Marcio Carlos Navroski

Deficiência hídrica no solo e seu efeito sobre transpiração, crescimento e desenvolvimento de mudas de duas espécies de eucalipto

Water is a critical component of plant metabolism, and a reduction in soil water availability may affect crop growth, development and yield. The objective of this study was to quantify the influence of soil water deficit on transpiration and on some growth (plant height and stem diameter) and development (main stem leaf number) parameters of Eucalyptus grandis (Hill ex Maiden) and E. saligna (Smith) seedlings. For this purpose, a greenhouse experiment was conducted at the Federal University of Santa Maria, RS, Brazil). The seedlings were planted on 10/1/2005 (PD1) and 5/12/2006 (PD2). Soil available water, expressed as the fraction of transpirable soil water (FTSW), and other parameters were measured daily during the period of water stress. Transpiration, which is an indicator of stomata closure, started to decrease at a FTSW of 0.9 (PD2) or 0.7 (PD1) in E. grandis, and at 0.7 for planting dates for E. saligna. These results suggest that stomata closure, in response to soil water deficit, occurs earlier in these two perennial species than in annual agricultural crops. Seedling growth and development parameter values began to decrease immediately after the onset of soil water deficit, even before transpiration was affected by the reduced soil water availability.

Plantio misto de Eucalyptus urograndis e Acacia mearnsii em sistema agroflorestal: I - Produção de biomassa

This study aimed to evaluate a mixed stand of Eucalyptus urograndis and Acacia mearnsii in an agroforestry system with corn ( Zea mays L.) in Bage, RS. The design entailed a randomized block with five treatments and three replicates (T1- 100E; T2- 100A; T3- 50E:50A; T4- 75E:25A e T5- 25E:75A), with 4.0 m x 1.5 m planting space. Three lines of corn were planted, between the eucalyptus and/or black-wattle lines. Ten months after the installation, the biomass from forest species were quantified and separated in fractions (leaf, branch and stem). Corn biomass was collected at the end of the cycle and separated in fractions (leaf, straw, grain, corn cob and stem). In mixed stands, the treatment T5 (25E:75A) showed the highest biomass accumulation, being 35.1% in the leaves, 25.8% in branches and 39.1% in stem. The black wattle showed higher growth than the initial eucalyptus, both alone and in the mixed stand. The yield of corn was between 1.01 to 1.26 Mg ha -1 , which was not statistically different (p>0.05) between treatments.

In vitro ESTABLISHMENT AND MULTIPLICATION OF GENOTYPES OF Eucalyptus dunnii MAIDEN

This study aimed at evaluating the effect of genotypes of Eucalyptus dunnii on in vitro establishment and also the influence of genotypes grown in different concentrations of 6-Benzylaminopurine (BAP) on in vitro multiplication. Explants were obtained from 10 parent plants selected in the field as a function of their superior phenotype characteristics. For in vitro establishment, 10 genotypes were evaluated, while in vitro multiplication consisted of 30 treatments which corresponded to combinations of six genotypes found to succeed in the in vitro establishment and five BAP concentrations (0, 0.25, 0.50, 0.75, and 1.0 mg L-1). Different behaviors were observed regarding the genotypes as to in vitro establishment rates, in which genotypes 3, 6 and 7 had establishment rates of over 70%, against 40% to 6.6% for the other genotypes. Genotypes 1, 5, 8 and 9 were later discarded due to the reduced number of explants successfully established. Factors such as microbial contamination and phenol oxidation posed a threat to in vitro establishment. The genotypes of Eucalyptus dunnii interacted differently with BAP in in vitro multiplication, noting that the concentration 0.50 mg L-1 positively influenced bud formation on the explants in most genotypes. Hyperhydricity was relatively low when 0.50 mg L-1 BAP was used and thus does not pose a threat to in vitro multiplication of nodal segments of Eucalyptus dunnii.

