CaCl2 Solution Sprayed on Leaves Changes the Nutrition and Qualitative Properties of Pomegranate (Punica granatum L. cv. Hicaznar)

Bu calismanin amaci, Aydin (Turkiye) ekolojik kosullarinda 2016 ve 2017 yillarinda Hicaznar cesidinde farkli dozlarda kalsiyum klorur (CaCl2) uygulamalarinin meyve verimi, bazi kalite ozellikleri ve bitkinin beslenmesine etkisini belirlemektir. Calismada agaclara kontrol dozu disinda % 0.2, 0.4, 0.6, 0.8 ve 1.0 kalsiyum klorur (CaCl2) cozeltileri puskurtulerek uygulanmistir. Cozelti dozlari, 15 Haziran ve 15 Agustos'ta meyve yetistirme mevsimi boyunca iki kez uygulanmistir. Elde edilen sonuclara gore, CaCl2 uygulamalari ile meyve verimi, kabuk kalinligi, meyve uzunlugu, capi ve agirliklari kontrol dozuna gore artmistir. Yaprak CaCl2 uygulamalari, yaprak Ca icerigini % 60 arttirmistir. Artan CaCl2 dozlarina paralel olarak N ve Ca disindaki diger bitki besin maddelerinin konsantrasyonlari azalmistir. Yaprak P icerigi bu durumda etkilenmemistir. Sonuc olarak Hicaznar cesidinde yapraklara uygulanacak CaCl2 uygulama dozu % 0.6 olarak belirlenmistir.


Introduction
Pomegranate's homeland Turkey, Middle East, south-southeast of Iran, the Caucasus and including also northern India is known to be a large region. The fruit of the pomegranate, which is one of the subtropical climate fruit species, can be evaluated in various ways in the food industry as well as for fresh consumption (Çelik et al., 2019). Today, pomegranate cultivation is carried out in a wide area from Australia to South Africa, USA and China (Ünal, 2011). Hicaznar pomegranate is one of the main varieties in pomegranate cultivation in Turkey. Turkey's total pomegranate production was realized as 600 021 tonnes in 2020 (TUIK, 2020).
Calcium is an obligatory and a very important mineral for plants. It performs structural functions in the cell walls and membranes of the plant. It is also required as a balancing agent against inorganic and organic anions. Middle lamellae of cells that expand in calcium deficiency weaken and crack. (White, 2001;Asgharzade et al., 2012).
During the development of the fruit, its nutrition is the most important factor determining fruit quality and post-harvest performance (Schuman et al., 1973). The calcium intake and distribution in the plants are affected by the movement of water in the organs that become apparent and the use of calcium in the transport route (Saure, 2005). Although there is enough calcium in the garden soil, the occurrence of calcium deficiency creates great economic losses and becomes a problem for many fruit types (Montanaro et al., 2006).
Proper fruit ripening is related to calcium. The low calcium content in the fruit causes susceptibility to many physiological and pathological diseases and a short shelf life (Conway et al., 1992;Fallahi et al., 1997). It has been determined that calcium application before harvest prevents physiological disorders as well as delaying maturity and increasing fruit quality in many fruit species (Hernandez Munoz et al., 2006). Foliar application of calcium significantly increases the calcium content in fresh fruit and the effectiveness of ripening and aging-related changes (Pooviah, 1979).
This study was carried out based on the method of spraying pomegranate leaves at different levels and in two periods of CaCl 2, a powerful source of calcium, and the results of the effects on some quality characteristics and nutrition of pomegranate are discussed in this article.

