Biomass of tree species as a response to planting density and interspecific competition

Planting trees is an important way to promote the recovery of degraded areas in the Caatinga region. Experiments (E1, E2, and E3) were conducted in a randomized blocks design, with three, three, and five replicates, respectively. The objectives were to evaluate biomass of the shoots of: a) gliricidia (G) and sabiá (S), as a response to planting density; b) G, S, and neem (N) in competition; c) G, and S in agroforestry. E1 was conducted in split-plots, and planting densities (400, 600, 800, 1000, and 1200 plants ha-1) as subplots. E2 consisted of a factorial comprising the following plots: GGG, NGN, SGS, NNN, GNG, SNS, SSS, GSG, NSN (each letter represents a row of plants). E3 was conducted with G and S in agroforestry experiment. The trees were harvested after 54, 42, and 27 months old, in E1, E2 and E3, respectively. In E1, G presented higher green biomass of the stems and leaf at smaller densities than S, but lower green biomass of branches at most densities. The species did not differ for mean stem dry biomass and leaf dry biomass, but G showed higher branch dry biomass at most densities. Higher planting densities increased green and dry biomass of stems, branches, and leaves in S, but decreased those characteristics in G, with the exception of leaf dry mass, which was not influenced by density. In E2, the behavior of each species was identical in plots containing the same or different species. Griricidia showed the highest green biomass of stems and branches, and the highest values for geren biomass of the leaf were observed for gliricidia and neem. The highest stem, branch, and leaf dry biomass values were obtained for G, S, and N, respectively. In E3, G was superior for stem and leaf green biomass, and for stem and branch dry biomass. There were no differences between species for the other biomass values.

EVALUATION OF THE POTENTIAL OF SEED RAIN AS AN ALTERNATIVE FOR FOREST RESTORATION IN PERMANENT PRESERVATION AREAS1

ABSTRACT The ecological restoration of degraded areas using seeds collected in forest remnants has shown significant results. This study was developed to verify the potential of seed rain to regenerate forest fragments of a Permanent Preservation Area (PPA) in the Apa River Basin which is located in the southwestern portion of the Mato Grosso do Sul state, Brazil. To develop the study, we installed 25 collectors measuring 1 m2 each, which were systematically distributed on an area of 1.5ha. Seed gathering was conducted in a monthly basis throughout the year of 2013. A total of 26.411 propagules were identified and distributed among 50 species, 45 genera and 32 families. In terms of the propagules distribution, 70.51% were identified as trees, 22.8% as lianas, 6.5% as shrubs, 0.1 as herbaceous, 0.05% as palm and 0.05% could not be classified. The value for the Shannon Diversity Index was (H') = 1.67 and the Pielou Evenness index was (J) = 0.42. These results indicate that the seeds rain has low species diversity with the abundance of a few species. The overall results suggest that seed rain can be a potential technique for restoration of the PPAs and other forested areas. However, it is necessary to enhance the diversity of tree species.

Application of electrokinetic Fenton process for the remediation of soil contaminated with HCB

Electrokinetic remediation coupled with Fenton oxidation, widely called as Electrokinetic Fenton process is a potential soil remediation technique used for low permeable soil. The applicability of the process has been proved with soil contaminated with a wide range of organic compounds from phenol to the most recalcitrant ones such as PAHs and POPs. This thesis summarizes the major findings observed during an Electrokinetic Fenton Process study conducted for the remediation of low permeable soil contaminated with HCB, a typical hydrophobic organic contaminant. Model low permeable soil, kaolin, was artificially contaminated with HCB and subjected to Electrokinetic Fenton treatments in a series of laboratory scale batch experiments. The use of cyclodextrins as an enhancement agent to mobilize the sorbed contaminant through the system was investigated. Major process hindrances such as the oxidant availability and treatment duration were also addressed. The HCB degradation along with other parameters like soil pH, redox and cumulative catholyte flow were analyzed and monitored. The results of the experiments strengthen the existing knowledge on electrokinetic Fenton process as a promising technology for the treatment of soil contaminated with hydrophobic organic compounds. It has been demonstrated that HCB sorbed to kaolin can be degraded by the use of high concentrations of hydrogen peroxide during such processes. The overall system performances were observed to be influenced by the point and mode of oxidant delivery. Furthermore, the study contributes to new knowledge in shortening the treatment duration by adopting an electrode polarity reversal during the process.

