Increased atmospheric carbon dioxide concentration: effects on eucalypt rust (Puccinia psidii), C:N ratio and essential oils in eucalypt clonal plantlets

Abstract

Evaluation of impacts of high CO 2 atmospheric concentration is strategically important for the development of adaptation measures and sustainable crop management. The objective of this study was to evaluate the effects of increased atmospheric CO 2 concentration on eucalypt rust (Puccinia psidii), C:N ratio, yield and chemical composition of essential oils and growth of eucalypt clonal plantlets. Two clones with different levels of rust resistance were studied: a Eucalyptus urophylla 9 E. camaldulensis hybrid (VM 01) and an E. urophylla (clone MN 463). The experiments were performed in open-top chambers (OTCs) with CO 2 mean concentrations (lmol mol À1 ) of 399 (unenclosed control), 412 (OTCs with ambient CO 2 concentration) and 508 (OTCs with high CO 2 concentration) and in closed chambers (CCs) with CO 2 mean concentrations of 390, 405, 520 and 700. Increased atmospheric CO 2 concentrations resulted in a decrease in rust pustules per leaf, uredinia per leaf area, spores per uredinia and area under the disease progress curve in VM 01 (hybrid) clonal plantlets. The disease did not occur in MN 463 clonal plantlets, which demonstrated that high CO 2 concentrations did not change the level of rust resistance. Plant growth of the two clones was stimulated by up to 23% in height and 26% in stem diameter in OTCs and by 18% for both clones in CCs. An increased C:N ratio in leaves, stems and roots was observed only for the VM 01 clonal plantlets. Essential oils produced by VM 01 (2.8 g 100 g À1 ) and MN 463 (1.4 g 100 g À1 ), as well as the major essential oil compounds (80% 1.8-cineole for VM 01; 50% 1.8-cineole and 32% a-pinene for MN 463), were not altered. In this study, increased concentrations of atmospheric CO 2 favourably impacted eucalypt growth and reduced rust severity, while not influencing the production of essential oils.

Plant growth and leaf-spot severity on eucalypt at different CO2concentrations in the air

“…Otherwise, Novriyanti et al (2012) observed no positive effects of elevated CO 2 concentrations on growth of eucalypts, despite increases on net photosynthetic rate. The increase in plant height and shoot dry weight, as observed in the present study, was also observed by Santos et al (2013) and Ghini et al (2014), in clonal eucalypt plantlets grown under high air-CO 2 concentrations for approximately 60 days.…”

“…Moreover, it also increases plant growth, based on the height and shoot dry matter weight of the seedlings. These favorable effects of rising atmospheric CO 2 concentration on the severity of C. candelabrum leaf-spot and eucalypt growth agree with the results obtained by Santos et al (2013) and Ghini et al (2014) for Ceratocystis wilt and rust, respectively. (1) Values followed by equal letters do not differ, by Tukey's test, at 5% probability.…”

“…Studying the impacts of rising CO 2 concentrations, Santos et al (2013) observed that at high air-CO 2 concentrations the plantlets of two eucalyptus clones had longer disease incubation period and lower severity of wilt caused by Ceratocystis fimbriata. Ghini et al (2014) observed that increasing CO 2 concentration decreased rust severity caused by Puccinia psidii on eucalypt clonal plantlets. Both Santos et al (2013) and Ghini et al (2014) verified that plantlet growth increased with rising air-CO 2 concentration.…”

“…Ghini et al (2014) observed that increasing CO 2 concentration decreased rust severity caused by Puccinia psidii on eucalypt clonal plantlets. Both Santos et al (2013) and Ghini et al (2014) verified that plantlet growth increased with rising air-CO 2 concentration.…”

Impacto do aumento da concentração atmosférica de dióxido de carbono sobre a ferrugem e o crescimento do cafeeiro

“…Dois conjuntos de OTCs foram utilizados, o primeiro foi construído conforme Pritchard & Amthor (2005), e o segundo, conforme versão modificada de Ghini et al (2014). Cada um desses conjuntos foi composto por seis OTCs, das quais três receberam aplicação de CO 2 , e as outras três permaneceram com a concentração ambiente de CO 2 do ar.…”