Abdur Rab

Light-induced biochemical variations in secondary metabolite production and antioxidant activity in callus cultures of Stevia rebaudiana (Bert)

Stevia rebaudiana (S. rebaudiana) is a very important species with worldwide medicinal and commercial uses. Light is one of the major elicitors that fluctuate morphogenic potential and biochemical responses. In the present study, we investigated the effect of various spectral lights on biomass accumulation and secondary metabolite production in callus cultures of S. rebaudiana. Leaf explants were placed on Murashige and Skoog (MS) medium and exposed to various spectral lights. 6-Benzyle adenine (BA) and 2, 4-dichlorophenoxy acetic acid (2, 4-D; 2.0 mgl(-1)) were used for callus induction. The control light (16/8h) produced optimum callogenic response (92.73%) than other colored lights. Compared to other colored lights, control grown cultures displayed maximum biomass accumulation (5.78 gl(-1)) during a prolonged log phase at the 18th day of growth kinetics. Cultures grown under blue light enhanced total phenolic content (TPC; 102.32 μg/g DW), total flavonoid content (TFC; 22.07 μg/g DW) and total antioxidant capacity (TAC; 11.63 μg/g DW). On the contrary, green and red lights improved reducing power assay (RPA; 0.71Fe(II)g(-1) DW) and DPPH-radical scavenging activity (DRSA; 80%). Herein, we concluded that the utilization of colored lights is a promising strategy for enhanced production of antioxidant secondary metabolites in callus cultures of S. rebaudiana.

Impact of calcium chloride concentrations and storage duration on quality attributes of peach ( Prunus persica )

To investigate the impact of CaCl2 concentrations and storage duration on quality of peach (Prunus persica), a research was conducted at postharvest Laboratory, Department of Horticulture, The University of Agriculture, Peshawar, Pakistan during 2012–2013. The experiment was laid out in Completely Randomized Design (CRD) with factorial arrangement repeated three times. The peach fruits (cv. Texas A 69) were harvested at physiological maturity stage from peach orchard, Horticulture Farm. The fruits were dipped in 0, 2 and 4% CaCl2 solution for 10 min and transferred to cold storage having ±8–10°C with relative humidity of 80–85%. The application of CaCl2 solution and storage duration significantly influenced the fruit quality of peach fruit. However, the application of CaCl2 solution significantly reduced weight loss (4.98%), disease incidence (2.08%), total sugars (5.31%), TSS-Acid ratio (16.27), TSS(7.380Brix) and increased the fruit firmness (2.21 kg cm–2) titratable acidity (0.47%) and Ascorbic acid (5.35 mg/100 g) of peach fruits. The storage duration of peach fruit also significantly affected the fruit quality attributes during storage. The peach fruit stored for 30 days showed less fruit firmness (0.74 kg cm–2) and titratable acidity (0.31%), Ascorbic acid (4.45 mg/100 g) and increased weight loss (19.74%), disease incidence (16.11%), total sugars (6.07%), TSSAcid ratio (27.62) and TSS(8.540Brix) of peach fruit. Based on the findings of this study, it is concluded that the peach fruit should be treated with 4% CaCl2 solution to retain the quality attributes for 30 days storage.

Effect of Mixture of Nitrogen from Poultry Manure and Urea on Mineral Profile of Tomato Grown in KPK-Pakistan

ABSTRACT Nitrogen has a role in plant mineral nutrition, and so a better way of supplying nitrogenous fertilizers is demanded to promote plant nutrition and clean environment. The present study was, therefore, designed to maintain plant mineral requirements and control environmental pollution. Tomato cultivars, that is, Falcon and Rio Grande, were supplied with a mixture of poultry manure (PM) and urea in various proportions in 2009 and 2010. All tested factors (N source, cultivar, and year) alone and in combination significantly (P ≤ 0.05) affected the mineral profile of tomato fruit. Treatment 75:25 resulted in highest uptake of calcium (Ca), iron (Fe), zinc (Zn), and copper (Cu) in cultivar Rio Grande during 2010. Similarly, highest concentration of boron (B) was recorded in Rio Grande fed with 50:50 of PM and urea, respectively. It was concluded that a combination of PM and urea in ratios of 75:25 and 50:50 performed well in achieving the optimal mineral contents in the tomato fruits.

