INITIAL DEVELOPMENT OF FIVE TREE SPECIES NATIVE TO THE ATLANTIC FOREST IN RECOMPOSITION PLANTATIONS IN SOUTHERN BRAZIL

The regularization of rural properties in the molds of the New Forest Code depends on the silvicultural study of the native species of the Brazilian biomes. The objective of this study was to evaluate the initial growth of five native tree species of the Atlantic Forest, with a view to their use in forest restoration projects. The following species were produced in the nursery, planted in the field, and evaluated for performance: Araucaria angustifolia, Mimosa scabrella, Trichilia claussenii, Schizolobium parahyba, and Cordia trichotoma. These species were distributed in two different areas, based on the randomized block experimental design. In experiment 1, the species A. angustifolia, M. scabrella, and C. trichotoma were distributed in three randomized blocks, each composed of 11 plants of each species. In experiment 2, the species A. angustifolia, M. scabrella, T. claussenii, and S. parahyba were distributed in three randomized blocks, each one composed of five plants of each species. In general, S. parahyba and M. scabrella showed faster development than the other species and, in this regard, are promising candidates for forest areas constitution or reconstitution in which there is interest in obtaining economic returns in less time. Araucaria angustifolia and T. claussenii showed relatively low development, whereas C. trichotoma showed intermediate development in relation to the other species studied. Despite their differences in performance, all species proved to be suitable for use in reforestation, mainly in the region where the study was developed

GROWTH AND PHYSIOLOGY OF Balfourodendron riedelianum SEEDLINGS IN THE NURSERY AND IN THE FIELD

The present study aimed to determine the effect of different container volumes and doses of controlled release fertilizer (CRF) on the morphophysiological aspects of Balfourodendron riedelianum seedlings in the nursery and verify if these responses were replicated in the field. For the production of seedlings in nursery, three container volumes (180 and 280 cm³ polypropylene tubes and 500 cm³ plastic bags) and four doses of CRF (0, 4, 8, and 12 g L-1 of substrate) were tested, and the seedlings were grown for 240 days. At the end of the nursery period, the following parameters were measured: height (H); stem diameter (SD); dry mass of shoot, root, and total; root length; leaf area; and chlorophyll fluorescence. The H/SD ratio and the Dickson Quality Index were calculated. The same treatments were evaluated in the field at 540 days after planting. Survival, height, and diameter increase, aerial dry mass, leaf area, chlorophyll a fluorescence and chlorophyll index (a, b and total) were measured. Basic fertilization using CRF had a positive influence on the production of B. riedelianum seedlings. It is recommended to use a 180 cm³ tube and a dose of 12 g L-1 CRF for the production of seedlings. The results obtained in the nursery for the production of seedlings were confirmed to occur in the field

Aspectos eco-fisiológicos limitantes da regeneração natural

Natural regeneration comprises the initial stages of establishment and development, and is considered a slow and unpredictable process, due to the complex interaction between the successful establishment of seedlings and different environmental factors. Thus, the aim of this study was show a review addressing eco-physiological factors influencing the natural regeneration of forests as reserves of seed, production and seed dispersal, germination and dormancy, temperature, and water availability and light. Knowledge of the effect of these factors and their interactions with the community are essential to forest management, regarding its management and revegetation of disturbed areas. Thus, simulations of regeneration constitute naturally a very useful tool.A regeneração de florestas compreende as etapas iniciais de estabelecimento e desenvolvimento, sendo considerada um processo lento e imprevisível, devido à complexa interação entre o sucesso no estabelecimento de plântulas e os fatores ambientais. Desse modo, esse trabalho teve como objetivo apresentar uma revisão bibliográfica abordando aspectos ecofisiológicos que influenciam a regeneração natural de florestas, como reserva da semente, produção e dispersão de sementes, dormência e germinação, temperatura, e disponibilidade de água e luz. O conhecimento do efeito desses fatores e suas interações com a comunidade são essenciais para a gestão das florestas, no que tange o seu manejo e a revegetação de áreas alteradas. Nesse sentido, simulações de regeneração constituem, naturalmente, uma ferramenta muito útil

