Anatomia Kranz, estructura y distribucion de cloroplastos en hojas de yuca (Manihot esculenta Crantz)

To determine the presence of Kranz anatomy, chloroplast structure and distribution in cassava leaf tissues, a selection was made among materials of CIAT`s germplasm bank. Two materials were selected, var. MCol 22 and hybrid CM 507-37; work was also carried out with maize var. Swan Laposta C48B (monocotyledonous C4 plant), Amaranthus dubius (dicotyledonous C4 plant), and an advanced bean line (dicotyledonous C3 plant). Leaves of the different species were cut and observed under both optical and electronic microscopes to determine the differences or similarities between cassava plants and standard C3/C4 plants. Important differences were observed in cassava leaves in relation to each standard. Parenchyma palisade tissue occupies almost 70 percent of the leaf thickness, forming a funnel-like structure. A crown of cells larger than those of the surrounding spongy parenchyma was observed; chloroplasts were arranged in centrifugal position, similar to the typical Kranz anatomy of C4 plants. The ultrastructural differentiation of the chloroplasts, located in spongy and palisade parenchyma and in the crown around the vascular bundle, in spite of not yet being clear, evidences the possible function of the crown around the vascular bundle, explaining the biochemical and photosynthetic performance of the plant. (AS

Analysing vulnerability: a multi-dimensional approach from Colombia s upper Cauca river basin

In Colombia, agriculture is an economic mainstay, creating direct employment for much of the country s population. Agriculture s dependence on predictable seasonal patterns leaves many communities vulnerable to climate change. Vulnerability assessments attempt to quantify the degree to which a system will need to adapt to climate change impacts or whether it even has the capacity to do so. Such assessments have been criticised for their uncertainty and lack of applicability at the local or regional scale. However, a project in Colombia s Upper Cauca River Basin has taken a new approach to vulnerability assessment, using a model based on four dimensions of vulnerability. This brief provides an overview of the project as well as key considerations for vulnerability analyses that are inclusive, integrated and sensitive to social and political complexities

Caracteristicas fotosinteticas de la yuca (Manihot esculenta Crantz): Productos iniciales de fijacion con (14)CO2

Cassava, bean, and maize leaves were fed with (14)CO2 in light; the primary products of photosynthesis were identified 5 and 10 s after assimilation. In cassava, approx. 40-60 percent were incorporated in C4 acids with 30-50 percent in phosphoglyceric acid, which indicates that cassava possesses the C4 photosynthetic cycle. However, due to the lack of typical Kranz anatomy, appreciable C assimilation takes place directly through the Calvin- Benson-Bassham cycle. (AS (extract)