Rhizosphere assisted biodegradation of benzo(a)pyrene by cadmium resistant plant-probiotic Serratia marcescens S2I7, and its genomic traits.

Melia azedarach-rhizosphere mediated degradation of benzo(a)pyrene (BaP), in the presence of cadmium (Cd) was studied, using efficient rhizobacterial isolate. Serratia marcescens S2I7, isolated from the petroleum-contaminated site, was able to tolerate up to 3.25 mM Cd. In the presence of Cd, the isolate S2I7 exhibited an increase in the activity of stress-responsive enzyme, glutathione-S-transferase. Gas Chromatography-Mass spectroscopy analysis revealed up to 59% in -vitro degradation of BaP after 21 days, while in the presence of Cd, the degradation was decreased by 14%. The bacterial isolate showed excellent plant growth-promoting attributes and could enhance the growth of host plant in Cd contaminated soil. The 52,41,555 bp genome of isolate S. marcescens S2I7 was sequenced, assembled and annotated into 4694 genes. Among these, 89 genes were identified for the metabolism of aromatic compounds and 172 genes for metal resistance, including the efflux pump system. A 2 MB segment of the genome was identified to contain operons for protocatechuate degradation, catechol degradation, benzoate degradation, and an IclR type regulatory protein pcaR, reported to be involved in the regulation of protocatechuate degradation. A pot trial was performed to validate the ability of S2I7 for rhizodegradation of BaP when applied through Melia azedarach rhizosphere. The rhizodegradation of BaP was significantly higher when augmented with S2I7 (85%) than degradation in bulk soil (68%), but decreased in the presence of Cd (71%).

Growth dynamics of different half-sib families of Melia azedarach Linn.

The genetic diversity and growth dynamics of fifty-three half-sib families of eleven provenance sources and one bulk seed mixed population of fast growing forest tree species i.e. Melia azedarach were studied at two stand ages viz., fourth year (mid-rotation) and eighth year (end-rotation) to determine the selection stage in northern India. Significant variations were reported between and within seed provenances in all growth characters at both rotational ages. The broad sense heritability was higher at mid-rotational age. This revealed the growth is genetically controlled but with the time environmental effects escort the growth pattern. Growth pattern was different at each stand age. Growth is diameter dependent and the pattern was crown growth type. Families maintained their superiority over the time for tree height, basal diameter and diameter at breast height, which indicated a strong potential to identify good performing families for future plantation program. This study concluded that early stage selection is appropriate that later stage selection for all parameters studied except clear bole height that is much influenced by management practice and environment factors also. Neighbor-joining clustering with similarity index revealed that it is not necessary that the families, originated in one region were distributed in one cluster, indicating that families with same geographic origin could have undergone changes for different characters under selection.

Melia azedarach plants show tolerance properties to water shortage treatment: an ecophysiological study.

Candidate species for reforestation of areas prone to drought must combine water stress (WS) tolerance and economic or medicinal interest. Melia azedarach produces high quality timber and has insecticidal and medicinal properties. However, the impact of WS on M. azedarach has not yet been studied. Two-month old M. azedarach plants were exposed to WS during 20 days. After this period, plant's growth, water potential, photosynthetic performance and antioxidant capacity were evaluated. WS did not affect plants' growth, but induced stomatal closure, reduced net CO2 assimilation rate (A) and the intercellular CO2 availability in mesophyll (C(i)). WS also reduced the photosynthetic efficiency of PSII but not the pigment levels. WS up-regulated the antioxidant enzymes and stimulated the production of antioxidant metabolites, preventing lipid peroxidation. Therefore, despite some repression of photosynthetic parameters by WS, they did not compromise plant growth, and plants increased their antioxidant capacity. Our data demonstrate that M. azedarach juvenile plants have the potential to acclimate to water shortage conditions, opening new perspectives to the use of this species in reforestation/afforestation programs of drought prone areas.

