Processo germinativo de sementes de paineira sob estresses hídrico e salino

O ambiente mutável provoca múltiplos estresses, que podem limitar a germinação da semente e a emergência e sobrevivência da plântula. Os objetivos deste trabalho foram determinar o efeito dos estresses hídrico e salino na viabilidade e vigor de sementes de paineira (Chorisia speciosa St. Hil.) e o limite máximo de tolerância a esses estresses. Para avaliação do efeito do estresse hídrico foram utilizadas soluções de manitol e PEG 6000; para o estresse salino, soluções de NaCl, KCl e CaCl2. Após a punção do tegumento, quatro repetições de 50 sementes por tratamento foram submetidas à germinação em substrato de papel-filtro umedecido com as soluções de diferentes potenciais osmóticos e incubadas a 27ºC. As sementes apresentaram menor tolerância ao estresse hídrico simulado com PEG 6000 em relação ao simulado com manitol. O limite máximo de tolerância à seca está situado entre -0,6 e -0,7 MPa de PEG 6000 e entre -1,4 e -1,6 MPa de manitol. Independentemente dos sais utilizados, a porcentagem de germinação decresceu com a diminuição do potencial osmótico do meio. O limite máximo de tolerância ao estresse salino foi o mesmo para todos os sais avaliados e está situado entre -1,0 e -1,2 MPa. A paineira pode ser classificada como glicófita, com moderada tolerância aos sais NaCl, KCl e CaCl2.

Carbon sources and polyethylene glycol on soybean somatic embryo conversion

Somatic embryogenesis is an efficient method for the production of target cells for soybean genetic transformation. However, this method still offers low percentages of plant regeneration, and perhaps is related to the maturation process and high morphological abnormalities of the matured embryos. This study aimed to identify a maturation medium that could contribute to the outcome of more efficient plant regeneration results. Embryogenic clusters, derived from cotyledons of immature seeds of the soybean cultivars Bragg and IAS5, were used as starting material for embryos development. Different maturation media were tested by using 6% maltose, 3% sucrose or 6% sucrose, combined with or without 25 g L-1 of the osmotic regulator polyethylene glycol (PEG-8000). The histodifferentiated embryos were quantified and classified in morphological types. Percentages of converted embryos were analyzed. Cultivar Bragg resulted in higher matured embryo quantities, but lower percentages were obtained for the conversion in comparison to cultivar IAS5. While the addition of PEG did not affect the number of embryos converted into plants, 6% sucrose enhanced the conversion percent significantly.

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Contient : 1° « Les Croniques que OROSIUS compila... », histoire universelle ; 2° « Les anciennes Histoires des Romains »

Highway Work Zone Capacity Estimation Using Field Data from Kansas, TPF-5(081), 2015

Although extensive research has been conducted on urban freeway capacity estimation methods, minimal research has been carried out for rural highway sections, especially sections within work zones. This study attempted to fill that void for rural highways in Kansas, by estimating capacity of rural highway work zones in Kansas. Six work zone locations were selected for data collection and further analysis. An average of six days’ worth of field data was collected, from mid-October 2013 to late November 2013, at each of these work zone sites. Two capacity estimation methods were utilized, including the Maximum Observed 15-minute Flow Rate Method and the Platooning Method divided into 15-minute intervals. The Maximum Observed 15-minute Flow Rate Method provided an average capacity of 1469 passenger cars per hour per lane (pcphpl) with a standard deviation of 141 pcphpl, while the Platooning Method provided a maximum average capacity of 1195 pcphpl and a standard deviation of 28 pcphpl. Based on observed data and analysis carried out in this study, the suggested maximum capacity can be considered as 1500 pcphpl when designing work zones for rural highways in Kansas. This proposed standard value of rural highway work zone capacity could be utilized by engineers and planners so that they can effectively mitigate congestion at or near work zones that would have otherwise occurred due to construction/maintenance.

Français 64

Contient : 1° « Les Croniques que OROSIUS compila... », histoire universelle ; 2° « Les anciennes Histoires des Romains »

Joannis de Muris tractatus de mensurandi ratione.

Colbertinus

1.° Joannis de Muris tractatus de mensurandi ratione. — 2.° Anonymi opus cujus is est titulus : liber practicorum geometriae. — 3.° Aultre maniere de mesurer par le gnomon, c'est a scavoir par le dos de l'astrolabe. — 4.° Alius tractatus de geometria practica. — 5.° Traité d'arithmetique.

Colbertinus

Flavii Vegetii Renati rei militaris epitome, libris quatuor.

Colbertinus

1.° Flavii Vegetii Renati rei militaris epitome, libris quatuor. — 2.° Anicii Manlii Severini Boëtii de consolatione philosophiae libri quinque.

Colbertinus

Vitellionis perspectiva.

Colbertinus

1.° Joannis Campani theorica planctarum. — 2.° Canon tabulae tabularum : authore Magistro Joanne de Muris.

Colbertinus

1.° Anonymi canones in Alphonsi Regis tabulas. — 2.° Tractatus de duodecim domibus coeli, ex diversis authoribus concinnatus. — 3.° Sigilla Magistri Arnaldi de Villanova. — 4.° Compilatio Leopoldi, Ducis Austriae filii, de astrorum scientia. — 5.° Anonymus de judiciis astrorum ad medicinam pertinentibus. — 6.° Speculum Alberti Magni de nominibus librorum astronomiae.

Philiberti de la Mare