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Abstract

Environmental factors and the addition of adjuvants to the spray tank mix may interfere with glyphosate efficiency in hairy fleabane control. The objective of this study was to evaluate the effect of air temperature and the addition of ammonium sulfate (NH4)2SO4 to glyphosate in the control of glyphosate-resistant (GR) and -susceptible (GS) hairy fleabane. Treatments consisted of air temperatures of 12°C and 25°C, six doses of glyphosate from zero to 2,880 g · ha−1, the presence or absence of (NH4)2SO4 in the spray solution, and one GS and another GR biotype. At the lowest tested dose (180 g · ha−1), control of the GR biotype was 91% and 20% when the plants were kept at 12°C and 25°C, respectively, reducing the resistance factor (RF) by 9.30 times and was associated to the reduction of temperature. The addition of (NH4)2SO4 increased the control by 10−20% at high glyphosate doses and at 25°C. The resistance of hairy fleabane to glyphosate was completely reversed when the plants were maintained at 12°C. At this temperature, resistant plants were controlled even at doses well below that recommended for the control of this species. At 25°C, a dose four times higher than that recommended was required for satisfactory control. At the field level, under situations of low temperatures, it was possible to improve the efficacy of glyphosate applications in hairy fleabane control, if there were no other mechanisms of resistance involved.

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Authors and Affiliations

Giliardi Dalazen
Alexandre Pisoni
Christian Menegaz
Aldo Merotto Jr.
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Abstract

Ligninolytic enzymes are employed for the production of second-generation biofuel to minimize fuel crisis. Additionally, they play a crucial role in global carbon cycle and a variety of applications in food, agriculture, paper and textile industries. On a large scale production of ligninolytic enzymes, microorganisms can be cultured on lignocellulosic wastes. In the present study, proximate analysis including acid detergent lignin (ADL), acid detergent cellulose (ADC), acid detergent fi ber (ADF) and acid insoluble ash (AIA) were performed for Platanus orientalis (chinar), Bauhinia variegata (orchid tree), Pinus roxburghii (chir pine), wheat straw and wheat husk. Platanus orientalis was selected as substrate because of higher lignin contents for the production of ligninolytic enzymes by Aspergillus flavus. Solid State Fermentation was used and Response Surface Methodology was employed for optimizing various parameters and enzymes production. Maximum production was achieved at temperature 32°C, fermentation period 120 hours, pH 4.5, inoculums size 3.5 mL, substrate mesh size 80 mm, substrate size 7 g. Maximum purifi cation of laccase, manganese peroxidase (MnP) and lignin peroxidase (LiP) was achieved with 50%, 60% and 40% ammonium sulfate respectively and it was enhanced by gel filtration chromatography. Characterization of enzymes shows that Laccase has 35°C optimum temperature, 4.5 pH, 0.289 mM Km and 227.27 μM/ml Vmax. Manganese peroxidase has 30°C optimum temperature, 5.5 pH, 0.538 mM Km and 203.08 μM/ml Vmax. Lignin peroxidase has 30°C optimum temperature, 3 pH, 2 mM Km and 2000 µM/ml Vmax. Protein concentrations found in crude extracts and partially purified enzymes are respectively: laccase 1.78 and 0.71 mg/ml, MnP 1.59 and 0.68 mg/ml. LiP, 1.70 and 0.69 mg/ml.
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Authors and Affiliations

Jehangir Khan
1 3
Muahammad Javaid Asad
1
Raja Tahir Mahmood
2
Feeroza Hamid Wattoo
1
Tayyaba Zainab
1
Sidrah Nazir
1
Muhammad Basir Shah
4
Dawood Ahmed
5

  1. University Institute of Biochemistry and Biotechnology, PMAS-Arid Agriculture University Rawalpindi, Pakistan
  2. Department of Biotechnology, Mirpur University of Science and Technology (MUST), Mirpur-10250 (AJK), Pakistan
  3. Department of Biosciences, University of WAH, WAH Pakistan
  4. Department of Plant Breeding & Genetics, Balochistan Agriculture College Quetta, Pakistan
  5. Department of Medical Laboratory Technology, Haripur University, Haripur, KPK, Pakistan

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