Micropropagation of paradise tree (Melia azedarach) by in vitro culture of axillary buds.

Paradise tree (Melia azedarach L.) is a multipurpose ornamental and timber tree, and its extracts are used to make insecticides and fungicides. Conventional propagation is done by seeds; however, sexual reproduction results in wide genetic variability. Therefore, clonal propagation is desirable to reduce genetic variation. This chapter describes a protocol for in vitro propagation of paradise tree by axillary buds. There are major steps for this protocol. Firstly, shoot induction by in vitro culture of axillary buds, excised from potted plants obtained by rooting of cuttings of 10-15-year-old adult trees. The initiation medium was composed of Murashige and Skoog medium (MS) supplemented with 0.5 mg/L BAP (benzylaminopurine), 0.1 mg/L IBA (indolebutyric acid), and 0.1 mg/L GA(3) (gibberellic acid). Secondly, multiplication of the regenerated shoots on MS medium amended with 0.5 mg/L BAP and 0.1 mg/L GA(3). Thirdly, rooting of the regenerated shoots on MS medium containing 0.1 mg/L IBA. Fully well-developed plants were transferred to pots containing sand, peat moss, and perlite (1:1:1), and maintained initially in the greenhouse or plastic tunnels.

Effect of morphological heterogeneity of somatic embryos of Melia azedarach on conversion into plants.

Embryogenic cultures were initiated from immature Melia azedarach (Meliaceae) zigotic embryos. Explants were induced on Murashige and Skoog (1962) medium with 4.54 microM thidiazuron or 0.45 microM dichlorophenoxyacetic acid. After 6 weeks of culture on induction medium, somatic embryos were categorized in four morphological classes based on the presence of single or fused embryos and if they remained united or not to the original explant; that were evaluated histologically. The somatic embryos of every category were transferred, in groups or individually, on a 1/4 MS medium. Bipolar embryos, the more typically normal ones, had well defined shoot and root apical meristems and produced single plants; subcultured individually their conversion was 28%, and subcultured in groups the conversion declined to 6.8%. Fused embryos subcultured in groups had only a 2.1% conversion and produced plants with fused stems. None conversion rate in the others classes was associated to poorly developed shoot and root meristematic areas or with their absence. The converted plants were acclimatized and transferred, in a mist, to soil, with an independent of the class 95% survival rate.

Effect of morphological heterogeneity of somatic embryos of Melia azedarach on conversion into plants

Embryogenic cultures were initiated from immature Melia azedarach (Meliaceae) zigotic embryos. Explants were induced on Murashige and Skoog (1962) medium with 4.54 microM thidiazuron or 0.45 microM dichlorophenoxyacetic acid. After 6 weeks of culture on induction medium, somatic embryos were categorized in four morphological classes based on the presence of single or fused embryos and if they remained united or not to the original explant; that were evaluated histologically. The somatic embryos of every category were transferred, in groups or individually, on a 1/4 MS medium. Bipolar embryos, the more typically normal ones, had well defined shoot and root apical meristems and produced single plants; subcultured individually their conversion was 28%, and subcultured in groups the conversion declined to 6.8%. Fused embryos subcultured in groups had only a 2.1% conversion and produced plants with fused stems. None conversion rate in the others classes was associated to poorly developed shoot and root meristematic areas or with their absence. The converted plants were acclimatized and transferred, in a mist, to soil, with an independent of the class 95% survival rate.

[Evaluation of efficacy of ripe and unripe fruit oil extracts of Melia azedarach against Rhipicephalus (Boophilus) microplus (Acari: ixodidae)]. / Avaliação da eficácia de extratos oleosos de frutos verdes e maduros de cinamomo (Melia azedarach) sobre Rhipicephalus (Boophilus) microplus (Acari: Ixodidae).