Biosynthesis of triacylglycerols (tags) in plants and algae

Triacylglycerols (TAGs), which consist of three fatty acids bound to a glycerol backbone, are major storage lipids that accumulate in developing seeds, flower petals, pollen grains, and fruits of innumerous plant species. These storage lipids are of great nutritional and nutraceutical value and, thus, are a common source of edible oils for human consumption and industrial purposes. Two metabolic pathways for the production of TAGs have been clarified: an acyl CoA-dependent pathway and an acyl-CoA-independent pathway. Lipid metabolism, specially the pathways to fatty acids and TAG biosynthesis, is relatively well understood in plants, but poorly known in algae. It is generally accepted that the basic pathways of fatty acid and TAG biosynthesis in algae are analogous to those of higher plants. However, unlike higher plants where individual classes of lipids may be synthesized and localized in a specific cell, tissue or organ, the complete pathway, from carbon dioxide fixation to TAG synthesis and sequestration, takes place within a single algal cell. Another distinguishing feature of some algae is the large amounts of very long-chain polyunsaturated fatty acids (VLC-PUFAs) as major fatty acid components. Nowadays, the focus of attention in biotechnology is the isolation of novel fatty acid metabolizing genes, especially elongases and desaturases that are responsible for PUFAs synthesis, from different species of algae, and its transfer to plants. The aim is to boost the seed oil content and to generate desirable fatty acids in oilseed crops through genetic engineering approaches. This paper presents the current knowledge of the neutral storage lipids in plants and algae from fatty acid biosynthesis to TAG accumulation

THE INFLUENCE OF FERTILIZER TYPE AND Trichoderma harzianum INOCULATION ON THE GROWTH AND PHYSIOLOGY OF YOUNG PLANTS OF Cordia americana

In this study, we sought to determine the influence of combined treatments with different types of fertilizer and inoculation of the fungus Trichoderma harzianum on the growth and physiological characteristics of young plants of Cordia americana. To this end, we adopted a completely randomized experimental design, comprising six replications in a 5 × 2 factorial scheme, to assess the effects of five different types of fertilizer applied with or without T. harzianum inoculation. At 180 days post-planting, we performed measurements of plant height, stem diameter, leaf dry mass, root dry mass, stem dry mass, total dry mass, leaf area, Falker’s chlorophyll index, and chlorophyll fluorescence. It was found that the combined application of T. harzianum and a controlled-release fertilizer or manure-based organominerals was effective in enhancing the growth of C. americana plants under conditions similar to those in the field. The use of controlled-release fertilizer as a base fertilization was found to have a positive influence on all evaluated variables and was effective in maximizing the initial development of C. americana plants. Granulated fertilizers derived from swine manure were established to promote plant growth and photosynthetic efficiency, thereby confirming their efficacy as a fertilizer for the cultivation of C. americana

EFEITOS DA CHUVA ÁCIDA EM RECURSOS FLORESTAIS

A poluição atmosférica tem aumentado em níveis preocupantes, gerando consequências danosas a saúde humana e ao meio ambiente. A chuva ácida é um fator que está atrelado à elevação do grau poluente no ar, a qual tem recebido atenção científica, devido seu possível prejuízo. Com o objetivo de aglomerar informações sobre os efeitos da chuva ácida, foi realizada uma revisão bibliográfica em artigos científicos que tratam da deposição ácida e recursos florestais. Os resultados compilados evidenciaram vários problemas decorrentes da chuva ácida: lixiviação de nutrientes; necrose; desfolhação; elevação da acidez do solo; restrição à ocorrência de fungos micorrízicos. Ficou evidente a importância de experimentos com chuva ácida simulada, pois identificam efeitos da acidez sobre as plantas. Constatou-se também que espécies vegetais são bons bioindicadores da qualidade ambiental. Portanto, é de grande importância que se esclareçam os danos oriundos da precipitação ácida sobre ecossistemas florestais, sendo que a prevenção evitará danos ecológicos e financeiros

