Phenotypic plasticity of root system and shoots of Sorghum bicolor under different soil water levels during pre-flowering stage.

In order to understand possible relationships among the features of plant organs located above and below soil, their correlation and how it might affect strategies for drought adaptation, two sorghum lines contrasting in drought tolerance (BR007-sensitive and 99100-tolerant) were cultivated under different soil water levels during pre-flowering stage. Half of the plants of each genotype remained under daily irrigation to maintain the soil moisture close to FC, and the other half was subjected to WD. After 10 days in these conditions, physiological and anatomical characteristics of the lines were evaluated and then water supply was restored and maintained at optimum levels by the end of the cycle. At physiological maturity, the root morphology and agronomic parameters associated to productivity were analyzed. Regardless the variation in the soil moisture, plants of the line 99100 presented values significantly superior for HI, RDB and LA compared to plants of the BR007 line, whereas the A values were lower. Only line 99100 plants increased VFRL compared to its counterparts under FC. The lack of change in root morphology in line BR007 plants was accompanied by increase in CAT activity and lower DBV in leaves. The increase in CAT activity was not sufficient to reduce the pool of H2O2 in leave cells of BR007 under WD, leading to a decrease in FvFm. Thus, the H2O2 accumulated in the leaf was deviated to the lignin biosynthesis, corroborating the lower DVB in leaves of BR007 line under WD, compared to line 99100 under WD. In addition, BR007 plants showed smaller DBC under WD, which simultaneously led to an increase in NBC. Such structural and functional adjustment at the leaf level would compensate the absence of changes in the root architecture in response to the stress generated by the WD

Phenotypic plasticity of root system and shoots of Sorghum bicolor under different soil water levels during pre-flowering stage.

In order to understand possible relationships among the features of plant organs located above and below soil, their correlation and how it might affect strategies for drought adaptation, two sorghum lines contrasting in drought tolerance (BR007-sensitive and 99100-tolerant) were cultivated under different soil water levels during pre-flowering stage. Half of the plants of each genotype remained under daily irrigation to maintain the soil moisture close to FC, and the other half was subjected to WD. After 10 days in these conditions, physiological and anatomical characteristics of the lines were evaluated and then water supply was restored and maintained at optimum levels by the end of the cycle. At physiological maturity, the root morphology and agronomic parameters associated to productivity were analyzed. Regardless the variation in the soil moisture, plants of the line 99100 presented values significantly superior for HI, RDB and LA compared to plants of the BR007 line, whereas the A values were lower. Only line 99100 plants increased VFRL compared to its counterparts under FC. The lack of change in root morphology in line BR007 plants was accompanied by increase in CAT activity and lower DBV in leaves. The increase in CAT activity was not sufficient to reduce the pool of H2O2 in leave cells of BR007 under WD, leading to a decrease in FvFm. Thus, the H2O2 accumulated in the leaf was deviated to the lignin biosynthesis, corroborating the lower DVB in leaves of BR007 line under WD, compared to line 99100 under WD. In addition, BR007 plants showed smaller DBC under WD, which simultaneously led to an increase in NBC. Such structural and functional adjustment at the leaf level would compensate the absence of changes in the root architecture in response to the stress generated by the WD.Made available in DSpace on 2017-06-06T23:54:28Z (GMT). No. of bitstreams: 1 Phenotypicplasticity.pdf: 435561 bytes, checksum: 0e778c5d00d14b199a96d77133f11e52 (MD5) Previous issue date: 2016-12-01201

Emissões otoacústicas por produtos de distorção em ovinos normais e após indução de hiperinsulinemia Distortion product otoacoustic emissions in sheep before and after hyperinsulinemia induction

As emissões otoacústicas transientes evocadas e as emissões otoacústicas por produtos de distorção vêm assumindo importância significativa na identificação de alterações cocleares. OBJETIVO: Através da monitorização das emissões otoacústicas, registrar os limiares dos produtos de distorção em condições normais e na presença de modificações eletrofisiológicas nas células ciliadas externas cocleares de ovelhas após a indução de hiperinsulinemia aguda. MATERIAL E MÉTODO: Estudo experimental com sete ovelhas no grupo-controle e sete no grupo-estudo. Os níveis de insulina e glicose foram verificados simultaneamente ao registro das emissões otoacústicas por produtos de distorção de 10 em 10 minutos, até o tempo de 90 minutos. O grupo-controle recebeu soro fisiológico, e o grupo-estudo, injeção em bolo de 0,1 U/kg de insulina humana regular. RESULTADOS: Houve diminuição significante nos limiares dos produtos de distorção no grupo-estudo em relação ao grupo-controle nas freqüências acima de 1.500 Hz e após o tempo de 60 minutos (P < 0,001). CONCLUSÃO: O estudo permitiu estabelecer os limiares das emissões otoacústicas por produtos de distorção em ovelhas com constante reprodutibilidade, o que mostra que o método é adequado para uso em investigações audiológicas e otológicas. Ficou, ainda, plenamente identificado que o hiperinsulinismo agudo foi capaz de provocar relevantes modificações nestes limiares.<br>Transient evoked otoacoustic emissions and distortion product otoacoustic emissions have gained significant importance in the identification of cochlear alterations. AIM: To record distortion product thresholds through the monitoring of otoacoustic emissions in normal conditions and in the presence of electrophysiologic changes in cochlear outer hair cells in sheep after hyperinsulinemia induction. MATERIAL AND METHODS: Experimental study, with seven sheep in the control group and seven in the study group. Insulin and glucose concentrations were measured simultaneously for the recording of distortion product otoacoustic emission every 10 minutes, all the way to 90 minutes. The control group received saline solution, and the study group received a bolus injection of 0.1 U/kg of regular human insulin. RESULTS: There was a significant reduction in distortion product thresholds in the study group when compared to the control group at frequencies greater than 1,500Hz and after 60 minutes (P < 0.001). CONCLUSION: This study established distortion product otoacoustic emission thresholds in sheep with constant reproducibility, demonstrating that the method is adequate for use in audiology and otology investigations. Results also fully confirm that acute hyperinsulinemia may cause important changes in these thresholds

Crescimento, partição de biomassa e fotossíntese em plantas jovens de Genipa spruceana submetidas ao alagamento

Genipa spruceana Steyerm (Rubiaceae) is a species often found in flooded environments in the central Amazonia. The objective of this study was elucidate possible adaptive strategies that enable this species to occupy environments under flooding, targeting the potential of the species for restoration of floodplains. In order to achieve these objectives growth traits, number of leaves, leaf expansion, biomass production, carbon assimilation and stomatal conductance were investigated in G. spruceana seedlings subjected to treatments: 1- Non flooded plants (control –SA), 2- partially flooded (PA) and 3- completely flooded (TA) up to 90 days. Flooded treatments (PA and TA) induced smaller increments in all variables of height and diameter growth when compared to the control treatment. With increase of flooding, biomass allocation to leaves decreased until complete leaf abscission in TA, while increased in the stem. In PA treatment was observed reduction in C assimilation rates of 58% and 64% after 60 and 90 days, respectively, and 96% after 60 days in TA treatment. However, in the end of the experiment all treatments presented 100% of survival. Our results indicate that the loss of leaves and gain of the stem biomass can be protective strategy to alleviate the harmful effects of the flooding. On the other hand, the maxim survival rates suggest that G. spruceana exhibit high potential for establishment in frequently flooded areas