Hexanic extracts gotten of the fruits of cinamomo (Melia azedarach) were tested on engorged females and larvae of Rhipicephalus (Boophilus) microplus. Four extracts were produced: one of unripe fruits and three of ripe fruits, being one with the fruits immediately processed, another one with fruits stored for five months and one tested after storage of the extract for 2 (two) years at 4 degrees C. The tests were made in triplicate, in 0.25% - 0.0156% dilutions. The effectiveness of extracts was evaluated through the comparison of the Reproduction Estimate of the groups "controlled and treated" for females, of mortality for the larvae, and of the calculation of the DL50 and the relative power for larvae and females. The extract of unripe fruits presented the effectiveness varying the 3.6% - 100% for females, and of ripe fruits it varied of 5.2% - 99.7%. The two extracts caused a mortality of 100% of the larvae in the highest concentrations. The extract of stored fruits presented effectiveness of 14% - 83% on females, while the extract stored in refrigerator presented effectiveness of 8.4% 100% and both did not present larvicidal effect. The results demonstrate a superiority of the unripe extract, with a minor DL50 and superior power 1.497 times to the extract of ripe fruits.

Avaliação da eficácia de extratos oleosos de frutos verdes e maduros de cinamomo (Melia azedarach) sobre Rhipicephalus (Boophilus) microplus (Acari: Ixodidae) / Evaluation of efficacy of ripe and unripe fruit oil extracts of Melia azedarach against Rhipicephalus (Boophilus) microplus (Acari: ixodidae)

Extratos hexânicos obtidos dos frutos de Melia azedarach foram testados sobre fêmeas ingurgitadas e larvas de Rhipicephalus (Boophilus) microplus. Foram produzidos quatro extratos: um de frutos verdes e três com frutos maduros, sendo um com os frutos imediatamente processados, outro com frutos armazenados por cinco meses e um testado após armazenamento do extrato por 2 (dois) anos a 4ºC. Os testes foram feitos em triplicata, em diluições de 0,25 por cento a 0,0156 por cento. A eficácia dos extratos foi avaliada através da comparação da Reprodução Estimada dos lotes "controle e tratado" para fêmeas, da mortalidade para as larvas, e do cálculo das DL50 e da potência relativa para larvas e fêmeas. O extrato de frutos verdes apresentou uma eficácia variando de 3,6 por cento a 100 por cento para fêmeas, e o de frutos maduros variou de 5,2 por cento a 99,7 por cento. Os dois extratos causaram uma mortalidade de 100 por cento das larvas nas maiores concentrações. O extrato de frutos armazenados apresentou eficácia de 14 por cento a 83 por cento sobre fêmeas, enquanto o extrato armazenado em geladeira apresentou eficácia de 8,4 por cento a 100 por cento e ambos não apresentaram efeito larvicida. Os resultados obtidos demonstram uma superioridade do extrato verde, com uma menor DL50 e potência 1,497 vezes superior ao extrato de frutos maduros.

Hexanic extracts gotten of the fruits of cinamomo (Melia azedarach) were tested on engourged females and larvae of Rhipicephalus (Boophilus) microplus. Four extracts were produced: one of unripe fruits and three of ripe fruits, being one with the fruits immediately processed, another one with fruits stored for five months and one tested after storage of the extract for 2 (two) years at 4ºC. The tests were made in triplicate, in 0.25 percent- 0.0156 percent dilutions. The effectiveness of extracts was evaluated through the comparison of the Reproduction Estimate of the groups "controlled and treated" for females, of mortality for the larvae, and of the calculation of the DL50 and the relative power for larvae and females. The extract of unripe fruits presented the effectiveness varying the 3.6 percent - 100 percent for females, and of ripe fruits it varied of 5.2 percent - 99.7 percent. The two extracts caused a mortality of 100 percent of the larvae in the highest concentrations. The extract of stored fruits presented effectiveness of 14 percent - 83 percent on females, while the extract stored in refrigerator presented effectiveness of 8.4 percent 100 percent and both did not present larvicidal effect. The results demonstrate a superiority of the unripe extract, with a minor DL50 and superior power 1.497 times to the extract of ripe fruits.

