O presente estudo teve por objetivo a avaliação do efeito de estádios de maturidade de cultivares de milho (Zea mays L.) para produção de silagem sobre os parâmetros agronômicos e qualitativos da planta e das frações que a compõem. Foram avaliados seis híbridos de milho para silagem, colhidos em oito estádios de maturidade, em dois anos agrícolas, safra de 2002 e 2003. As plantas atingiram o teor de matéria seca (MS) recomendado para ensilagem (32 a 35% MS) entre 92 e 112 dias após a semeadura (DAS). O híbrido CO 32 apresentou os maiores (P<0,05) teores de MS da planta e do colmo, e as menores (P<0,05) produções MS do colmo ao longo do período de avaliação, enquanto o híbrido P 3041 obteve os menores (P<0,05) teores de MS da planta e do colmo. Os híbridos DKB 333B e AG 1051, de ciclo normal, apresentaram as maiores (P<0,05) produções de colmo no 1&#186;, 3&#186;, 4&#186;, 5&#186; e 8&#186; corte. O avanço da maturidade resultou em aumentos (P<0,05) no teor de MS da planta (de 14,5 para 46%) e do colmo (de 16,9 para 28%), produção de MS da planta (de 9,6 para 20,9 t MS/ha) e produção de grãos (de 0 para 9,3 t MS/ha). Aumentos (P<0,05) nos teores de MS das frações folha (de 23,2 para 48,8%), sabugo (de 10,0 para 55,5%) e grãos (de 50,4 para 70,9%) também foram observados ao longo do tempo. Além disso, observou-se aumentos (P<0,05) nas porcentagens de sabugo (de 1,6 para 9,2%) e grãos (de 0 para 43,4%), e redução (P<0,05) na porcentagem de colmo (de 63,4 para 29,5%) e folhas (de 27,5 para 10,8%). Com o avanço da maturidade foram observados aumentos (P<0,05) nos teores médios de amido da planta (1,8 a 26,1%) e do grão (60,2 a 91,9%); e na produção de matéria seca digestível (PMSD) da planta (7,2 a 16,3 t/ha) e do grão (3,3 a 8,9 t/ha). Em contrapartida, verificou-se redução (P<0,05) nos teores de fibra em detergente neutro (FDN) da planta (71,9 para 52,8%); FDN digestível da planta (64,7 para 54,4%) e do colmo (55,2 para 39,6%); proteína bruta (PB) da planta (12,5 para 7,0%) e do colmo (7,0 para 4,2%); e na digestibilidade verdadeira in vitro da MS (DVIVMS) do colmo (66 para 53,7%) e do grão (99,1 para 96,4%). No ponto de ensilagem, os híbridos P 3041, AG 1051 e Z 8550 foram os materiais que apresentaram as características mais desejáveis na confecção de silagem de qualidade. Para a fração colmo, o híbrido Z 8550 apresentou os menores (P<0,05) teores de PB e FDN, e os maiores (P<0,05) teores de FDN digestível, DVIVMS e PMSD. Os híbridos P 3041, DKB 333B e AG 1051, de endosperma duro, apresentaram juntamente com o híbrido Z 8550, as maiores (P<0,05) PMSD do colmo. No ponto de ensilagem, o maior (P<0,05) teor de amido do grão foi observado para os híbridos de endosperma duro (P 3041 e DKB 333B), enquanto que a maior (P<0,05) DVIVMS do grão foi verificada para os materiais de endosperma dentado (AG 5011 e AG 1051). A avaliação detalhada da planta, levando em consideração a produtividade, a participação percentual dos seus componentes, além da composição química intrínseca dos mesmos é fundamental para a adequação do processo de ensilagem e êxito dos sistemas de produção. / The objective of this experiment was to evaluate the effect of the maturity stage of corn (Zea mays L.) cultivars for silage production on agronomic and qualitative parameters of plant and its compounds. Six corn silage cultivars were evaluated in eight maturity stages, and two harvesting seasons (2002 and 2003). The plants reached the recommended dry matter (DM) content for silage production (32 to 35% DM) between 92 and 112 days after sowing (DAS). The cultivar CO 32 showed the highest (P<0.05) plant and stem DM content, and the lowest (P<0.05) stem DM production along the evaluation period, while P 3041 cultivar achieved the lowest (P<0,05) plant and stem DM content. The normal maturity cycle cultivars DKB 333B and AG 1051, showed the highest (P<0.05) stem production at 1st, 3rd, 4th, 5th and 8th harvesting age. As maturity advance there were increases (P<0.05) of plant DM content, (from 14.5 to 46%), stem DM content (from 16.9 to 28%), plant DM production (from 9.6 to 20.9 t DM/ha) and grain production (from 0 to 9.3 t DM/ha). Increases (P<0.05) of leaves DM content (from 23.2 to 48.8%), cob DM content (from 10 to 55.5%), and grains DM content (from 50.4 to 70.9%) were observed according to the maturity stage. Furthermore, resulted in increases (P<0.05) in cob percentage (from 1.6 to 9.2%) and grain percentage (from 0 to 43.4%), and decreases (P<0.05) in stem percentage (from 63.4 to 29.5%) and leaves percentage (from 27.5 to 10.8%) as plants matured. Plant maturing resulted in increases in plant (1.8 to 26.1%) and grain (60.2 to 91.9%) starch content, and in the plant (7.2 to 16.3 t/ha) and grain (3.3 to 8.9 t/ha) digestible DM production. However there were verified decreases (P<0.05) in plant (71.9 to 52.8%) neutral detergent fiber (NDF), plant (64.7 to 54.4%) and stem (55.2 to 39.6%) digestible NDF, plant (12.5 to 7.0%) and stem (7.0 to 4.2%) crude protein (CP), and stem (66 to 53.7%) and grain (99.1 to 96.4%) in vitro true dry matter digestibility (IVTDMD) content. At the ensilage moment, P 3041, AG 1051 and Z 8550 cultivars showed the most desirable characteristics for silage production with quality. For the stem fraction, Z 8550 cultivar showed the lowest (P<0.05) CP and NDF content, and the highest values (P<0.05) for stem digestible NDF, IVTDMD, and digestible DM productions. The cultivars P 3041, DKB 333B and AG 1051, with hard endosperm, showed together with Z 8550 cultivar, the highest (P<0.05) stem DDMP. For the grain, it was observed that at the ensilage moment, the highest (P<0.05) starch content was verified for the hard endosperm cultivars (P 3041 and DKB 333B), while the highest (P<0.05) IVTDMD was observed for the soft endosperm cultivars (AG 5011 e AG 1051). Grain DDMP was similar (P>0.05) for the evaluated cultivars.