Materials and Methods
The experiment was conducted during 2016 and 2017 in a 25 years old Hicaznar pomegranate cultivar commercial orchard located in Aydın (Turkey) ecological condition. In the vegetation duration (between March and November), the total rainfall is 660.9 mm in 2016 and 729.1 mm in 2017. In addition, the average temperature was 20.1 °C in 2016 and 21.2 °C in 2017. The average temperature in the research duration is coherent with the long-term average temperature (20.5 °C) and the total rainfall is compatible with the long-term total rainfall (647.0 mm).
In April, soil samples were taken from the research orchard, air-dried, and sieved through a 2 mm sieve. The soil characteristics and analysis methods of the orchard were presented in Table 1. When the orchard soil analysis results are evaluated; pomegranate orchard is lower calcareous and medium organic matter content, slightly acidic, clay loamy, and lower salinity (EC: Electirical conductivity). However, it was determined that soil samples were sufficient by macro and micronutrients (Kacar, 1994).
Leaf samples were collected on four sides of the trees from that year's shoots to determine leaf nutrient concentrations. The samples were before washed with mains water and after with distilled water. Then dried at 65 ± 5 ° C for 2 days. Samples removed from the oven were made ready for analysis. Total N, Kjeldahl method, foliar P concentration spectrophotometrically (Shimadzu UV-1208, 430 nm), K, Ca, Mg, Fe, Cu, Zn, and Mn contents were analyzed using atomic absorption spectrophotometer (Kacar and İnal, 2008).
The research was planned according to the randomized parcel design. The applications are stated below.
1-Control (0% CaCl 2 tree -1 ), 2-0.20% CaCl2 tree -1 , 3-0.40% CaCl2 tree -1 , 4-0.60% CaCl2 tree -1 , 5-0.80% CaCl2 tree -1 , 6-1.00% CaCl2 tree -1 Regular fertilization was carried out in the experimental orchard. Every year, 2.5 kg of 20:20:20 compound fertilizer, 0.5 kg of potassium nitrate, and 1.0 kg of Urea were applied per tree. The experiment consisted of 3 replications, 3 trees in each replica and 6 applications; It was carried out on 54 trees (6 x 6 planting order). The CaCl2 solutions were applied twice (June 15 and August 15) by sprayed to leaves. The water requirement of the plants was met with the drip irrigation system in the orchard. Irrigation was measured with an evaporation pot and water was applied according to the moisture in the soil. Cultural weed cleaning is done regularly in the pomegranate orchard.
Leaf samples of Hicaznar pomegranate varieties were taken 10 September in the middle of the annual shoots of fruitless (Özkan et al., 1999). As a result of applications were determined to yield per tree (kg tree -1 ), fruit length (cm), diameter (cm), peel thickness (mm), foliar macro and micronutrients in 2016 and 2017 years.
Analysis of variance (ANOVA) and Duncan's tests were conducted with a P≤0.05 significance level using SPSS Version 22 (IBM Corp., 2013) statistical software.

Fruit yield
Applied CaCl2 doses, statistically increased fruit yield per tree. According to statistical results, significant relationships were found between application doses and fruit yield (Figure 1). The highest fruit yield was determined as 23.0 kg tree -1 in the 2016 year and 22.8 kg tree -1 in the 2017 year at 0.6% CaCl2 dose, 22.6 kg tree -1 in the first year and 22.7 kg tree -1 in the second year at 0.8% CaCl2 dose.
They reported that calcium applied by spraying to pomegranate plant was effective on yield and fruit quality in tangerine (Eroğul et al., 2011), cherry (Simon, 2006), apple (Raese, 2000 andWojcik et al., 2002).   Fruit yield increased 23% at 0.6% CaCl2 dose compared to the control dose. Besides, the average tree yield was realized to be around 22 kg in 0.8% and 1.0% CaCl2 applications. Results were determined that foliar Ca applications increased fruit yield in parallel with the studies conducted by Güneri et al. (2014); Korkmaz and Aşkın (2015); Bakeer (2016).

The some quality properties of pomegranate
According to the results, statistically significant relationships were determined between the applied CaCl2 doses and all the qualitative parameters indicated in Table 2. Only fruit diameter was not affected by CaCl2 doses in 2016. However, statistical differences were obtained according to application doses in 2017. The highest fruit diameter was found to be 16.3 cm at a dose of 0.8% CaCl2 in the same year. The size of the fruit is highly influenced by environmental and cultural care conditions as determined by the genetic characteristics of the variety (Al-Maiman and Ahmad, 2002). The highest fruit weights were recorded as 626 g in the 2016 year and 624 g in the 2017 year at a dose of 0.6% CaCl2. However, the highest fruit length was determined as 14.2 and 14.4 cm at 0.6% CaCl2 dose in both application years, respectively. Finally, in parallel with increasing application doses, fruit peel thickness increased. The highest fruit peel thickness value was 5.02 mm at 1.0% CaCl2 application in the first year and 5.03 mm at 0.8% CaCl2 application in the second year. In some pomegranate varieties, it has been determined that there is a relationship between some morphological and physiological characteristics, leaf characteristics, and nutritional level, and a high correlation between leaf N and K / Ca ratio and pell thickness (Hepaksoy et al., 1998). In many studies, it was determined that foliar calcium applications increased pomegranate fruit quality properties (Bakeer, 2016;Korkmaz et al., 2016 ).

