Aamir Ali

In vitro conservation and production of vigorous and desiccate tolerant synthetic seeds in Stevia rebaudiana

cultures for encapsulation. The explants were taken from green houses and tissue culture laboratory of AgriBiotech Research Farms, Lahore, Pakistan. Different concentrations of sodium alginate and calcium chloride affect the shape and germination of artificial seeds. A gelling matrix of 3% sodium alginate and 100 mM calcium chloride was found most suitable for the formation of firm, clear and isodiametric ideal beads. No effect of the duration of sodium alginate treatment on bead formation was observed. However, timing of CaCl

Initiation, proliferation and development of micro-propagation system for mass scale production of banana through meristem culture

Explants were taken from field grown plants in 2010. The shoot apical meristem of different sizes was cultured on Murashige and skoog’s (MS) medium supplemented with different concentrations and combinations of 6-benzylamino-purine (BAP), kinetin (Kin) and α- naphthaleneacetic acid (NAA) either alone or in combination with each other under different temperature conditions ranging from 23 to 27°C. Shoot formation response from shoot apical meristem showed that MS medium containing 1.0 mg/l BAP showed best response for shoot formation. For shoot multiplication, MS medium containing 1.0 mg/l BAP + 0.25 mg/l kin provided the best multiplication response which was 8 shoot per culture vial within 21.6 days after inoculation into shoot multiplication medium. Shoot formation and multiplication response was also affected by temperature variations. The best results were obtained at 27°C ± 1°C. By increase or decrease in temperature, the rate of in vitro response was also decreased. For rooting of well developed in vitro shoots MS medium supplemented with 1.0 mg/l Indole-3- butyric acid (IBA)+ 0.5 mg/l NAA showed 3.6 roots per plant after 6.8 days of inoculation into rooting medium with an average root length of 2.4 cm. 100% hardening response was obtained in Peat moss after 21 days of transplantation in glass house. The experiments were designed in completely randomized pattern. Key words: Murashige and skoog’s medium, proliferation, banana, micro propagation system.

Application of Bacillus megaterium MCR-8 improved phytoextraction and stress alleviation of nickel in Vinca rosea

ABSTRACT The current research was performed to evaluate the effect of Bacillus megaterium MCR-8 on mitigation of nickel (Ni) stress in Vinca rosea grown on Ni-contaminated soil (50, 100, and 200 mg Ni kg−1 soil). The treated plants exhibited reduced growth, biomass, gas exchange capacity, and chlorophyll (Chl) content under Ni stress. The inoculated plants growing in Ni-contaminated media exhibited relatively higher growth, total soluble protein, and proline contents. Similarly, bacterial inoculation improved the activity of antioxidant enzymes including superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), and ascorbate peroxidase (APX) under Ni stress. The Ni stress alleviation in inoculated plants was attributed to the reduced level of malondialdehyde (MDA) and hydrogen peroxide (H2O2), enhanced synthesis of protein, proline, phenols, and flavonides in conjunction with improved activity of antioxidant enzymes. The growth-promoting characteristics of microbe such as 1-aminocyclopropane-1-carboxylate deaminase (ACCD) and phosphate solubilization activity, siderophore, and auxin production capability also improved the growth and stress mitigation in inoculated plants. Furthermore, the inoculated plants exhibited higher value for bioconcentration factor (BCF), translocation factor (TF), and resulted in higher loss of Ni content from soil. The current results exhibited the beneficial role of B. megaterium MCR-8 regarding stress alleviation and Ni phytoextraction by V. rosea.

Effect of Pseudomonas fluorescens RB4 and Bacillus subtilis 189 on the phytoremediation potential of Catharanthus roseus (L.) in Cu and Pb contaminated soils.