Caracterização quali-quantitativa do material combustível e estoque de carbono em vegetação de capoeira, Santa Maria, RS / Quali-quantitative characterization of fuel material and carbon stock in capoeira vegetation, Santa Maria, RS

A quantificação do acúmulo e determinação das características do material combustível em áreas de vegetação é uma ferramenta importante para a elaboração de estimativas de risco de incêndios florestais. O objetivo do presente estudo foi quantificar os teores de biomassa do material combustível e alocação de carbono da vegetação de uma área de capoeira no campus da Universidade Federal de Santa Maria, em Santa Maria, RS. O material combustível foi coletado em parcelas de 1m², distribuídas aleatoriamente na área e classificado em duas classes de diâmetro (I - maior que 1/4” e II - menor que 1/4”). Determinou-se o percentual de umidade, teor de biomassa e o estoque de carbono alocado. A umidade foi em torno de 50% para ambas classes analisadas. A quantidade de material combustível apresentada pela capoeira totalizou 18,6 Mg ha-1, sendo que a fração de menor diâmetro representou 93% do material combustível existente na área. O carbono fixado na biomassa seca da vegetação foi d de 4,92 Mg.ha-1. Assim, evidencia-se que em caso de ocorrência de incêndio, este pode alcançar elevada intensidade e grande velocidade de propagação, sendo necessário adotar medidas preventivas. As estimativas de estoque de carbono obtidos podem ser usadas como subsídios para a elaboração de planos de prevenção de incêndios florestais em áreas de capoeira

Evolutionary view of acyl-CoA diacylglycerol acyltransferase (DGAT), a key enzyme in neutral lipid biosynthesis

<p>Abstract</p> <p>Background</p> <p>Triacylglycerides (TAGs) are a class of neutral lipids that represent the most important storage form of energy for eukaryotic cells. DGAT (acyl-CoA: diacylglycerol acyltransferase; EC 2.3.1.20) is a transmembrane enzyme that acts in the final and committed step of TAG synthesis, and it has been proposed to be the rate-limiting enzyme in plant storage lipid accumulation. In fact, two different enzymes identified in several eukaryotic species, DGAT1 and DGAT2, are the main enzymes responsible for TAG synthesis. These enzymes do not share high DNA or protein sequence similarities, and it has been suggested that they play non-redundant roles in different tissues and in some species in TAG synthesis. Despite a number of previous studies on the DGAT1 and DGAT2 genes, which have emphasized their importance as potential obesity treatment targets to increase triacylglycerol accumulation, little is known about their evolutionary timeline in eukaryotes. The goal of this study was to examine the evolutionary relationship of the DGAT1 and DGAT2 genes across eukaryotic organisms in order to infer their origin.</p> <p>Results</p> <p>We have conducted a broad survey of fully sequenced genomes, including representatives of Amoebozoa, yeasts, fungi, algae, musses, plants, vertebrate and invertebrate species, for the presence of DGAT1 and DGAT2 gene homologs. We found that the DGAT1 and DGAT2 genes are nearly ubiquitous in eukaryotes and are readily identifiable in all the major eukaryotic groups and genomes examined. Phylogenetic analyses of the DGAT1 and DGAT2 amino acid sequences revealed evolutionary partitioning of the DGAT protein family into two major DGAT1 and DGAT2 clades. Protein secondary structure and hydrophobic-transmembrane analysis also showed differences between these enzymes. The analysis also revealed that the MGAT2 and AWAT genes may have arisen from DGAT2 duplication events.</p> <p>Conclusions</p> <p>In this study, we identified several DGAT1 and DGAT2 homologs in eukaryote taxa. Overall, the data show that DGAT1 and DGAT2 are present in most eukaryotic organisms and belong to two different gene families. The phylogenetic and evolutionary analyses revealed that DGAT1 and DGAT2 evolved separately, with functional convergence, despite their wide molecular and structural divergence.</p