Taxa transpiratória de mudas de eucalipto em resposta a níveis de água no solo e à convivência com braquiária

Silva, Wilson da; Ferreira, Lino Roberto; Silva, Antônio Alberto da; Firmino, L.E.

doi:10.1590/s0100-204x2000000500009

Cited by 6 publications

(6 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…As water availability in the soil decreases, the transpiration rate also decreases as a result of stomatal closure. The instantaneous control of the transpiration stream by the stomata is an important defense mechanism used by many species in arid environments in order to avoid excessive water loss by transpiration (Gucci et al, 1996;Nogueira et al, 1998;Silva et al, 2004) and eventual death by desiccation (Silva et al, 2000).…”

Section: Introductionmentioning

confidence: 99%

Stomatal changes induced by intermittent drought in four umbu tree genotypes

Silva

Nogueira

Vale

et al. 2009

Braz. J. Plant Physiol.

View full text Add to dashboard Cite

Transpiration (E), diffusive resistance (r s ) and anatomical parameters were measured in plants of four grafted umbu tree genotypes (GBUs 44, 48, 50 and 68) in order to evaluate alterations induced by intermittent drought and possible genotypic variations. Transpiration measurements were taken daily until stomatal closure by withholding water. Measurements were also taken, when the plants were re-watered and the watering was interrupted again. This cycle was repeated for a period of 31 days (stress period). The control plants were also irrigated daily. A regular pattern in the stomatal opening/closing mechanism was observed throughout the watering period, exhibiting intra-specific differences. Stomatal behavior of GBU 44 and GBU 68 had correlation with air temperature (Tar), relative humidity (RH) and vapor pressure deficit (VPD), whereas GBU 50 had correlation with photosynthetically active radiation (PAR). GBU 48 had no correlation with these environmental factors. Anatomical alterations in response to drought were observed in stomatal density (SD), reductions in the stomatal index (SI) and stomatal aperture size (SA). The anatomical features of the GBU 48 genotype remained unaltered. There was an inversion in tissue proportion in GBU 44 under stress conditions, reducing the spongy parenchyma and increasing palisade parenchyma thickness. The inverse occurred with GBU 68, while the remaining genotypes were unaltered. The results found in this study suggest that GBU 68 is the most drought-sensitive genotype and anatomical changes induced by intermittent drought are not enough to explain the physiological differences between genotypes.Key words: diffusive resistance, Spondias tuberosa, stomatal density, transpiration, water deficitMudanças estomáticas e anatômicas induzidas pela seca intermitente em quatro genótipos de umbuzeiro: A transpiração (E), a resistência difusiva (r s ) e parâmetros anatômicos foram medidos em mudas enxertadas de quarto genótipos de umbuzeiro (BGU s 44, 48, 50 and 68) com o objetivo de avaliar alterações e possíveis variações genotípicas induzidas pela seca intermitente. As medidas de transpiração foram tomadas diariamente até ocorrer o fechamento estomático das plantas sob suspensão da irrigação, e após a reirrigação e suspensão da rega novamente, repetindo-se este ciclo por um período de 31 dias (período de estresse). As plantas controle foram irrigadas diariamente. Foi observado um padrão regular no mecanismo de abertura e fechamento estomático ao longo dos períodos de rega, exibindo diferenças entre os genótipos. O comportamento estomático dos genótipos BGU 44 e BGU 68 se correlacionaram com a temperatura do ar (Tar), umidade relativa (RH) e déficit de pressão de vapor (VPD), enquanto que o BGU 50 apresentou correlação com a radiação fotossinteticamente ativa (PAR). BGU 48 não apresentou correlação com os fatores ambientais. Foram observadas alterações anatômicas em resposta à seca na densidade estomática (SD), reduções no índice estomático (SI) e abertura do ostíolo (SA). As carac...

show abstract

Section: Introductionmentioning

confidence: 99%

Stomatal changes induced by intermittent drought in four umbu tree genotypes

Silva

Nogueira

Vale

et al. 2009

Braz. J. Plant Physiol.

View full text Add to dashboard Cite

show abstract

“…Silva et al (2000) observed that, regardless the water level in the soil, B. brizantha was more competitive in the early stage of development than the Eucalyptus citriodora and E. grandis species. Toledo et al (2000), evaluating control ranges of B. decumbens in the formation of Eucalyptus urograndis forests (E. grandis x E. urophylla), 3 x 3 m spaced, verified that the weeds begin to significantly reduce the growth of eucalyptus from 14-28 days of coexistence and that a period of 140 days of control is necessary to ensure the full development of culture in the first year of its development cycle.…”

Section: Introductionmentioning

confidence: 92%

“…In this case, the species that access and use resources more efficiently or continue to grow, even with low levels of resources, will exceed (Machado et al, 2010). In this regard, Silva et al (2000) state that, by having fast early growth of roots and shoots, B. brizantha presents strong competition for growth resources with eucalyptus. Toledo et al (2001) The maximum height of eucalyptus plants (4.94 m) was observed at 360 DAP with crown diameter equal to 2.5 m (Figure 1).…”

