Mechanism of endocarp-imposed constraints of germination of Lannea microcarpa seeds

Lannea microcarpa, a multipurpose tree species from the dry African savanna, sheds seeds that often display inhibition of germination. The underlying mechanism was investigated using seeds processed from fully matured fruits collected from natural stands in Burkina Faso. Germination of fresh seeds was variable (16¿28%), while they did not germinate after drying and rehydration. Mechanical scarification of the endocarp at the proximal end of the seeds increased germination to 83¿94%. Scarification on the distal end led to delayed radicle emergence through the produced hole in c. 40% of the seeds. The endocarp was permeable to water and respiratory gases. Increased water content in scarified seeds was associated with radicle extension during germination. Intact and scarified non-germinated seeds displayed a moderate rate of respiration with respiratory quotient (RQ) values of c. 1. Respiration increased and RQ decreased to c. 0.7 with radicle emergence. Ethylene evolution peaked in both intact and scarified seeds at the beginning of incubation and then decreased to low values. Inhibition of ethylene production by 1¿5 mM 2-amino-ethoxyvinylglycine (AVG) caused only a partial decrease of germination of the scarified seeds. Intact non-germinated seeds gradually lost viability during incubation at 30°C, but could be rescued by delayed scarification before day 15 of incubation. It is concluded that radicle emergence in dry L. microcarpa seeds is inhibited only mechanically. The mechanical properties of the endocarp are attributed to irreversible structural changes of the lignin¿hemicellulose complex, which occur during drying

Regional ecology Kursk region

Ecology implies the relationship of organisms, communities among themselves and with the environment. Russia has enough difficult situation with ecology, because Russia is one of the most polluted countries in the world. Economic situation exacerbates ecological one, and the severity of the prevailing negative trends is growing every day. Major rivers shallows, large amount of small rivers vanish; superficial water pollution, depletion and pollution of the groundwater, drinking water quality degradation, seas pollution, deforestation are big problems in the Russian Federation. Plowing up of turf-covered slopes, low quality agricultural methods cause accelerated soil erosion. Also there was a large degradation of the land resources in the recent years. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3606

Some aspects of teaching language skills to students of non-linguistic specialities

The article analyses some approaches to teaching language skills to students of non-linguistic specialities, considers the ways of enhancing teaching strategies in the study process

Los estímulos de mayor frecuencia en la compra de los consumidores de Centroamérica

En el presente estudio se identificaron los estímulos de mayor frecuencia en la compra y se determinaron los patrones de consumo para los bienes de uso común y bienes duraderos de los consumidores de Centroamérica. Según el nivel de profundidad del estudio, la investigación fue comparativa, el diseño no experimental, y la población fue compuesta por los habitantes de los países de Centroamérica: Nicaragua, Salvador, Honduras, Guatemala y Costa Rica. Como estímulos de mayor frecuencia de compra de bienes básicos se pueden mencionar sus precios, seguido por la cercanía de los centros comerciales y lugares de compra de las casas de habitación. En el caso de los bienes duraderos, los estímulos se diferencian según las clases de productos, y entre los más frecuentes están el precio, los atributos de productos como sus funciones y la calidad, la marca (especialmente para los equipos tecnológicos) y el diseño (para las joyas, ropa, calzado y vehículos). Los patrones de consumo tanto de los bienes de uso común, como de los bienes duraderos, en su mayoría coinciden en los cinco países de Centroamérica, con ciertas diferencias en Costa Rica, relacionadas con una fuerte influencia cultural europea y estadounidense en el casco urbano, y en Guatemala, relacionada con un alto porcentaje de la población indígena, que ha logrado conservar muchos hábitos y tradiciones, y que deja su huella en los hábitos de consum

Competition of Gas Pipeline Projects: A Multi-Player Game of Timing

We use game theory to construct a model of investment in gas pipeline projects competing for a regional gas market. The model is designed as a multi-player game with integral payoffs, in which times of entering the market act as players' strategies. For each player, we identify the location of player's best responses to strategies chosen by other players. On this basis, we reduce the original game to a game with a finite number of strategies for each player. We introduce a regularity condition and for a regular game of timing prove the existence of a Nash equilibrium. An application of this result to a symmetric game of timing allows us to give the entire description of the set of all Nash equilibrium points. Finally, we construct a finite algorithm for finding player's best responses and the Nash equilibrium points in the game. The presented approach can be used to analyze competition of large-scale technological and energy transportation projects in situations where the investment periods of sales and the appearance of every new supplier on the market drastically effects the market price