Effect of N-nutrition and irrigation on fruit production of carob (Ceratonia siliqua)

This paper is part of the contributions to the Proceedings of the 3rd Internacional Symposium on Inorganic Nitrogen Assimilation, held in Tiberias, Israel, 6-11 September, 1992A combined fertilization and irrigation experiment was initiated in order to see whether such treatment could improve the productivity of carob (Ceratonia siliqua L. cv. Mulata) on Mediterranean marginal lands. Mature carob trees (20–30 years old) were submitted to 3 different irrigation levels (100%;, 50%; and 0%;) based on daily standard evaporation values, measured with a class A pan. For each water level either 21 or 63 kg N ha−1 was applied as ammonium nitrate. The results reported here refer to a two-year experiment, and show that the productivity of the trees could be improved due to a positive interaction between water and N application. In addition, they suggest that also under the normal dry conditions of these Mediterranean systems nitrogen application is effective, even without irrigation

Nitrate reduction in seedlings of carob (Ceratonia siliqua L.)

ACESSO via B-on: http://dx.doi.org/doi:10.1111/j.1469-8137.1991.tb00041.xThe distribution of nitrate reduction in young caroh plants (Ceratonia siliqua L. cv. Mulata) was studied. Plants (three months old) were grown in aerated nutrient solutions under greenhouse conditions. Reduction of nitrate was estimated both in the leaves and in the roots by: (a) accumulation of nitrite in vitro, (b) accumulation of nitrite in vivo and (c) disappearance of nitrate in vivo. Disappearance of nitrate in vivo offered the closest estimation of the rate of nitrate reduction. Leaves consistently showed rates of nitrate reduction lower than those in roots, regardless of assay method. Lowering root temperature had no marked effect on the distribution of nitrate reductase activity in the plant; increasing nitrate concentration in the shoot, however, markedly increased leaf nitrate reduction. The relatively low level of nitrate reductase in leaves appears to be caused mainly by a limitation of nitrate transport from root to shoot. Nitrate reduction takes place in both the root and the shoot of young carob plants with the shoot accounting for approximately 20" (, of total nitrate reduction in the plant

International Journal of Sustainable Development and Planning.

The International Journal of Sustainable Development and Planning is an interdisciplinary journal covering the subjects of environmental design and planning, environmental management, spatial planning, environmental planning, environmental management and sustainable development in an integrated way as well as in accordance with the principles of sustainability. In the beginning of the 21st century, despite major scientific and technological accomplishments, the struggle for a cleaner environment as well as for rational organization of space is not settled. It is clear to us that environmentalists, planners, policy makers, engineers and economists have to work together in order to ensure that environmental protection, spatial co-ordination and economic development could all be achieved without compromising the ability of future generations to meet their own requirements. In recent years, an increase in spatial and environmental problems in many countries has led to a crisis in environmental planning and management. The increasing urbanization of the world coupled with the issues of environmental pollution, resource shortages and economic restructuring demand that a lot of effort will be required in order to make our cities sustainable. Moreover, problems of sustainable planning and management are not restricted to urban areas, since rural areas face serious environmental challenges. The aim of the International Journal of Sustainable Development and Planning is to inform its readers about all aspects of environmental planning and management. The journal includes subjects ranging from social to technical environmental management issues, having always as an axis the concept of sustainable planning and development

Interations between nitrate and ammonium during uptake by carob seedlings and the effect of the form of earlier nitrogen nutrition

This paper is part of the contributions to the Proceedings of the 3rd Internacional Symposium on Inorganic Nitrogen Assimilation, held in Tiberias, Israel, 6-11 September, 1992Seedlings of carob (Ceratonia siliqua L. cv. Mulata) were used in two sets of experiments in order to evaluate; (1) the reciprocal effects of each nitrogen form on net uptake of nitrate and ammonium, and (2) the effect of earlier nitrogen nutrition on ammonium versus nitrate uptake. In the former group of experiments we studied the kinetics of nitrate and ammonium uptake as well as the interference of each of the two forms with net uptake of ammonium and nitrate by both nitrogen depleted and nitrogen fed carob seedlings. On the whole, nitrogen depletion led to increase in both affinity and Vmax of the system for both forms of nitrogen, at the same time as the effects of nitrate on uptake of ammonium and vice versa were concentration dependent. In the second group of experiments the effects of earlier nitrogen nutrition on nitrate and ammonium uptake were characterized, and in this case we observed that: (a) if only one form of N was supplied, ammonium was taken up in greater amounts than nitrate; (b) the presence of ammonium enhanced nitrate uptake; (c) ammonium uptake was inhibited by nitrate; (d) there was a significant effect of the earlier nitrogen nutrition on the response of the plants to a different nitrogen source. The latter was evident mainly as regards ammonium uptake by plants grown in ammonium nitrate. The interactions between nitrate and ammonium uptake systems are discussed on the basis of the adaptation to the nitrogen source during early growth

Uptake of ammonium and nitrate by carob (Ceratonia siliqua) as affected by root temperature and inhibitors

This paper is part of the contributions to the Proceedings of the 3rd Internacional Symposium on Inorganic Nitrogen Assimilation, held in Tiberias, Israel, 6-11 September, 1992Seedlings of carob (Ceratonia siliqua L. cv. Mulata) were grown in nutrient solution culture for 5 weeks, with or without nitrogen at different root temperatures (10, 16, 22, 30, 35 or 40deg;C) and with the air temperature kept between 20 and 24°C. The nitrogen was given as either ammonium or nitrate. At all root temperatures studied, nitrogen-depleted plants developed higher net uptake rates for nitrogen than plants grown in the presence of nitrogen. Temperature affected the kinetic parameters of nitrate uptake more than those of ammonium uptake. With increasing root temperature, the Km of ammonium uptake decreased, but to a lesser extent than the Km for nitrate. The increase in Vmax of ammonium uptake with temperature was also less noticeable than that for nitrate uptake. Ammonium and nitrate uptakes were inhibited in a similar way by respiratory or protein synthesis inhibitors. It may be noted that ammonium uptake in the presence of inhibitors at 40°C was higher than uptake at 10°C without inhibitors. Some similarities between the transport mechanisms for nitrate and ammonium are underlined in the present work. Components of both transport systems displayed saturation kinetics and depended on protein synthesis and energy. The following components of nitrate uptake were distinguished: (a) a passive net influx into the apparent free space; (b) a constitutive active uptake and (c) active uptake dependent on protein synthesis. We may similarly define three ammonium uptake systems: (a) a passive influx into the apparent free space; (b) passive diffusion uptake at high temperature and (c) active uptake dependent on protein synthesis. The possible role of the ratio between mechanism (c) and mechanism (b) as determinant of ammonium sensitivity is discussed