ABSTRACT The remediation of heavy metal-contaminated soils has become a critical issue due to toxic effects of these metals on living organisms. The current research was conducted to study the effect of Pseudomonas fluorescens RB4 and Bacillus subtilis 189 on the growth and phytoremediation potential of Catharanthus roseus in Cu- and Pb-contaminated soils. The bacterial strains exhibited significantly higher level of water-extractable Pb and Cu in Pb, Cu, and Cu+Pb-contaminated. The P. fluorescens RB4 inoculated plants, produced 102%, 48%, and 45% higher fresh weight (FW) in soils contaminated with Cu, Pb, and both elements, respectively, as compared to un-inoculated control plants. Similarly, B. subtilis 189 inoculated plants produced 108%, 43%, and 114% more FW in the presence of Cu, Pb, and both elements. The plants co-cultivated with both bacteria exhibited 121%, 102%, and 177% higher FW, in Cu, Pb, and both elements contaminated soils, as compared to respective un-inoculated control. Co-cultivation of P. fluorescens RB4, B. subtilis 189, and P. fluorescens RB4 + B. subtilis 189 resulted in higher accumulation of Cu and Pb in shoots of the C. roseus grown in contaminated soils as compared to un-inoculated control. Bacterial treatments also improved the translocation and metal bioconcentration factors. The growth and phytoextraction capability of C. roseus was improved by inoculation of P. fluorescens RB4 and B. subtilis 189.

Role of Ni-tolerant Bacillus spp. and Althea rosea L. in the phytoremediation of Ni-contaminated soils

ABSTRACT In our current study, four nickel-tolerant (Ni-tolerant) bacterial species viz, Bacillus thuringiensis 002, Bacillus fortis 162, Bacillus subtilis 174, and Bacillus farraginis 354, were screened using Ni-contaminated media. The screened microbes exhibited positive results for synthesis of indole acetic acid (IAA), siderophore production, and phosphate solubilization. The effects of these screened microbes on Ni mobility in the soil, root elongation, plant biomass, and Ni uptake in Althea rosea plants grown in Ni-contaminated soil (200 mg Ni kg−1) were evaluated. Significantly higher value for water-extractable Ni (38 mg kg−1) was observed in case of Ni-amended soils inoculated with B. subtilis 174. Similarly, B. thuringiensis 002, B. fortis 162, and B. subtilis 174 significantly enhanced growth and Ni uptake in A. rosea. The Ni uptake in the shoots and roots of B. subtilis 174-inoculated plants enhanced up to 1.7 and 1.6-fold, respectively, as compared to that in the un-inoculated control. Bacterial inoculation also significantly improved the root and shoot biomass of treated plants. The current study presents a novel approach for bacteria-assisted phytoremediation of Ni-contaminated areas.

Amelioration of Cadmium Stress in Gladiolus (Gladiolus grandiflora L.) by Application of Potassium and Silicon

ABSTRACT Gladiolus corms were grown in media contaminated with cadmium (Cd) (50 mg kg−1) and supplemented with silicon (Si) and potassium (K). The role of Si and K for mitigation of Cd toxicity was evaluated. Cd-induced stress generated significantly increased level of oxidative stress markers including hydrogen peroxide (H2O2), and malondialdehyde (MDA) in gladiolus. The application of K and Si improved the production of protein and proline in the treated plants. Moreover, K and Si supplemented plants exhibited an improvement in the activity of antioxidant enzymes and a reduction in the level of MDA, H2O2 and Cd uptake under Cd stress. Application of K and Si also enhanced the uptake of mineral nutrients including calcium (Ca), magnesium (Mg), manganese (Mn), sulfur (S) and K. The plants supplemented with K and Si exhibited a higher amount of total phenolics and flavonoids. The combined effect of Si and K was more pronounced regarding beneficial effects on gladiolus plants compared to individual effect of these elements under Cd stress. The current research reveals that Si and K may improve gladiolus growth by decreasing the oxidative stress and Cd uptake and by increasing the activity of antioxidant defense enzymes, the quantity of secondary metabolites and plant nutrition.

Role of Burkholderia cepacia CS8 in Cd-stress alleviation and phytoremediation by Catharanthus roseus

ABSTRACT The current study was performed to assess the effect of Burkholderia cepacia CS8 on the phytoremediation of cadmium (Cd) by Catharanthus roseus grown in Cd-contaminated soil. The plants cultivated in Cd amended soil showed reduced growth, dry mass, gas-exchange capacity, and chlorophyll contents. Furthermore, the plants exhibited elevated levels of malondialdehyde (MDA) and hydrogen peroxide (H2O2) under Cd stress. The bacterized plants showed higher shoot length, root length; fresh and dry weight. The improved stress tolerance in inoculated plants was attributed to the reduced quantity of MDA and H2O2, enhanced synthesis of protein, proline, phenols, flavonoids, and improved activity of antioxidant enzymes including peroxidase, superoxide dismutase, ascorbate peroxidase, and catalase. Similarly, the 1-aminocyclopropane-1-carboxylate deaminase activity, phosphate solubilization, auxin, and siderophore production capability of B. cepacia CS8 improved growth and stress alleviation in treated plants. The bacterial inoculation enhanced the amount of water extractable Cd from soil. Furthermore, the inoculated plants showed higher bioconcentration factor and translocation factor. The current study exhibits that B. cepacia CS8 improves stress alleviation and phytoextraction potential of C. roseus plants growing under Cd stress.

