Ambreen Akhtar

Study on Black Gram (Vigna mungo L.) Infected with Meloidogyne incognita under the Influence of Pseudomonas fluorescens, Bacillussubtilis and Urea

Pot studies were carried out to assess the growth and biochemical components of Vigna mungo L. cultivar ‘Azad- 2’ with the root-knot nematode and treated with two biofertilizers viz. Pseudomonas fluorescens strain CHA0, and Bacillus subtilis strain Bs-5. The plants were grown in soil at N50 and N100 doses of urea. Uninoculated untreated plants served as control. From the results, it was evident that V. mungo plants exhibited profused vegetative growth at N100 dose of urea as was observed in the treatment 5. The plants of treatment 5 were inoculated with P. fluorescens CHA0 (20 ml). The number of nodules per plant was found increased to 14.33 per plant, total chlorophyll content by 2.91 mg/g of leaf tissue, leghaemoglobin by 3.81 mg/g, and protein content in leaves and seeds by 0.83 and 0.76 mg/g, respectively, when compared with the control and the plants that received different doses of B. subtilis Bs-5 in the absence of the root-knot nematode. Significant reduction in gall number (41.66) and number of nematodes per gram of root (4.66) was recorded in the treatment 5.

Management of Root-Knot Disease in Phaseolus vulgaris Using Potassium Fertilizer and Biocontrol Agents

The experiment was conducted to determine the effect of different doses of potassium fertilizer (K2O) along with the biofertilizers, Trichoderma harzianum, and Pochonia chlamydosporia, in the management of the root-knot disease caused by the root-knot nematode (Meloidogyne incognita) and on the growth and physiological parameters of Phaseolus vulgaris. From the result it was observed that the application of potassium along with biofertilizers in the treatment T-7 in which plants were treated with double dose of potassium along with both fungal biocontrol agents and root-knot nematode, improved all the growth as well as biochemical parameters viz, chlorophyll, protein, nitrate reductase, nitrogen and phosphorus contents and reduced the number of galls per root system in comparison to the control and other treatments.

Interaction between Meloidogyne incognita and Pochonia chlamydosporia and their effects on the growth of Phaseolus vulgaris

An experiment was conducted to test the effect of different doses of 2, 4 and 8 g/2 kg of soil of Pochonia chlamydosporia against the root-knot nematode (Meloidogyne incognita) on Phaseolus vulgaris. It was observed that inoculation of plant with the nematode alone, and 15 days prior to fungal inoculation, reduced the plant growth when compared with the plant with fungal application followed by the nematode. Plant length, fresh and dry weight, chlorophyll, carotenoid, protein contents and nitrate reductase activity decreased in nematode-infested plants. Application of higher dose of 8 g/2 kg of soil of P. chlamydosporia increased all the plant growth parameters as well as biochemical parameters. Highest number of galls per root system was recorded on the plants infested with nematode but not treated with the fungus. However, application of fungus prior to nematode inoculation improved the plant growth and reduced the number of galls and the number of egg masses per root system.

Induced variations in quantitative traits by EMS and SA treatments in Linum usitatissimum L.

The Linum usitatissimum L. var.NDL-2002 has high oil yield potential. The seeds of the variety were exposed to different concentrations (0.02–0.10%) of ethyl methane sulphonate (EMS) and sodium azide (SA). Observations on germination, germination inhibition, morphology, plant height, yield parameters, branches per plant, etc. were recorded in M1 generation in control and treated plants. Leaves notching, effect on internodal length were observed and also the more adverse effect of EMS was observed than SA.

Effect of bark extract of different plant species on the hatching of Meloidogyne incognita

An in vitro experiment was conducted to evaluate the effect of bark extract of different plant species viz., Azadirachta indica, Acacia nilotica, Emblica officinalis, Eucalyptus citriodora, Mangifera indica and Terminalia arjuna at varying concentration levels S, S/2, S/10 and S/100 on the hatching of Meloidogyne incognita. One hundred per cent inhibition was observed with Azadirachta indica under both un-decomposed and decomposed conditions. The effect was decreased with Acacia nilotica, Emblica officinalis, Eucalyptus citriodora, Mangifera indica and Terminalia arjuna, respectively. Effect of decomposed bark extract on hatching was more pronounced as compared to un-decomposed bark extract.

Studies on the Histopathological Responses of Vigna Mungo towardsMeloidogyne Incognita at Different Time Intervals

The pot experiments on Vigna mungo with five replicates for each treatment were set up in the Department of Botany, Aligarh Muslim University, Aligarh, Uttar Pradesh (27°52’59” N to 78°04’59” E; 180 m above sea level), India. Histological studies of the roots of infected plants were carried out after 24 h, 48 h, 72 h, 5 days, 10 days, 15 days, 21 days, 25 days and 30 days of inoculation. The second-stage juveniles penetrated into the roots and moved intercellularly by separating the cell walls after 24 h. The first sign of infection observed after 48 h of inoculation was hypertrophy in the cells, around the head of the juvenile. The cytological changes in the hypertrophied cells became more prominent after 72 h of inoculation, and the cells transformed into discrete giant cells. The giant cell cytoplasm became dense and stained darkly, the size of the nuclei and the nucleoli increased after five days of inoculation. Ten days after inoculation, the width of vessel elements was also increased. The second-stage juveniles moulted into the third stage. After 21 days of nematode exposure, the hypertrophied and hyperplastied parenchyma cells were observed adjacent to the giant cells. At several occasions, the giant cell complexes appeared to be surrounded by abnormal xylem comprising of abnormal vessel elements, which were transformed from the hypertrophic and hyperplastic parenchymatous tissue. The head region of the nematode was in contact with the giant cells while remaining part of the body expanded and caused disruptions in the arrangement of vascular and cortical tissues, as was observed after 25 days of inoculation. After 30 days of nematode inoculation, egg masses were found associated with all the mature females. The tissues were disrupted as the egg masses were pushed out to the surface of the root. Several eggs enclosed first stage juveniles.