Browsing by Author "Franco, J."
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- Allelopathic effects of extracts from several plant species on seed germination and seedlings growth of Lactuca sativa LPublication . Gonçalves, Sandra; Franco, J.; Romano, AnabelaThe ability of a plant species to inhibit germination of other plants is an untapped resource for weed control in crops that could revolutionize organic crop production. The main objective of this study was to evaluate the allelopathic potential of aqueous (5 and 10%, w/v) and methanolic (50mg ml-1) extracts from several plant species (Arbustus unedo L., Ericaceae; Daphne gnidium L., Thymeleaceae; Myrtus communis L., Myrtaceae; Olea europea L., Oleaceae; Pistacia lentiscus L., Anacardiacceae; Quercus suber L., Fagaceae; Ruscus aculeatus L., Liliaceae, Rhododendron ponticum subsp baeticum (Boissier & Reuter) Handel-Mazzetti, Ericaceae) on seed germination and seedling growth of Lactuca sativa. To test the phytotoxicity 500µl of the extract were added separately over filter papers (9cm diameter) in Petri dishes. It was observed that methanolic extracts from M. communis and R. aculeatus completely inhibited seed germination, and almost all the extracts tested reduced seed germination and/or seedling growth. The inhibition of root growth was generally higher than of shoot growth, with the highest percentages of root inhibition being observed with the aqueous extracts of D. gnidium (80 and 72% for the extract at 5 and 10%, respectively) and R. aculeatus (74 and 78%), and with the methanolic extract of Q. suber (74%). Besides inhibiting seedling growth other morphological abnormalities occurred in the presence of the extracts. Roots of treated plants were thicker with a brownish color as compared to controls. Studies are being conducted to investigate the phytotoxic effect of the extracts on physiological and biochemical processes during germination and seedlings growth.
- Connectivity, neutral theories and the assessment of species vulnerability to global change in temperate estuariesPublication . Chust, G.; Albaina, A.; Aranburu, A.; Borja, A.; Diekmann, O. E.; Estonba, A.; Franco, J.; Garmendia, J. M.; Iriondo, M.; Muxika, I.; Rendo, F.; Rodriguez, Juan; Ruiz-Larrañaga, O.; Serrão, Ester; Valle, M.One of the main adaptation strategies to global change scenarios, aiming to preserve ecosystem functioning and biodiversity, is to maximize ecosystem resilience. The resilience of a species metapopulation can be improved by facilitating connectivity between local populations, which will prevent demographic stochasticity and inbreeding. This investigation estimated the degree of connectivity among estuarine species along the north-eastern Iberian coast, in order to assess community vulnerability to global change scenarios. To address this objective, two connectivity proxy types have been used based upon genetic and ecological drift processes: 1) DNA markers for the bivalve cockle (Cerastoderma edule) and seagrass Zostera noltei, and 2) the decrease in the number of species shared between two sites with geographic distance. Neutral biodiversity theory predicts that dispersal limitation modulates this decrease, and this has been explored in estuarine plants and macroinvertebrates. Results indicate dispersal limitation for both saltmarsh plants and seagrass beds community and Z. noltei populations; this suggests they are especially vulnerable to expected climate changes on their habitats. In contrast, unstructured spatial pattern found in macroinvertebrate communities and in C. edule genetic populations in the area suggests that estuarine soft-bottom macroinvertebrates with planktonic larval dispersal strategies may have a high resilience capacity to moderate changes within their habitats. Our findings allow environmental managers to prioritize the most vulnerable species and habitats to be restored.
- Taste panel quality evaluation of 'Hayward' kiwifruit of different originsPublication . Franco, J.; Melo, F.; Guilherme, R.; Neves, N.; Curado, F.; Antunes, Maria DulceIn Portugal, the regions of Entre-Douro e Minho and Beira Litoral have exceptional conditions for the production of good quality kiwifruit. However, demand exceeds local supply resulting in importation of kiwifruit from Italy, Chile and New Zealand. Taste panels were run in December, May and June to study the preferences of Portuguese consumers for 'Hayward' kiwifruit. In December, a comparison was made between kiwifruit from Portugal and Italy, in May between kiwifruit from Portugal and Chile and in June between kiwifruit from Portugal, Chile and New Zealand. Attributes assessed by panellists were: appearance, texture, flavour, sweetness and acidity. The same samples were analyzed for: weight, equatorial and longitudinal diameter, firmness, soluble solids (as measured by refractometer) and titratable acidity. In May, panellists preferred Portuguese kiwifruit, but in December and June the preference was not so clear. In December, Portuguese kiwifruit were not at the eating ripe stage and in June they were at the end of their storage life (bad appearance but better flavour, sweetness and texture).
- The effect of calcium applications on kiwifruit quality preservation during storagePublication . Antunes, Maria Dulce; Neves, N.; Curado, F.; Rodrigues, S.; Franco, J.; Panagopoulos, ThomasIt is well known that calcium increases storage life of many fruits. This study investigated the effect of vine calcium application, as well as postharvest application on storage behaviour of 'Hayward' kiwifruit. Three applications of 0.03% CaCl2 or CaO were made in June, July and September. After harvest half of the fruit from sprayed vines were dipped in a solution of 2% CaCl2; the other fruit were untreated. All fruit were then stored at 0 degrees C and relative humidity of about 90-95%. Results for fruit of the size range 85-105 g are discussed. Kiwifruit dipped in 2% CaCl2 postharvest maintained higher firmness through storage than undipped fruit, but soluble solids content was only slightly lower after storage. This suggests that postharvest dipping of kiwifruit in 2% CaCl2 benefits storage life. The concentrations of 0.03% CaCl2 (Antistip) or 0.03% CaO (Chelal) used in vine applications seem to be too low and higher concentrations should be tried.