Leguminous seeds are generally highly nutritious and have been used in the human diet for many centuries. The peasants of Asia and elsewhere grow leguminous seeds on small plots of land for their own consumption. The seeds are allowed to dry in the fields and are stored for use throughout the year. Dried seeds are either ground finely for use in baking or the whole seeds are boiled and used to make soups and curries. It has been known for centuries that seeds of the same variety may display variation in their cookability. The producer of commercial pea soups today is very aware of the variability in the cooking quality of his raw materials, as it may be necessary for him to change processing conditions to ensure the uniformity of the final product. [...]

In 1917, McBeth (43) found that applied ammonium waa fixed by subsoils. Later workers showed that fixation occurred through entrappment of the ammonium ion in interlattice spaces of certain clay minerals. ln recent years, ammonium fixation by clay minerals has been intensively studied by American investigators. [...]

No description available.

No description available.

To assess the availability of bracken and the factors influencing frond yields, this thesis investigated the growth and phenology of bracken populations across Scotland in relation to site characteristics.  The change in elements in fronds and litter from April to November was analysed, along with the concentrations of the carcinogen Ptaquiloside (Pta).  Frond dry matter yields increased to maximum in August/September, falling to those in November.  In September/October, frond yields ranged from 4.70-15.9 DM t ha^-1.  Frond concentrations of phosphorus and potassium reduced, and concentrations of calcium and magnesium increased from May to November.  Frond Pta concentrations reduced during this period also, with the highest concentration recorded of 5792 mg kg^-1 in May 2002 at Loch Grannoch, SW Scotland. This thesis also investigated the effects of harvesting of fronds, and the burning and clearing of litter on the yield of frond dry matter, yield and content of ash and on Pta concentrations in fronds.  The concentration of twenty-one elements, the CaCO₃ equivalence and pH of this ash were determined, and the effect of harvesting of fronds on subsequent yields was assessed.  Harvesting during the growing season reduced the preceding yield of fronds, but not if harvested after senescence.  A positive regression was found between frond DM and ash yields.  The maximum yield of K in ash was harvested in August/September, at around 180 kg ha^-1.  Calculations of the value of bracken ash using August 2001 K concentrations and the cost of other organic K sources came to between £219-£980 t^-1.  The ash produced had a mean pH of 11.9, and mean calcium carbonate equivalence of 52%.  Lifting litter increased the density of fronds, and burning litter increased the soil available Mg concentrations and Ca concentrations in the ash.  Pta concentrations in fronds that emerged in reaction to harvesting were higher compared to those fronds first harvested at the same time.

No description available.

No description available.

The toxicity of plant lectins to insects after oral ingestion was investigated by incorporating the proteins into insect diets. Bioassays carried out using an artificial diet system demonstrated that kidney bean (Phaseolus vulgaris) lectin (PHA) caused a significant decrease in survival of larvae of the tomato moth, Lacanobia oleracea. Jackfruit (Artocarpus integrifolia) lectin (jacalin) and black mulberry (Morus nigra) lectin both caused a significant decrease in growth of the peach potato aphid (Myzus persicae) when compared to controls in an artificial diet based bioassay. Interactions of lectins with insect gut tissues in vivo were studied by immunolocalisation. Binding of the snowdrop lectin (Galanthus nivalis agglutinin;GNA) and jack bean (Canavalia ensifomiis) lectin (Concanavalin A; Con-A) to the digestive tract of L oleracea larvae was observed and localised at the electron microscope level after oral ingestion of the proteins. GNA was also observed to bind to the midgut of the two-spot ladybird Adalia bipunctata. No disruption of the brush border membrane of either L oleracea or A. bipunctata was observed. Binding of GNA to the peritrophic membrane of L. oleracea was observed by fluorescence microscopy. Histological evidence of lectin binding to insect guts in vivo was corroborated by in vitro studies, which showed that the lectins GNA and Con- A bind to sections of the digestive tract of L. oleracea larvae. Binding of Con-A to proteins from brush border membranes, solubilised brush border membranes and peritrophic membranes was also observed. The use of confocal microscopy showed that GNA bound to the midgut and haemocytes of the peach potato aphid Myzus persicae, both when incubated with isolated tissues and cells and when fed orally to live insects, providing evidence for transport of GNA across the gut wall. Larvae of L.oleracea fed the lectins GNA and PHA showed a significant increase in polyphenoloxidase levels within the haemolymph, suggesting that the lectins were causing systemic responses in the insects. A partial sequence for leucine aminopeptidase a potential receptor for lectin binding was obtained from a cDNA library constructed from the midgut of the tomato moth larvae.

No description available.

No description available.