Effects of fly ash amendments in soil (0%, 25% and 50% vol/vol), Ralstonia solanacearum, Meloidogyne incognita and Phomopsis vexans were observed on the growth, chlorophyll and carotenoid contents of eggplant. Addition of 25% fly ash in soil caused a significant increase in plant growth, chlorophyll and carotenoid contents over plants grown without fly ash. However, amendments of 50% fly ash in soil had an adverse effect on the growth, chlorophyll and carotenoid contents of eggplant. Inoculation of the pathogens caused a significant reduction in growth, chlorophyll and carotenoid contents. Inoculation of R. solanacearum caused the greatest reduction followed by P. vexans and M. incognita. Root galling and nematode multiplication was reduced with the increase in fly ash. Wilting and blight indices were 3 in plants grown in 0% and 25% fly ash amended soil while 4 in 50% fly ash amended soil.
A total of 32 bacterial isolates including
(N=12) and phosphate-solubilizing bacteria (N=10) were isolated and tested for siderophore, HCN, ammonia, indole acetic acid production and phosphate solubilization
. The bacterial cultures were positive for siderophore, HCN and ammonia. Among the isolates,
A4 displayed 35 and 14 μg ml
of IAA, respectively, whereas
produced 19 (
PSB1) and 17 μg ml
PSB10) of IAA in Luria Bertani broth. The diameter of the P solubilization zone varied between 4 (
PSB1) and 5 mm (
PSB10) and a considerable amount of tricalcium phosphate (7 and 8 μg ml
PSB10, respectively) was released in liquid medium, with a concomitant drop in pH. The effects of N
-fixing and PS bacteria on the growth, chlorophyll content, seed yield, grain protein and N uptake of chickpea plants in field trials varied considerably between the treatments. Nodule number and biomass were significantly greater at 90 days after sowing (DAS), decreasing by 145 DAS. Seed yield increased by 250% due to inoculation with
PSB10, relative to the control treatment. Grain protein content ranged from 180 (
PSB1) to 309 ng g
PSB10) in inoculated chickpea. The N contents in roots and shoots differed considerably among the treatments.
A diallel cross involving six wheat varieties, namely Sehar 06, Punjab 96, GA 2002, Barani 83, Kohistan 97 and Chakwal 86 was carried out to determine the mode of gene action for some physio-morphological traits under water stress conditions. Analysis of variance showed highly significant differences among genotypes for all the traits studied. Additive type of gene action with partial dominance was observed for flag leaf area, stomatal frequency, leaf venation, days to heading and spike density while 100-grain weight was controlled by over dominance. Additive type of gene actions shows the fruitfulness of early selection for the traits while over dominance type of gene action indicates selection in later generations. Epistasis was absent for all the traits studied.
Authors:M. Sajjad, S.H. Khan, M.Q. Ahmad, A. Rasheed, A. Mujeeb-Kazi and I.A. Khan
A panel of 94 diverse hexaploid wheat accessions was used to map quantitative trait loci (QTL) underlying the yield related traits on chromosome 3A. Population structure and kinships were estimated using unlinked SSR markers from all 21 chromosomes. Analysis of variance revealed significant difference among accessions; however, genotype × year interaction was non-significant for majority of yield related traits. A mixed linear model (MLM) approach identified six QTLs for four traits that individually accounted for 10.7 to 17.3% phenotypic variability. All QTLs were consistently observed for both study years. New putative QTLs for the maximum fertile florets per spike and spike length were identified. This report on QTLs for yield related traits on chromosome 3A will extend the existing knowledge and may prove useful in marker-assisted selection (MAS) for development of high yielding cultivars.
Authors:A. Rahman, K. Khan, G. Al-Khaledi, I. Khan and Sreeja Attur
Cognitive impairment is a common feature of both lead exposure and hyperphosphorylation of tau. We, therefore, investigated whether lead exposure would induce tau hyperphosphorylation. Wistar rat pups were exposed to 0.2% lead acetate via their dams’ drinking water from postnatal day 1 to 21. Lead in blood and brain were measured by atomic absorption spectrophotometry and the expression of tau, phosphorylated tau and various serine/threonine protein phosphatases (PP1, PP2A, PP2B and PP5) in the brain was analyzed by Western blot. Lead exposure significantly impaired learning and resulted in a significant reduction in the expression of tau but increased the phosphorylation of tau at Ser199/202, Thr212/Ser214 and Thr231. PP2A expression decreased, whereas, PP1 and PP5 expression increased in lead-exposed rats. These results demonstrate that early postnatal exposure to lead decrease PP2A expression and induce tau hyperphosphorylation at several serine and threonine residues. Hyperphosphorylation of tau may be a mechanism of Pb-induced deficits in learning and memory.