Identification and characterization of CIP2A as a novel oncogenic inhibitor of PP2A

Inhibition of the tumor suppressor protein phosphatase 2A (PP2A) activity has been identified as one of the five key alterations required for human cell transformation. Regardless of this crucial role in human cancer development, the detailed mechanisms by which PP2A inhibition occurs in human cancers remain largely uncharacterized. PP2A regulates a plethora of cellular signaling cascades. One of the targets of PP2A is Myc oncoprotein, which is destabilized and degraded in response to PP2A-mediated dephosphorylation of Myc serine 62. In this study we identify Cancerous Inhibitor of PP2A (CIP2A) as a previously uncharacterized endogenous inhibitor of PP2A in human cancer cells. CIP2A inhibits PP2A activity leading to subsequent stabilization of the Myc protein. CIP2A promotes malignant growth of cancer cells in vitro and xenograft tumor formation in vivo and is overexpressed in cancer. Moreover, we explored the effect of CIP2A on global transcriptional profiles and validated a CIP2A-dependent transcriptional signature. Analysis of the CIP2A signature revealed both Myc-dependent and -independent functions for CIP2A. Importantly, we demonstrate that the CIP2A signature has clinical relevance in human breast cancer subtypes. Finally, we identify the genes potentially mediating the long-term growth suppression in CIP2A depleted cancer cells. Taken together, this work identifies CIP2A as a novel human oncoprotein and describes its function in cancer cells. These results may open novel possibilities for patient stratification and therapeutic intervention of cancer.

Electro-Oxidation Treatment of Pulp and Paper Mill Circulating Waters and Wastewaters

Interest in water treatment by electrochemical methods has grown in recent years. Electrochemical oxidation has been applied particularly successfully to degrade different organic pollutants and disinfect drinking water. This study summarizes the effectiveness of the electrochemical oxidation technique in inactivating different primary biofilm forming paper mill bacteria as well as sulphide and organic material in pulp and paper mill wastewater in laboratory scale batch experiments. Three different electrodes, borondoped diamond (BDD), mixed metal oxide (MMO) and PbO2, were employed as anodes. The impact on inactivation efficiency of parameters such as current density and initial pH or chloride concentration of synthetic paper machine water was studied. The electrochemical behaviour of the electrodes was investigated by cyclic voltammetry with MMO, BDD and PbO2 electrodes in synthetic paper mill water as also with MMO and stainless steel electrodes with biocides. Some suggestions on the formation of different oxidants and oxidation mechanisms were also presented during the treatment. Aerobic paper mill bacteria species (Deinococcus geothermalis, Pseudoxanthomonas taiwanensis and Meiothermus silvanus) were inactivated effectively (>2 log) at MMO electrodes by current density of 50 mA/cm2 and the time taken three minutes. Increasing current density and initial chloride concentration of paper mill water increased the inactivation rate of Deinococcus geothermalis. The inactivation order of different bacteria species was Meiothermus silvanus > Pseudoxanthomonas taiwanensis > Deinococcus geothermalis. It was observed that inactivation was mainly due to the electrochemically generated chlorine/hypochlorite from chloride present in the water and also residual disinfection by chlorine/hypochlorite occurred. In real paper mill effluent treatment sulphide oxidation was effective with all the different initial concentrations (almost 100% reduction, current density 42.9 mA/cm2) and also anaerobic bacteria inactivation was observed (almost 90% reduction by chloride concentration of 164 mg/L and current density of 42.9 mA/cm2 in five minutes). Organic material removal was not as effective when comparing with other tested techniques, probably due to the relatively low treatment times. Cyclic voltammograms in synthetic paper mill water with stainless steel electrode showed that H2O2 could be degraded to radicals during the cathodic runs. This emphasises strong potential of combined electrochemical treatment with this biocide in bacteria inactivation in paper mill environments.

