Descriptors for morphological and biochemical characterization of Bhela (Semecarpus anacardium L.): An underutilized plant of tropics

Genetic Resources and Crop Evolution - Semecarpus anacardium L. is a potential underutilized edible, highly nutritious fruit crop with ample medicinal properties grown in some localized pockets of...     

How the root zone modifies soil wettability: Model experiments with alfalfa and wheat

To investigate the effect of plants on soil water repellency (SWR), two column experiments with wheat (Triticum aestivum) and alfalfa (Medicago sativa) with a growing period of three months had been carried out under constant and near‐natural climatic conditions. Model soils with defined wettability were created by mixing a natural sandy loam subsoil with different proportions of a wettable and a hydrophobized pure quartz sand, resulting in a wettable model soil and three model soils with increasing level of subcritical SWR (initial contact angle CA > 0° and < 90°). Results showed a significant decrease of the mean CA after the experiments compared to the initial CA while the mean CA was constant for plant free columns used as a reference. CA as a function of depth in some cases showed a depth dependent variation with decreased CA at the bottom or as well at top and bottom. The deviation from the initial CA was most pronounced for wheat under constant climatic conditions. Changes in CA could be related to changes in pH, i.e., CA was decreased and pH increased. Subcritical WR at the beginning of the growth period affected significantly the moisture content profiles during the entire growing season as well as plant dry mass production. We expect that plant root exudates of plants widely used for foot production cause directly or indirectly pH‐related modifications of the WR level in the root zone dependent on plant species and the ambient climatic conditions.     

Serological evidence of FMD subclinical infection in sheep population during the 1999 epidemic in Morocco.

During 1999, 11 outbreaks of foot and mouth disease (FMD) were declared in the east and central part of Morocco. All the FMD clinical cases reported were cattle. In order to analyse the serological status of sheep from the FMD outbreak areas, 598 sheep sera were tested using a liquid-phase blocking ELISA (LPBE) to detect antibodies against FMDV structural proteins. The study confirmed the presence of FMDV specific antibodies in 77 clinically normal sheep, indicating that unrecognised FMDV-infected sheep could represent a potential risk of FMD dissemination in Morocco.Subsequently, sera from flocks of sheep that had been exposed to FMD outbreaks were assayed by an indirect ELISA using the recombinant FMDV non-structural protein 3ABC expressed in E. coli to evaluate the potential use of this serological test in future epidemiological studies and the development of FMD control strategies. The results indicated that the 3ABC-ELISA was able to detect antibodies indicative of infection with FMDV in asymptomatic sheep in field conditions.     

Pulmonary ventilation in a population of hatching chick embryos

Two experiments were made to study pulmonary ventilation in the hatching chick embryo with particular reference to the part played by the air cell.

The hatchability of embryos without access to the air cell was the same as for normally positioned embryos. The lungs of about 35 per cent of the normally hatching embryos were inflated in the air cell, but 65 per cent were inflated after breathing atmospheric air. The shell was cracked but not pipped before the outer membrane was penetrated. Comparisons between different groups of normally and abnormally positioned unhatched embryos revealed that the air cell had an insignificant respiratory value, but that the mechanical advantages of the large end seemed apparent.

The time relationships between lung inflation, inner membrane perforation, pipping, yolk sac retraction, outer membrane perforation, lung discoloration and hatchability were studied. Equations were derived for the regression on time of each of the seven variables studied. Statistically insignificant differences in hatchability were observed between the 2 groups of embryos which hatched from the large or small end of the egg.

It is suggested that lung inflation occurs when a certain threshold in the respiratory movements of thoracic muscles is reached. The threshold is attained by the rising anoxia, and probably other stimuli. The chick embryo's lungs, which lack elastic recoil, respond to the threshold and start utilising air. It is doubtful whether the embryo needs the very high partial pressure of carbon dioxide in the air cell. It is feasible to believe that CO₂ is an inevitable metabolic by‐product, and that it is stored in the air cell. The air cell also serves as a resting place for the chick while retracting the yolk sac. Through evolution, however, the chick embryo may have built up a high physiological tolerance to the CO₂ which it encounters upon entering the air cell.     

