Revised / 2 pp.

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Orientador: João Nakagawa / Banca: Cláudio Cavariani / Banca: Ana Ana Dionisia da Luz Coelho Novembre / Resumo: O uso de sementes de alta qualidade é de grande importância na implantação e no estabelecimento da lavoura no campo e o vigor das sementes pode afetar não só o estabelecimento mas também influenciar o crescimento, o desenvolvimento e a produtividade das plantas. O presente trabalho teve como objetivo estudar o teste de envelhecimento acelerado tradicional (com água), utilizando sementes de aveia preta com e sem tratamento fungicida, e o envelhecimento acelerado com solução saturada de cloreto de sódio (NaCl), visando identificar o período de exposição e a temperatura para a classificação dos níveis de vigor de lotes dessas sementes. O estudo foi realizado utilizando cinco lotes de sementes de aveia preta, constituídas de sementes comerciais ou produzidos na Fazenda Experimental Lageado - UNESP - Câmpus de Botucatu. Foram realizados testes para a caracterização da qualidade inicial dos lotes, tais como os de germinação, emergência de plântulas, condutividade elétrica, comprimento de plântulas normais e anormais, massa de 1000 sementes, e o estudo de envelhecimento acelerado tradicional (com água ), com e sem tratamento fungicida, e envelhecimento acelerado com solução saturada de sal (NaCl) por períodos de 24, 48, 72, 96 e 120 horas de condicionamento às temperaturas de 40, 43 e 45oC. Os resultados permitiram concluir que o teste de envelhecimento acelerado é adequado para estimar o vigor de sementes de aveia preta. Assim, o teste de envelhecimento acelerado tradicional pode ser conduzido à temperatura de 40oC por 24 ou 48 horas e a 43 ou 45oC por 48 horas; o envelhecimento acelerado com solução saturada de sal a 40, 43 ou 45oC por 24 horas e o envelhecimento acelerado tradicional com sementes tratadas a 40oC por 24 ou 48 horas, a 43oC por 48 horas ou a 45oC por 24 horas de condicionamento. / Abstract: The use of seeds of high quality has great importance in the implantation and establishment of the crop in the field, the seeds vigour can not only affect the establishment, but also influence the growth, development and productivity of the plants. The present work had as its objective to study the traditional of accelerated aging (with water), in black oats seeds with and without fungicid treatment, and the accelerated aging with saturated solution of salt (NaCl), by aiming to identify the exposition period and temperature that allow the classification of lots of black oats seeds in different vigour levels. The study was carried out by using five lots of black oats seeds from commercial procedure or seeds produced in Fazenda Experimental Lageado, UNESP Campus de Botucatu. The tests were carried out to the characterization of initial quality of the seed lots, by tests of germination, seedlings emergency in the field, electrical conductivity, length of normal and abnormal seedlings and mass of 1000 seeds and the studies of accelerated aging consisted the traditional (with water), with and without fungicid treatment, and accelerated aging with saturated solution of salt (NaCl) for periods of 24, 48, 72, 96 and 120 hours, conditioning at temperatures of 40, 43 and 45oC. The studies concluded that the test of accelerated aging is adjusted to evaluate the vigor of black oats seeds. The test of accelerated aging traditional can be led at the temperature of 40o C for 24 or 48 hours and at 43 or 45oC for 48 hours; the accelerated aging with saturated solution of salt at 40, 43 or 45oC for 24 hours and the traditional accelerated aging with treated seeds at 40oC for 24 or 48 hours, 43oC for 48 hours or 45oC for 24 hours of conditioning. / Mestre

Victoria blight of oats is caused by the fungus Cochhobolus victoriae. This fungus is pathogenic due to its ability to produce the host-selective toxin victorin. Previously, a 100-kD protein that binds victorin in vivo only in susceptible genotypes was identified as the P protein of the glycine decarboxylase complex (GDC). Victorin is a potent in vivo inhibitor of GDC. Leaf slices pretreated with victorin displayed an effective Victorin inhibited the concentration for 50% inhibition (EC������) of 81 ��M for GDA. glycine-bicarbonate exchange reaction in vitro with an EC������ of 23 ��M. We also identified a 15-kD mitochondrial protein in susceptible and resistant genotypes that hound victorin. Amino acid sequence analysis indicated this protein is the H protein component of the GDC. Thus, victorin specifically binds to two components of the GDC. Victorin had no detectable effect on GDC in isolated mitochondria, apparently due to the inability of isolated mitochondria to import victorin. The interaction of victorin with the GDC may be central to victorin's mode of action. Supporting this observation is the finding that CO��� gives partial protection against victorin. Elevated CO��� is known to ameliorate the effect of GDC inhibition. Victorin treated plants incubated in the light develop more severe symptoms than dark-incubated plants. Victorin appears to induce a plant-wide signal transduction cascade, resulting in diverse effects. Victorin induces specific proteolytic cleavage of the Rubisco large subunit (LSU). Leaf slices incubated with victorin for 4 hours in the dark accumulate a form of LSU which is cleaved after the N-terminal lysine 14. LSU cleavage in leaf slices is prevented by the protease inhibitors E-64 and calpeptin. LaCl��� prevents this cleavage of LSU and LaCl��� also confers complete protection against victorin at the whole plant level. Victorin also causes lipid peroxidation as measured by MDA accumulation. DNA laddering is seen in leaves after 3 hr treatment with toxin. The ethylene inhibitors AOA and STS give significant protection against victorin at the whole plant level, and also prevent LSU cleavage. / Graduation date: 1998

