The vesicular-arbuscular mycorrhizal symbiosis

Vesicular-arbuscular mycorrhiza fungi are associated with the majority ot the terrestrial plants. Their function ranges from stress alleviation to bioremediation in soils polluted with heavy metals. However, our knowledge about this symbiosis is still limited. For the semi-arid tropics, where some african countries are located, there is a great possibility of using mycorrhizas as a biological tool for sustainable agriculture. This review gives an overview on the mycorrhizal benefits and recomends some management practices for the semi-arid Africa conditions. Key words: Arbuscular mycorrhizal fungi, endomycorrhizas, soil fungi, symbiosis, vesicular arbuscular mycorrhiza. African Journal of Biotechnology Vol. 2 (12), pp. 539-546, December 200

Acessibilidade à informação sobre a política monetária nos Bancos Centrais : avaliação da prática de transparência no Banco de Moçambique

Tese de mestrado. Ciência da Informação. Faculdade de Engenharia. Universidade do Porto. 201

Evaluation of four Mozambican cowpea landraces for drought tolerance

The southern part of Mozambique is vulnerable to drought, affecting the country’s food production, and thus requires more drought-tolerant crops. Four local cowpea landraces, Massava nhassenje, Timbawene moteado, Namarua and Tete-2, which are currently widely used by local Mozambican farmers, were evaluated for their drought tolerance with the aim to identify the most drought-tolerant landrace and also a phenotypic marker easily applicable for drought-tolerance selection under local Mozambican conditions. Above- and below-ground plant characteristics, including biomass, protein content, proteolytic activity, symbiotic nitrogen fixation and nodule number, were measured in a greenhouse under well-watered and drought conditions using vermiculite as the plant growth medium. The key finding was that variability exists among the landraces for growth under drought with Timbawene moteado displaying significantly higher leaf dry biomass, leaf and nodule protein content, and symbiotic nitrogen fixation and the lowest increase in proteolytic activity compared to all other landraces. Timbawene moteado might be suitable for inclusion into a future cowpea breeding program in Mozambique and might also be tested in other areas in Mozambique experiencing drought stress. Furthermore, leaf dry biomass might be selected as a simple and informative marker for future screening of the Mozambican cowpea germplasm for drought tolerance.Cooperação UEM-Sida/SAREC and also partially by the British Council via a Development Partnerships in Higher Education grant to the University of Eduardo Modlane in Mozambique (DelPHE 18).http://www.tandfonline.com/loi/tjps20hb201

Minimising the effects of drought stress on growth of two peanut cultivars, using arbuscular mycorrhiza (AM) inoculants

Peanut (Arachis hypogaea L.) is a major cash crop in the semi-arid tropics, where it is mainly grown under rainfed conditions. Inadequate soil fertility (especially N and P), drought and diseases are important factors causing low yields. Peanut forms two types of symbiotic associations with micro-organisms, one with Bradyrhizobium involving N2-fixation and with arbuscular mycorrhizal fungi (AM). The positive effect of AM fungi on plant growth and development make AM a potentially very useful biological resource of assuring high plant productivity, with minimum application of chemical fertilizers or pesticides. Effects of two different AM inoculants on root colonization, leaf growth and dry matter accumulation and distribution were studied in two peanut cultivars: Local and Falcon. The cultivars differed in their dry matter partitioning pattern, drought tolerance strategies and degree of colonisation with AM inoculants (Quilambo, 2000). The plants were grown for 13 weeks, in a non-sterile soil Mozambican soil with and without drought stress. The indigenous Soil Mozambique inoculant significantly increased root colonisation, leaf growth and dry matter in both cultivars under drought stress conditions. The commercial Hannover inoculant increased growth only under well-watered conditions. In general, there was a tendency of allocating more dry matter to the pods with inoculation, followed by leaves, while drought stress and non-inoculation, delayed the formation of pods. Drought stress effects could be alleviated by inoculation with Soil Mozambique inoculant. Therefore, peanut productivity, particularly under drought stress, may be improved by an adequate management of the AM symbiosis. Key Words: AM inoculation, arbuscular mycorrhiza, drought stress, growth and peanut Journal of Tropical Microbiology Vol.1(1) 2002: 22-2

Functioning of peanut (Arachis hypogea L.) under nutrient deficiency and drought stress in relation to symbiotic associations

Peanut is a common crop in the semi-arid tropics and for the majority of the population in southern Mozambique it is yet an irreplaceable constituent of the daily diet. The peanut yields, however, have decreased in the last years due to (I) low soil fertility, mainly low nitrogen (N) and phosphorus (P), (II) growing of unimproved landraces, (III) poor agricultural practices and, (IV) drought stress. ... Zie: Summary

