MINERAL NUTRIENT CONTENT OF TOMATO PLANTS IN AQUAPONIC AND HYDROPONIC SYSTEMS: EFFECT OF FOLIAR APPLICATION OF SOME MACRO- AND MICRO-NUTRIENTS

Effects of foliar applications of some micro- and macro-nutrients on mineral nutrient content of tomato leaves and fruits were investigated in an aquaponic system in comparison with a hydroponic system. Fourteen days old tomatoes seedlings were transplanted on to growth bed of aquaponic and hydroponic systems. Foliar nutrients application began 30 days after transplantation. Eight treatments were used, untreated control and foliar application at the rate of 250 mL plant^?1 with 0.5 g L^?1 potassium sulfate (K₂SO₄), magnesium sulfate (MgSO₄ 7H₂O), ferrous (Fe)- ethylenediamine-N,N′-bis (EDDHA), manganese sulfate (MnSO₄ H₂O), boric acid (H₃BO₃), zinc chloride (ZnCl₂), and copper sulfate (CuSO₄ 5H₂O). Foliar application of potassium (K), magnesium (Mg), iron (Fe), manganese (Mn), zinc (Zn), and copper (Cu) increased their corresponding concentrations in the leaves of aquaponic-treated plants. On the other hand, foliar spray of K, Fe, Mn, Zn, and Cu caused a significant increment of applied element concentrations in the fruits of hydroponic-grown plants. These findings indicated that foliar application of some elements can effectively alleviate nutrient deficiencies in the leaves of tomatoes grown on aquaponics.     

INVESTIGATIONS ON FOLIAR SPRAY OF BORON AND MANGANESE ON OIL CONTENT AND CONCENTRATIONS OF FATTY ACIDS IN SEEDS OF SUNFLOWER PLANT RAISED THROUGH SALINE WATER IRRIGATION

The objective of this experiment was to evaluate the effect of foliar fertilization of some micronutrients [i.e., manganese (Mn) and boron (B)] on reproductive yield and fatty acid concentrations of a standard sunflower hybrid (‘NuSun 636') irrigated with different concentrations of saline water made by dissolving sea salt. Reproductive yield showed a significant decrease with the increase in salt in the rooting medium. However, foliar sprays of boric acid (H₃BO₃) and manganese chloride (MnCl₂) showed a significant increase in seed number, seed weight, and oil content of seeds in the nonsaline control, which persisted even under saline water irrigation. An increase under the MnCl₂ spray was more than with H₃BO₃ irrespective of non saline or saline water irrigation. Increasing levels of salinity appeared to be responsible for a decrease in oleic monounsaturated fatty acid concentration and an increase in the linoleic polyunsaturated, palmitic and stearic saturated fatty acid content whereas no significant change was found in linolenic polyunsaturated fatty acid content. Foliar applications of H₃BO₃ and MnCl₂ brought some beneficial alteration in fatty acid concentrations of sunflower. Foliar application of H₃BO₃ caused a significant increase in palmitic and stearic saturated fatty acids and linoleic polyunsaturated fatty acids in control as well as under saline conditions. Oleic monounsaturated fatty acid concentration showed a decline under H₃BO₃ treatment irrespective to nonsaline or saline conditions. Foliar applications of MnCl₂ increased the concentration of palmitic saturated fatty acid and oleic monounsaturated fatty acid irrespective to the plant growth under non saline or saline conditions. While stearic saturated fatty acid, linoleic and linolenic polyunsaturated fatty acid decreased with the application of manganese as compared to the non sprayed control.     

COMPARISON OF YIELD,NUTRIENT SOLUTION CHANGES AND NUTRITIONAL STATUS OF GREENHOUSE TOMATO GROWN IN RECIRCULATING AND NON-RECIRCULATING NUTRIENT SOLUTION SYSTEMS

Studies were carried out in the years 2005–2007 with greenhouse tomato (Lycopersicon esculentum Mill.) cv. ‘Emotion F₁’ grown in rockwool with the recirculating and non-recirculating nutrient solution systems. No significant differences were found in yields of fruits in both systems. In the recirculating system there was more intensive accumulation of sodium (Na), calcium (Ca), chloride (Cl), and zinc (Zn) in the root environment. Leaves of tomato grown in the recirculating nutrient solution system showed a higher content of Ca, magnesium (Mg), and Zn. There were no differences in the contents of nitrates and nitrites in fruits. In the recirculating system, the following savings were recorded: 42.5% of water and (in%): 42.1 nitrogen (N)- ammonium (NH₄), 56.0 N- nitrate (NO₃), 31.4 phosphorus (P), 52.1 potassium (K), 63.5 Ca, 47.9 magnesium (Mg), 49.4 sulfur (S)- sulfate (SO₄), 51.9 Cl, 50.9 iron (Fe), 47.9 Zn, 24.6 manganese (Mn), 53.3 copper (Cu) and 47.2 boron (B). A high effectiveness in decreasing of bacteria number in drain water by UV irradiation was found.     