GENETIC VARIATION FOR GROWTH VARIABLES OF Eucalyptus benthamii MAIDEN & CAMBAGE AND E. smithii R. T. BAKER PROVENANCES IN SOUTHERN BRAZIL

Southern Brazil encompasses areas with a subtropical climate, with significant number of frosts, which challenge or even impair growing tropical eucalypts. Eucalyptus benthamii and E. smithii rise as alternative species of subtropical origin with considerable frost-tolerance. Here we accessed the genetic variation for diameter at breast height (DBH), height (H), volume (VOL), bifurcation and straightness of four provenances of E. smithii and two of E. benthamii, cultivated in randomized block design in a farm in Rio Negrinho, Santa Catarina, southern Brazil. We found considerable genetic variability for the traits, all directly associated with the selection for wood production and quality. In general, most of the genetic variability was found within the provenances (Qd ranged from 63.6 to 73.1%), except for straightness (Qd = 13.5% and Qst = 81.9%). Although predicting genetic gains with provenance trials might have some drawbacks, the application of the REML/BLUP method was able to predict genetic gains for the growth variables DBH, H and VOL for provenances of the two species. The highest genetic gains were predicted for a provenance of E. smithii originated from Australia (13% for DBH, 5% for H and 6.1% for VOL). However, the genetic gains from a E. benthamii provenance from Santa Catarina state were not negligible (1.2% for DBH, 1.8 for H and 2.2% for VOL). Our results provide insights for further progeny trials aimed at investigating additive genetic variance and their components, which could improve the genetic control of the traits and assist breeding programs of E. smithii and E. benthamii. VARIAÇÃO GENÉTICA PARA VARIÁVEIS DE CRESCIMENTO DE PROCEDÊNCIAS DE Eucalyptus benthamii MAIDEN & CAMBAGE E E. smithii R. T. BAKER DO SUL DO BRASIL RESUMO: O Sul do Brasil apresenta áreas com clima subtropical, com número significativo de geadas, que dificultam ou, até mesmo, impossibilitam o crescimento de eucaliptos tropicais. Eucalyptus benthamii e E. smithii surgem como espécies alternativas de origem subtropical com considerável tolerância a geadas. Estudou-se a variação genética para diâmetro a altura do peito (DAP), altura (H), volume (VOL) e tortuosidade em quatro procedências de Eucalyptus smithii e duas de E. benthamii, plantadas em delineamento em blocos casualizados em área experimental do município de Rio Negrinho, Santa Catarina, sul do Brasil. Foi encontrada variabilidade genética considerável para os caracteres investigados, todos diretamente associados com a seleção para produção e qualidade da madeira. Em geral, a maior proporção da diversidade genética foi encontrada dentro das procedências (Qd variou de 63,6 a 73,%), exceto para tortuosidade (Qd = 13,5% e Qst = 81,9%). Embora a predição de ganhos genéticos com testes de procedências apresente limitações, o emprego do método REML/ BLUP permitiu predizer ganhos genéticos para as variáveis DAP, H e VOL nas procedências e indivíduos das duas espécies. Os ganhos genéticos mais elevados foram preditos para uma procedência de E. smithii originária da Austrália (13% para DAP, 5 % para H e 6,1% para VOL). Contudo, os ganhos genéticos potenciais com a procedência de E. benthamii de Santa Catarina não foram negligenciáveis (1,2% para DAP, 1,8% para H e 2,2% para VOL). Estes resultados representam importantes contribuições para a realização de testes de progênies posteriores para investigar a variação genética aditiva e seus componentes, o que pode aprimorar o conhecimento do controle genético dos caracteres e auxiliar no desenvolvimento de programas de melhoramento genético de E. smithii e E. benthamii.

Qualidade de sementes e mudas de Cedrela fissilis Vell. em função da biometria de frutos e sementes em diferentes procedências

Cedrela fissilis is a Brazilian native species with outstanding use in the timber sector and in the recovery of degraded areas. There is a need for a better understanding of the differences and genetic gains that may exist in relation to different origins and progenies. The objective of the study was to analyze the biometry of fruits and seeds of Cedrela fissilis as a function of different origins and matrices related to the initial growth of seedlings, besides evaluating the best photoperiod in germination. The seeds were collected in matrices from two sources (Fernandes Pinheiro and Lapa) for biometry and the weight of one thousand seeds per matrix. Seeds of the two provenances were submitted to different photoperiods (12, 16 and 24 hours of white light and 24 hours in the dark), the germination and the germination rate index (ORI) was evaluated. The initial growth of the seedlings was evaluated through the measurement of morphological characteristics after every 30 days. The experiments were performed in a completely randomized design and the data submitted to analysis of variance at the 5% level, the averages being compared by the Tukey test and/or polynomial regression. There were biometric differences between fruits and seeds between the matrices, with no relation to the origin. Regarding the germination rate and ORI among the provenances, Fernandes Pinheiro presented the best results. In relation to the photoperiod, there was no difference in germination in relation to light levels, and the ORI was higher for seeds germinated in the dark. Fernandes Pinheiro obtained higher initial growth of the seedlings in relation to the Lapa origin and this difference increases throughout the evaluations. In general, the experiments showed a difference between the provenances, having a relation with the quality of seeds and seedlings formed.