Effect of Sowing Time and Plant Density on the Growth and Production of Roselle (Hibiscus sabdariffa)

Experiments were conducted to see the response of roselle to different sowing dates and plant spacing. Six different sowing dates (seed sown at 10 days intervals on 6 May, 16 May, 26 May, 5 June, 15 June and 25 June) were used as main plots and six different planting densities (2, 3, 5, 7, 11 and 18 plants m) as sub plots. Results showed that plant height, stem diameter, number of leaves, number of calyces per plant, fresh weight of calyces per plant, dry weight of calyces per plant and calyces yield per ha was significantly affected by different sowing dates as well as planting densities. Maximum plant height (175 cm), stem diameter (3.1 cm), number of leaves per plant (636), number of calyces per plant (104), calyces fresh (206 g) and dry (21.7 g) weight plant, and calyces yield per ha (1427 kg) was recorded for the plants sown on 6 May, while these traits decreased with delayed sowing. For plant densities, the tallest plants (155 cm) with maximum calyces yield per ha (2496 kg) were observed at the highest density of 18 plants m, though the per plant stem diameter (2.9 cm), number of leaves (653), number of calyces (99), calyces fresh (205 g) and dry (24.9 g) weight were higher at the lowest density of 2 plants m. It was concluded that 6 May sowing and 18 plants m planting density produced the highest yield per ha in roselle crop.

Effect of exposure time and incubation period of various sterilants and antioxidants on the in vitro morphogenesis of guava explants

This experiment was carried out to investigate the effects of various surface sterilants and antioxidants during in vitro propagation of guava (Psidium guajava L.). Different sterilants and exposure time significantly affected survival in shoot tip explants. Maximum survival response (43.3%) was observed when shoot tips were exposed to 2% NaOCl followed by 0.05 % HgCl2 and 4% CaOCl with 36.7 and 33.3 % survival respectively. Similarly 5 and 10 minutes exposure times were statistically at par with each other. The interaction between different sterilants and exposure time was non significant. As compared to soot tips explants, the effect of different sterilants on the survival of nodal explants was also significant. The highest survival response of 31.7% was shown by 0.05% HgCl2 followed by 4% CaOCl and 2% NaOCl (29.2 and 26.7%) respectively. Similarly the response of different exposure times (5 and 10 minutes) in case of nodal explants was non significant. Among all anti oxidants and incubation periods applied, dark incubation of cultures for 24 hours was effective which eliminated (34.3%) browning followed by dip of explants in 75:50 mg l -1 citric acid and ascorbic acid (31.8%) while control was inferior to all and gave 11.7% browning elimination. Similarly the effect of antioxidants on type of explants (shoot tip and nodal explants) was also significant. The highest response of 37.8 % was recorded in shoot tip explants while in nodal explants it was 14.5% only. The inter action between antioxidants and explants types was also significant. In over all, the highest browning elimination of 55% was recorded in shoot tip explants when cultures were kept in dark for 24 hours. Whereas the most inferior results were shown by control treatments where only 6.7 and 16.7% browning was eliminated in tips and nodal explants.

Gibberellic acid (GA3), an influential growth regulator for physiological disorder control and protracting the harvesting season of sweet orange.

Citrus particularly sweet orange occupies an exalted position in fruit industry. Quality sweet orange production is affected by various factors including fruit physiological disorders and harvesting season which contribute towards consumer preference. This study was designed to find out an economically feasible solution to these problems. Three Original Research Article American Journal of Experimental Agriculture, 4(11): 1355-1366, 2014 1356 different GA3 treatments (10, 20 and 30ppm) were applied as a foliar spray to three different sweet orange cultivars (Blood Red, Mosambi and Succari) at full bloom stage to investigate its influence on Physiological disorder in fruits as well as in shoots, fruit growth and fruit maturity delay. The obtained results revealed that all GA3 treatments specially 30ppm significantly controlled fruit as well as shoots physiological disorders and was also found efficient in case of fruit maturity delay as compared to untreated trees. Finally we were able to conclude that; 30ppm GA3 should be applied as a foliar spray to control fruit and shoot physiological disorders and to protract the harvesting season of sweet orange.