Shahid Akbar Khalil

Efficient regeneration for enhanced steviol glycosides production in Stevia rebaudiana (Bertoni).

An efficient method of regeneration for antidiabetic plant (Stevia rebaudiana) has been established for healthy biomass and main steviol glycosides (SGs) production, using different PGRs and agar concentrations. Higher callus induction (93.3%) was recorded when leaf explants were placed on an MS medium supplemented with 3.5 gL(-1) agar and 2.0 mgL(-1) 2,4-D. The addition of 7.0 gL(-1) agar and BA (1.0, 2.0 and 4.0 mgL(-1)) significantly (P<0.01) influences shooting response (100%). A maximum mean shoot length (13.03 cm) and 28 shoots per explant were observed on a medium containing 1.0 mgL(-1) BA. However, the maximum number of leaves (132.67) was encouraged by the addition of BA (1.0 mgL(-1)) and Kin (1.0 mgL(-1)). Lower agar (3.5 gL(-1)), IAA (2.0 mgL(-1)), and NAA (2.0 mgL(-1)) concentrations significantly influence the rooting percent (100%), the mean root length (2.9 cm), and the number of roots per plantlet (26.3). These plantlets were successfully acclimatized in the soil. The BA (3.0 mgL(-1)) in combination with Kin (3.0 mgL(-1)) and 3.5 gL(-1) agar increases dulcoside-A content (Dul-A; 71.8 μg/g-DW) in shoots compared to control (50.81 μg/g-DW). Similar PGRs with 7.0 gL(-1) significantly increases the production of steviosides (Stev. 82.48 μg/g-DW). A higher rebaudioside-A content (Reb-A; 12.35 μg/g-DW) was observed in shoots that underwent the addition of BA (1.0 mgL(-1)) and 7.0 gL(-1) agar than in control (07.39 μg/g-DW). Hereby, we developed an efficient and cost-effective method for regeneration and major SGs production, which could be helpful for future studies on this species.

In vitro regeneration of plantlets from unpollinated ovary culture in sweet orange (Citrus sinensis L. Osbeck)

Callogenesis and organogenesis of ovary of sweet orange ( Citrus sinensis ) cv. Blood red was carried on Murashige and Skoog (MS) medium supplemented with different concentrations and combinations of N 6 benzyl adenine (BA), 1-napthaleneacetic acid (NAA) and 2,4-D. 1 mg/l BA + 0.5 mg/l NAA on MS medium was the most effective in callus induction and proliferation. Maximum number of shoots (11) was recorded on the medium with 2 mg/l NAA + 3 mg/l BA. The best medium for root induction was MS together with 2.5 mg/l indole-3-acetic acid (IAA) + 2 mg/l indole–3-butyric acid (IBA), where maximum (16) plantlets were rooted. The regenerated plantlets were successfully acclimatized in jiffy pots containing sterilized soil mixture of sand, silt and clay in 1:1:1 ratio to study their response to in vivo conditions. Key words: Citrus, blood red, ovary culture, callus induction, regeneration, plant growth regulators.

Antioxidant activity via DPPH, gram-positive and gram-negative antimicrobial potential in edible mushrooms

Edible mushrooms (EMs) are nutritionally rich source of proteins and essential amino acids. In the present study, the antioxidant activity via 1,1-diphenyl-2-picrylhydrazyl (DPPH) and antimicrobial potential in EMs (Pleurotus ostreatus, Morchella esculenta, P. ostreatus (Black), P. ostreatus (Yellow) and Pleurotus sajor-caju) were investigated. The DPPH radical scavenging activity revealed that the significantly higher activity (66.47%) was observed in Morchella esculenta at a maximum concentration. Similarly, the dose-dependent concentrations (200, 400, 600, 800 and 1000 µg) were also used for other four EMs. Pleurotus ostreatus exhibited 36.13% activity, P. ostreatus (Black (B)) exhibited 30.64%, P. ostreatus (Yellow (Y)) exhibited 40.75% and Pleurotus sajor-caju exhibited 47.39% activity at higher concentrations. Furthermore, the antimicrobial potential were investigated for its toxicity against gram-negative bacterial strains (Escherichia coli, Pseudomonas aeroginosa, Salmonella typhi, Klebsiella pneumonia, Erwinia carotovora and Agrobacterium tumifaciens), gram-positive bacterial strains (Bacillus subtilis, Bacillus atrophaeus and Staphylococcus aureus) and a fungal strain (Candida albicans) in comparison with standard antibiotics. Antimicrobial screening revealed that the ethanol extract of P. ostreatus was active against all microorganism tested except E. coli. Maximum zone of inhibition (13 mm) was observed against fungus and A. tumifaciens. P. sajor-caju showed best activities (12.5 mm) against B. subtilis, B. atrophaeus and K. pneumonia. P. ostreatus (Y) showed best activities against P. aeroginosa (21.83 mm), B. atrophaeus (20 mm) and C. albicans (21 mm). P. ostreatus (B) exhibited best activities against C. albicans (16 mm) and slightly lower activities against all other microbes except S. typhi. M. esculenta possess maximum activities in terms of inhibition zone against all microorganisms tested except S. typhi.

