Seeds of alfalfa (Medicago sativa) and white clover (Trifolium repens) were primed in 3 priming solutions [2% NaCl, 2% KNO3 and 300 g/L polyethylene glycol (PEG)] for 2 days at 20°C and their subsequent germination compared with that of untreated seed. Four replications of 50 seeds for germination and 25 seeds for emergence were arranged in a 2-factor factorial completely randomised design. All...

Transfer of an IncP plasmid carrying the Rhizobium meliloti nodFE, nodG, and nodH genes to Rhizobium trifolii enabled R. trifolii to nodulate alfalfa (Medicago sativa), the normal host of R. meliloti. Using transposon Tn5-linked mutations and in vitro-constructed deletions of the R. meliloti nodFE, nodG, and nodH genes, we showed that R. meliloti nodH was required for R. trifolii to elicit both...

Identifying the genetic basis of parallel phenotypic evolution provides insight into the process of adaptation and evolutionary constraint. White clover (Trifolium repens) has evolved climate-associated adaptive clines in cyanogenesis (the ability to produce hydrogen cyanide upon tissue damage) in several world regions where it has been introduced. Gene-deletion polymorphisms at the CYP79D15 an...

An apparatus was developed for the measurement of transpiration rates of Trifolium repens. The transpiration rates were measured under controlled conditions of soil water stress and soil temperature. Other environmental parameters such as air temperature, relative humidity, light intensity and air speed were held constant. Diffusive resistances were calculated and stomatal aperture changes were...

The ethnopharmacology of Madeira and Porto Santo Islands is extremely interesting because of the cultural and biogeographic features of this region, which make it a centre of medicinal plant diversity (richness of endemic flora, geographical isolation in the Atlantic sea, crosscultural influences, and past abundance of local healers). The medicinal flora of Madeira is composed of 259 species. S...

Triphysaria is a facultative root parasite in the Scrophulariaceae family. Similar to other related parasites, the development of the parasitic life cycle is initiated by molecular signals released from appropriate host roots. Using a differential display, we isolated cDNAs preferentially abundant in T. versicolor roots exposed to Trifolium repens (white clover) root exudates in vitro. Sequence...

Pot-culture experiments were used to examine the individual and combined effects of Cu and Cd pollutants on Trifolium repens L. seedlings, both on their growth and their active oxygen metabolism system, mainly superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD) activities. The results showed that the negative action took place at low concentrations of Cu (less than 500 ppm) and Cd ...

Heliothis virescens F. is an important polyphagous pest that can develop on >100 plant species, including 20 economic crops. Populations of this insect are believed to be locally maintained on a few crops and weed hosts in Washington County, MS. To find the intrinsic value of these plants for the development of H. virescens populations, we fed different laboratory and wild colonies with fresh a...

Arbuscular mycorrhizal (AM) fungi are biotrophic symbionts colonizing about two-thirds of land plant species and found in all ecosystems. They are of major importance in plant nutrient supply and their diversity is suggested to be an important determinant of plant community composition. The diversity of the AM fungal community composition in the roots of two plant species (Agrostis capillaris a...

Organic dairy farmers often introduce alternative pasture species, such as chicory (Cichorium intybus) and narrow-leaved plantain (Plantago lanceolata), to their swards because of their higher mineral contents, yet they are concerned about the presence of weed species such as docks (Rumex spp.) and dandelion (Taraxacum officinale). The mineral content and nutritive value of both desired and les...