The use of an enzyme-linked immunosorbent assay for tropical theileriosis research in Morocco

An enzyme-linked immunosorbent assay (ELISA) using sonicated purified Theileria annulata piroplasms was compared with an indirect immunofluorescent antibody test (IFAT) during a vaccination trial in cattle to test different doses and passage numbers of an attenuated T. annulata-infected lymphoblastoid cell-line, and also with Giemsa-stained blood smears during an epidemiological field study of tropical theileriosis in Morocco. The sensitivities of both the ELISA (0.56) and the IFAT using T. annulata piroplasm antigen (0.56) were lower than the IFAT using schizont antigen (0.94) for detecting serum antibodies from 18 cattle immunised 38 days previously with cell-line. The ELISA was, however, the most sensitive test after 180 days (0.50 compared with 0.06 for the piroplasm IFAT and 0.39 for the schizont IFAT), and each test detected antibodies in all sera after challenge with live T. annulata sporozoites. There were minor differences in the ability of blood smear examinations and the ELISA to detect infected and uninfected cattle in the field study at the start and end of the disease season. Initially, the sensitivity and specificity of blood smears were both 0.96 and for the ELISA were 0.83 and 0.86, whereas at the end of the season sensitivity and specificity of blood smears were 0.96 and 0.86 and for the ELISA were 0.95 and 0.94. The specificity of the ELISA was affected by the presence of calves with colostral antibodies, and if these were disregarded the specificities before and after the season were 0.94 and 1.00.     

Phytotoxic effect of Sesbania virgata (Cav.) Pers. On seeds of agronomic and forestry species

Sesbania virgata(Cav.) Pers.is a pioneer species native to South America able to release allelochemicals that affect germination and development of other plant species.The aim of this work was to evaluate the allelopathic effect of S.virgata on the germination and development of co-occurring species from gallery forest and on agronomic species.Two forest native species,Enterolobium contortisiliquum(Vell.) Morong and Sapindus saponaria L.,and two agronomic species(these as control),Oryza sativa L.and Solanum lycopersicum L.were used in the lab and greenhouse assays with seeds and leaf extracts of S.virgata.Agronomic species were more affected than native species when co-germinated with seeds of S.virgata.The germination percentage and speed germination index of the agronomic species were reduced in both in vitro and greenhouse assays.In the same assays,the seeds of native species showed no significant differences in the parameters mentioned.However,the initial growth of the four species assayed was affected,with reduction in plant length and shoot diameter followed by significant reduction in plantlet shoot and root weights.In the assays with irrigation of S.virgata leaf extracts,no significant inhibitory effects on germination were observed for all species.Height and shoot diameter of the native species were not affected by the leaf extracts,nor were fresh and dry weights.However,these parameters increased in the agronomic species as they were irrigated with leaf extracts.Based on our data we conclude that seed leachates of S.virgata affect germination and seedling development of other species,suggesting that its invasive behavior is due mainly to seed allelochemicals.Although with less pronounced effects on native species,allelopathy of S.virgata might also influence Interspecific competition in its natural environment.     

Antibacterial activity of Alangium salviifolium flowers

The methanol extract of Alangium salviifolium flowers showed a wide spectrum of antibacterial activity against both gram-positive and gram-negative bacteria.     

Improving the Traditional Acacia Senegal-Crop System in Sudan: The Effect of Tree Density on Water Use, Gum Production and Crop Yields

The traditional Acacia senegal bush-fallow in North Kordofan, Sudan, was disrupted and the traditional rotational fallow cultivation cycle has been shortened or completely abandoned, causing decline in soil fertility and crop and gum yields. An agroforestry system may give reasonable crop and gum yields, and be more appealing to farmers. We studied the effect of tree density (266 or 433 trees ha⁻¹) on two traditional crops; sorghum (Sorghum bicolor) early maturing variety and karkadeh (Hibiscus sabdariffa), with regard to physiological interactions, yields and soil water depletion. There was little evidence of complementarity of resource sharing between trees and crops, since both trees and field crops competed for soil water from the same depth. Intercropping significantly affected the soil water status, photosynthesis and stomatal conductance in trees and crops. Gum production per unit area increased when sorghum was intercropped with trees in low or high density. However, karkadeh reduced the gum yield significantly at high tree density. Yields of sorghum and karkadeh planted within trees of high density diminished by 44 and 55% compared to sole crops, respectively. Intercropping increased the rain use efficiency significantly compared to trees and field crops grown solely. Karkadeh appears to be more appropriate for intercropping with A. senegal than sorghum and particularly recommendable in combination with low tree density. Modification of tree density can be used as a management tool to mitigate competitive interaction in the intercropping system.     

Germacranolides from Anvillea radiata

The aerial parts of Anvillea radiata yielded a new germacranolide, 8alpha,9alpha-epoxyparthenolide (3), together with two known compounds, 9alpha-hydroxyparthenolide (1) and parthenolid-9-one (2). The structures of the compounds were elucidated from IR, HRMS, 1H and 13C-NMR, COSY, HETCOR, HMBC and HOHAHA spectral data. The major component 1 was tested for its cytotoxicity and antibacterial activity.