Section: Height and Diameter At Ground Levelmentioning

confidence: 99%

Eucalyptus growth in silvopastoral system under different crown dia meters

et al. 2013

View full text Add to dashboard Cite

-The aim of this study was to evaluate the effect of different crown diameters on the early growth of eucalyptus intercropped withKeywords: agroforestry systems, weed competition, control ranges.RESUMO -Objetivou-se neste trabalho avaliar o efeito de diferentes diâmetros de coroamento sobre o crescimento inicial de plantas de eucalipto em sistema silvipastoril com Brachiaria decumbens. O experimento foi realizado em área de pastagem estabelecida de B. decumbens, na qual foi plantado o eucalipto híbrido urograndis (clone GG100), no espaçamento de 8 x 3 m. Utilizou-se o delineamento de blocos ao acaso com seis repetições. Os tratamentos consistiram de cinco diâmetros de coroamento (0,0, 1,0, 1,5, 2,0 e 3,0 m) no entorno das plantas de eucalipto. Ao longo do experimento foram realizadas cinco capinas com enxada, conforme os diferentes diâmetros de coroamento, visando manter as plantas de eucalipto livres da interferência de B. decumbens. Aos 90, 180, 270 e 360 dias após o plantio (DAP), foram avaliados a altura e o diâmetro nas plantas de eucalipto e, aos 360 DAP, a biomassa da parte aérea e a área foliar. Aos 90 DAP, verificou-se que as plantas não capinadas tiveram menor crescimento, quando comparadas às submetidas aos coroamentos. Diâmetros de coroamento de 2,51 e 2,64 m permitiram maior crescimento em altura e em diâmetro ao nível do solo das plantas de eucalipto, respectivamente, em todas as épocas avaliadas. A produção da biomassa e a área foliar por planta, aos 360 DAP, também foram influenciadas pelos diâmetros de coroamento. O coroamento em torno de 2 m proporcionou condições favoráveis ao crescimento inicial das plantas de eucalipto e menor comprometimento na área ocupada pela forrageira.Palavras-chave: sistemas agroflorestais, matocompetição, faixas de controle.MACHADO, M.S. et al.

show abstract

“…The interference of these species can reduce the growth of plants, the dry matter of leaves, stems, branches and roots, leaf number and leaf area (Silva et al, 1997;Toledo et al, 2000Toledo et al, , 2001. Moreover, it may have allelopathic effects, causing reductions in photosynthetic activities of eucalypt plants (Silva et al, 2000b;Souza et al, 2003).…”

Section: Introductionmentioning

confidence: 99%

Eucalypt Growth Submitted to Management of Urochloa spp.

et al. 2016

View full text Add to dashboard Cite

-The objective of this work was to evaluate the initial growth and the physiological characteristics of eucalypt submitted to different managements of signalgrass. The experiment was conducted in a protected environment, using a randomized blocks design with five repetitions. The treatments were arranged in a (5 x 2) + 1 factorial design, and the first factor corresponded to the types of weed management (no control; chemical control keeping the signalgrass shoot on the soil; chemical control with removal of the signalgrass shoot; mechanical control keeping the signalgrass shoot on the soil, and mechanical control with removal of the signalgrass shoot); the second factor corresponded to the two weeds species (U. brizantha and U. decumbens) and a control relative to the eucalypt in monoculture. The eucalypt growth was not affected by the presence of the Urochloa species until 50 days after treatments (DAT). However, the coexistence of these species with eucalypt for 107 DAT reduced the collar diameter, total dry matter, and the leaf area, but did not alter the characteristics related to photosynthesis and transpiration. The control method adopted, with removal or maintenance of the signalgrass shoot, regardless of species, did not change the initial eucalypt growth. It can be concluded that the coexistence of eucalypt with Urochloa decumbens or Urochloa brizantha for 105 days reduces the eucalypt growth. However, the use of chemical or mechanical control, with or without removal of signalgrass residue, were effective methods to prevent interference of these weeds.Keywords: control methods, physiological variables, initial growth, Urochloa (syn. Brachiaria), eucalypt. RESUMO -O objetivo deste trabalho foi avaliar o crescimento inicial e as características fisiológicas do eucalipto submetido a diferentes manejos do capim-braquiária. O experimento foi realizado em ambiente protegido, no delineamento de blocos casualizados com cinco repetições. Os tratamentos foram arranjados em esquema fatorial (5 x 2) + 1, sendo o primeiro fator correspondente aos tipos de manejo da planta daninha (ausência de controle, controle químico mantendo no solo a parte aérea do capim-braquiária, controle químico retirando a parte aérea do capim-braquiária, controle mecânico mantendo no solo a parte aérea do capim-braquiária e controle mecânico retirando a parte aérea do capim-braquiária) o segundo às espécies de capim-braquiária (Urochloa brizantha e Urochloa decumbens), além de uma testemunha referente ao eucalipto em monocultivo. O crescimento do eucalipto não foi alterado pela presença das espécies de capim-braquiária até os 50 dias após a aplicação dos tratamentos (DAT

show abstract

Taxa transpiratória de mudas de eucalipto em resposta a níveis de água no solo e à convivência com braquiária

Cited by 6 publications

References 10 publications

Stomatal changes induced by intermittent drought in four umbu tree genotypes

Stomatal changes induced by intermittent drought in four umbu tree genotypes

Eucalyptus growth in silvopastoral system under different crown dia meters

Eucalypt Growth Submitted to Management of Urochloa spp.

Contact Info

Product

Resources

About