weight and reduction of splitting percentage in the fruits of trees which is girdled. The main reason for this difference is the tension entered into the girdled trees at the interval between the application of the treatment and the wound healing.Conclusion According to the results of this study, it was found that the process of girdling results in weight and volume enhancement of the fruit. In addition, the quantitative and qualitative traits investigated in the experiment were different in the two cultivars of red peel sweet and sour-sweet. In addition, girdling was effective on the pomegranate splitting, which is one of the important issues in the plantation of this fruit. However, the timing of the girdling at the full bloom and the four months after full blooming had the greatest effect on reduction of the severity of this complication.
Hamid Mohammadi; Gholamhossein Davarynejad; Masud Khezri
Abstract
Introduction: Pistachio is one of the most important horticultural crops in Iran, USA, Turkey and some Mediterranean countries. Some physiological problems such as abscission of inflorescence buds, blankness, non-splitting, early splitting, cracking and nut deformation reduce the pistachio yield and ...
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Introduction: Pistachio is one of the most important horticultural crops in Iran, USA, Turkey and some Mediterranean countries. Some physiological problems such as abscission of inflorescence buds, blankness, non-splitting, early splitting, cracking and nut deformation reduce the pistachio yield and quality. A proper nutrition management of pistachio orchard might decrease the physiological problems and increasing the yield. Calcium is an essential plant macro-nutrient that has several distinct functions within plants. These functions can be divided into main areas including effects on membranes, enzymes, cell walls, and interactions of calcium with phytohormones. Free polyamines (putrescine, spermine, spermidine), are the widely distributed of N containing organic molecules binding to the intracellular anions (DNA, RNA, chromatin and proteins). They are also known to possess several regulatory functions. In plants, they have been associated with regulating many physiological processes, such as organogenesis, embryogenesis, floral initiation and development, leaf senescence, fruit development and ripening, and abiotic and biotic plant stress responses. Although the spray application of calcium compound and free polyamine has been investigated separately, application of calcium compounds combined with free polyamines has not been investigated yet. Therefore, the aim of this study was to evaluate the effect of combined treatments of calcium and free polyamines on decreasing the physiological problems and improving the yield of ‘Ahmad-Aghaii’ pistachio trees.
Materials and Methods: This experiment was carried out in a commercial 20-year old ‘Ahmad-Aghaii’ pistachio orchard in Rafsanjan, Iran. It was arranged as factorial based on randomized completely block design with three replications. The treatments were control, calcium compounds (calcium nitrate and calcium chloride at concentration of 0.5%) combined with free polyamines (putrescine, spermidine and spermine at concentration of 0.5 mM). Spraying were applied at different growth stages including two weeks after full bloom (stage 1), six weeks after full bloom (just before endocarp hardening) (stage 2) and the combination sprays of stage 1 and stage 2. Different traits including the percentages of abscission of inflorescence buds, cracking, blankness, early splitting, nut deformation, non-splitting and splitting as well as yield, leaf area and vegetative growth were measured. The individual shoot was the experimental unit and analyses of variance were performed using the General Linear Models procedure of SAS. Means were separated by Duncan’s multiple range test (P < 0.05).
Results and Discussion: Results showed that the main physiological problems of pistachio crop were decreased by application of calcium compounds combined with free polyamines. Spray application of the mentioned treatments was more effective at combined stages of 1 and 2 rather than the stages separately. It was resulted that calcium nitrate combined with spermine and spermidine treatments at combined stages of 1 and 2 reduced the abscission of inflorescence buds, blankness, nut deformation and non-splitting. Also, it was found that calcium nitrate combined with spermidine at combined stages of 1 and 2 reduced the percentage of early splitting while splitting and yield were increased. Spray application of free polyamines combined with calcium compounds did not affect the length and diameter of current-year shoots but significantly increased the leaf area. It seems that calcium plays a key role in conjunction with free polyamines especially spermidine and spermine in decreasing the abscission of inflorescence buds via improving the stability of cell wall and preventing abscission layer formation. It also seems that polyamines reduce the abscission of inflorescence buds by antagonism with ethylene, possibly by competing for S-adenosylmethionine (SAM), a common precursor of both plant bioregulators. Increasing the shoot yield and decreasing the percentage of blankness might be due to improving leaf photosynthesis as well as regulating kernel growth and development. It was found that free polyamines and calcium might promote a regulatory system against environmental stresses especially heat, drought and salinity which are the main concerns of pistachio growers.
Conclusion: According to the results, the application of calcium compounds combined with free polyamines could reduce the physiological problems and increased the yield of ‘Ahmad-Aghaii’ pistachio. Among calcium treatments, calcium nitrate was significantly more effective than calcium chloride. In the case of free polyamines, both spermidine and spermine were more effective than putrescine. It was concluded that application of calcium nitrate combined with spermidine or spermine at both stages (stage 1 + 2) was the most effective treatments in reducing physiological problems and increasing the yield of pistachio trees.
