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

Abstract

Resumo -O objetivo deste trabalho foi avaliar o efeito do aumento da concentração de dióxido de carbono atmosférico sobre o crescimento de plantas e a severidade da ferrugem (causada por Hemileia vastatrix) em cafeeiro (Coffea arabica). Utilizaram-se as cultivares 'Obatã IAC 1669-20' e 'Catuaí Vermelho IAC 144', moderadamente resistente e suscetível à doença, respectivamente. Os tratamentos consistiram de 400 e 508 μmol mol -1 de CO 2 atmosférico, em dois tipos de estufas de topo aberto (OTC). As plantas das duas cultivares, cultivadas nas OTCs com adição de CO 2 , apresentaram aumento de área foliar, e da taxa de crescimento em altura e em diâmetro do caule, em comparação às plantas cultivadas em estufas à concentração ambiente de CO 2 ; porém, as cultivares não diferiram quanto ao teor de cera das folhas. Em 'Catuaí Vermelho IAC 144', a severidade da ferrugem diminuiu com o aumento da concentração de CO 2 , quanto ao número de lesões, área foliar lesionada, número de lesões esporuladas, área lesionada esporulada, percentagem de área foliar lesionada e área abaixo da curva de progresso da doença; no entanto, em 'Obatã IAC 1669-20', a severidade da doença não variou. A incidência de folhas lesionadas por planta, o período latente, a germinação de urediniósporos e a formação de apressórios não são alterados, à dose de 508 μmol mol -1 de CO 2 , em ambas as cultivares.Termos para indexação: Coffea arabica, Hemileia vastatrix, aquecimento global, CO 2 , mudanças climáticas. Impact of increasing atmospheric concentration of carbon dioxide on coffee leaf rust and coffee plant growthAbstract -The objective of this work was to evaluate the effect of increasing the atmospheric concentration of carbon dioxide on plant growth and leaf rust severity (caused by Hemileia vastatrix) on coffee (Coffea arabica). The 'Obatã IAC 1669-20' and 'Catuaí Vermelho IAC 144' cultivars, moderately resistant and susceptible to the disease, respectively, were used. The treatments consisted of 400 and 508 μmol mol -1 atmospheric CO 2 , in two types of open-top chambers (OTC). Plants of the two cultivars, grown in OTCs with addition of CO 2 , showed increased leaf area, and increased growth rate of height and stem diameter, in comparison with plants in OTCs with ambient CO 2 concentration; however, the cultivars did not differ for leaf-wax content. On 'Catuaí Vermelho IAC 144', rust severity reduced at increased CO 2 concentration, for number of lesions, lesioned leaf area, number of sporulated lesions, sporulated leaf area, percentage of lesioned area, and area under disease progress curve; however, on 'Obatã IAC 1669-20', the disease severity did not vary. The incidence of lesioned leaves per plant, latent period, urediniospore germinations, and appressorium formation are not changed by the 508 μmol mol -1 CO 2 dose in both cultivars.

Severity of melon powdery mildew as a function of increasing temperature and carbon dioxide concentration

“…On the other hand, the increase of the disease occurred in alfafa (Medicago sativa L.) -Uromyces striatus J. Schrot (Santos, 2015). The coffee cultivar 'Obatã IAC 1669-20' was not influenced by the increase in CO 2 concentration in the rust severity (H. vastatrix) (Tozzi & Ghini, 2016). This diversity of responses confirms the importance of studies for each pathosystem, evaluating their specificities.…”

“…& Br. (Tozzi & Ghini, 2016), eucalyptus (Eucalyptus spp.) -Puccinia psiidi Winter (Ghini et al, 2015) and soy ((Glycine max (L.) Merrill) -Phakospsora pachyrhizi Sidow (Lessin & Ghini, 2009).…”

“…Increasing CO 2 concentration induces stomatal closure, consequently improving water use efficiency, protecting against water stress and increasing plant defense (Abdelgawad et al, 2016). In addition, this gas acts positively on increasing plant biomass (Tozzi & Ghini, 2016). However, this increase may represent a larger amount of tissue to be infected by leaf pathogens, facilitating growth, sporulation and dissemination (Debela & Tola, 2018).…”

Mitigation of the Negative Impact of Warming on the Coffee Crop: The Role of Increased Air [CO2] and Management Strategies

“…Altered temperature may further promote extreme weather events, alter intra-and interannual precipitation patterns with long periods of drought and/or heavy rainfalls, partial melting of glacial ice, and consequently rising of the sea level [1]. Climate changes, particularly global warming, has a severe impact on the Earth's ecosystem and pose serious threats to agricultural sustainability [4][5][6], which is one of the human activities most vulnerable to climatic variation, since plants require optimal growing conditions to produce desired quantity and quality products [7,8]. On the other hand, global demand for food is increasing as it is linked to the rapidly growing populations, which together with climate constraints, may compromise world food security [9].…”

“…The evidence of improved coffee performance under enhanced [CO 2 ] was further obtained with other C. arabica genotypes (Obatã IAC 1669-20 and Catuaí Vermelho IAC 144) under field conditions using free-air CO 2 enrichment (FACE) system, showing increased photosynthesis and decreased photorespiration, without changes in stomatal and mesophyll conductance, for an air [CO 2 ]o f5 5 0μLL À1 [33]. Additionally, coffee plants grown under elevated [CO 2 ] were more vigorous, with increased leaf area, growth rate at height and stem diameter, showing as well increased grain yield by 14.6 and 12.0% for Catuaí Vermelho 144 and Obatã IAC 1669-20, respectively,[8,32], although average yield increases of 28% were also reported after three harvests[37] when compared to plant grown at ambient[CO 2 ]. Another study also demonstrated that coffee trees grown under 550 μLC O 2 L À1 presented increase in photosynthesis of leaves from upper and lower canopy layers, inhibition of photorespiration, and no apparent sign of photosynthetic downregulation, when compared to plants grown under ambient [CO 2 ]( 3 9 0μLL À1 )[98].…”