Khizar Hayat Bhatti

Mitigating the Effects of Salinity by Foliar Application of Salicylic Acid in Fenugreek

Present research work was conducted to alleviate the salinity-induced harmful effect on biomass production and physiochemical attributes of fenugreek by foliar application of salicylic acid. Two varieties (Deli Kabul and Kasuri) were grown in salt treated (100 mM NaCl) and untreated (0 mM NaCl) growth medium. Two levels of salicylic acid (0 mg L−1 and 100 mg L−1) were applied through foliar method. Salinity stress significantly reduced the growth biomass in both varieties. Higher shoot fresh weight was recorded in Deli Kabul, while lower in Kasuri. Such reduction in growth biomass was mitigated by the foliar application of SA in both plants. Salinity caused a marked reduction in gas exchange attributes including net CO2 assimilation rate, transpiration rate, stomatal conductance, and substomatal CO2 concentration. Exogenous applied salicylic acid also overcomes the reduction in gas exchange attributes of the plants. The varieties “Deli Kabul” and “Kasuri” showed higher and lower net CO2 assimilation rate, respectively. These results indicate that growth medium salinity induced reduction in biomass production, gas exchange attributes, and also chlorophyll contents whereas the application of SA through foliar method can be used to protect plant growth and improve these attributes under salt stress.

Chitosan-immobilized pectinolytics with novel catalytic features and fruit juice clarification potentialities

Biological macromolecules are primarily composed of complex polysaccharides that strengthen microbial growth for the production of industrially relevant enzymes. The presence of polysaccharides in the form of the disrupted cell wall and cell materials are among major challenges in the fruit juice industry. The breakdown of such biological macromolecules including cellulose and pectin is vital for the juices processing. In this background, pectinolytic enzymes including polygalacturonase (PG), pectin lyase (PL), and pectin methylesterase (PME) were isolated from Aspergillus ornatus, statistically optimized and purified via ammonium sulfate fractionation (ASF), dialysis, and Sephadex G-100 gel permeation chromatography. After passing through Sephadex G-100 column, PG, PL, and PME were 2.60-fold, 3.30-fold, and 4.52-fold purified with specific activities of 475.2U/mg, 557.1U/mg, and 205.7U/mg. The active PG, PL, and PME, each separately, were surface immobilized using various concentrations of chitosan and dextran polyaldehyde as a macromolecular crosslinking agent. Prior to exploit for juice clarification purposes, various parameters including pH, thermal and Michaelis-Menten kinetic constants of purified and chitosan-immobilized fractions were investigated. A considerable improvement in the pH and thermal profiles was recorded after immobilization. However, the negligible difference between the Km and Vmax values of purified free and chitosan-immobilized fractions revealed that the conformational flexibility of pectinolytics was retained as such. A significant color and turbidity reductions were recorded after 60min treatment with CTS-PG, followed by CTS-PME, and CTS-PL. It can be concluded that the clarification of apples, mango, peach, and apricot juices was greatly affected by CTS-PG, CTS-PME, and CTS-PL treatments rendering them as potential candidatures for food industry applications.

Transgenic tobacco with rice zinc-finger gene OsLOL2 exhibits an enhanced resistance against bacterial-wilt

LSD1-related proteins have been found to regulate programmed cell death (PCD) and disease related signaling in the plants. Rice LSD1-like (OsLOL1) gene was involved in regulation of cell death and OsLOL2 (rice zinc-finger gene) has been reported to regulate plant growth and disease resistance in plants. Bacterial-wilt is a devastating disease caused by Ralstonia solanacearum that needs to be controlled effectively. To achieve this purpose, Agrobacterium-mediated transgenic tobacco plants were generated, which hold OsLOL2 gene in their genome encoding zinc-finger proteins. Selection of the T2 OsLOL2 transgenic lines was accomplished using molecular techniques, and later on their physiological characterization was done. Southern-blot assay of the selected transformed lines reveals that the transgene has been incorporated into the tobacco genome. On infection with R. solanacearum strains (GMI1000 and RS1000), the selected T2 transgenic tobacco lines showed enhanced resistance against bacterial-wilt when compared to control plants. Moreover, relatively less bacterial proliferation occurred in the infected stem-tissues of the transgenic lines. Owing to smaller bacterial populations, relatively fewer blockages in xylem vessels were observed during microscopy in the transgenic lines as compared to control.

SCRUTINIZATION OF SOIL SEED BANK FROM ARID TO MESIC HABITATS OF DERA GHAZI KHAN

The research was conducted to investigate the persistent soil seed bank composition and its relation to the above-ground vegetation of upland area (piedmont) to low land area (alluvial) landscape from arid to mesic region of Dera Ghazi Khan. A transact of 40 kilometers was laid down from arid to mesic habitat. At each 2 km a quadrate of 1 m−2 sizes was thrown in the field to collect a soil sample of 2kg from soil cores ranging 0-15 cm deep for the analysis of soil seed bank. Twenty different sites were sampled by throwing 6 quadrates at each site making a total of 120 samples. Three thousand seeds were obtained of 50 different species from all the collected samples. Soil seed bank density m−2 was higher in the alluvial plains of Dera Ghazi Khan. Most of the perennial species, which were xerophytic in nature such as Aerua persica, Calotropis procera, Fagonia indica, Leptadaenia pyrotechnica, Peganum hermala, Rhazya stricta and Suaeda fructicosa were found in the piedmont (arid) soil habitat and the soil seed bank relatively less than the species found in the alluvial (Mesic) soil habitat, which were mostly of annual life span such as Chenopodium murale, Euphorbia prostrata, Medicago denticulata, Fumaria indica, and Withania somnifera. From this study it is concluded that the similarity found between soil seed bank and above ground vegetation of both historic types of habitats piedmont (arid) and alluvial (mesic) of Dera Ghazi Khan