Somayeh Gholamnejad

Investigation of optimum calcium, boron and NH4/NO3 ratios on increasing of quality, yield, structural and physiological changes of tomato fruit

This study aims to introduce the optimal ratio of calcium, boron, and ammonium to nitrate for improved quality, yield, and structural and physiological changes of tomato fruit. Two sets of experiments were carried out, at the first one different ratios of ammonium/total N as: N1= 0%, N2= 25%, N3= 50% and N4= 75% and different level of Ca as: Ca1= 80, Ca2= 160 Ca3= 320 mg/l of nutrient solution were examind. At the second experiment set, different levels of B as: B1=0, B2= 0.3 and B3= 0.6 mg/l and Ca as: Ca1= 80, Ca2= 160 Ca3= 320 mg/l were investigated in the chosen level of ammonium ratio from the first experiment. The lower levels of ammonium nitrogen toghter with high levels of calcium, caused higher yield and the highest fruit weight was also related to low levels of ammonium and calcium. The N2 in each of the three calcium levels caused more firmness of the fruit. In all ratios of ammonium to total nitrogen, increased concentration of calcium, increased the amount of the auxin and the maximum amount of this hormone was observed in N1 and Ca3, while for abscisic acid, the highest amount of this hormone was associated to the N4 and Ca1 treatment. Increase in the ratio of ammonium nitrogen to total nitrogen, decreased the amount of calcium in the flower and the stem ends of the fruit. N1 had the greatest effect on the tomato plant's growth characteristics and the highest calcium absorption was observed in this treatment. In the interaction calcium and boron, the lowest calcium concentration in 0.6 mg / l boron was the highest stem length, and the highest calcium concentration without boron application caused the highest stem diameter. In general, increased concentration of calcium reduces decreased stem length and increased diameter while the increased concentration of boron reduces increased stem length and decreasing diameter. The high concentrations together with the high concentrations of boron caused the highest number of fruit. Therefore, increased the concentration of calcium and also increased the concentration of boron caused increased the number of fruits. The fruit treated plants of with high concentrations of calcium were the lowest percentage of ion leakage in each three levels of boron. High concentrations of calcium without boron application and then two other levels of at the same high calcium levels cause the highest levels of chlorophyll and photosynthesis in the plant. In general, the increased amount of calcium followed an increased in chlorophyll and photosynthesis. The fruits of the treated plants with the high calcium concentration without boron application had the highest anthocyanins content. Increased concentration caused an increase in the amount of anthocyanin. The high calcium concentration in each three levels of boron caused the highest amount of fruit lycopene. Increased calcium concentration caused an increase in the amount of lycopene in the fruit. The highest number of days required for color breakdown of the fruit from green to orange was related to the treatment of high concentration of calcium in each three levels of boron. Increase calcium concentration caused increased the number of days required for color breakdown, while increased boron concentration caused this color breakdown to occur more rapidly. The highest activity was the enzyme pectin methylesterase in treated plants with calcium levels without boron application. With increased mount boron also increased the concentration of this element in the aerial parts and the tomato fruit. increased concentration of calcium significantly increased this element in the aerial parts, root and fruit. The highest calcium amount was observed in the flowerbeds and stem of treated plants with a high calcium concentration without boron application. With increased calcium concentration this element increased in flowerbeds and stem of the tomato fruit.