The beneficial role of potassium in Cd-induced stress alleviation and growth improvement in Gladiolus grandiflora L.

ABSTRACT Heavy metal contaminated agricultural soils are one of the most important constraints for successful cultivation of crops. The current research was conducted to evaluate the role of potassium (K) on plant growth and amelioration of cadmium (Cd) stress in Gladiolus grandiflora under greenhouse conditions. G. grandiflora corms were sown in media contaminated with 0 (C), 50 (Cd50) and 100 (Cd100) mg Cd kg−1 soil. The plants growing in Cd-contaminated media exhibited reduced gas exchange attributes, chlorophyll (Chl) contents, vegetative and reproductive growth as compared to control. The plants raised in Cd contaminated media showed reduced nutrition yet higher Cd contents. However, supplementation of 60 mg Kg−1 K in treated plants (C+K, Cd50+K and Cd100+K) improved quantity of total soluble protein and proline (Pro) along with activity of antioxidant enzymes including superoxide dismutase (SOD), catalase (CAT), peroxidase (POD) and ascorbate peroxidase (APX) under Cd stress. Similarly, K supplementation reduced the level of malondialdehyde (MDA) and hydrogen peroxide (H2O2) in treated plants. Potassium supplemented plants exhibited better vegetative and reproductive growth. The improved stress tolerance in K supplemented plants was attributed to the reduced quantity of MDA and H2O2, enhanced synthesis of protein, proline, phenols, flavonides and improved activity of antioxidant enzymes. The present research supports the application of K for alleviation of Cd stress in G. grandiflora.

Comparative Physiological and Morphological Characterization of SaltTolerance in Raphanus sativus L.

Salt stress is one of the main constraints for successful crop production throughout the world. Different physiological and morphological plant attributes help in prediction of plant growth and yield under salt stress. The core objective of current research was to characterize physiological and morphological parameters of different varieties of radish (Raphanus sativus) involved in salt stress resistance. Our results exhibited that morphological and physiological parameters including total soluble proteins, total soluble sugars, root length and leaf area had strong correlation with salt stress. The reduced quantity of morphological and physiological features excluding reducing sugars exhibited low coefficient of variation along with positive and significant correlation with yield of the plants. These morphological and physiological characteristics of crop may be used to assume salt stress tolerance in crop.

QTL Analysis in Plants: Ancient and Modern Perspectives

Quantitative traits exhibit continuous variation, indicating their control through multiple genes. Segregating populations are used to mine out associations between phenotypic and genotypic variations. Phenotyping performed for a specific trait and its variation in the population is justified with genotypic variation obtained through genetic markers application. A snapshot of genotypic variation is strictly dependent on the number and density of the markers applied. Parental and marker information is required to correlate genetic and phenotypic data for quantitative trait loci (QTL) analysis. For many years (now becoming obsolete), it has been of core importance to identify QTL with such methodology. Failure had to be faced by the researcher because the DNA region identified for phenotypic variation was much wider, and needed to be narrowed down by further dense marker application in that area to obtain required and accurate results. Nowadays the focus is on high-throughput technologies to obtain genome-wide resolution: high-throughput sequencing (HTS) is one of them. A comprehensive map of genomic variations can be produced with resequencing or reference genome sequences. Along with expression profiling, new molecular markers can be searched out with QTL analysis. Genomic-assisted breeding by studying the evolutionary variations in crops has many applied aspects as well. As compared to the conventional biparental population, presently the focus is on raising multiparent advanced generation inter-cross (MAGIC) populations to explore the genetic basis of quantitative traits. Probabilities of alleles of interest across the whole genome are calculated through the Hidden Markov Model (HMM). Different software packages (such as R-package, Qgene) are used for the estimates. Such whole-genome approaches in QTL analysis are a powerful and recently used technique. In this chapter, all these recent and modified modern techniques are reviewed with the most recent upcoming details. Traditional and modern QTL analyses have clearly been differentiated on applicable grounds.