http://hdl.handle.net/10451/4314 Fri, 24 May 2013 17:47:53 GMT 2013-05-24T17:47:53Z http://hdl.handle.net/10451/4348 Title: Evaluation of parameters affecting the rooting of hardwood cuttings in Ceratonia siliqua L Authors: Cabrita, R.; Graça, J.; Schwab, L.; Martins-Loução, M. A. Abstract: Vegetative propagation by rooted cuttings will be a useful tool in reflorestation only when rooting problems are overcome. Intensive studies on promoter factors of rool induction will be necessary. This paper represents a systematic study of different parameters affecting the rooting of carob shoot cuttings. Seasonal effects, hormonal treatment efficiency and cultivars were examined. Hardwood cuttings of carob were excised both on March and April. An acclimatization period under freeze conditions followed by an hormone treatment of 4000 and 8000 mg/1 indole butiric acid was tested. After this treatment cuttings were inserted in a rooting bench with expanded clay as substrate and maintaining inside the greenhouse for a two month period. Splitting the lower segment of the cutting, prior to placing them on the clay have no significant results on rooting. On cuttings harvested on March, the response seems to be conditioned principally by the hormonal concentration, in spite of those from April where cultivar seems to have the most influence on rooting ability. Rooted plantlets present a high mortality after transplnatation to a soil mixture under greenhouse conditions. Description: Comunicação apresentada no II Simposium Internacional sobre La Garrafa, de 29 de Setembro a 1 de Outubro de 1987 em Valência. Thu, 01 Jan 1987 00:00:00 GMT http://hdl.handle.net/10451/4348 1987-01-01T00:00:00Z http://hdl.handle.net/10451/4347 Title: Aspectos fisiológicos do descortiçamento em Querqus suber Authors: Correia, O. A.; Oliveira, G; Martins-Loução, M. A.; Catarino, F. M Abstract: Quercus suber is the primary source of industrial cork, and can produce cork every 9-10 years. The main objective of the present work was to investigate the influence of the bark stripping of the cork-oak on the stomacal activity and water relations. For this purpose, diurnal variations on transpiration, stomacal conductance and water potencial were studied before and after bark stripping during July and August 1989. The stripping on the trees had been done at various levels. The water loss by the stripping surface was also measured. These preliminary results show that the stress caused by stripping on these trees is different according to the stripping area. The transpiration is immediatly reduced after stripping, under the conditions of these investigations and high stripping coeficients. Sendo o sobreiro uma espécie que proporciona sucessivas tiradas de cortiça, um dos aspectos que importa salientar é o dos exagerados descortiçamentos, que poderão ser um factor de decréscimo de produtividade. Neste trabalho foi estudada a reacção de plantas submetidas a diferentes coeficientes de descortiçamento no que respeita aos parâmetros fisiológicos relacionados com o balanço hídrico e economia de água. Foram efectuados estudos ecofisiológicos em árvores descortiçadas nos meses de Julho 89/Agosto 89, tendo sido estudada a variação diurna da transpiração, condutância estomática e condutividade hidráulica. Foi igualmente determinada a perda de água, por evaporação, através do tronco até à formação de nova periderme. São apresentados resultados preliminares que põem em evidência o stress que o descortiçamento provoca nestas plantas e que é tanto mais grave quanto maior for o coeficiente de descortiçamento aplicado. Description: Comunicação apresentada no I Congresso Ibérico de Ciências Hortícolas, 18 a 21 de Junho de 1990 em Lisboa. Mon, 01 Jan 1990 00:00:00 GMT http://hdl.handle.net/10451/4347 1990-01-01T00:00:00Z http://hdl.handle.net/10451/4346 Title: Some physiological effects of neutron-gamma rays on carob seed germination Authors: Sousa, A.; Martins-Loução, M. A. Abstract: This paper sumarizes a work with neutron-gamma radiation on carob seed germination. Morfhological aspects of growth and physiological responses during seedling development have been studied in order to understand the factors influencing plant radiosensitivity. Dormant seeds have been irradiated with different dose rates - 5, 500, 11, 000, 22,000 and 88,000 rad – of neutron-gamma radiation. It was observed that seed imbibition was not affected by such radiation. During germination alteration of the normal rate of some vital physiological processes was observed, in spite of the Great genetic variability presented by the plant material. Nevertheless the degree of physiological disturbance observed did not enable the further viability of seedlings on the three lower dose rates. It was observed a stimulatory effect on seedling growth, cotyledon area and photosynthesis, under 22,000 rad of dose rate. The seedlings under 88,000 rad, after a previous period of low growth and poor development, have had no further growth. There are a considerable number of potencial applications of ionizing radiation in food preservation. These include, for instance, desinfestation of storage plant products such as fruits and seeds. In all cases where food for human consumption is irradiated there is a possibility that adverse changes may occur. On caron dormant seeds it was observed that the extent of such changes depends on dose rate. In some cases the changes were neglibile or could be controlled. The application of this technique to carob storage in a pratical and useful fashion seems feasible in the near future. Description: Comunicação apresentada no II Simposium Internacional sobre la Garrofa, nos dias 29 de Setembro a 31 de Outubro de 1987 em Valência. Thu, 01 Jan 1987 00:00:00 GMT http://hdl.handle.net/10451/4346 1987-01-01T00:00:00Z http://hdl.handle.net/10451/4345 Title: Efeito da concentração de cálcio no crescimento de plântulas de alfarrobeira Authors: Cruz, Cristina; Martins-Loução, Maria Amélia; Lips, S. Herman Abstract: The effect of increasing Ca+2 concentration in nutrient solutions containing different NO3-/NH4+ ratios on carob plants was assessed on growth rate chlorophyll content and gas exchange. A significant increase on growth was observed when increasing Ca+2 concentration from 3 to 6 mM in media containing nitrate. Raising the Ca+2 concentration from 6 to 12 mM produced a sharp decrease in growth of carob seedlings independently of the nitrogen type in their nutrient solution. Chlorophyll content and photosynthesis rate increased in plants growing in all combinations of NO3- and NH4+, when Ca+2 concentration was increased up to 6 mM. At higher Ca+2 concentrations, photosynthesis is affected according to the type of nitrogen in the medium. O estudo do efeito de concentrações crescentes de Ca+2 no desenvolvimento de plântulas de alfarrobeira (Ceratonia siliqua L.) foi realizado com base na avaliação da produção de biomassa, conteúdo em clorofila e trocas gasosas. Verificou-se um aumento significativo do crescimento das plântulas com o aumento da concentração de Ca+2 de 3 para 6 mM em presença de nitrato ou de nitrato amoniacal. Em todas as plântulas, independentemente da fonte de azoto, o aumento da concentração de Ca+2 plântulas, independentemente da fonte de azoto, o aumento da concentração de Ca+2 de 6 para 12 mM provocou uma drástica redução no crescimento. O aumento da concentração de Ca+2 de 3 para 6 mM tem, também, como consequência um aumento significativo do conteúdo em clorofila e da taxa fotossintética em todas as plântulas. As concentrações de Ca+2 mais elevadas a taxa fotossintética segue padrões diferentes de acordo com a fonte de azoto presente na solução nutritiva. Tanto as plântulas tratadas com nitrato amoniacal apresentam uma acentuada descida da taxa fotossintética. Description: Comunicação apresentada no I Congresso Ibérico de Ciências Hortícolas, 18 a 21 de Junho de 1990 em Lisboa. Mon, 01 Jan 1990 00:00:00 GMT http://hdl.handle.net/10451/4345 1990-01-01T00:00:00Z