Mäskin sisältämän ligniinin modifiointi PCD-hapetuksella

Teoriaosassa tutkittiin mäskin muodostumista oluentuotantoprosessissa, ligniiniä ja sen pilkkoutumista hapetuksella, eri kehittyneitä hapetusmenetelmiä ja hapetuksella saatavia potentiaalisia pääkomponentteja. Kehittyneissä hapetusmenetelmissä keskityttiin pääasiassa pulssitettuun koronapurkaukseen perustuvaan PCD-menetelmään (Pulsed Corona Discharge). Tutkittavana pääkomponenttina toimi glyoksyylihappo. Työn kokeellisessa osassa tutkittiin mäskistä erotetun ligniinin pilkkoutumista PCD-hapetuksella. Tässä menetelmässä hapetus perustuu sähköpurkauksen aikana syntyvien hydroksyyliradikaalien ja otsonin muodostumiseen, jotka voivat toimia hapettimina. Kokeissa käytettiin oluentuotannosta saatua mäskiä, josta ligniiniä liuotettiin natriumhydroksidi-vesi-liuoksen avulla uuttamalla.. Tämän jälkeen liuosta käsiteltiin PCD laitteistossa. PCD-käsiteltyä tuotetta analysoitiin mittaamalla ligniinin ja aldehydien pitoisuudet siitä spektrofotometrin avulla. Työn tarkoituksena on tutkia PCD hapetusmenetelmän soveltuvuutta mäskin sisältämän ligniinin muokkaamiseen siten, että siitä syntyvää tuotetta voitaisiin käyttää jossakin muussa sovelluksessa, kuten esimerkiksi lääkkeiden raaka-aineena lääketeollisuudessa. PCD hapetusmenetelmä on koronasähköpurkauksiin perustuva laite, jota käytetään pääasiassa vedenpuhdistuksessa hajoittamaan haitallisia orgaanisia yhdisteitä. Tämän työn perusteella ligniiniä hajosi, aldehydejä muodostui ja hapetusnäytteiden pH laski hapetusajan kasvaessa. Tämä viittasi vahvasti glyoksyylihapon muodostumiseen PCD-laitteistossa.

Potential for seed bank formation of two weed species from Brazilian Amazonia

The potential for seed bank formation of two perennial weed species, Ipomoea asarifolia (Desr.) Roem. & Schult. (Convolvulaceae) and Stachytarpheta cayennensis (Rich.) M. Vahl (Verbenaceae), both common in Amazonia , was evaluated in a degraded pasture area in eastern Brazilian Amazonia . Seeds were enclosed in nylon mesh packets and placed at the soil surface or buried at 5 or 10 cm deep. The number of viable seeds was recorded at 6, 10, 14 and 18 months after burial. Results showed that S. cayennensis has the ability to form persistent soil seed bank, while I. asarifolia seeds do not build up in the soil seed bank. For S. cayennensis and, to some extent, for I. asarifolia, seed survival was highest at greater burial depths.

Unexpected effects of pigeon-peas (Cajanus cajan) in the restoration of rupestrian fields

Several degraded areas can be found along the Highway MG-010 that crosses the Espinhaço Mountain Biosphere Reserve in the Brazilian state of Minas Gerais. Restoration by planting the legume Cajanus cajan was implemented in some of these areas. The present study compares plant species richness, diversity, abundance, equitability, similarity, and soil composition between restored and non-restored areas, in an attempt to evaluate the effectiveness of the use of C. cajan in the restoration process in the mountain environment. Each treatment (restored and non-restored) had four sampling areas, each with three 300 m² plots. We counted and identified every individual plant found within these plots. We also collected soil from the superficial layer (0-10 cm) of each sampling area in both treatments. The areas where C. cajan was planted revealed lower species richness, diversity, and plant abundance. The soil of these areas also contained higher levels of Phosphorus and Magnesium. Plant equitability and similarity between plots and other soil components (pH, Nitrogen, Aluminum, Calcium, Potassium, H+Al, sum of bases - SB, cation exchange capacity - CTC, base saturation - V%, aluminum saturation - M%) did not differ between the two treatments. Contrary to the expectations, soil enhancement in the quartzitic soil poor in nutrients in the rupestrian fields can facilitate the invasion by exotic plants, which are not adapted to the lack of nutrients. As it appears, the use of C. cajan in restoration projects represents a mistake and future restoration plans should avoid the use of exotic species, given that they may cause negative effects on the native plant community, as demonstrated here in the rupestrian fields.

