Despite growing concern about transgenes escaping from fields, few studies have analysed the genetic diversity of crops in an agroecosystem over several years. Accurate information about the dynamics and relationship of the genetic diversity of crops in an agroecosystem is essential for risk assessment and policies concerning the containment of genetically modified crops and their coexistence w...

Despite the importance of mutualism as a key ecological process, its persistence in nature is difficult to explain since the existence of exploitative, "cheating" partners that could erode the interaction is common. By analogy with the proposed policing strategy stabilizing intraspecific cooperation, host sanctions against non-N(2) fixing, cheating symbionts have been proposed as a force stabil...

Mixture crops, as opposed to pure sowing crops, are characterised by more stable output, reduced expenditure on pesticides as well as smaller environment pollution thanks to the biological diversification of species. It seems mixture crops have good prospects while the pro-ecology movements are growing in popularity. The growth and development of plants, both in natural and formed ecosystems, a...

Sustainable agriculture is a holistic approach to produce food, fiber, feed and fuel in a way that does not damage the environment and also must meet the needs of the present and future population of the world, while considering agro-ecosystem health, social and economic equity and profitability. Therefore, the sustainable agriculture cannot be isolated from the concept of sustainable developme...

Legume root nodule nitrogen-fixing activity is severely affected by osmotic stress. Proline accumulation has been shown to induce tolerance to salt stress, and transgenic plants over-expressing Delta(1)-pyrroline-5-carboxylate synthetase (P5CS), which accumulates high levels of proline, display enhanced osmotolerance. Here, we transformed the model legume Medicago truncatula with the P5CS gene ...

Increasing of world population marks a serious need to create new crop cultivars and medicinal plants with high growth and production at any environmental situations. Among the environmental unfavorable conditions, salinity is the most widespread in the world. Crop production and growth severely decreases under salt stress; however, some crop cultivars show significant tolerance against the neg...

Two nitrogen-fixing root nodule symbioses between soil bacteria and higher plants have been described: the symbiosis between legume and rhizobia and actinorhizal symbioses between plants belonging to eight angiosperm families and the actinomycete Frankia. We have recently shown that the subtilisin-like Ser protease gene cg12 (isolated from the actinorhizal plant Casuarina glauca) is specificall...

Based upon considerations of a theoretical model of N/N fractionation during steady-state nitrate uptake from soil, we hypothesized that, for plants grown in a common soil environment, whole-plant dN (dP) should vary as a function of the transpiration efficiency of nitrogen acquisition (FN/v) and the difference between dP and root d N (dP 2 dR). We tested these hypotheses with measurements of s...

■ Abstract Transgenic plants expressing insecticidal proteins from the bacterium, Bacillus thuringiensis (Bt), are revolutionizing agriculture. Bt, which had limited use as a foliar insecticide, has become a major insecticide because genes that produce Bt toxins have been engineered into major crops grown on 11.4 million ha worldwide in 2000. Based on the data collected to date, generally these...