Effective temperature for overcoming dormancy of 'Fuyu' persimmon tree buds

The objective of this study was to evaluate the effective temperature for overcoming the dormancy of 'Fuyu' persimmon tree buds. Stem samples were collected three times between 2013 and 2014. Stems were maintained in a climate incubator chamber at 3, 6, 9, and 12 °C. For each temperature, five numbers of additional chilling hours (CH) (0, 240, 384, 528, and 672 CH) were studied. The experimental design was completely randomized in a 5 × 4 factorial design (chilling hours × temperatures) with four replications with 10 cuttings. The maintenance of branches at cold temperatures from 3 to 12 °C intensified endodormancy of the buds when the plants were at the beginning of endodormancy. The most effective temperatures for overcome dormancy when the buds were in transition from paradormancy to endodormancy were from 3 to 6 °C. When the buds were already in endodormancy, temperatures of 3, 6, 9, and 12 °C were effective for the accumulation of cold and overcoming dormancy. The increase in the number of chilling hours from 3 to 12 °C induced budburst and the temperature of 12 °C was able to slowly induce and overcome bud dormancy.

Cryopreservation of banana's cv Grand Naine in vitro rhizomes

ABSTRACT The preservation of banana genetic material is usually performed through seedlings. However, most banana cultivars do not produce seed and are propagated vegetatively. Therefore, cryopreservation is a feasible technique that allows the preservation of banana genotypes indefinitely. For the success of cryopreservation protocols, the selection of cryoprotectants and pre-freezing techniques are important factor. Therefore, the objective of this study was to verify the effects of different cryoprotectants with and without 1% phloroglucinol and pre-cooling periods on the development of a protocol for cryopreservation of in vitro rhizomes ofMusa accuminata(AAA) cv Grand Naine banana. The addition of 1% phloroglucinol to the cryoprotective solutions, such as PVS2 enhanced recovery of cryopreserved banana rhizomes. In addition, pre-cooling of explants in ice for 3 hours in PVS2 + 1% of phloroglucinol allowed efficient cryopreservation of banana rhizomes, followed by successful recovery and regeneration of in vitro shoots of banana cv Grand Naine.

Shoot and root interference of morning glory on the initial growth of sugarcane

ABSTRACT Among weeds, morning glories comprise a very important group of climbing plants that infest sugarcane crops. The objective of this study was to evaluate the shoot and root interference of Merremia cissoides on the initial growth of sugarcane cultivar RB 966928. The experiment consisted of five treatment groups: (i) sugarcane monocropping, (ii) morning glory monocropping, (iii) sugarcane intertwined with morning glory but inseparate boxes, (iv) sugarcane intertwined with morning glory in attached boxes and (v) sugarcane with morning glory in attached boxes with morning glory prevented from intertwining with the sugarcane. The experimental design consisted of randomized blocks with four replicates. Merremia cissoides adversely affected the initial growth of the RB 966928 sugarcane starting at 90 days after transplanting (DAT). This effect increased with the time of intercropping, reaching at 180 DAT with a reduction of 57.3% in height,15.5% in stalk diameter, 90.4% in leaf areas, 86.6 and 75.2% in stalk and leaf dry mass, respectively. These reductions primarily due to the weed intertwining with the sugarcane plants because the weed had a physical choking and shading effect. This negative effect of morning glory on the sugarcane plants increased when they shared the substrate (i.e., when they competed for space and water), which also adversely affected weed growth, reducing 50.2% leaf areas and 42.1% shoot dry mass. The leaf area and the stalk and leaf dry mass of sugarcane are the characteristics more sensitive to the weed interference. Thus, both the shoot and root of M. cissoides interferes negatively in the growth of sugarcane, with the effect proportional to the period of coexistence, highlighting the detrimental effect on the stem (greater economic interest), and may also compromise the mechanical harvesting of the crop.