<p>Three studies were conducted to evaluate the nutritional value of different oat (Avena sativa) forage cultivars (Assiniboia, Bell and Baler) that were newly emerged cultivars as a result of extensive oat growing conditions in western Canada. A total tract digestibility trial using 24 sheep (n=6) in a completely random design was conducted to assess apparent digestibility of dry matter (DM), organic matter (OM), crude protein (CP), crude fat (EE), acid detergent fiber (ADF), neutral detergent fiber (NDF), hemicellulose, non-structural carbohydrate, acid detergent lignin (ADL), soluble crude protein (SCP), non-protein nitrogen (NPN) and neutral detergent insoluble crude protein (NDICP) in Assiniboia silage, Bell hay, Baler hay and Rosser (barley- Hordeum vulgare) silage. Rumen in situ degradability characteristics of DM, OM, CP, ADF and NDF were determined on Assiniboia silage, Bell hay, Baler hay and Rosser silage at 96 to 0 h using a Holstein cow fitted with a rumen fistula. A dairy production trial using 8 multiparous Holstein cows at 90±20 DIM averaging 41 kg d-1 milk yield, in a 2 × 3 switch-back design was conducted to compare the production response of the cows fed either 48 percent Assiniboia silage or Rosser silage (DM basis) in total mixed rations with the concentrate portion consisting mainly of rolled barley, canola meal and soy meal.</p> <p>Digestibility of DM, OM, NDF, NPN, NDICP and EE were not different for Assiniboia and Rosser silages. Digestibility of DM, NDF and ADF were similar for Baler hay and Rosser silage. Digestibility of hemicellulose, NSC and ADL were similar for all forages. Sheep voluntary intakes of DM, OM, NDF, ADF and EE, except CP were similar across the forages. Assiniboia silage provided more nutrients to the rumen than the hays due to the higher rumen disappearance and effective degradabilities of DM and CP, and lesser undegradable DM, CP, NDF and ADF (P<0.05). Estimated carbohydrate and protein fractions of Assiniboia and Rosser silages were similar. Assiniboia silage was typically comparable to Rosser silage whereas Baler hay was compatible to Bell hay which in contrast was chemically inferior to Baler hay in NDF and TDN content. An increase (8%, P<0.05) in milk fat percentage was observed in cows fed the Assiniboia diet. Milk protein and lactose percentages, and protein yield were higher (P<0.05) in the cows fed the Rosser diet. However, 3.5% fat corrected milk yields were similar. Milk fatty acids (FA) when Assiniboia diet was fed, showed a remarkable increase (P<0.05) in oleate percentage and yield while the others were not different. The increase in oleate content resulted in an increase (P<0.05) in unsaturated FA to saturated FA ratio. Therefore Assiniboia silage would be useful to increase unsaturated long chain milk fat content. It is concluded that Assiniboia silage could substitute for Rosser silage in dairy rations.</p>

Graduation date: 1994

<p>Three studies were conducted to evaluate the nutritional value of different oat (Avena sativa) forage cultivars (Assiniboia, Bell and Baler) that were newly emerged cultivars as a result of extensive oat growing conditions in western Canada. A total tract digestibility trial using 24 sheep (n=6) in a completely random design was conducted to assess apparent digestibility of dry matter (DM), organic matter (OM), crude protein (CP), crude fat (EE), acid detergent fiber (ADF), neutral detergent fiber (NDF), hemicellulose, non-structural carbohydrate, acid detergent lignin (ADL), soluble crude protein (SCP), non-protein nitrogen (NPN) and neutral detergent insoluble crude protein (NDICP) in Assiniboia silage, Bell hay, Baler hay and Rosser (barley- Hordeum vulgare) silage. Rumen in situ degradability characteristics of DM, OM, CP, ADF and NDF were determined on Assiniboia silage, Bell hay, Baler hay and Rosser silage at 96 to 0 h using a Holstein cow fitted with a rumen fistula. A dairy production trial using 8 multiparous Holstein cows at 90±20 DIM averaging 41 kg d-1 milk yield, in a 2 × 3 switch-back design was conducted to compare the production response of the cows fed either 48 percent Assiniboia silage or Rosser silage (DM basis) in total mixed rations with the concentrate portion consisting mainly of rolled barley, canola meal and soy meal.</p> <p>Digestibility of DM, OM, NDF, NPN, NDICP and EE were not different for Assiniboia and Rosser silages. Digestibility of DM, NDF and ADF were similar for Baler hay and Rosser silage. Digestibility of hemicellulose, NSC and ADL were similar for all forages. Sheep voluntary intakes of DM, OM, NDF, ADF and EE, except CP were similar across the forages. Assiniboia silage provided more nutrients to the rumen than the hays due to the higher rumen disappearance and effective degradabilities of DM and CP, and lesser undegradable DM, CP, NDF and ADF (P<0.05). Estimated carbohydrate and protein fractions of Assiniboia and Rosser silages were similar. Assiniboia silage was typically comparable to Rosser silage whereas Baler hay was compatible to Bell hay which in contrast was chemically inferior to Baler hay in NDF and TDN content. An increase (8%, P<0.05) in milk fat percentage was observed in cows fed the Assiniboia diet. Milk protein and lactose percentages, and protein yield were higher (P<0.05) in the cows fed the Rosser diet. However, 3.5% fat corrected milk yields were similar. Milk fatty acids (FA) when Assiniboia diet was fed, showed a remarkable increase (P<0.05) in oleate percentage and yield while the others were not different. The increase in oleate content resulted in an increase (P<0.05) in unsaturated FA to saturated FA ratio. Therefore Assiniboia silage would be useful to increase unsaturated long chain milk fat content. It is concluded that Assiniboia silage could substitute for Rosser silage in dairy rations.</p>

Revised

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