Ameer Khan

Inducing salt tolerance in wheat by exogenously applied ascorbic acid through different modes

ABSTRACT In order to assess whether exogenous application of ascorbic acid (AsA) through different ways could alleviate the adverse effects of salt-induced adverse effects on two wheat cultivars differing in salinity tolerance, plants of a salt tolerant (‘S-24’) and a moderately salt sensitive (‘MH-97’) cultivar were grown at 0 or 120 mM sodium chloride (NaCl). Ascorbic acid (100 mg L−1) was applied through the rooting medium, or as seed soaking or as foliar spray to non-stressed and salt stressed plants of wheat. Salt stress-induced reduction in growth was ameliorated by exogenous application of ascorbic acid through different ways. However, root applied AsA caused more growth enhancement under saline conditions. Leaf ascorbic acid, catalase (CAT), peroxidase (POD), and superoxide dismutase (SOD) activities were also maximal in salt stressed plants of both cultivars treated with AsA through the rooting medium. Furthermore, leaf ascorbic acid, CAT, POD, and SOD activities were higher in salt stressed plants of ‘S-24’ than those of ‘MH-97’. Root applied AsA caused more enhancements in photosynthetic rate. Root applied AsA caused more reduction in leaf sodium (Na+) compared with AsA applied as a seed soaking or foliar spray. Overall, AsA-induced growth improvement in these two wheat cultivars under saline conditions was cultivar specific and seemed to be associated with higher endogenous AsA, which triggered the antioxidant system and enhanced photosynthetic capacity.

FOLIAR APPLICATION OF ZINC INFLUENCES THE LEAF MINERAL STATUS, VEGETATIVE AND REPRODUCTIVE GROWTH, YIELD AND FRUIT QUALITY OF ‘KINNOW’ MANDARIN

Deficiency of zinc (Zn) is widespread in many citrus orchards of Pakistan, consequently hampering fruit yield. Effects of foliar applications of zinc sulfate on tree nutrition, growth, productivity and fruit quality were studied on ‘Kinnow’ mandarin. Leaf nitrogen (N), calcium (Ca), and manganese (Mn) were highest for trees sprayed with 0.2% zinc sulfate, while phosphorus (P) and iron (Fe) were highest with 0.6% zinc sulfate and potassium (K) and Zn were highest with 0.8% Zn sulfate applications. Trees sprayed with 0.6% zinc sulfate exhibited highest increase in height, crown width and stem girth, fruit diameter, fruit weight, ascorbic acid contents, and total phenolics compared to all other treatments. Pre-harvest fruit drop was lowest and total number and weight of fruit per tree was highest at harvest with 0.4% zinc sulfate application. In conclusion, foliar application of zinc sulfate up to 0.6% improved tree mineral nutrients, growth, and productivity with better fruit quality in ‘Kinnow’ mandarin.

FOLIAR APPLICATION OF BORON INFLUENCES THE LEAF MINERAL STATUS, VEGETATIVE AND REPRODUCTIVE GROWTH, YIELD AND FRUIT QUALITY OF ‘KINNOW’ MANDARIN (CITRUS RETICULATA BLANCO.)

The effects of foliar application of boron (B) in the form of boric acid on vegetative and reproductive growth, yield and fruit quality of ‘Kinnow’ mandarin (Citrus reticulate Blanco.) were investigated. Kinnow mandarin was sprayed with different concentrations of boric acid viz. (0.1%, 0.2%, 0.3% and 0.4%) at fruit set stage. Leaf nitrogen (N), phosphorus (P), potassium (K), B, and zinc (Zn) along with flush length, tree height, tree spread and tree trunk diameter increased, while leaf length and leaf age showed non-significant results after foliar B application. Yield of the ‘Kinnow’ mandarin was significantly affected by foliar application of B and a significant increase in fruit weight at harvest was also observed. Soluble solid concentration (SSC): titratable acidity (TA) ratio, ascorbic acid, total sugars, total phenolic content (TPC) and total antioxidants significantly affected, while pH of juice, SSC, TA, reducing sugars and non-reducing sugars showed non- significant results.

Health risk assessment of heavy metals and metalloids via dietary intake of a potential vegetable (Coriandrum sativum L.) grown in contaminated water irrigated agricultural sites of Sargodha, Pakistan

ABSTRACT Levels of Mo, As, Se, Fe, Cu, Zn, Ni, and Pb were determined in a vegetable commonly consumed in Pakistan. Samples were collected from three different sites (Ratokala, Phularwan, and Mailowal) supplied with three different water sources. Mo and Pb in water and Mo and As in C. sativum were higher than the suggested standards at the international level. Lower bioconcentration factor and pollution load index were seen at Site-I than at other sites. A positive association was found between the rhizosphere metals and those of the vegetable at all three sites. Enrichment factor at three sites ranged from 0.28 to 10.39. The highest value of daily intake of metals was found for Fe (0.245 mg/kg/day) and of the health risk index for As (70.41) at the wastewater inundated site. It is inferred that uptake of Mo, As, Cu, Ni, and Pb through C. sativum represents a high health danger to the individuals using this vegetable.

