Comportamento de clones de eucalipto em resposta a disponibilidade hídrica e adubação potássica
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Data
2011-02-15
Autores
Mendes, Hélio Sandoval Junqueira [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
O trabalho objetivou avaliar o efeito do suprimento de potássio no desempenho de clones de eucalipto submetidos a duas condições de disponibilidade hídrica em casa de vegetação utilizando características biométricas e fisiológicas. Cinco genótipos de eucalipto foram submetidos a dois níveis de adubação potássica (K0 – sem complementação potássica e K1 – adição de 166 mg.dm-3 de K) e a dois regimes de irrigação (RI1 – irrigação diária, até o solo atingir 60% dos poros preenchidos com água (PPA), ou seja, plantas sem restrição hídrica, e RI2 - plantas irrigadas até o solo atingir 60% PPA, com posterior suspensão da irrigação, até o aparecimento de sintomas iniciais de deficiência hídrica). Foram conduzidos sete ciclos de suspensão de irrigação, sendo a quantidade de água reposta em cada vaso determinada pelo método gravimétrico. No início e ao final do experimento, foram avaliados o diâmetro do coleto, a altura, o número de folhas, a área foliar e a massa de matéria seca de folhas, caule, raízes, da parte aérea e total. Nos momentos de máximo estresse hídrico, foram avaliadas as seguintes características fisiológicas: teor relativo de clorofila total (ICC), medida da eficiência quântica do fotossistema II (Fv/Fm), taxa de assimilação líquida (A), condutância estomática (gs), taxa de transpiração (E), eficiência intrínseca do uso da água (EUAintr=A/E), eficiência instantânea do uso da água (EUAinst=A/gs), conteúdo relativo de água (CRA) e, ao final do experimento foi determinado o potencial hídrico foliar ( f). O experimento foi estabelecido no delineamento de blocos ao acaso, em esquema fatorial 5 x 2 x 2 (5 genótipos, 2 regimes de irrigação e 2 níveis de adubação potássica), com cinco repetições por tratamento. As médias de tratamentos foram comparadas pelo teste de Tukey a 5% de probabilidade...
The present study aimed to evaluate the supply potassium effect on the performance of the five eucalypt clones subjected to two water availability conditions in greenhouse from biometric and physiological traits. Five eucalypt genotypes were subjected to two levels of potassium supply (K0 – no potassium supplementation and K1 – addition of 166 mg dm-3 K) and two irrigation regimes (RI1- daily irrigation until the soil reaches 60% of pores filled with water (PFW), that is plants no water restriction, and RI2 – plants watered until the soil reaches 60% (PFW), with subsequent water suspension until the appearance of early water stress symptoms). Seven cycles of irrigation suspension were conducted, and the amount water replaced in each pot was determined by gravimetric method. At the beginning and the end of the experiment, were measured the collar diameter, height, leaf number, leaf area and dry weight mass of leaves, stems, roots, aerial parts and total. In the moment of maximum water stress were evaluated the following physiological traits: the chlorophyll content index (CCI), the quantum efficiency of photosystem II (Fv/Fm), net assimilation rate (A), stomatal conductance (gs), transpiration (E), intrinsic water use efficiency (WUEintr = A/E) and instantaneous water use efficiency (WUEinst = A/gs), relative water content (RWC) and at the end of the experiment was determined the leaf water potential ( f). The design experiment was established in the randomized blocks in factorial scheme 5 x 2 x 2 (5 genotypes, two irrigation regimes and two levels of potassium supplies), with five replicates. The treatment means were compared by Tukey test at 5% probability. Eucalypt clones present reduction in the biometric and physiological traits values under water limitations. For the physiological traits, the potassium supply caused effect reduction of the water stress. To the biometric... (Complete abstract click electronic access below)
The present study aimed to evaluate the supply potassium effect on the performance of the five eucalypt clones subjected to two water availability conditions in greenhouse from biometric and physiological traits. Five eucalypt genotypes were subjected to two levels of potassium supply (K0 – no potassium supplementation and K1 – addition of 166 mg dm-3 K) and two irrigation regimes (RI1- daily irrigation until the soil reaches 60% of pores filled with water (PFW), that is plants no water restriction, and RI2 – plants watered until the soil reaches 60% (PFW), with subsequent water suspension until the appearance of early water stress symptoms). Seven cycles of irrigation suspension were conducted, and the amount water replaced in each pot was determined by gravimetric method. At the beginning and the end of the experiment, were measured the collar diameter, height, leaf number, leaf area and dry weight mass of leaves, stems, roots, aerial parts and total. In the moment of maximum water stress were evaluated the following physiological traits: the chlorophyll content index (CCI), the quantum efficiency of photosystem II (Fv/Fm), net assimilation rate (A), stomatal conductance (gs), transpiration (E), intrinsic water use efficiency (WUEintr = A/E) and instantaneous water use efficiency (WUEinst = A/gs), relative water content (RWC) and at the end of the experiment was determined the leaf water potential ( f). The design experiment was established in the randomized blocks in factorial scheme 5 x 2 x 2 (5 genotypes, two irrigation regimes and two levels of potassium supplies), with five replicates. The treatment means were compared by Tukey test at 5% probability. Eucalypt clones present reduction in the biometric and physiological traits values under water limitations. For the physiological traits, the potassium supply caused effect reduction of the water stress. To the biometric... (Complete abstract click electronic access below)
Descrição
Palavras-chave
Plantas - Nutrição, Eucalipto, Melhoramento florestal, Deficiência hidrica, Biological control, Drought, Choropyll content, Plant nutrition, Forest tree improvement, Photosystem II
Como citar
MENDES, Hélio Sandoval Junqueira. Comportamento de clones de eucalipto em resposta a disponibilidade hídrica e adubação potássica. 2011. ix, 43 f. Dissertação (mestrado) - Universidade Estadual Paulista, Faculdade de Ciências Agrárias e Veterinárias, 2011.