3 resultados para Lens Tuero, Jesús Angel

em Brock University, Canada


Relevância:

20.00% 20.00%

Publicador:

Resumo:

Low levels of ionizing radiation induce two translocation responses in soybean: a reduction in photoassimilate export from leaves and a change in the distribution pattern of exported photoassimilate within the plant. In this investigation these responses have been further studied specifically to ascertain the site of radiation damage and to better understand the physiological responses observed. Experimentally the primary data was obtained from studies in which a mature trifoliate leaf of a young soybean plant (Glycine ~ L. cultivar Harosoy '63) is isolated in a closed transparent chamber and allowed to photoassimilate 14C02 for 15 minutes. This is followed by an additional 45 ~_il'1;ute period before the plant is sectl.o ne d an d 14 C-ra dl' oactl.v.l ty d eterml. ne d'l n a 11 parts. Such 14c data provides one with the magnitude and distribution pattern of translocation. Further analyses were conducted to determine the relative levels of the major photosynthetic products using the techniques of paper chromatography and autoradiography. Since differences between control and irradiated P 1 ants were not 0 b serve d l' n t h e par tl't"lo nlng 0 f 14 C between the 80% ethanol-soluble and -insoluble fractions 14 or in the relative amounts of C-products of photosynthesis, the reduction in export in irradiated plants is not likely due to reduced availability of translocatable materials. Data presented in this thesis shows that photoassimilate export was not affected by gamma radiation until a threshold dose between 2.0 and 3.0 krads was reached. It was also observed that radiation-induced damage to the export process was capable of recovery in a period of 1 to 2 hours provided high light intensity was supplied. In contrast, the distribution pattern was shown to be extremely radiosensitive with a low threshold dose between .25 and .49 krads. Although this process was also capable of recovery,lt" occurred much earlier and was followed by a secondary effect which lasted at least for the duration of the experiments. The data presented in this thesis is interpreted to suggest that the sites of radiation action for the two translocation responses are different. In regards to photoassimilate export, the site of action of ionizing radiation is the leaf, quite possibly the process of photophosphorylation which may provide energy directly for phloem loading and for membrane integrity of the phloem tissue* In regards to the pattern of distribution of exported photoassimilate, the site is likely the apical sink, possibly the result of changes of levels of endogenous hormones. By the selection of radiation exposure dose and time post-irradiation, it is possible to affect independently these two processes suggesting that each may be regulated independent of the other and involves a distinct site.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Academic exchange programmes provide opportunities for teacher candidates to study at educational institutions abroad wherein they are able to learn more about different cultures, teaching practices, and build cross-cultural relationships. This paper is an exploration into my teacher candidate experience abroad. The relevant research on this topic indicates that teacher certification should take an active role in creating opportunities for teacher candidates to participate in educational experiences abroad because of their benefits. The knowledge that a teacher gains through abroad experiences is one of the strongest factors in helping to build authentic global classrooms. In addition, these programmes allow for fuller understanding of a global context and the chance to understand someone else’s story. This review and synthesis of literature and research findings prepares a foundation for how teacher candidates, and hopefully, how policy makers can work toward creating a more inclusive global classroom for students.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The wrestler's name is Maurice "The Angel" Tillet and the number stamped on the reverse of the card is 459. He was born in France and moved to North America to start a wrestling career. He suffered from acromegaly - a condition where bones continue to grow uncontrollably. His appearance made him a classic villain in the wrestling ring.