Pressure filtration characteristics of enzymatically hydrolyzed biomass suspensions

Enzymatic hydrolysis of lignocellulosic polymers is likely to become one of the key technologies enabling industrial production of liquid biofuels and chemicals from lignocellulosic biomass. Certain types of enzymes are able to hydrolyze cellulose and hemicellulose polymers to shorter units and finally to sugar monomers. These monomeric sugars are environmentally acceptable carbon sources for the production of liquid biofuels, such as bioethanol, and other chemicals, such as organic acids. Liquid biofuels in particular have been shown to contribute to the reduction of net emissions of greenhouse gases. The solid residue of enzymatic hydrolysis is composed mainly of lignin and partially degraded fibers, while the liquid phase contains the produced sugars. It is usually necessary to separate these two phases at some point after the hydrolysis stage. Pressure filtration is an efficient technique for this separation. Solid-liquid separation of biomass suspensions is difficult, because biomass solids are able to retain high amounts of water, which cannot be readily liberated by mechanical separation techniques. Most importantly, the filter cakes formed from biomaterials are compressible, which ultimately means that the separation may not be much improved by increasing the filtration pressure. The use of filter aids can therefore facilitate the filtration significantly. On the other hand, the upstream process conditions have a major influence on the filtration process. This thesis investigates how enzymatic hydrolysis and related process conditions affect the filtration properties of a cardboard suspension. The experimental work consists of pressure filtration and characterization of hydrolysates. The study provides novel information about both issues, as the relationship between enzymatic hydrolysis conditions and subsequent filtration properties has so far not been considered in academic studies. The results of the work reveal that the final degree of hydrolysis is an important factor in the filtration stage. High hydrolysis yield generally increases the average specific cake resistance. Mixing during the hydrolysis stage resulted in undefined changes in the physical properties of the solid residue, causing a high filtration resistance when the mixing intensity was high. Theoretical processing of the mixing data led to an interesting observation: the average specific cake resistance was observed to be linearly proportional to the mixer shear stress. Another finding worth attention is that the size distributions of the solids did not change very dramatically during enzymatic hydrolysis. There was an observable size reduction during the first couple of hours, but after that the size reduction was minimal. Similarly, the size distribution of the suspended solids remained almost constant when the hydrolyzed suspension was subjected to intensive mixing. It was also found that the average specific cake resistance was successfully reduced by the use of filter aids. This reduction depended on the method of how the filter aids were applied. In order to obtain high filtration capacity, it is recommended to use the body feed mode, i.e. to mix the filter aid with the slurry prior to filtration. Regarding the quality of the filtrate, precoat filtration was observed to produce a clear filtrate with negligible suspended solids content, while the body feed filtrates were turbid, irrespective of which type of filter aid was used.

Sorption and desorption of picloram in soils under pastures in Brazil

The objective of this work was to determine the coefficients of sorption and desorption of picloram in Ultisol (PVA) and Oxisol (LVA), displaying different physical and chemical characteristics. Samples of soil were collected at the 0 20 cm depth in degraded pasture areas in Viçosa-MG. Firstly, the equilibrium time between the herbicide in solution and the herbicide which was sorbed in the soil was determined by the Batch Equilibrium method. The time required was 24 hours. Sorption and desorption studies were carried out under controlled laboratory conditions; the sorption evaluation consisted in adding 10.0 mL of herbicide solutions at different concentrations to tubes containing 2.00 g of soil, with vertical rotary agitation being maintained during the pre-determined equilibrium time. After centrifugation, supernatant extract cleaning and filtration, herbicide concentration was determined by high performance liquid chromatography (HPLC) with UV detection at 254 nm. Desorption was evaluated using the samples in the tubes after the sorption tests. The Freundlich model was used for interpretation of the sorption process. Ultisol showed higher adsorption coefficient (Kf a) compared with Oxisol, which may be attributed to the lower pH of the soil and its higher organic matter content. Desorption process occurred in both soils; the LVA allowed greater release of the previously sorbed molecules.