Authors:A. Khan, H.H. Liu, A. Ahmad, L. Xiang, W. Ali, A. Khan, M. Kamran, S. Ahmad and J.C. Li
Higher plant population and nitrogen management is an adopted approach for improving crop productivity from limited land resources. Moreover, higher plant density and nitrogen regimes may increase the risk of stalk lodging, which is a consequence of complex interplant competition of individual organs. Here, we aimed to investigate the dynamic change in morphology, chemical compositions and lignin promoting enzymes of the second basal inter-nodes altering lodging risk controlled by planting density and nitrogen levels. A field trial was conducted at the Mengcheng research station (33°9′44″N, 116°32′56″E), Huaibei plain, Anhui province, China. A randomized complete block design was adopted, in which four plant densities, i.e., 180, 240, 300, and 360 × 104 ha−1 and four N levels, i.e., 0, 180, 240, and 300 kg ha−1 were studied. The two popular wheat varieties AnNong0711 and YanNong19 were cultivated. Results revealed that the culm lodging resistance (CLRI) index of the second basal internodes was positively and significantly correlated with light interception, lignin and cellulose content. The lignin and cellulose contents were significantly and positive correlated to light interception. The increased planting density and nitrogen levels declined the lignin and its related enzymes activities. The variety AnNong0711 showed more resistive response to lodging compared to YanNong19. Overall our study found that increased planting densities and nitrogen regimes resulted in poor physical strength and enzymatic activity which enhanced lodging risk in wheat varieties. The current study demonstrated that stem bending strength of the basal internode was significantly positive correlated to grains per spike. The thousand grain weight and grain yield had a positive and significant relationship with stem bending strength of the basal internode. The results suggested that the variety YanNong19 produces higher grain yield (9298 kg ha−1) at density 240 × 104 plants ha−1, and 180 kg ha−1 nitrogen, while AnNong0711 produced higher grain yield (10178.86 kg ha−1) at density 240 × 104 plants ha−1 and with 240 kg ha−1 nitrogen. Moreover, this combination of nitrogen and planting density enhanced the grain yield with better lodging resistance.
Authors:Z. A. Siddiqui, A. Khan, M. R. Khan and E. F. Abd-Allah
Effects of ZnO nanoparticles (NPs) were studied on lentil plants inoculated with Alternaria alternata, Fusarium oxysporum f. sp. lentis, Xanthomonas axonopodis pv. phaseoli, Pseudomonas syringae pv. syringae and Meloidogyne incognita. Plant growth, chlorophyll, carotenoid contents, nitrate reductase (NR) activity and nodulation of lentil both in the presence and absence of Rhizobium sp. were examined in a pot test. Inoculation of plants with A. alternata / F. oxysporum f. sp. lentis / X. axonopodis pv. phaseoli / P. syringae pv. syringae or M. incognita caused a significant reduction in plant growth, number of pods per plant, chlorophyll, carotenoids and NR activity over uninoculated control. Inoculation of plants with Rhizobium sp. with or without pathogen increased plant growth and number of pods per plant, chlorophyll, carotenoids and NR activity. When plants were grown without Rhizobium, a foliar spray of plants with 10 ml solution of 0.1 mg ml–1of ZnO NPs per plant caused a significant increase in plant growth and number of pods, chlorophyll, carotenoid contents and NR activity in both inoculated and uninoculated plants. Spray of ZnO NPs to plants inoculated with Rhizobium sp. caused non significant increase in plant growth, number of pods per plant, chlorophyll, carotenoid contents and NR activity when plants were either uninoculated or inoculated with pathogens. Numbers of nodules per root system were high in plants treated with Rhizobium sp. but foliar spray of ZnO NPs had adverse effect on nodulation. Inoculation of plants with test pathogens also reduced nodulation. Spray of ZnO NPs to plants reduced galling, nematode multiplication, wilt, blight and leaf spot disease severity indices.
Authors:A. Rehman, M. Sajjad, S.H. Khan, R.J. Peña and N.I. Khan
The allelic variation for Glu-1, Glu-3 loci and presence of IBL-1RS translocation was determined in 126 spring wheat accessions. The most common alleles at Glu-1 loci were Glu-A1b (59.52%), Glu-B1c (41.26%), and Glu-D1d (57.14%) and at Glu-3 loci were Glu-A3c (56.45%), Glu-B3j (29.36%), and Glu-D3b (76.98%). Modern Pakistani wheat varieties carried superior alleles at Glu-1 and Glu-3 loci for bread-making quality and had no negative influence of secalin protein-synthesized by 1BL-1RS translocation. For LMW-GS, the most common combination was Glu-A3c, Glu-B3j and Glu-D3b. The loci Glu-B1 and Glu-B3 had the highest allelic diversity of Glu-1 and Glu-3 loci, respectively.
Authors:J. A. Guroo, M. Khan, A. Ahmad, A. Azam and Z. A. Siddiqui
Effect of Graphene oxide (GO) was observed on Meloidogyne incognita and Macrophomina phaseolina and on the growth of lentil in pot experiment. Treatment of plants with 10 ml solution of GO with 125, 250 and 500 ppm concentration caused a significant increase in plant dry weight over control. Inoculation of plants with M. incognita or M. phaseolina caused a significant reduction in plant dry weight over uninoculated control. Treatment of plants with 125, 250 and 500 ppm GO and subsequent inoculation with M. incognita or M. phaseolina caused a significant increase in plant dry weight over plants inoculated without GO pretreatment. Treatment of 500 ppm GO caused a greater increase in plant dry weight of M. incognita or M. phaseolina inoculated plants followed by 250 ppm and 125 ppm. Numbers of nodules per root system were high in plants without pathogen. Inoculation of M. incognita or M. phaseolina caused reduction in nodulation. However, treatment of GO in all the three concentrations had no significant effect on nodulation in plants both with and without pathogens. Treatment of GO resulted in reduced galling, nematode multiplication and root-rot index. Greater reduction in galling, nematode multiplication and root-rot index were observed in plants treated with 500 ppm GO followed by 250 ppm and 125 ppm. Indices were reduced to 4, 3 and 2, respectively, when plants with M. phaseolina were treated with 125, 250 and 500 ppm GO. This study shows that the use of GO is useful for the management of M. incognita and M. phaseolina on lentil.