Patrícia da Costa Zonetti

Allelopathy of leaf extracts of jatropha (Jatropha curcas L.) in the initial development of wheat (Triticum aestivum L.)

espanolEl objetivo de la investigacion fue evaluar el efecto de los extractos obtenidos a partir de hojas de Jatropha curcas L. sobre la germinacion y el crecimiento inicial del trigo. Las acuosas y alcohol (etanol y metanol) extractos de hojas secas se prepararon de la concentracion de 50 mg/ml. A partir del extracto crudo se hicieron diluciones, obteniendo diferentes concentraciones. Algunos de los extractos acuosos ensayados se trataron en autoclave. Durante siete dias, las caracteristicas de germinacion y crecimiento de plantulas de trigo fueron evaluados con los diferentes tratamientos. No hubo efecto de extractos acuosos en el porcentaje de germinacion de las semillas; sin embargo, los extractos metanolicos y etanolicos 5% afectaba la germinacion de un cultivar en estudio. Hubo una disminucion en el indice de velocidad de germinacion cuando las semillas se incubaron con extracto crudo acuoso y extracto de metanol. Los extractos afectaron el crecimiento de las plantulas y el mas fitotoxico era el extracto en etanol 5%. Los extractos autoclave promovieron una reduccion en todos los parametros evaluados. Los resultados aqui presentados muestran los extractos de hojas secas de Jatropha que promueven efectos alelopaticos sobre el trigo. EnglishThe objective of this study was to evaluate the effect of extracts obtained from leaves of Jatropha curcas L. on germination and initial growth of wheat. The aqueous and alcohol (ethanol and methanol) extracts of dried leaves were prepared in the concentration of 50 mg/mL. From the crude extract were made dilutions and obtained different concentrations. Some of the aqueous extracts tested were autoclaved. Over seven days, the germination characteristics and growth of wheat seedlings were evaluated with the different treatments. There was no effect of aqueous extracts on percentage of seed germination, however the methanolic and ethanolic extracts 5% affected the germination of a cultivar in study. There was a decrease in the germination speed index when the seeds were incubated with crude aqueous extract and methanol extract. The extracts affected the growth of seedlings and the most phytotoxic was the ethanol extract 5%. The autoclaved extracts promoted a reduction in all parameters evaluated. The results presented here show the extracts of dried leaves of jatropha promoted allelopathic effects on wheat.

Plant growth of Laelia tenebrosa Rolfe treated with gibberellic acid and grown on different substrates

espanolSe evaluo el efecto del acido giberelico (GA3) y de diferentes sustratos en el crecimiento de plantas de Laelia tenebrosa oriundas de la germinacion in vitro, trasplantadas para bandejas colectivas, aclimatadas y tras nueve meses utilizadas en dos experimentos: a) evaluacion del efecto de la pulverizacion con GA3 (0, 25, 50, 100 e 200 mgL-1) con cuatro plantas/florero y siete repeticiones; b) evaluacion del efecto de los sustratos: polvo de coco, cascara de Pinus sp., polvo de coco + cascara de Pinus sp., polvo de coco + cascara de Pinus sp. + carbon y polvo de coco + cascara de Pinus sp. + carbon + cascara de nueces, con cinco plantas/ florero y siete repeticiones. Tras 360 dias se evaluo: supervivencia, altura de la parte aerea, numero de hojas y brotes, largura y anchura de las hojas y largura de la raiz. Diferencias significativas fueron observadas para todas las variables excepto anchura de las hojas con pulverizacion con GA3 y mejores resultados con 25, 50 y 200 mgL-1. Diferencias significativas fueron observadas para numero de brotes, largura de las hojas y mayor raiz, con mejores resultados cuando las plantas fueron cultivadas con polvo de coco + cascara de Pinus sp. y polvo de coco + cascara de Pinus sp.+ carbon + cascara de nueces. EnglishThe effect of gibberellic acid (GA3) and different substrates on the growth of Laelia tenebrosa was evaluated. In vitro germinated plants were transplanted to trays, acclimatized, and after nine months used in two experiments: (a) effect of different substrates: coconut powder, Pinus sp. bark, coconut powder + Pinus sp. bark, coconut powder + Pinus sp. bark + charcoal and coconut powder + Pinus sp. bark + charcoal + crushed walnut shells, with five plants/pot and seven repetitions; (b) effect of pulverization with GA3 (0, 25, 50, 100 and 200 mg L-1) with four plants/pot and seven repetitions. After 360 days, the following variables were evaluated: survival rate, shoot height, number of leaves and buds, length and width of leaves and root length. Significant differences were found for number of buds, length of leaves and roots, with the best results for the plants grown in coconut powder + Pinus sp. bark and coconut powder + Pinus sp. bark + charcoal + walnut shells. Significant differences were found with pulverization with GA3 for all variables except for leaf width and the best results were obtained with 25, 50 and 200 mg L-1.