VEGETATIVE RESCUE AND ROOTING OF CUTTINGS OF DIFFERENT STOCK PLANTS OF Sequoia sempervirens

Sequoia is a fast-growing, long-living species, producing durable timber. The aim of this study was to test different methods for the vegetative rescue of Sequoia sempervirens trees over 40 years old, made at different periods of the year, and, later, testing the rooting of individualized cuttings in planned arrays. Twenty-four individual sequoias were rescued, applying girdling and semi-girdling at three different heights (-10, 0, and 30 cm). The first collection was made 90 days after application of the treatments, being repeated at 150, 240, and 360 days. The percentage of budding trees and the number of shoots per array were registered. In all collections, shoots produced cuttings, which were placed for rooting in mini-tunnels. Cutting survival (%), rooting (%), and number of roots were registered, per array, and per collection. The species vegetative rescue proved to be efficient for the production of shoots for stem cuttings, especially with girdling at 30 cm and semi-girdling at -10 cm. However, it is difficult to define the best method, mainly because of the genetic effect among stock plants. The rooting of cuttings, of recovered material, presented good results (average >65%), also with great differences among stock plants. The potential for rooting of cuttings varied according to different planting periods, with high rooting rates in all seasons, especially in summer. Sequoia sempervirens shows the potential for vegetative rescue and cloning by rooting of cuttings, and this may lead to new studies, with a view towards fixing clones. RESGATE VEGETATIVO E ENRAIZAMENTO DE ESTACAS DE DIFERENTES MATRIZES DE Sequoia sempervirens RESUMO: Sequoia é uma espécie de rápido crescimento, longeva e de madeira durável. O objetivo do estudo foi testar diferentes métodos de resgate vegetativo em árvores com mais de 40 anos de idade de Sequoia sempervirens, realizados em distintas épocas do ano e posterior enraizamento de estacas individualizadas por planta matriz. Resgataram-se 24 indivíduos de sequoia, aplicando-se anelamento e semianelamento em três diferentes alturas (-10, 0 e 30 cm). A primeira coleta foi efetuada 90 dias após aplicação dos tratamentos, sendo repetida aos 150, 240 e 360 dias. Contabilizou-se a porcentagem de árvores com brotações e o número de brotações por matriz. Em todas as coletas as brotações originaram estacas que foram colocadas para enraizar em estufim. No enraizamento das estacas analisou-se a sobrevivência (%), enraizamento (%) e número de raízes por matriz por coleta. O resgate vegetativo da espécie mostrou-se eficiente na produção de brotações para a estaquia, destacando-se o anelamento a 30 cm e o semianelamento a -10 cm. Entretanto, há dificuldade em definir qual o melhor método, principalmente em função do efeito genético entre matrizes. O enraizamento de estacas do material resgatado apresentou bons resultados (média >65%), também com grande diferença entre as matrizes. Diferentes épocas de estaquia alteraram o potencial de enraizamento, contudo, com altos índices de enraizamento em todas as estações do ano, principalmente no verão. Sequoia sempervirens apresenta potencial de resgate vegetativo e clonagem por estaquia, sendo possível conduzir novos trabalhos com vistas a fixação de clones.