Träd i tropiska våtmarker har uppmärksammats som en viktig källa till regionala och globala metan (CH4) utsläpp, då träd fungerar som utsläppskanaler för metan som bildas i sedimenten. Dock finns det en osäkerhet gällande säsongsvariation och rumslig variation samt mängden CH4 utsläpp från träd, eftersom kunskapen kring regionala flöden är begränsad. Därför strävar vi efter att optimera provtagningsinsatser för att öka möjligheten till representativa uppskattningar för olika typer av skogsekosystem och förbättra kunskapen om rumslig och temporär variabilitet för framtida mätningar i Amazonas. Vi undersökte variabiliteten i flöden av CH4 från träd belägna i tre periodvis översvämmade platser (Solimões, Negro and Tapajós) längs Amazonfloden, med olika karaktäristiska egenskaper. Studien genomfördes in situ med slutna kammare på 36 träd vid de tre provplatserna, under olika hydrologiska säsonger. Platserna visade en stor säsongsvariation i CH4-flöden, med de största bidragen under högvattensäsong. En signifikant skillnad mellan två av platserna upptäcktes endast under högvatten och detta kan vara ett resultat av vattnets varierande fysikaliska och kemiska egenskaper. Med hänsyn till variation inom studieplatserna har indelning av zoner betydelse för mätning av CH4-flöden i träd, då vattennivån är en påverkande faktor. En stor rumslig variation upptäcktes, med lägre flöden i zonen närmast land och med det högsta flödet i zonen där förhållanden varierar mest mellan blött och torrt. Detta mönster kan beaktas genom att utföra provtagningar längs zonerna med hänsyn till vattenavståndet. / Tropical wetland-adapted trees are recognized as an important source of regional and global methane (CH4) emissions, by transport of soil gas through wetland trees. However, spatiotemporal variability and controls on the magnitude of tree-mediated CH4 emissions remain unknown as fluxes are poorly constrained. Therefore, we aim to optimize sampling efforts to yield representative emission estimates for distinct types of forest ecosystems and improve knowledge on spatial and temporal variability. We examined the variability in tree stem mediated CH4 fluxes in situ, located in three different floodplains (Solimões, Negro and Tapajós) with various characteristics, during different hydrological seasons. The sampling was conducted by measuring fluxes from 36 trees at each location using closed chambers. All the three study sites, situated in the Amazon region, displayed seasonal variability in CH4 fluxes, with the largest contributions observed during the wet season. A significant difference between Solimões and Negro was detected during the wet season and this may be a result of the different chemical and physical characteristics between the sampling locations. As for within the study sites, zones played a significant role for CH4 flux from trees since the water level influences the fluxes. A strong spatial variability (lower fluxes in the land zone, and the highest flux obtained in the zone with greatest variability between dry and wet conditions) was found. This pattern can be addressed by sampling along flooded and non-flooded zones. / The Global Methane Budget

