RESUMEN
Moisture stress induced in premature seeds due to the breakdown of funiculus in Alphonso mango led to the burst ofethylene evolution, which in turn caused a sudden increase of polyphenol oxidase activity in the pulp, resulting in thedevelopment of a black spot near the seed base. Reduced levels of very long chain fatty acids in 70% mature seeds withblack spots were associated with a sudden increase of cytokinins followed by a rapid rise of starch-metabolizing enzymesculminating in the onset of pre-germination events. Concurrently, an overproduction of p-OH benzoic acid inhibitedamylase and polygalacturonase enzymes and led to partial degradation of the stored starch and pectin in the pulp. A paralleldrop in climacteric ethylene production by the pulp led to incomplete ripening coupled with changes in composition, textureand aroma of the pulp, characteristic of spongy tissue. The results have provided strong experimental evidence to supportthe fact that increased competition for resources among developing fruits for the synthesis of seed fat plays a critical role inspongy tissue formation in Alphonso mango. The major highlight of the study is that rapid ethylene evolution by prematureseed is an early warning sign for the initiation of spongy tissue formation in Alphonso mango.
RESUMEN
The influence of different factors on shoot proliferation and the occurrence of hyperhydricity in teak (Tectona grandis L.) have been studied. Four concentrations of BA (2.22, 4.44, 6.66 and 8.88 µM) and a control treatment with 0 BA were examined. Aiming at reducing the costs during commercial propagation by using gelrite in stead of agar, the use of both gelling agent in the proliferation and hyperhydricity was tested. In order to evaluate if hyperhydricity can be reduced by increasing the gelrite concentration in the culture medium, three concentrations (2.0, 2.5 and 3.0 g L-1) were tested in combination with 4.44 µM BA. The proliferation and occurrence of hyperhydricity during 21 successive subcultures were evaluated. The highest proliferation was achieved in the treatments with 6.66 or 8.88 µM BA. They yielded 5.22 and 5.56 shoots/explant, respectively. But also, the highest percent of hyperhydric shoots was achieved in this treatment. Gelrite resulted in a higher proliferation, but also an almost two times higher hyperhydricity as compared to agar-solidified media. Satisfactory reduction in hyperhydricity (18%) was achieved with 3.0 g L-1 gelrite. However, the successive subcultures onto proliferation in this treatment favored hyperhydricity compromising shoot quality and it´s competence to proliferate. in vitro teak plants were ex vitro rooted and then transferred to greenhouse conditions for acclimatization; ten weeks after transfer they were ready for field plantation.
Se estudió la influencia de diferentes factores en la proliferación y la ocurrencia de la hiperhidricidad in teca (Tectona grandis L.). Se probaron cuatro concentraciones de BA (2,22; 4,44; 6,66 and 8,88 µM) y un control sin BA. Con el objetivo de reducir los costos durante la propagación comercial se experimentó sustituir el agar por el gelrite, para lo cual se estudió en efecto de ambos gelificantes en la proliferación y la hiperhidricidad de los brotes. Se estudiaron, tres concentraciones de gelrite (2,0; 2,5 and 3,0 g L-1) combinadas con 4,44 µM BA, con el objetivo de evaluar si la hiperhidricidad podía ser reducida incrementando la concentración de gelrite. Se evaluó la proliferación de brotes y la ocurrencia de la hiperhidricidad durante 21 subcultivos. Se logró una alta proliferación de brotes en los tratamientos con 6,66 y 8,88 µM BA (5,22 y 5,56 brotes), pero el porcentaje de brotes hiperhídricos también se incrementó. El gelrite resultó en una alta proliferación de brotes, pero con mayor incidencia de la hiperhidricidad que el medio gelificado con agar. Se obtuvo una reducción satisfactoria de la hiperhidricidad (18%), cuando la concentración de gelrite se incrementó hasta 3,0 g L-1. No obstante, la multiplicación de los brotes en este tratamiento más allá del 11no subcultivo favoreció la hiperhidricidad, lo que afectó la calidad de los brotes y su competencia para la proliferación. Las plantas fueron enraizadas ex vitro, transferidas a condiciones de invernadero para su aclimatización y diez semanas después de la transferencia estaban listas para la plantación en campo.
Asunto(s)
Agricultura Forestal , Células TecalesRESUMEN
O presente trabalho foi desenvolvido com o objetivo de avaliar a tolerância de maçãs 'Gala' a temperaturas baixas, em diferentes períodos, durante o armazenamento. Os tratamentos avaliados foram as temperaturas de 0 (padrão); -0,8 e -1,6°C, durante quatro meses de armazenamento refrigerado (AR) e durante oito meses em atmosfera controlada (AC) a 1,0kPa de O2 + 2,0kPa de CO2; e de combinação dessas temperaturas por diferentes períodos de tempo no início ou no final do armazenamento. Observando os resultados, as temperaturas de 0 e 0,8°C proporcionaram melhor qualidade aos frutos em relação a -1,6°C, em AR. Em AC, a qualidade dos frutos foi superior em 0°C, em comparação com as temperaturas de 0,8 e -1,6°C. As temperaturas de -1,6°C, para o AR, e de -0,8 e -1,6°C, para AC, quando aplicadas no início do armazenamento, foram mais prejudiciais à qualidade dos frutos do que seu uso no período final de armazenamento, provocando, principalmente, degenerescência interna, dano externo e podridões.
This research was carried out to evaluate the tolerance of 'Gala' apples to low temperatures in different periods during storage. The treatments were the temperature of 0°C (standard); -0.8°C and -1.6°C, during 4 months in cold storage and during 8 months in CA storage at 1,0kPa of O2 + 2,0kPa of CO2, and combinations of these temperatures with different times in the beginning or in the end of the storage period. Observing the results, the temperatures of 0°C e -0.8°C showed better quality than in -1.6oC after 4 months of cold storage. AC fruit quality was higher in 0°C when compared with -0.8°C and -1.6°C. The temperatures of -1.6°C for cold storage and of -0.8°C and -1.6°C for controlled atmosphere storage, when used in the beginning of storage period were more damaging to quality than in the end of storage, causing mainly internal breakdown, injury of peel and decay.