Arbuscular mycorrhizal inoculation of peanut in low-fertile tropical soil. II. Alleviation of drought stress

The effect of drought stress and inoculation with an indigenous Mozambican and a commercial arbuscular mycorrhizal (AM) inoculant on root colonization and plant growth and yield was studied in two peanut (Arachis hypogaea L.) cultivars-a traditional, low-yielding Mozambican landrace (Local) and a modem, high-yielding cultivar (Falcon)-grown in a non-sterile Mozambican soil. In these cultivars, AM mycorrhizal colonization was not substantially reduced by drought stress. Growth and yield of inoculated plants subjected to drought stress were increased in comparison with non-inoculated ones. The indigenous Mozambique inoculant significantly increased leaf and root growth in both cultivars under drought stress by preventing an increase in root weight ratio (RWR) and maximum root-length to leaf-area ratio (MRLAR). The commercial Hannover inoculant had a positive effect on growth only under well-watered conditions, this result was due most likely to a lesser ability to adapt to drought conditions to which the AM fungal strains in Mozambique inoculant are frequently exposed. Such drought-stress effects on growth could be alleviated by inoculation with Mozambique inoculant, particularly because of its ability to decrease sensitivity of the host plant to reduction in leaf expansion. Therefore, an adequate management of the AM symbiosis may improve peanut productivity, particularly under drought stress and in small-scale fanning systems

Potencial alelopático do extracto de ramos terminais de Casuarina equisetifolia em estacas e sementes de Ipomoea pes-caprae (l.) R.br e Canavalia rosea (Sw.) DC.

In the coastal zone of Maputo City the Casuarina equisetifolia is common due to its use as stabilizer of dunes and windbreaks. However, this species has a potential to colonize open areas in dunes, by replacing the native vegetation and threatening the biodiversity, in a phenomenon called allelopathy. This study aimed at evaluating the allelopathic potential of the terminal branches of C. equisetifolia in the germination and growth of Ipomea pes-caprae and Canavalia rosea. For that, seeds and cuttings of both species were placed in soil and were irrigated with different concentrations of the extract of terminal branches of C. equisetifolia at 0%, 25%, 50%, 75% and 100%. The germination of I. pes-caprae seeds showed to be more sensitive to the allelopathic effect compared to C. rosea. The germination decreased with the increase of extract concentration of C. equisetifolia reaching significant values at 100% to C. rosea and  at 50% for I. pes-caprae, respectively.  For the cuttings, the C. rosea the number of leaves decreased with the increase of the extract concentration while in I. pes-caprae the 75% significantly increased the number of leaves. The survival of C. rosea decreased significantly at 100% extract of C. equisetifolia while I. pes-caprae was affected significantly at 50% extract. The results indicated that C. equisetifolia plays an allelopathic effect on the pioneer native species of the dunes, which explain the scarcity of vegetation under its canopies, being a factor to be considered when used to recover vegetation in these areas.Na zona costeira da Cidade de Maputo a Casuarina equisetifolia é comum pelo seu uso como estabilizador de dunas e quebra-ventos. Esta espécie possui potencial para colonizar áreas abertas nas dunas, substituíndo a vegetação nativa e ameaçando a diversidade biológica, num fenómeno denominado alelopatia. O presente estudo teve como objectivo avaliar o potencial alelopático do extracto aquoso de ramos terminais de C. equisetifolia na germinação de sementes e crescimento de Ipomoea pes-caprae e Canavalia rosea. Para tal, foram colocadas sementes e estacas de ambas espécies em solo sob diferentes concentrações de extracto aquoso de ramos terminais de C. equisetifolia a 0%, 25%, 50%, 75% e 100%. No final da experiência, a germinação das sementes de I. pes-caprae mostrou maior sensibilidade ao efeito alelopático do extracto de C. equisetifolia do que C. rosea. A germinação decresceu com o aumento da concentração do extracto atingindo valores significativos a 100% e 50% para C. rosea e I. pes-caprae, respectivamente. Em estacas, o número de folhas de C. rosea decresceu com o aumento da concentração do extracto de C. equisetifolia enquanto que em I. pes-caprae apresentou um aumento significativo a 50%. A sobrevivência das estacas decresceu significativamente a 100% e 50% do extracto de C. equisetifolia, em C. rosea e I. pes-caprae, respectivamente. Os resultados indicam que a C. equisetifolia exerce um efeito alelopático sobre as espécies nativas pioneiras das dunas, o que justifica a escassez de vegetação sob suas copas, sendo um factor a considerar quando usada na recuperação da vegetação nessas áreas