THE USE OF HYDROGEL COMBINED WITH APPROPRIATE SUBSTRATE AND FERTILIZER IMPROVE QUALITY AND GROWTH PERFORMANCE OF Mimosa scabrella BENTH. SEEDLINGS

Mimosa scabrella is a pioneer species that occurs mainly in the ombrophilous mixed forests of southern Brazil, assuming considerable economic relevance. As limited information is available concerning the most adequate substrates for producing seedlings of this species, we evaluated the combined effect of hydrogel with three types of substrates and four fertilizers in the initial growth and quality of seedlings of M. scabrella. The substrates were prepared with distinct proportions of a commercial organic substrate, vermiculite (VM) and pine bark (PB): 1 (70% of TF, 10% of VM and 20% of PB), 2 (40% of each TF and VM and 20% of PB), and 3 (70% of TF, 10% of VM and 20% of PB). The fertilizers consisted of a slow release formula (A), a traditional NPK (B), a compost of superphosphate and potassium chloride (C) and no fertilizer (D). The three soil mixtures were combined with each fertilizer in the presence or absence of hydrogel (factorial arrangement). The use of hydrogel promoted a positive effect on the growth of M. scabrella seedlings, probably by retaining more water and enabling increased nutrient absorption. In general, the polymer implicated in increased Dickson quality index (DQI). Additionally, the combination of organic compound and vermiculite in equilibrated proportions aid by pinus bark (substrate 2) were the best substrate. Finally, adding the fertilizers A or B resulted in the best growth performance. In conclusion, the combined effect of hydrogel, substrate mixture and fertilizers improved the quality indexes of M. scabrella seedlings. O USO DE HIDROGEL COMBINADO COM SUBSTRATO E FERTILIZANTE ADEQUADOS MELHORAM A QUALIDADE E CRESCIMENTO DE MUDAS DE Mimosa scabrella BENTH. RESUMO: Mimosa scabrella é uma espécie pioneira que ocorre principalmente na floresta ombrófila mista do Sul do Brasil, apresentando considerável importância econômica. Considerando as limitadas informações acerca dos substratos mais adequados para a produção de mudas da espécie, neste trabalho avaliou-se o efeito combinado do uso de hidrogel com três tipos de substratos e quatro fertilizantes no crescimento inicial e qualidade de mudas de M. scabrella. Os substratos foram preparados com proporções distintas de um substrato orgânico comercial, vermiculita (VM) e casca de pinus (PB): 1 (70% de TF, 10% de VM e 20% de PB), 2 (40% de TF e VM e 20% of PB), e 3 (70% de TF, 10% de VM e 20% de PB). Os fertilizantes consistiram de uma fórmula de liberação lenta (A), o tradicional NPK (B), um composto de superfosfato simples e de cloreto de potássio (C) e com fertilizante ausente (D). Os três compostos de substratos foram combinados com cada fertilizante na presença ou ausência de hidrogel (arranjo fatorial). O uso de hidrogel promoveu um efeito positivo no crescimento das mudas de M. scabrella, provavelmente retendo mais água e permitindo maior absorção de nutrientes. No geral, o polímero implicou em aumento no índice de qualidade de Dickson (DQI). Adicionalmente, a combinação do composto orgânico e vermiculita em proporções equilibradas adicionado de casca de pinus (substrato 2) constituíram o melhor substrato. A adição dos fertilizantes A e B resultaram na melhor performance de crescimento. Concluiu-se que a combinação de hidrogel com substrato composto e fertilizantes melhoraram os índices de qualidade de mudas de M. scabrella.

Multiplicação in vitro de segmentos apicais caulinares de segurelha (Satureja hortensis L.)

This study aimed to evaluate the effect of BAP in the presence and absence of NAA, on the in vitro multiplication of shoot apical segments of Satureja hortensis. The explants were isolated from seedlings germinated in vitro and cultured in nutrient medium MS. The experimental design was completely randomized in a 2x5 factorial arrangement, corresponding to the concentrations of NAA (0 and 1 µM) and BAP (0, 5, 10, 15 and 20 µM), with six replicates, each consisting of three explants. For the percentage of explants with shoots, there was no significant effect for the factor BAP, increasing as the concentration of BAP grows. The variable number of shoots per explant showed interaction between factors, with the highest shoot formation in the presence of NAA and BAP in the range of 10 -15 µM. In the presence of auxin, the highest value occurred with 15 µM BAP, tending to decline regardless of the presence of NAA. The rooting of the apical segments was higher in the presence of NAA and absence of BAP, decreasing with increasing cytokinin. Leaf number was influenced by the higher concentration of BAP, and the amount of 15 µMhadthe largest number, tending to decrease with increasing concentration. The concentration of 15 µM BAP, regardless of NAA, provided better results in the multiplication of the species, producing increased number of shoots and leaves, except for rooting, whichwas influenced by auxin.