Somatic embryogenesis in Carica papaya as affected by auxins and explants, and morphoanatomical-related aspects

ABSTRACT The aim of this study was to evaluate somatic embryogenesis in juvenile explants of the THB papaya cultivar. Apical shoots and cotyledonary leaves were inoculated in an induction medium composed of different concentrations of 2,4-D (6, 9, 12, 15 and 18 µM) or 4-CPA (19, 22, 25, 28 and 31 µM). The embryogenic calluses were transferred to a maturation medium for 30 days. Histological analysis were done during the induction and scanning electron microscopy after maturing. For both types of auxin, embryogenesis was achieved at higher frequencies with cotyledonary leaves incubated in induction medium than with apical shoots; except for callogenesis. The early-stage embryos (e.g., globular or heart-shape) predominated. Among the auxins, best results were observed in cotyledonary leaves induced with 4-CPA (25 µM). Histological analyses of the cotyledonary leaf-derived calluses confirmed that the somatic embryos (SEs) formed from parenchyma cells, predominantly differentiated via indirect and multicellular origin and infrequently via synchronized embryogenesis. The secondary embryogenesis was observed during induction and maturation phases in papaya THB cultivar. The combination of ABA (0.5 µM) and AC (15 g L-1) in maturation medium resulted in the highest somatic embryogenesis induction frequency (70 SEs callus-1) and the lowest percentage of early germination (4%).

Bacteria in combination with fertilizers promote root and shoot growth of maize in saline-sodic soil

Salinity is the leading abiotic stress hampering maize (Zea mays L.) growth throughout the world, especially in Pakistan. During salinity stress, the endogenous ethylene level in plants increases, which retards proper root growth and consequent shoot growth of the plants. However, certain bacteria contain the enzyme 1-aminocyclopropane-1-carboxylate (ACC) deaminase, which converts 1-aminocyclopropane-1-carboxylic acid (an immediate precursor of ethylene biosynthesis in higher plants) into ammonia and α-ketobutyrate instead of ethylene. In the present study, two Pseudomonas bacterial strains containing ACC-deaminase were tested separately and in combinations with mineral fertilizers to determine their potential to minimize/undo the effects of salinity on maize plants grown under saline-sodic field conditions. The data recorded at 30, 50 and 70 days after sowing revealed that both the Pseudomonas bacterial strains improved root and shoot length, root and shoot fresh weight, and root and shoot dry weight up to 34, 43, 35, 71, 55 and 68%, respectively, when applied without chemical fertilizers: these parameter were enhanced up to 108, 95, 100, 131, 100 and 198%, respectively, when the strains were applied along with chemical fertilizers. It can be concluded that ACC-deaminase Pseudomonas bacterial strains applied alone and in conjunction with mineral fertilizers improved the root and shoot growth of maize seedlings grown in saline-sodic soil.

In vitro regeneration in olive (Olea europaea L.) cv, ‘Frontio’ from nodal segments.

An efficient and reproducible protocol for plantlet regeneration from nodal segments of Olive cv ‘Frontio’ has been developed. Media and explants browning due to exudation of phenolics from the explants were controlled by fortification of the medium with 100 mg/L ascorbic acid. Best establishment of olive explants was observed on half-strength MS salts fortified with 2.0 mg/L 6-benzylaminopurine (BAP), which resulted in 56.2% of bud break and 93.7% survival whereas, a combination of full strength MS medium with 1.0 mg/L each of 3-indole-butyric-acid (IBA) and kinetin was found to be the best for shoot multiplication, in terms of number of shoots (3.6 shoots/explant) and shoot length (2.2 cm). The in vitro shoots were rooted on half-strength MS medium fortified with 0.2 mg/L IBA and 0.2 mg/L α-naphthalene acetic acid (NAA) with 1.5 g/L activated charcoal, which supported optimum rooting (60 %), with an average of 2-3 roots/shoot, about 2.4 cm length were produced on four weeks of culture.