Efficient In Vitro Regeneration of Sugarcane (Saccharum Officinarum L.) from Bud Explants

ABSTRACT The regeneration potential of the economically important plant Saccharum officinarum (Sugarcane) was investigated. Callus induction and shoot regeneration along with somatic embryogenesis were induced from bud explants incubated on Murashige and Skoog (MS)-medium supplemented with different plant growth regulators (PGRs) and white sugar. The best callus induction (83.33%) was observed on explants incubated on MS-medium plus 1.0 mg·l−1 2,4-dichlorophenoxyacetic acid (2,4-D) and 4.0 mg·l−1 2,4-D (70%) after 6 weeks of culture. Other combinations (BA, IBA, IAA, NAA and GA3) of PGRs were less effective than 2,4-D. It was observed that lower concentrations of 2,4-D induced somatic embryos in bud explants of Saccharum officinarum, whereas higher concentrations induced non-embryogenic calli. Subsequent sub-culturing of calli onto MS-medium supplemented with BA (6-benzyladenine) induced shoot organogenesis. Highest shoot induction (98%) was recorded for 2.0 mg·l−1 after 3 weeks of culture. With this concentration of BA, maximum number of (178) shoots per explant were recorded, and, when the shoots were transferred to elongation medium, the longest shoots (9.4 cm) were recorded. However, 5.6 cm long shoots were also recorded with 3.0 mg·l−1 zeatin. No root induction hormones were used for rooting. The elongated shoots started rooting upon maturation. A maximum rooting (84%), number of roots/shoot (21) and mean root length of 5.0 cm were observed on medium containing 2.0 mg·l−1 BA along with 1.0 mg·l−1 GA3. The regenerated plantlets were successfully acclimated in field conditions.

Antioxidant activity influenced by in vivo and in vitro mutagenesis in sugarcane ( Saccharum officinarum L.)

The antioxidant potential (1,1-diphenyl-2-picrylhydrazyl (DPPHo)-scavenging activity) of in vitro regenerated and induced mutant sugarcane (Saccharum officinarum L.) was investigated. Efficient callus induction and shoot regeneration were induced in bud explants when incubated on Murashige and Skoog (MS) medium supplemented with different plant growth regulators (PGRs). Best callogenesis was observed on MS-medium supplemented with 3 mg L -1 2,4 dichlorophenoxyacetic acid (2,4 D) and on ½ MS medium with 2 mg L -1 2,4 D after 30-days of culture. Almost 85% shoot organogenesis was observed on MS-medium supplemented with 2 mg L -1 6-benzyladenine (BA) and 0.5 mg L -1 gibberellic acid (GA3) within 30 days. Optimum percentage rooting (89%), were obtained for 2 mg L -1 of BA alone. Mother plant setts were irradiated with 60Co mutagen source. Assay of antioxidant activity of in vitro and in vivo grown tissues was evaluated as gross parameter of medicinal efficacy. Significantly higher antioxidant activity (60%) in in vitro regenerated sugarcane was observed as compared to induced mutant (57%) and mother plant (53%). Key words: Saccharum officinarum, in vitro regeneration, induced mutation, antioxidant.

Developmental variation during seed germination and biochemical responses of Brassica rapa exposed to various colored lights

Light acting as elicitor or stress inducer, it plays a pivotal role in all developmental processes of plant providing necessary building blocks for growth and primary and secondary metabolites production. The main objective of the current study was to investigate the individual effect of colored lights on developmental processes and production of polyphenolics contents in Brassica rapa. In this study, the red and white lights (control) were found to be the most effective sources for seed germination (91%) in Brassica rapa. Similarly, red light enhanced radicle growth (102 mm), while green light suppressed radicle growth (60 mm) as compared to control (67 mm). The red light also promoted the plumule growth (50 mm) as compared to control (37 mm). The maximum biomass gain (67 mg) was observed under red light as compared to control (55 mg). Currently, the maximum total phenolics content (9.49 mg/g-DW) and phenolics production (379.616 mg/L) was observed under the influence of blue lights as compared to control (0.23 mg/g-DW and 8.91 mg/L). Similarly, the blue lights also enhanced the biosynthesis of total flavonoids content (2.2611 mg/g-DW) and flavonoids production (90.44 mg/L) as compared to control (0.0318 md/g-DW and 0.8268 mg/L). The current results represents that red and blue lights are the most effective sources for plantlets development and production of polyphenolics content in Brassica rapa.

Development of sparse-seeded mutant kinnow (Citrus reticulata Blanco) through budwood irradiation

Kinnow is the major fruit of Pakistan and has a high export potential due to its excellent fruit and juice quality. However, high number of seeds (25 ± 5) per fruit is limiting its export on a large scale. Benefiting from the induced mutations for selectivity, especially in the vegetatively propagated fruit crops like citrus, induced mutation for seedlessness in Kinnow with gamma irradiation of dormant bud which was attempted at the Nuclear Institute for Agriculture and Biology (NIAB), Faisalabad. Dormant bud irradiation-cum-grafting technique was employed, using the Citrus jambhiri rootstock for propagation of the scion. A sparse seeded (5 ± 3 seeds/fruit) mutant was evolved from an exposure dose of 20 Gy. The mutant was put to the conventional propagation up to mV 5 , for confirmation of the continuity of the mutation. The sparse seeded mutation was found to be a solid and stable one. The quality parameters in fruit and juice of the mutant were comparable with its parent. Key words : Kinnow, seedlessness, dormant bud, gamma irradiation, mutant kinnow.