Ali Imani; Khosro Parvizi; Hamdollah Beyrami jam; Ebrahim Hadavi
Abstract
Introduction: Iron chlorosilicon caused by calcium carbonate can be controlled widely with iron chelate in nutrition management of gardens, but it has high costs and potential environmental hazards. Such constraints have led to alternative strategies for managing iron nutrition in relation to soil and ...
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Introduction: Iron chlorosilicon caused by calcium carbonate can be controlled widely with iron chelate in nutrition management of gardens, but it has high costs and potential environmental hazards. Such constraints have led to alternative strategies for managing iron nutrition in relation to soil and plant parameters. Almond rootstocks and almond x peach hybrids (GF 677) are widely used as the rootstock for almonds, peaches and nectarines in the Mediterranean basin, moreover, in addition to its drought resistance, has a high tolerance to iron chlorosis. Different references of almond tree have introduced this fruit tree as a chlorosis resistant, but it shows different ranges of chlorosis when grafted on almond x peach hybrids such as GF677 and GN15. Therefore, this study carried out to evaluate the effect of calcium bicarbonate on some physiological characteristics of selected almond cultivars on the GN15 rootstock.
Materials and Methods: This research was conducted during 2015 and 2016 to evaluate the resistance to bicarbonate and the amount of chlorosis produced in selected almond cultivars on the hybrid rootstock (peach and almond) as a factorial experiment with completely randomized design with three replications in greenhouse conditions. The first factor consisted of different concentrations of calcium bicarbonate (0, 20, 10, 30 and 40 mmol L-1) and the second factor included nine selected almond cultivars grafted to the GN15 rootstock and a GN15 (non-grafted) rootstock. Almond cultivars included 9 cultivars including Supernova, 25-1, 40-13, Mamaei, 16-1, Kaghazi, Sahand, 200A, 7-9, and GN15 rootstock. Each plot included a pot, where the rootstock planted. In the spring, the cultivars and GN15 rootstock planted in plastic pots with soil compositions including perlite (50%) and cocopeat (50%). After sufficient growth of these rootstocks in the pots, almond cultivars were grafted onto them and immediately after the transplantation, the calcium bicarbonate treatments began after proper growth of the scions. In order to apply bicarbonate treatment, 1.62, 3.23, 4.86 and 6.48 g L-1 calcium bicarbonate (Ca (HCo3) 2) were added to the pots. In addition, 10% of calcium bicarbonate added also to the pots because of the deficiency of 10% chemical purity. After applying the treatments, chlorophyll, chlorophyll a and b, carotenoids, chlorophyll fluorescence were measured in two stages at intervals of 30 and 90 days. After the end of the growth period, the length and diameter of the current season branches and the leaf length and width of each almond cultivar were measured and recorded in different treatments. Two-way ANOVA of the data was carried out using SAS software (v. 8.02, SAS Institute, Cary, NC) and the means were compared based on Duncan’s multiple range test.
Results and Discussion: Based on the ANOVA results, it was determined that the effects of calcium bicarbonate, cultivar and their interactions on the content of chlorophyll a and b were statistically significant (p≤0.01). The lowest decrease levels of chlorophyll a and b were found in the leaflets of Kaghazi, Mamaei, saplings, 25-1, and 40-13 cultivars, but the highest decrease was observed in Supernova cultivar, 7-9, and GN15. The reasons for decreasing the chlorophyll content of the leaf with the increase of bicarbonate levels can be related to iron deficiency and its deactivation and the role of iron in the synthesis of chlorophyll. Nevertheless, the difference for chlorophyll depletion at different levels of bicarbonate in different cultivars can be due to the capacity of these cultivars to tolerate higher levels of bicarbonate and the possibility of the synthesis of chloroplastic proteins in leaf cells even with a relative lack of iron. In all cultivars, as well as the GN15 rootstock, the level of carotenoids decreased with increasing concentrations of calcium bicarbonate. However, the response of the cultivars was different. Under bicarbonate conditions, reducing leaf iron concentration reduces chlorophyll and carotenoids. The results of the mean comparison showed that bicarbonate induced height growth reduction and branch diameter in the current season, while the reaction of the studied rootstocks were also different. So that the highest decrease in growth rate was observed in Supernova, 7-9 cultivars and GN15 rootstock and the lowest decrease of growth rate were found in the cultivars of Kaghazi, 1.25-1 and -40-13. High concentrations of bicarbonate, by disabling and decreasing iron absorption, indirectly reduces DNA synthesis, cell division, and thus decreases cell growth and plant biomass. The results of this study are in agreement with Ghasemi et al. (2010) in different responses of the rootstock to bicarbonate concentration on the height and diameter decreasing of current season branch. Mean comparison of data showed that the length and width of leaf area in all studied cultivars decreased with increasing concentration of calcium bicarbonate in irrigation water. Also, leaf length and width decrease in rootstock grafted cultivars had a significant difference, so that the lowest reduction in leaf length and width was in pepper, midwifery and 25-1, and the highest leaf area decrease in Supernova cultivars, 7-9 and GN15 base was observed. Leaf growth decreases in calcareous soils due to a decrease for iron in the symplast. The specific effects of high bicarbonate on leaf growth in almond cultivars and the different reaction of almond rootstocks in this study are in agreement with Tedaion et al. (2004) results in orange, as well as Wahom et al. (2001) in olive and peach.