Determinants of Polylepis (Rosaceae) Forest Distribution and Treeline Formation in the High Andes

High elevation treelines are formed under common temperature conditions worldwide, but the functional mechanisms that ultimately constrain tree growth are poorly known. In addition to environmental constraints, the distribution of high elevation forests is largely affected by human influence. Andean Polylepis (Rosaceae) forests are an example of such a case, forests commonly growing in isolated stands disconnected from the lower elevation montane forests. There has been ample discussion as to the role of environmental versus anthropogenic causes of this fragmented distribution of Polylepis forests, but the importance of different factors is still unclear. In this thesis, I studied functional, environmental and anthropogenic aspects determining Polylepis forest distribution. Specifically, I assessed the degree of genetic determinism in the functional traits that enable Polylepis species to grow in cold and dry conditions. I also studied the role of environment and human influence constraining Polylepis forest distribution. I found evidence of genetically determined climatic adaptations in the functional traits of Polylepis. High elevation species had reduced leaf size and increased root tip abundance compared to low elevation species. Thus these traits have potentially played an important role in species evolution and adaptation to high elevation habitats, especially to low temperatures. I also found reduced photosynthesis rate among high elevation tree species compared to low elevation species, supporting carbon source limitation at treelines. At low elevations, Polylepis forest distribution appeared to be largely defined by human influence. This suggests that the absence of Polylepis forests in large areas in the Andes is the result of several environmental and anthropogenic constraints, the role of environment becoming stronger towards high elevations. I also show that Polylepis trees grow at remarkably low air and soil temperatures near treelines, and present new evidence of the role of air temperatures in constraining tree growth at high elevations. I further show that easily measurable indices of accessibility are related to the degree of degradation of Polylepis forest, and can therefore be used in the rapid identification of potentially degraded Polylepis forests. This is of great importance for the conservation and restoration planning of Polylepis forests in the Andes. In a global context, the results of this thesis add to our scientific knowledge concerning high elevation adaptations in trees, and increase our understanding of the factors constraining tree growth and forest distribution at high-­elevation treelines worldwide.

CARDINAL TEMPERATURES FOR GERMINATION OF THE MEDICINAL ANDDESERT PLANT, Calotropis procera

ABSTRACT Calotropis procera, Apocynaceae, is a wild perennial shrub that originated in the Persian deserts. It is known to provide key resources in degraded ecosystems to about 80 animal species. C. procera is regenerated by seed and produces lots of small seeds that are dispersed by wind; nonetheless, its density is very low. The purpose of this study is to estimate the cardinal temperatures including the base, optimum, and maximum temperatures of Calotropis procera looking at two different ecotypes in the Iranian desert. The germination behavior of C. procera seeds was tested at temperature regimens of 0, 5, 10, 15, 20, 25, 30, 35 and 40oC and was analyzed using linear regression models. The rate of germination increased between base and optimum thermal conditions, and decreased between optimum and maximum thermal conditions. The base, optimum and maximum temperatures for germination of C. procera seeds were estimated at 19.10, 30.75 and 47.80 oC for the Fars and 20.00, 31.82 and 49.69oC for the Zahedan desert, respectively. Temperature and germination were rated to determine the seeding dates of the C. procera. Overall, cardinal temperatures for germination were dependent on local climate characteristics for the range of adaptations in plant growth of the given species.

Atlantic Forest succession over calcareous soil, Parque Estadual Turístico do Alto Ribeira - PETAR, SP

The forest succession after abandonment of slash-and-burn agriculture over calcareous soil in Brazilian Atlantic Forest was assessed. This is one of the world's most threatened Biome, with only 8% remaining. The study area is located over calcareous soil inside the Alto Ribeira Touristic State Park (PETAR), southeast Brazil. The phytossociological survey showed a successional pattern dominated by species of Leguminosae, especially Piptadenia gonoacantha (Mart.) J.F. Macbr. This species occurs in calcareous soils as a substitute of Tibouchina pulchra (Cham.) Cogn. (Melastomataceae) that is the most usual dominant tree species in early succession over acidic soil, which is the most common situation in this Biome. These results are important for a better understanding of Neotropical forest biodiversity and characterize a unique genetic bank in this highly endangered Biome. They are also decisive to support actions regarding rehabilitation of degraded lands and a potential tool for Neotropical forest sustainable management, both inside and around the conservation unit.