Factors influencing rapid clonal propagation of Chlorophytum arundinaceum (Liliales: Liliaceae), an endangered medicinal plant

Chlorophytum arundinaceum is an important medicinal plant and its tuberous roots are used for various health ailment treatments. It has become an endangered species in the Eastern Ghats, and a rare medicinal herb in India, due to its excessive collection from its natural habitat and its destructive harvesting techniques, coupled with poor seed germination and low vegetative multiplication ratio. In order to contribute to its production systems, an efficient protocol was developed for in vitro clonal propagation through shoot bud culture. For this, multiple shoots were induced from shoot bud explants on Murashige and Skoog’s medium supplemented with 2.5-3.0mg/L BAP, 0.01-0.1mg/L NAA and 3% (w/v) sucrose. Inclusion of Adenine Sulphate (25mg/L) in the culture medium improved the frequency of multiple shoot production and recovered the chlorotic symptoms of the leaves. Media having pH 5.9 and 4% sucrose showed significant improvement on shoot bud multiplication and growth. In vitro flowering was observed when the subcultures were carried out for over four months in the same multiplication media. Rooting was readily achieved upon transferring the shoots on to half- strength MS medium supplemented with 0.1mg/L IBA and 2% (w/v) sucrose. Micropropagated plantlets were hardened in the green house, successfully established, and flowered in the field. This method could effectively be applied for the conservation and clonal propagation to meet the demand of planting materials. Rev. Biol. Trop. 59 (1): 435-445. Epub 2011 March 01.

Chlorophytum arundinaceum es una planta medicinal importante y sus raíces se utilizan en diversos tratamientos contra enfermedades. Se ha convertido en una especie en peligro de extinción en el Ghats Oriental y una hierba medicinal rara en la India, debido a la recolecta excesiva en su hábitat natural y la manera destructiva de cosecharla, asociado con una mala germinación y pobre multiplicación vegetativa. Para contribuir con sus sistemas de producción, se desarrolló un protocolo eficiente para la propagación clonal in vitro a través del cultivo de brotes. Para ello, los retoños múltiples fueron inducidos a partir de sus brotes en un medio Murashige y Skoog enriquecido con 2.5-3.0mg/L de BAP, 0.01-0.1mg/L de NAA y el 3% (w/v) sucrosa. La inclusión de sulfato de adenina (25mg/L) en el medio de cultivo mejoró la frecuencia de producción de brotes múltiples y se recuperaron los síntomas de clorosis de las hojas. Los medios con un pH de 5.9 y 4% de sucrosa mostraron una mejoría significativa en la multiplicación y crecimiento de las yemas. En la floración in vitro se observó cuando los subcultivos se llevaron a cabo durante más de cuatro meses para los mismos medios de multiplicación. El enraizamiento se logró fácilmente al transferir los brotes a un medio MS de intensidad media enriquecido con 0.1 mg/l de IBA y 2% (w/v) de sucrosa. Las plántulas micropropagadas maduraron en el invernadero, se establecieron exitosamente y florearon en el campo. Este método se podría aplicar para la conservación y propagación clonal con el fin de satisfacer la demanda de material de siembra.

Análise de crescimento de Bixa orellana L. sob efeito da inoculação micorrízica e adubação fosfatada / Analyses of Bixa orellana L. growth under the effects of mycorrhizal inoculation and phosphate fertilization

Este estudo objetivou avaliar o desenvolvimento de Bixa orellana L. em condições de viveiro sob efeito da inoculação micorrízica e adubação fosfatada. As plantas foram cultivadas em sacos de polietileno com 0,18 X 0,30 m e capacidade de 1,3 kg de substrato. O delineamento experimental utilizado foi inteiramente casualizado com seis tratamentos e trinta repetições. As dosagens de fósforo utilizadas foram 0, 4.200 e 8.400 g m-3 de substrato. O fungo micorrízico arbuscular (FMA) da espécie Glomus clarum, foi utilizado em metade dos tratamentos (com e sem micorrizas) com inoculação de 2 g do fungo. As avaliações ocorreram 30, 60, 90 e 120 dias após a emergência das plântulas. Determinou-se a massa seca de folhas, área foliar, massa seca total, razão de área foliar, área foliar específica, taxa assimilatória líquida, taxa de crescimento relativo e taxa de crescimento absoluto. O fungo micorrízico facilita a absorção de fósforo pelo urucum, atendendo a sua exigência em relação ao nutriente. A dose de fósforo de 4.200 g m-3 em associação com FMA Glomus clarum ou 8.400 g m-3, com ou sem essa associação, são indicadas para o crescimento de plantas de urucum em viveiro, por promoverem adequadas respostas dos índices fisiológicos, contribuindo com seu desenvolvimento.

