VALORES LIMÍTROFES PARA TRANSPIRAÇÃO, DESENVOLVIMENTO E CRESCIMENTO DE Corymbia citriodora (Hook.) K.D. Hill & L.A.S. Johnson EM RESPOSTA À DEFICIÊNCIA HÍDRICA NO SOLO1

Abstract

RESUMO -Quando a disponibilidade de água no solo é reduzida, as plantas respondem diminuindo a taxa de transpiração, o crescimento e o desenvolvimento, na tentativa de aclimatação à deficiência hídrica. Com o objetivo de quantificar essas respostas em mudas de Corymbia citriodora (Hook.) K.D. Hill & L.A.S. Johnson, foi utilizada a metodologia da fração de água transpirável no solo (FATS), em um experimento conduzido em casa de vegetação, sob o delineamento inteiramente casualizado, sendo dois níveis de suplementação hídrica, duas épocas de aplicação da deficiência hídrica e nove repetições. A FATS e os parâmetros de transpiração, crescimento e desenvolvimento foram medidos diariamente durante a aplicação da deficiência hídrica. A FATS crítica, em que a transpiração, o crescimento e desenvolvimento começam a ser reduzidos, foi distinta nas épocas de aplicação da deficiência hídrica devido à diferença das condições meteorológicas. Os valores elevados de FATS indicaram que a espécie possuiu boa aclimatação à deficiência hídrica no solo, quando comparada com as espécies anuais e outras perenes.Palavras-chave: Relações hídricas; Déficit de pressão de vapor; Fechamento estomático. THRESHOLDS FOR TRANSPIRATION, DEVELOPMENT AND GROWTH OF Corymbia citriodora (Hook.) K.D. Hill & L.A.S. Johnson IN RESPONSE TO SOIL WATER STRESSABSTRACT -When water availability in the soil is reduced, plants respond decreasing transpiration rate, growth and development in an attempt to acclimate to water deficit. To quantify these responses in seedlings of Corymbia citriodora (Hook.) K.D. Hill & L.A.S. Johnson, we used the methodology of the Fraction of Transpirable Soil Water (FTSW), in an experiment conducted in a greenhouse, in a completely randomized design with two levels of water supplementation, two application times of water deficiency and nine replicates. The FTSW and the transpiration, growth and development parameters were measured daily during the application of water deficiency. The FTSW threshold, in which transpiration, growth and development begin to be reduced, was variable for different application times of water stress due to the difference in weather conditions. The high values of FTSW indicate that the species has good acclimation to soil water deficit compared to annuals and other perennials species.

Thermal Requirements and Photoperiod Influence in the Leaf Development of Two Forest Species

“…A field experiment was carried out in the experimental area at 22° 30'S, 45° 27'W and 850 m of altitude and according to the Köppen-Geiger classification, the climate is Cwa-altitude tropical -with dry winters and hot and rainy summers (Abreu et al, 2015).…”

“…Acidity and fertility correction was performed in each pot through the addition of 10.18 g simple superphosphate (18%), 0.31 g potassium chloride (60%), 0.20 g ammonium 3/9 Thermal Requirements and Photoperiod… Floresta e Ambiente 2019; 26(4): e20190013 sulfate (20%) and liming with 12.32 g calcium carbonate according to the 5 th approximation (CFSEMG, 1999). Daily watering was performed in the morning, and in the afternoon in days of vapor pressure deficit (VPD) ≥15 hPa (Abreu et al, 2015). On rainy days, watering was not performed since plants were under good water supplementation.…”

“…LD was quantified through accumulated NL in the main stem during the seedling phase, which started when seedlings reached 50% emergence and finished when plants of each EU reached an average of 20 accumulated leaves (Martins et al, 2007;Abreu et al, 2015). NL count was performed once a week when each leaf presented limb ≥1.0 cm in length (Martins et al, 2007).…”

Physiological responses to drought of Cnidoscolus quercifolius Pohl in semi-arid conditions

“…This is one of the first plant species of the Caatinga to initiate foliar abscission with the onset of the dry period, which may be an adaptive strategy to reduce leaf area and, consequently, water loss by transpiration. The abscission is caused by ethylene, accelerating leaf senescence and abscision (Abreu et al, 2015). It can be seen that the above-mentioned changes are strategies quickly employed by the species, aiming to minimize the loss of water.…”

Desenvolvimento Vegetativo de Cesalpinea ferrea e Anadenanthera macrocarpa: I - Estimativa das Temperaturas Cardinais

“…O DV foi quantificado através do número de folhas emitidas na haste principal (NF) durante a fase de muda (FM). A FM para o pau-ferro foi definida pela contabilização do NF desde a emergência até, em média, 20 NF (Martins et al, 2007;Abreu et al, 2015). Para o angicovermelho foi utilizado o patamar de 12 NF, o qual é o ideal para a comercialização de mudas desta espécie e reflete, em média, 40 cm de altura (Oliveira et al, 2016).…”