DAIRY MANURE AND NITROGEN FERTILIZER EFFECTS ON RESIDUAL NITRATE AND PHOSPHATE, AND WHEAT YIELD IN A SANDY CLAY LOAM SOIL

Dairy manure (DM) rates of [0 (DM0), 30 (DM30)), 60 (DM60) Mg ha−1] and three nitrogen (N) rates [0 (N0), 125 (N125), 250 (N250) kg ha−1] were tested in a sandy clay loam, to evaluate their effects on growth and yield of wheat crop (Triticum aestivum L.), residual nitrate nitrogen (NO3-N) and phosphorus (P) concentrations in the surface soil, and selected soil physical measurements [saturated hydraulic conductivity (Ksat), and bulk density (BD)]. Increasing N and DM rates gave higher wheat yields, increased concentrations of residual NO3-N and P in the surface soil and improved Ksat and BD. Highest grain yield of 3.8 Mg ha−1 (70.3% more than the control) was observed in DM60 × N250 treatment. Residual accumulation of N-NO3 and P in the surface soil at high N and/or DM application rates suggests the need to carefully manage N and DM inputs on farm fields to avoid environmental contamination.

INDUCING SALT TOLERANCE ON GROWTH AND YIELD OF SUNFLOWER BY APPLYING DIFFERENT LEVELS OF ASCORBIC ACID

This experiment was conducted in the Department of Biological Sciences, University of Sargodha, Sargodha, Pakistan during the year 2008–2009 to evaluate the effect of ascorbic acid to minimize the toxicity of salinity on sunflower. For this purpose different concentrations of ascorbic acid (0, 50, 100 mg L−1) were applied through foliar spray at vegetative stage of sunflower plants. The experiment was laid out in completely randomized block design. In this study, growth, yield and physiological parameters of the sunflower plants were collected to investigate the effect of ascorbic acid under salt stress. Concentration of 100 mg L−1 of ascorbic acid applied as foliar spray significantly enhanced the fresh and dry weight of shoot of sunflower, photosynthetic pigments, ions uptake such as potassium (K+) and calcium (Ca2+) and 100 achene weight of sunflower. These findings led us to conclude that foliar applied ascorbic acid could mitigate the adverse effects of salinity on sunflower.

Effect of ellagic acid on growth and physiology of canola (Brassica napus L.) under saline conditions

ABSTRACT Salinity stress is limiting growth and productivity of plants in many areas of the world. Plants adopted different strategies to minimize the effect of salt stress. A pot experiment was conducted to investigate the morphological and physiological changes produced in Canola (Brassica napus) by exogenous application of ellagic acid (EA) under saline conditions. EA is an antioxidant, expected to reduce the effect of salinity stress. The seeds of two canola cultivars, Rainbow and Oscar, were soaked for 6 h with different concentrations of EA (0, 55 and 110 µg/ml). The soaked seeds were sown in small pots. Salt stress was imposed on the plants by applying NaCl solutions of different concentrations (0, 60 and 120 mM) and the duration of stress was for four weeks. Salinity stress reduced seed germination and disturbed the morphological and physiological attributes of B. napus. Application of EA as seed soaking reduced the effect of salinity and enhanced the growth of plants. Overall, we could confirm a significant role of EA by inducing salinity tolerance in B. napus.

Comparative Analysis of Ascorbic Acid Concentration in Two Varieties ofCitrus (Citrus sinensis, Citrus limetta) Collected from Different Tehsils ofDistrict Sargodha, Pakistan

Citrus is one of the most commonly consumed fruits in Pakistan. The present study was conducted to evaluate ascorbic acid concentration in Citrus sinensis and Citrus limetta collected from different tehsils of District Sargodha. All the varieties have good source of vitamin c, but the highest concentration was reported in Citrus sinensis, which was collected from tehsil Sahiwal and that was 89.69 mg/100 mL and lowest reported in Citrus limetta 33.155 mg/100 mL, which was collected from Tehsil Silanwali.

Heavy Metals Assessment in Vegetables Irrigated with Wastewater: A Case Study in District Sargodha, Pakistan

An experiment was conducted to evaluate the heavy metals toxicity in vegetables irrigated with wastewater. Different experimental sites were selected from district Sargodha, Pakistan. Samples of wastewater, contaminated soil and vegetables irrigated with wastewater were collected and analyzed. Concentration of heavy metals such as Cadmium (Cd), Copper, (Cu), Chromium (Cr), Zinc, (Zn) and Iron (Fe) were determined from soil, water and vegetables samples irrigated with wastewater and fresh water. Cadmium concentration was present from 0.1 to 0.3 µgg -1 , chromium concentration from 0.03 to 0.11 µgg -1 , Copper concentration from 0.2 to 0.7 µgg -1 , iron concentration was