Prolonged Waterlogging Reduces Growth and Yield in Broccoli Plants (Brassica oleracea var. italica)

The crop of broccoli in tropical regions is of great importance among flowering vegetables; however, the yield of this crop is severely impacted by climatic variations that can cause floods. In Tunja, Colombia, a study was carried out under greenhouse conditions in which the tolerance of broccoli plants to prolonged waterlogging was evaluated. One group of plants were kept under waterlogging conditions until most of them showed severe symptoms of chlorosis while another group was grown under regularly drained and watered soil conditions as a control. Waterlogging caused the death of 20% of the plants, reduced the height of the plants by 42.9%, the thickness of the stem by 42.1%, the foliar area by 87%, the chlorophyll content in the leaves by 96.6%, and the total dry weight per plant by 79.9%. The absolute and relative growth rates decreased by 80 and 24.4%, respectively. Waterlogging also prevented flower production and caused a 23.7% increase in the accumulation of biomass in roots but reduced it by 24.5% in leaves. Likewise, the net assimilation rate fell 72.3% when waterlogged and the values of allometric variables which express growth were altered by this stressor. Consequently, it can be inferred that these plants have a low tolerance to waterlogging; however, the most severe impact caused by waterlogging was the inability of plants to develop flowers. The lack of flowers is devastating due to their economic and commercial importance of broccoli, and they are the primary justification for the cultivation of these plants.

     

Marine Antimalarials

Malaria is an infectious disease causing at least 1 million deaths per year, and, unfortunately, the chemical entities available to treat malaria are still too limited. In this review we highlight the contribution of marine chemistry in the field of antimalarial research by reporting the most important results obtained until the beginning of 2009, with particular emphasis on recent discoveries. About 60 secondary metabolites produced by marine organisms have been grouped into three structural types and discussed in terms of their reported antimalarial activities. The major groups of metabolites include isonitrile derivatives, alkaloids and endoperoxide derivatives. The following discussion evidences that antimalarial marine molecules can efficiently integrate the panel of lead compounds isolated from terrestrial sources with new chemical backbones and, sometimes, with unique functional groups.     

Screening of Yucatecan plant extracts to control Colletotrichum gloeosporioides and isolation of a New Pimarene from Acacia pennatula

Screening of seven Yucatecan plant extracts to look for fungicidal activity for the control of Colletotrichum gloeosporioides was carried out. Bioassay-directed purification of the root extract of one of the most active plants, Acacia pennatula, resulted in the isolation of the new compound 15,16-dihydroxypimar-8(14)-en-3-one (1), which in the in vitro bioassay "agar dilution" was shown to have growth, sporulation, and germination inhibition activity. Nuclear magnetic resonance spectroscopic techniques were used to elucidate its structure.     

Breeding beans for resistance to terminal drought in the Lowland tropics

In the lowland regions of Latin America, a large proportion of beans are sown at the beginning of a dry season where a guaranteed terminal (end-of-season) drought will reduce yields. This study was undertaken to identify lines within two black bean recombinant inbred line (RIL) populations with resistance to terminal drought. The two RIL populations were developed from crosses between a drought resistant line, B98311 from Michigan, with TLP 19 and VAX 5, two lines from CIAT with improved disease resistance and adaptation to growing conditions in Latin America. The RIL populations were evaluated in experiments conducted in Zamorano, Honduras and Veracruz, Mexico under drought stress and well-watered (non-stress) treatments. Yields were reduced in each experiment by drought and the fungal pathogen, Macrophomina phaseolina. Drought stress, disease pressure and low yields contributed to high coefficients of variation (CV), which made it difficult to select superior lines. Selection was based on rank of geometric mean (GM) yield calculated from the yield in the stress and non-stress treatments. One RIL, L88-63 ranked first in GM yield at both locations. Subsequent testing in Honduras and Michigan confirmed the high yield potential and broad adaptation of L88-63. Breeding beans for drought resistance in lowland tropical environments should also include breeding for resistance to M. phaseolina. This revised version was published online in July 2006 with corrections to the Cover Date.     

Conservation status of the San Christóbal pupfish Profundulus hildebrandi Miller (Teleostei: Profundulidae) in the face of urban growth in Chiapas,Mexico

1. Profundulus hildebrandi, the San Cristóbal pupfish, is a small cyprinodontiform fish endemic to the closed basin of San Cristóbal de Las Casas, a fast‐growing city in highland Chiapas, Mexico. This study constitutes the first population study of this endangered taxon. 2. In order to judge its conservation status, its distribution and habitat were described, and its population size was estimated through a capture–recapture technique. To the extent possible, present conditions of its habitat were compared with historic information, mainly old city maps and photographs. 3. Introduction of largemouth bass (Micropterus salmoides) coincided with local extirpation of P. hildebrandi. Other risk factors related to urban growth include pollution of streams, as well as habitat destruction, fragmentation, and modification; about 60% of the original pupfish habitat is heavily polluted by sewage. 4. Although its population size is apparently large (probably more than 8000), its very restricted distribution, its shrinking habitat and the increasing risk factors provide justification to consider P. hildebrandi as an endangered fish, according to the Mexican Official Norm and the Red Book of the IUCN. Copyright © 2004 John Wiley & Sons, Ltd.     

Multinomial logit estimation of a diameter growth matrix model of two Mediterranean pine species in Spain

• Introduction   

Understanding diameter growth of the Mediterranean pine species is fundamental for evaluating and making appropriate strategic decisions in forest management. A matrix diameter growth model for two Mediterranean pine forest ecosystems in Spain has been developed.     

Diterpenoids from Cascarilla (Croton eluteria Bennet)

Cascarilla is a commercially available and cheap source of polyfunctionalized diterpenoids belonging to the clerodane structural type. In addition to the bitter triol cascarillin, 10 additional new diterpenoids (eluterins A-J) have been isolated and characterized by spectroscopic means. Structural diversity within cascarilla clerodanes involves mainly the linkage between the carbocyclic and the heterocyclic moieties and the functionalization of C-3, C-4, and C-6 of the decalin core. Cascarillin was shown to be a mixture of interconverting gamma-lactols and not a gamma-hydroxyaldehyde as previously reported.     

A global stochastic index for water quality: The case of the river Turia in Spain

Which are applicable in all Member States. Those directives specify a set of physical and chemical characteristics, which depend on the use the water is intended for, the parameters to be regularly controlled in a network of sampling points, and the limiting values of those parameters for each quality level. Hence, an administrative quality classification for each sampling point is obtained. This article proposes a stochastic quality index that takes into account the uncertainty surrounding the quality classification still remaining after the data have been observed. This stochastic index is built with the probability classification vector of each parameter. In order to obtain those vectors, a mixed-lognormal model is introduced and its statistical analysis developed. The methodology proposed here is then applied to the data observed in the La Presa station, one of the sampling points of the Spanish surface water quality network. Located on the river Turia, near the city of Valencia, its aim is to control the quality of water intended for the abstraction of drinking water. Its stochastic quality classification is obtained and compared with the legally applicable administrative one.