The macro and micro nutrients status of pomegranate leaves
The effect of CaCl2 solution doses on the change of macronutrients in pomegranate leaves is presented in Table 3. The findings obtained in this study clearly demonstrate the effect of CaCl2 solution doses on the intake of macronutrients and the interaction between them.
Although the doses of CaCl2 applied did not change statistically the N level of the plant in the 2016 year, major differences were obtained in the 2017 year. The highest N level was determined at 0.6% CaCl2dose (2.0% N). However, there was no statistically significant change in P level of the plant. On the other hand, reductions in foliar P concentrations were recorded in the final doses compared to the control.
Foliar K concentrations were tended to decrease rapidly after the first dose (0.2% CaCl2). The highest K concentration was detected in 0.2% CaCl2 dose (2016: 1.67%, 2017: 1.65%), and the lowest at 1.0% CaCl2 dose (2016: 1.52%, 2017: 1.55%). As expected in the study, as CaCl2 doses increased, foliar Ca concentrations increased at the same rate. This increase is 15% on average. However, foliar Mg concentrations gave a negative response to the administered CaCl2 doses and the lowest value was recorded at the last application dose. As a result, increasing doses of CaCl2 solution doses increased the only N and Ca concentrations in plants, but decreased P, K and Mg concentrations. Results of leaf analyses indicated that Ca application runs to a significant increase in the foliar Ca content when matched with the control dose. Increases in Ca contents after foliar Ca applications have been previously reported by Korkmaz et al. (2016). Interaction between nutrients in cultivated plants are closely related to plant nutrition and quality characteristics. In this context, calcium is an element that is subject to much work. Calcium, especially phosphorus, potassium, magnesium, and microelements have been confirmed by many studies (Altuntaş, 2016;Güneri et al., 2014;Eroğul 2011;Kacar and Katkat, 1998;Hepaksoy et al.,1998).
The high amount of Ca accumulation in the leaves is in contention with K, Mg and other micronutrients, especially P. Besides, Ca / N balance in the plant must be in balance for plant growth. The amount of Ca in the plant stabilizes the N state in the leaf up to a certain level and at increasing levels, Ca decreases the N accumulation in the leaves (Barker and Pillbeam, 2007;Kacar and Katkat, 2011).
In a study, due to the increased low calcium concentrations in the nutrient solution, the phosphorus content of the leaves in the rice plant was not affected, but when the calcium concentrations were further increased, the decrease in phosphorus coverage was more severe (Fageria, 2001). However, the results obtained are coherent with the research of Guneri et al. (2014).The macronutrient contents of the leaves have remained within the specified limit values for pomegranate (Sheik, 2006).The effect of CaCl 2 solution doses on the change of micronutrients in pomegranate leaves is shown in Table 4. The findings carry out in this research plainly demonstrate the effect of CaCl2 solution doses on the level of micronutrients. In study, doses of CaCl2 solution sprayed to leaves caused statistically significant differences in foliar micronutrient contents. Although the micronutrient contents of the leaves decreased with the doses applied, it remained within the specified limit values for pomegranate (Sheik, 2006). According to the findings, the highest Fe, Zn, Mn and Cu contents in 2016 and 2017 years were 221, 218, 50.1, 52.1, 53.4, 53.0, 44.9, and 45.3 mg kg -1 , respectively.
In addition, the increase in the calcium concentration of the nutrient solution micro-elements gave a more pronounced response, this response was generally in the direction of decline (Fageria, 2001). Similarly, increasing doses of Ca applied to leaves decreased micronutrient contents in leaves parallel to the study of Güneri et al. (2014). In this case, it shows us once again that there is a negative interaction between Ca and micronutrients.

Conclusions
CaCl2 solutions applied increased pomegranate fruit yield and some quality properties compared to the control dose. Increases in fruit yield, fruit weight, diameter, height, and peel thickness were determined as average 21%, 7.5%, 9%, 8%, and 13%, respectively. The applied CaCl2 solutions were increased the N and Ca concentrations compared to the control dose and no significant change was determined in the foliar P content. However, foliar K, Mg, Fe, Zn, Mn, and Cu concentrations were decreased. However, these decrease did not exceed 15% rate compared to control doses in the pomegranate leaves. The level of all plant nutrients in the leaves remained within the specified standard level ranges. Supplemental studies would be essential to anymore update the content and timing of the Ca fertilizations, with the purpose to reduce the proportion of some physiological irregularity and optimized nutrient in products such as pomegranate, which limits fruit qualitative and quantitative properties every year.