Ovule ontogeny of Tabebuia pulcherrima Sandwith (Bignoniaceae): embryo sac development

The chalazal megaspore develops in a Polygonum-type embryo sac. The amyloplast-rich endothelium is partially degraded during the expansion of the micropylar portion of the megagametophyte. Organization of the mature embryo sac is determined by the patterns of vacuolation, nuclear migration, spindle orientation and cellularization. The egg cell is slightly chalazal in relation to the synergids, and its micropylar end does not touch the micropylar channel. At the chalazal pole of the egg apparatus, the common walls between the synergids, the egg and central cells, despite their tenuity, are present in the mature megagametophyte. The polar nuclei do not fuse before fertilization and the antipodals are persistent until the first stages of endosperm formation. The taxonomic significance of some embryological characters for the Bignoniaceae is discussed.

Regulation of HSF2 and its function in mitosis

The cell is continuously subjected to various forms of external and intrinsic proteindamaging stresses, including hyperthermia, pathophysiological states, as well as cell differentiation and proliferation. Proteindamaging stresses result in denaturation and improper folding of proteins, leading to the formation of toxic aggregates that are detrimental for various pathological conditions, including Alzheimer’s and Huntington’s diseases. In order to maintain protein homeostasis, cells have developed different cytoprotective mechanisms, one of which is the evolutionary well-conserved heat shock response. The heat shock response results in the expression of heat shock proteins (Hsps), which act as molecular chaperones that bind to misfolded proteins, facilitate their refolding and prevent the formation of protein aggregates. Stress-induced expression of Hsps is mediated by a family of transcription factors, the heat shock factors, HSFs. Of the four HSFs found in vertebrates, HSF1-4, HSF1 is the major stress-responsive factor that is required for the induction of the heat shock response. HSF2 cannot alone induce Hsps, but modulates the heat shock response by forming heterotrimers with HSF1. HSFs are not only involved in the heat shock response, but they have also been found to have a function in development, neurodegenerative disorders, cancer, and longevity. Therefore, insight into how HSFs are regulated is important for the understanding of both normal physiological and disease processes. The activity of HSF1 is mainly regulated by intricate post-translational modifications, whereas the activity of HSF2 is concentrationdependent. However, there is only limited understanding of how the abundance of HSF2 is regulated. This study describes two different means of how HSF2 levels are regulated. In the first study it was shown that microRNA miR-18, a member of the miR-17~92 cluster, directly regulates Hsf2 mRNA stability and thus protein levels. HSF2 has earlier been shown to play a profound role in the regulation of male germ cell maturation during the spermatogenesis. The effect on miR-18 on HSF2 was examined in vivo by transfecting intact seminiferous tubules, and it was found that inhibition of miR-18 resulted in increased HSF2 levels and modified expression of the HSF2 targets Ssty2 and Speer4a. HSF2 has earlier been reported to modulate the heat shock response by forming heterotrimers with HSF1. In the second study, it was shown that HSF2 is cleared off the Hsp70 promoter and degraded by the ubiquitinproteasome pathway upon acute stress. By silencing components of the anaphase promoting complex/cyclosome (APC/C), including the co-activators Cdc20 and Cdh1, it was shown that APC/C mediates the heatinduced ubiquitylation of HSF2. Furthermore, down-regulation of Cdc20 was shown to alter the expression of heat shock-responsive genes. Next, we studied if APC/C-Cdc20, which controls cell cycle progression, also regulates HSF2 during the cell cycle. We found that both HSF2 mRNA and protein levels decreased during mitosis in several but not all human cell lines, indicating that HSF2 has a function in mitotic cells. Interestingly, although transcription is globally repressed during mitosis, mainly due to the displacement of RNA polymerase II and transcription factors, including HSF1, from the mitotic chromatin, HSF2 is capable of binding DNA during mitosis. Thus, during mitosis the heat shock response is impaired, leaving mitotic cells vulnerable to proteotoxic stress. However, in HSF2-deficient mitotic cells the Hsp70 promoter is accessible to both HSF1 and RNA polymerase II, allowing for stress-inducible Hsp expression to occur. As a consequence HSF2-deficient mitotic cells have a survival advantage upon acute heat stress. The results, presented in this thesis contribute to the understanding of the regulatory mechanisms of HSF2 and its function in the heat shock response in both interphase and mitotic cells.