Decorticated flax contains a significant amount of shive content, which limits applications of flax fibre. Separation of shives from the fibre is essential to improve the quality of flax fibre. Pneumatic method and a Sorter were implemented to meet the above objective. Terminal velocities of individual flax fibre and shive particles were investigated and their width, length, and mass were recorded. A sorting method was used for separation of short and long fibre for two grades of fibre: Grade 1 and Grade 2, with initial fibre purities of 51% and 15%, respectively. The ranges of terminal velocities for shive and fibre particles were 1.13 to 4.09 m/s and 0.51 to 1.07 m/s, respectively, which were significantly different. Fibre purity of approximately 80% for Grade 1 and 66% for Grade 2 were recorded from sorting, which were a significant improvement when compared to the initial purities. This study demonstrated the potential of the pneumatic and sorting methods for improving fibre quality. With the increase in resistant strains of microorganisms to antibiotics, researchers have started to explore plant parts to discover new antimicrobials. Since medieval times all portions of plants were used medicinally. Plant tissues, including stems, possess secondary metabolites (SMs), which have known antimicrobial properties. The purpose of this study was to investigate: the presence of antimicrobial compounds in stem extracts of canola, flax, hemp, and sweet clover; and study sorption-desorption behavior of their powdered stem material. GC-MS analysis of all extracts showed the presence of many SMs, including fatty acids, terpenoids, steroids, and sterols, etc. Many of the SMs found in the extracts have previously shown antimicrobial activity against a broad spectrum of organisms according to literature. Water sorption isotherms of stems showed a typical IUPAC Type II sigmoid curve similar to natural fibres. Equilibrium moisture content (EMC) of canola and sweet clover was significantly higher than flax and hemp at 95% RH, which were all higher than the fibre saturation point of wood (27%). The preliminary investigation via GC-MS showed promising results and water absorptivity results of stems can be used as the initial key property for many applications. / October 2015