Conclusion: Totally, the results of this study indicate that cultivar and rootstock cause the amount of chlorosis tolerance induced by calcium bicarbonate. In general, in terms of morphological and physiological traits studied in this research, Kaghazi and 25-1 cultivars are the most tolerant, while 7-9 and supernova are the most sensitive cultivars to bicarbonate.
Azizollah khandan Mirkohi; Nakisa Baie; Ebrahim Hadavi
Abstract
Introduction: Regular watering and application of nitrogenous fertilizers in turf-grasses is a conventional operation, especially in warm and dry or semi-dry climates, which arecommon in many parts of Iran. Nitrogen is a mobile nutrient in soil or substrates, especially in the form of nitrate. Nitrate ...
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Introduction: Regular watering and application of nitrogenous fertilizers in turf-grasses is a conventional operation, especially in warm and dry or semi-dry climates, which arecommon in many parts of Iran. Nitrogen is a mobile nutrient in soil or substrates, especially in the form of nitrate. Nitrate leaching due to the regular watering has been reported in many sources. The managing nitrogen application can help to minimize the loss of this element regarding the ability of soil-plant system. Attempts have been made to control the growth of turf-grass using various types of chemicals, but similar to the concerns associated with the consumption of nitrogenous fertilizers, this is also concerned with environmental pollutions. Therefore, the growth of turf grasses can be controlled without using chemicals and by limiting the use of nitrogen and managing the irrigation.The purposes of this study were to limit the application of nitrogen in order to control vegetative growth of the turf grass and maintain its visual quality, and to manage irrigation in order to preserve this mobile element (nitrogen) near the root system and prevent its leaching.
Materials and Methods:The effects of reduced water and nitrogen supply on the control of vegetative growth of turf grasses, commonly named as sport turf,were evaluated.Therefore, an experiment was designed in a factorial based on randomized complete block design with three replications. Mixed seeds of sport turf grass were planted with the density of 40 g m-2in boxes, which placed atthe depth of30 cm and leveled with sandy loam soil in mid-spring. Nitrogen was applied as ammonium nitrate via fertigation in five levels of 0, 0.5, 1, 1.5 and 2 mg m-2 month-1, andirrigation treatments performed at four levels of 100%, 80%, 60 % and 40% of field capacity. Watering was done every two days for 5 months during the warm season of the year after the first mowing on June 2013. Some traits such as plant height, fresh and dry weight, density, color and quality, and chlorophyll and proline contents were evaluated during growth period or at the end of the experiment.The data were subjected toananalysis of variance (SAS, 1996),and differences among the treatments were compared using Duncan’s multiple range test at 95% probability level.
Results and Discussion: The results showed that decreasein nitrogen level up to 0.5 gdid not significantly change density index,,whilethe index showed a significant reduction in treatment containing zero nitrogen application and the lowest irrigation regime (40% of the field capacity).Quality and color of the turf grass had no significant correlation with nitrogen treatment, while the factor was significantly decreased when irrigation regime of 40% of the field capacity was applied. It was determined that although color of the turf grass was greener with lower levels of water,a good color was found with high level of non-organic fertilizer at the time that the amount of nitrogen leaching was also limited. Therefore, regardless of the different nitrogen levels applied, quality and color indiceswerethe lowest when irrigation at 40% of field capacity was applied. Limiting the level of nitrogen up to 0.5 gramand irrigation up to 60% of field capacity was desirable to control and reduce the height of turf grass. Reduction in water level up to 80% of field capacity caused no significant changes in fresh weight, but a significant decreasewas resulted with the reduction of water consumption up to 60% of field capacity. The maximum fresh weight was found with 1.5 grams nitrogen. However, reducing nitrogen level upto 0.5 gramdid not bring about significant changes in this trait. Dry weight also followed the same pattern as fresh weight. Although reduction in the level of applied nitrogen did not reduce the height, it caused a significant reduction in fresh and dry weight of the turf grass. The highest chlorophyll content was found when 2 grams of nitrogen and irrigation regime of 40% of field capacity were used. Regardless of the nitrogen level, the highest chlorophyll content was found in irrigation of 40% of field capacity,while the lowest amount was observed in the treatment containing irrigation at100 and 80% of field capacity. Plants were dark green in 40% of field capacity. Proline content showedincreasealong with the decrease inirrigation as well as nitrogen levels.
Conclusion:Plant height, fresh and dry weight, chlorophyll and proline contents were significantly affected by limiting the use of nitrogen and water, but density and quality indices were not significantly influenced. Regardless of the nitrogen levels applied, quality and color traits were the lowest only in irrigation regime of 40% of field capacity. Therefore, it was concluded that reduction of nitrogen supply to 1 mg m-2 month-1and irrigation regime up to 60% of field capacity could result in thereduction ofvegetative growth of turf grass, while quality traits were not affected negatively.