This study aimed to evaluate the development of Bixa orellana L. under nursery conditions and subjected to the effects of mycorrhizal inoculation and phosphate fertilization. The plants were grown in polyethylene bags with dimensions of 0.18 x 0.30 m and capacity of 1.3 kg substrate. The adopted experimental design was completely randomized with six treatments and thirty replicates. The used phosphorus levels were 0, 4.200 and 8.400 g m-3 substrate. The arbuscular mycorrhizal fungus (AMF) of the species Glomus clarum was used in half of the treatments (with and without mycorrhizae) with inoculation of 2 g of the fungus. Evaluations occurred at 30, 60, 90 and 120 days after the emergence of seedlings. Leaf dry mass, leaf area, total dry mass, leaf area ratio, specific leaf area, net assimilation rate, relative growth rate and absolute growth rate were determined. The mycorrhizal fungus facilitates phosphorus uptake by annatto, fulfilling its requirement for the nutrient. The phosphorus level of 4.200 g m-3 in association with Glomus clarum or 8.400 g m-3, with or without this association, are indicated for annatto plant growth in nurseries since they promote appropriate responses of physiological indexes, contributing to the plant development.

Cytokinin preconditioning enhances multiple shoot regeneration in Pongamia pinnata (L) Pierre - a potential, non-edible tree seed oil source for biodiesel

An efficient, highly reproducible protocol for multiple shoot induction and plant regeneration of Pongamia pinnata has been successfully developed using cotyledonary node explants. This study also demonstrates that preconditioning of explant stimulates production of multiple shoots from cotyledonary nodes of P. pinnata. The highest direct shoot regeneration (90 percent) with an average of 18.4 +/- 3.1 shoots/explant were obtained when cotyledonary node explants were excised from seedlings germinated on Murashige and Skoog (MS) media supplemented with benzyladenine (BA) 1 mg l-1, and subsequently cultured on MS media with 1 mgl-1 thidiazuron (TDZ). Scanning electron microscope observations of cotyledonary node (CN) explants excised from pre-conditioned and normal seedlings, revealed larger buds with rapid development in BA-preconditioned CN explants. The addition of adenine sulphate significantly increased the average number of shoots per explant. The highest direct shoot regeneration (93 percent) with an average of 32.2 +/- 0.93 shoots/explant was obtained from BA-preconditioned CN when cultured on MS media supplemented with 1 mg l-1 TDZ and 200 mg l-1 adenine sulphate (ADS). Repeated shoot proliferation was observed from BA preconditioned CN explants up to 3 cycles with an average of 15 shoots/explant/cycle when cultured on MS media supplemented with 1 mg l-1 TDZ and 150 mg l-1 L-glutamine, thus producing 45 shoots/CN explant. Shoots were elongated on hormone free MS media and rooted on 1/2 MS media supplemented with 1 mg l-1 of IBA. Rooted shoots were successfully acclimatized and established in soil with 80 percent success. The highly regenerative system developed in this investigation for this important tree could be a useful tool for genetic transformation.

De novo shoot regeneration from root cultures of Garcinia indica Choiss.

Roots of plantlets of Garcinia indica when cultured for long time on half strength MS medium supplemented with BAP (0.44-2.22 microM) showed production of de novo shoots. Roots attached to mother plant showed more number of shoots, while excised root segments produced lesser shoots. Shoots (0.5-0.8 cm) were transferred to elongation medium consisting of Woody Plant Medium (WPM) supplemented with BAP (4.44-22.69 microM), IAA (5.71 microM) and kinetin (4.65 microM). It was observed that shoot length increased to 1-2 cm. WPM medium supplemented with NAA (2.69-10.74 microM) and IBA (4.90 microM) induced rooting within 20-25 days. Using the present protocol, 20-25 plantlets could be regenerated from single root explant within 3 to 4 months. The protocol has potential for large scale production of elite plants.

In vitro multiple shoot regeneration and plant production in Alysicarpus rugosus DC. var. heyneanus Baker.