The study was aimed at determining the metabolic fate of sucrose in intact sugarcane internodal tissue. Three aspects of the fate of sucrose in storage tissue of whole plants formed the main focus of the work. These were the rate of sucrose accumulation in the developing culm, the characterisation of partitioning of carbon into different cellular organic fractions in the developing culm and the occurrence of sucrose turnover in both immature and mature stem tissues. Specific attention was paid to confirming the occurrence of sucrose turnover in both immature and mature internodal tissue. This sucrose turnover has been described previously in both tissue slices and cell suspension cultures. However, certain results from previous work at the whole plant level have indicated that sucrose turnover does not occur in mature internodal tissue. Radiolabeled carbon dioxide (14CO2) was fed to leaf 6 of sugarcane culms of a high sucrose storing variety (Saccharum spp. hybrid cv. Nco376). All plants were of similar age (12 months) and were grown under similar conditions. The movement and metabolic fate of radiolabeled sucrose was determined at four time points, (6 hours, 24 hours, 7 days and 6 weeks) during a 6 week period. The metabolic fate of sucrose was determined in internodes number 3, number 6 and number 9. Internode 3 was found to have a relatively high hexose sugar content of 42 mg glc&fruc fw g-1 and a low sucrose content of 14 mg suc fw g-1. In contrast the sucrose content of internode 9 was much higher at 157 mg suc fw g-1 and the hexose sugar content much lower at 4.3 mg glc&fruc fw g-1. Based on previous work, the sugar content of internode 3 and internode 9 are characteristic of immature and mature tissues respectively. Internode 6 occupies an intermediary position between internode 3 and 6 with its sucrose content higher than its hexose sugar content, but with the hexose sugar content still being notable at 15 mg glc&fruc fw g-1. Although the metabolic fate of sucrose within sink tissue was the focal point of the study, the experimental design also allowed for certain aspects of sucrose production in the source to be investigated. The average photosynthetic rate for leaf 6 in full sunlight was estimated at 48 mg CO2 dm-2 s -1. During photosynthesis, only 30% of the fixed carbon was partitioned into the storage carbohydrate pool while the remaining 70% was partitioned into sucrose for immediate export from the leaf. This high rate of carbon fixation combined with a high rate of carbon export is characteristic of C4 plants such as sugarcane. On entering the culm, translocation of radiolabeled sucrose was predominantly basipetal with relatively little acropetal translocation. The majority of the radiolabeled carbon was found to be stored in mature internodes. No significant loss of radiolabeled carbon was observed in mature and elongating internodes over the study period. A 22% loss of total radiolabeled carbon was observed in immature internodes over the same period. This can probably be attributed to the higher rates of cellular respiration known to occur in immature tissues. There appear to be three phases of sucrose accumulation in the developing culm. Initially, the accumulation rate in rapidly growing tissue, as internode 3 develops into internode 6, is relatively low. This is followed by a rapid increase in the rate of sucrose accumulation during internode elongation, as internode 6 becomes internode 9. Finally, a decrease in the rate of sucrose accumulation is observed during late maturation, as internode 9 becomes internode 12. Determination of the sucrose content in internodes 3, 6 and 9 revealed that there is a notable increase in sucrose content during internode maturation. It is proposed that the higher sucrose content of mature tissue is not merely a consequence of the longer growth period of mature tissue, but is due to the increased rate of sucrose accumulation observed during internode elongation. Short-term (24 hours) analysis of carbon partitioning revealed that intemodal maturation was associated with a redirection of carbon from non-sucrose cellulal organic fractions to sucrose storage. In immature internodes only 20% of the total radiolabeled carbon was present in the sucrose pool 24 hours after feeding. In elongating internodes the figure increased to 54% while in mature internodes as much as 77% of the total radiolabeled carbon was retained in the sucrose pool. Concomitant with the increased carbon partitioning into stored sucrose down the developing culm is a decrease in carbon partitioning into the hexose sugar pool. In immature tissue, 42 % of the total radiolabel is present in the hexose sugar pool, while in mature tissue the percentage drops to 11%. This decrease is probably indicative of decreased levels of carbon cycling between the sucrose and hexose sugar pool as a result of internode maturation. Internode maturation was also found to be associated with a decrease in the amount of carbon in the water insoluble matter pool and the amino acid/ organic acid/ sugar phosphate pool. Thus, internode maturation is associated with a redirection of carbon from total respiration to sucrose storage. Long-term (6 weeks) analysis of carbon partitioning confirmed that sucrose storage in mature tissue is greater than that in immature tissue. From the 6 hour time point to the 6 week time point, an 87% reduction in the stored radiolabeled sucrose content was observed in immature internodes. During the same period only a 25% reduction in the stored radiolabeled sucrose was observed in mature internodes. Radiolabel loss from the radiolabeled sucrose pool in both mature and immature internodes was accounted for by relative radiolabel gains in other cellular organic fractions. At all time points during the study, and in all three tissues studied, radiolabel was found in the sucrose pool, the hexose sugars pool, the ionic pool and the water insoluble matter pool. The occurrence of radiolabel in the non-sucrose tissue constituents suggests that sucrose turnover is occurring in both immature, and mature internodal tissue. / Thesis (M.Sc.)-University of Natal, Durban, 2000.