RESPONSE OF LIME THYME TO SALINITY AND IONIC CONCENTRATION IN NUTRIENT SOLUTION

□ Plants from 60-day-old Lime Thyme (Thymus citriodorus) cuttings were potted in a medium of coconut fiber and peat moss and were treated with three different nutrient solutions: T1, T2, and T3. T1 was a standard nutrient solution; T2 was incremented with macronutrients up to an electrical conductivity (EC) of 2.8 dS m^?1; and T3 was the same as T1 but incremented up to an EC of 2.8 dS m^?1 with sodium chloride. The plants were then grown for 90 days in a greenhouse with natural daylight in Almería, Spain. Root growth was not affected by the treatments. The dry weight of the leaves and the total dry weight of the plants benefited from the salinity. The specific salinity of the sodium chloride negatively affected growth compared to the same salinity in the complete nutrient solution.     

EFFECT OF FOLIAR SPRAY OF SOLUBLE SILICIC ACID ON GROWTH AND YIELD PARAMETERS OF WETLAND RICE IN HILLY AND COASTAL ZONE SOILS OF KARNATAKA,SOUTH INDIA

Field experiments were conducted to evaluate the effect of foliar spray of soluble silicic acid on growth and yield parameters of wetland rice. The results revealed a significant effect on achieving higher grain and straw yield with foliar silicic acid over control. Foliar spray of silicic acid at 2 and 4 ml L^?1 increased the grain and straw yield and application of 8 ml L^?1 decreased the yield. Foliar spray of silicic acid at 4 ml L^?1 along with half dose of recommended pesticide effectively increased the yields over all other treatments. The content and uptake of silicon in grain and straw was recorded higher with the foliar spray of silicic acid over control. This investigation concludes that application of silicic acid at 4 ml L^?1 along with half dose of recommended pesticide as foliar spray increased the grain and straw yield, besides Si content and its uptake over control.     

INFLUENCE OF NITROGEN AND SALINITY LEVELS ON THE FRUIT YIELD AND CHEMICAL COMPOSITION OF TOMATO IN A HYDROPONIC CULTURE

Tomato seedlings were transferred to continuously, aerated plastic containers. Treatments consisted of three nitrogen (N) levels [0, 1.5, and 3% as ammonium chloride (NH₄Cl) and ammonium phosphate (NH₄H₂PO₄) 2:1 w/w] and three salinity levels (0, 30, and 60 mM using sodium chloride (NaCl) and calcium chloride (CaCl₂)]. Results indicated significant positive and negative responses in fruits fresh weight to nitrogen and salinity treatments, respectively. Number of fruits and root length decreased at high salinity level. Phosphorus (P) content was highest in fruits and lowest in roots. Fruit P uptake decreased with salinity applications in N controls. At low salinity levels, N application mitigated the salinity detrimental effects; however, such an effect was not observed at the high salinity level. Nitrogen application significantly decreased iron, zinc, copper, and manganese concentration and uptake. Application of nitrogen and salinity levels significantly increased the citric acid content of tomato fruits. Vitamin C content of fruits was neither influenced by nitrogen nor by salinity.     

EFFECT OF PACLOBUTRAZOL AND PUTRESCINE ON ANTIOXIDANT ENZYMES ACTIVITY AND NUTRIENTS CONTENT IN SALT TOLERANT CITRUS ROOTSTOCK SOUR ORANGE UNDER SODIUM CHLORIDE STRESS

The effects of paclobutrazol (PBZ) and putrescine (Put) on antioxidant enzymes activity, proline contents and nutrients uptake were studied on salt tolerant citrus rootstock sour orange. Six-month-old nucellar seedlings grown in pots and subjected to three levels of PBZ and two levels each of salinity and Put for 90 days. Seedlings treated with PBZ or Put alone or in combination had higher anti-oxidant enzymes activities, accumulation of proline and nutrients contents like potassium (K⁺) and calcium (Ca²⁺) under both saline and non-saline conditions. Further, application of PBZ or Put alone or in combination also reduced the accumulation of both Na⁺ and Cl^? ions in leaves and roots in NaCl stressed seedlings. A combined application of 250 mg L^?1 PBZ and 50 mg L^?1 Put proved to be more effective in improving proline and Ca²⁺ content and restricting accumulation of Na⁺ ions in leaf tissues.     

INFLUENCE OF ELEVATED PHOSPHORUS LEVELS IN NUTRIENT SOLUTION ON MICRONUTRIENT UPTAKE AND DEFICIENCY SYMPTOM DEVELOPMENT IN STRAWBERRY CULTURED WITH FERTIGATION SYSTEM

The relationship between the total amount of micronutrients absorbed by the above-ground plant tissue and the occurrence of visible micronutrient deficiency symptoms in two strawberry cultivars as influenced by elevated phosphorus (P) levels in fertigation solution was investigated. The plants were cultured with a fertilizer solution containing 0, 0.5, 1, 2, 4, or 6 mM P and tissue nutrient content were determined at 120 days after transplanting. Young leaves of the plants grown with nutrient solution P levels higher than 4 mM and 2 mM, respectively, in ‘Keumhyang’ and ‘Seonhong’, developed interveinal chlorosis. Tissue concentrations (mg·kg^?1 dry weight) of metallic micronutrients [iron (Fe), copper (Cu), manganese (Mn), and zinc (Zn)] in both cultivars did not decrease, but the total amount absorbed by the aboveground plant tissue decreased in the treatments in which nutrient deficiencies were observed. These results indicate that total amount of micronutrients is a better indicator of P-induced micronutrient deficiency.