A protocol for in vitro multiple shoot regeneration and plant production through seedling (shoot tip) culture was established for Alysicarpus rugosus DC. var. heyneanus Baker. Maximum number of adventitious shoots (14.4) per shoot tip explant were initiated after two subcultures on MS solid medium supplemented with IAA (2.85 microM) plus BAP (2.22 microM) after 4 weeks. Shoot elongation (3.0-3.5 cm) was achieved on MS medium without any hormones. Stunted shoots elongated on half MS medium without growth hormones. Rooting occurred in MS medium containing IAA (1.14 - 2.85 microM) alone or in combination with IBA (0.89 - 2.46 microM) and or NAA (1.07 - 2.69 microM). Maximum rooting was established in MS medium supplemented with IAA (2.85 microM). The plants were acclimatized successfully with 55% survival in pot containing cocoa peat and sand (1:1). After a month, hardened plants were transferred to pots with manure, garden soil and sand (1:2:1) for further growth and finally planted in field.

In vitro studies of Bacopa monnieri--an important medicinal plant with reference to its biochemical variations.

Micropropagation of Bacopa monnieri was achieved on MS and B5 medium supplemented with BAP and NAA using leaf explants and nodal segments. Best results were found on MS medium in both the explants with BAP (2.0 mg/l) showing higher percentage of regeneration. Besides that the biochemical parameters, like chlorophyll, carbohydrate, protein, of leaves both in vivo and in vitro have also been carried out in order to establish the sustainability of plants.

Regeneration of plantlets from in vitro raised leaf explants of Cleisostoma racimeferum Lindl.

Protocorm like bodies (PLBs), callus and shoot buds developed in culture from in vitro raised foliar explants of Cleisostoma racimeferum. Among the different basal media, better result was obtained on MS medium containing sucrose (3%) and BA (2 microM) with approximately 80% frequency after 40 days of culture. Young leaves (15 week old) produced better PLBs. Whole leaf placed vertically upside-up orientation can regenerate PLBs and shoot buds (80%). PLBs and shoot buds formed on entire surface of the leaves. Cultures on BA and NAA (2 and 2 microM respectively in combination) stimulated callus mediated regeneration (68%). The rooted plantlets regenerated within 8-10 week from PLBs and shoot buds on MS medium containing IAA and kinetin (2 microM each in combination). BA containing medium triggered multiple shoot bud formation, while NAA alone or in combination with other growth regulators was inhibitory. Incorporation of activated charcoal (0.01%) in the medium stimulated formation of repetitive PLBs and multiple shoot buds. Rooted plants were ready for harvest after 20-22 week of initiation of culture. About 65% of the potted plants survived after 3 months in the poly house.

In vitro mass multiplication of Ophiorrhiza mungo Linn.

A protocol for in vitro mass multiplication of plants through seedling (shoot) cultures was established for Ophiorrhiza mungo. Maximum number of adventitious shoots per shoot culture (10.4 +/- 1.72) was initiated on MS solid medium supplemented with BAP (2.22 microM) after 3 weeks. Shoots were further multiplied (12.8 +/- 2.8) through subculture of intact shoots and reculture of nodal segments of aseptic shoots (6.5 +/- 0.94) in MS solid medium containing BAP (0.89 microM). Shoot elongation (1.27 +/- 0.12 cm) was achieved in the medium containing GA3 (1.44 microM) in two weeks. Rooting was favoured in basal agar medium supplemented with IBA (12.3 microM) plus NAA (1.07 microM). The plants were successfully established (100%) in the pots containing sand and top soil (1:1) mixture in a period of two weeks.

Micropropagation of Glandularia perakii Cov. et Schn. (Verbenaceae), a native species with ornamental potential

Glandularia perakii is a perennial species with beautiful violet flowers that grows in the stony soil of Mendocine pedemont. A plentiful and prolonged flowering confers it an important ornamental potential. In this paper, a method of propagation of G. perakii from nodal segments is reported. Proliferating microshoot cultures were obtained by placing nodal segment on Murashige and Skoog medium (MS) supplemented with 20 g.L-1 of sucrose without growth regulators. In this medium multiplication rate after 20 days was 7.9. Rooted plants were acclimatized successfully.