Darbo objektas – pušų, eglių, beržų, alksnių medžių stiebai ir jų iš pagaminta apvaliosios medienos produkcija. Darbo tikslas – Išanalizuoti medienos tūrio skirtumus, kurie susidaro medienos apskaitai naudojant medžių stiebų su žieve tūrio, medžių tūrio struktūros ir rąstų tūrio lenteles. Darbo metodai – statistiniai, empiriniai. Darbo rezultatai. Atlikus tyrimus buvo gauna, kad stiebų tūrio lentelės vidutiniškai 2,2% didina visų medžių rūšių kartu paėmus stiebų su žieve tūrius. Stiebų tūrio lentelės vidutiniškai 4,4% didina pušų stiebų su žieve tūrį, ir 2,5% mažina juodalksnių stiebų su žieve tūrį. Tikrintų biržių imčių duomenys rodo, kad visų medžių rūšių kartu paėmus likvidikės medienos tūris, nustatytas pagal medžių tūrio struktūros lenteles, yra 3.5% padidintas. Vidutinis nelikvidinės medienos tūris bareliuose sudaro 15%. Rąstų tūrio lentelių tikslumas yra pakankamas apvalios medienos tūriui įvertinti. Tūrio skirtumo paklaida yra neesminė. Raktažodžiai: Stiebai, mediena, produkcija, tūrio skirtumai, žievė. / Work object - stems of pinus, picea, alnus and betula and from these produced round wood production. Work goal - to compare stems capacity of the same trees, which is evaluate by trees stems with bark tables with capacity, which is evaluated by compound Huber formula, by structure of trees capacity tables and by capacity of logs tables. Work methods – statisticals, empiricals. Work results – after research was noticed that tables of stems capacity increases all kinds of trees capacity including stems with bark about 2,2%. Tables of stems capacity about 4,4% increase volume of pinus stems with bark and about 2,5% reduce volume of alnus stems with bark. The material of checked plots shows that all kinds of trees liquidated wood capacity, which was evaluated by tables of trees capacity structure is increased 3.5%. Medium not commercial wood capacity in areas contains 15%. Accuracy of logs volume tables is unbiased.

The biochemical basis for the regulation of sucrose accumulation is not fully understood. The present study was thus aimed at investigating aspects of 'coarse' (enzyme activity) and 'fine' (metabolite) control of glycolytic enzyme activity in relation to carbon partitioning in the developing stalk (internodes 3 to 10), and between varieties with significant differences in sucrose content. Particular emphasis was placed on studying pyrophosphate: D-fructose-6-phosphate 1-phosphotransferase (PFP, EC 2.7.1.90), since this enzyme has been implicated in sucrose metabolism in other plant species. Within the developing stalk, internodal maturation was associated with a redirection carbon from the insoluble matter and total respiration (C02 production and biosynthesis) to sucrose storage. Between varieties, with significant variation in sucrose content, there was an inverse relationship between hexose monophosphate partitioning into respiration and sucrose. The reduction in carbon flux to respiration was not associated with a decline in the extractable specific activity of PK, PFK and PFP. There was also no alteration in the regulation of PK, PFK and FBPase by change in the mass action ratios. Hexose monophosphate concentration declined approximately two to three-fold from internodes 3 to 9 and Fru-6-P concentration was within the lower Km or 80.5 range (Fru-6-P) of PFP and PFK, respectively (as reported from the literature) . Within the developing stalk, substrate limitation might have contributed to the decline in carbon partitioning to respiration. In sugarcane, the levels of PFP activity were controlled in part by PFP protein expression. 8ugarcane PFP polypeptide(s) are resolved as a single protein with a molecular mass of approximately 72 kO. PFP catalysed a reaction close to equilibrium in all intemodes investigated, and the concentration of Fru-2,6-P2 was shown to be in excess of the requirement to stimulate PFP activity. Carbon flux from the triose-P to hexose monophosphate pool was apparent in sugarcane, suggesting that PFP activity was functional in vivo. The developmental profile of specific PFP activity was not positively correlated to the increasing rate of sucrose accumulation in the top ten internodes of the developing stalk. Between different sugarcane varieties, specific PFP activity was shown to be inversely correlated to sucrose content. / Thesis (Ph.D.)-University of Natal, Durban, 1997.

Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniversitet, 2005. / Härtill 4 uppsatser.

Diss. (sammanfattning). Uppsala : Sveriges lantbruksuniv., 2003. / Härtill 4 uppsatser.

Diss. (sammanfattning). Umeå : Sveriges lantbruksuniv., 2003. / Härtill 5 uppsatser.

Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniv. / Härtill 5 uppsatser.