Cryopreservation of somatic embryos of paradise tree (Melia azedarach L.).

In paradise tree (Melia azedarach L.), immature zygotic embryos sampled from immature fruits are the starting material for the production of somatic embryos. These somatic embryos are employed for freezing experiments. Immature fruits could be stored at 25 degrees C for up to 80 days without impairing the embryogenic potential of zygotic embryos, which represents a four-fold increase in immature fruit storage duration, compared with previous studies. Among the three cryopreservation techniques tested for freezing paradise tree somatic embryos, namely desiccation, encapsulation-dehydration and pregrowth-dehydration, only encapsulation-dehydration and pregrowth-dehydration led to successful results. The optimal protocol was the following: i) somatic embryos (encapsulated or not) pretreated in liquid Murashige & Skoog medium with daily increasing sucrose concentration (0.5 M/0.75 M/1.0 M); ii) dehydrated with silica gel to 21 - 26% moisture content (fresh weight basis), for encapsulation-dehydration, or to 19% moisture content, for pregrowth-dehydration; iii) frozen at 1 degree C/min from 20 degrees C to -30 degrees C with a programmable freezing apparatus; iv) rapid immersion in liquid nitrogen. The highest recovery achieved was 36% with encapsulation-dehydration and 30% with pregrowth-dehydration. Regrowth of frozen embryos was direct in most cases, as secondary embryogenesis originating from the root pole was observed on only around 10% of cryopreserved somatic embryos. Plants recovered from cryopreserved embryos presented the same phenotypic traits as non-frozen control plants.

Influence of genotype and explant source on indirect organogenesis by in vitro culture of leaves of Melia azedarach L.

In vitro regeneration of shoots from leaf explants of the Paradise tree (Melia azedarach L.) was studied. Three different portions (proximal portion, distal portion and rachis of the leaflets) of three developmental stages (folded, young still expanding and completely expanded) of leaves of 10-15 year old plants of seven genotypes were cultured on Murashige and Skoog (1962) medium (MS) supplemented with 1 mg x l(-1) benzylaminopurine (BAP) + 0.1 mg x l(-1) kinetin (KIN) + 3 mg x l(-1) adenine sulphate (ADS). The rachis of the leaflets of the completely expanded leaves was found to be the most responsive tissue, in most of the genotypes employed. Shoot regeneration occurred in leaf explants of all the genotypes tested. The best genotype for shoot regeneration was clone 4. Rooting was induced on MS medium supplemented with 2.5 mg x l(-1) 3-indolebutyric acid, IBA, (4 days) followed by subculture on MS lacking growth regulators (26 days). Complete plants were transferred to soil.

Influence of genotype and explant source on indirect organogenesis by in vitro culture of leaves of Melia azedarach L

In vitro regeneration of shoots from leaf explants of the Paradise tree (Melia azedarach L.) was studied. Three different portions (proximal portion, distal portion and rachis of the leaflets) of three developmental stages (folded, young still expanding and completely expanded) of leaves of 10-15 year old plants of seven genotypes were cultured on Murashige and Skoog (1962) medium (MS) supplemented with 1 mg x l(-1) benzylaminopurine (BAP) + 0.1 mg x l(-1) kinetin (KIN) + 3 mg x l(-1) adenine sulphate (ADS). The rachis of the leaflets of the completely expanded leaves was found to be the most responsive tissue, in most of the genotypes employed. Shoot regeneration occurred in leaf explants of all the genotypes tested. The best genotype for shoot regeneration was clone 4. Rooting was induced on MS medium supplemented with 2.5 mg x l(-1) 3-indolebutyric acid, IBA, (4 days) followed by subculture on MS lacking growth regulators (26 days). Complete plants were transferred to soil.