Search

Studies on the genetic diversity of coffee trees are important, considering their role in the maximization of productivity and quality. However, the success of a breeding program depends on the existence of genetic variability in the population under study. Our study aimed to evaluate the genetic diversity of the morpho-agronomic and anatomical leaf traits of different cultivars of Coffea arabica grown in the Gorongosa mountain region, in the area of Gorongosa National Park, Mozambique. The experiment assessed nine coffee cultivars based on their morpho-agronomic and anatomical traits. The plagiotropic branch diameter, leaf dry mass, leaf mass per area, number of epidermal cells + stomata, and stomatal form indicated differences among the studied cultivars. Among the nine C. arabica cultivars grown in the mountainous region of Gorongosa National Park, Mozambique, low genetic variability in morpho-agronomic traits was detected, while the genetic variability in leaf anatomical traits was higher. The nine cultivars were segregated into two groups, one consisting of Catucaí Amarelo 2SL and Catuaí Vermelho IAC 81, and the second consisting of Catuaí Amarelo IAC 39, Catucaí Vermelho 19/8, Acauã, Catucaí 785-15, Costa Rica, Catimor 128, and Catuaí Vermelho IAC 44. The cultivar segregation into the two groups indicated that the morpho-anatomical traits can be considered during the selection stages in breeding programs.

Climate changes boosted the frequency and severity of drought and heat events, with aggravated when these stresses occur simultaneously, turning crucial to unveil the plant response mechanisms to such harsh conditions. Therefore, plant responses/resilience to single and combined exposure to severe water deficit (SWD) and heat were assessed in two cultivars of the main coffee-producing species: Coffea arabica cv. Icatu and C. canephora cv. Conilon Clone 153 (CL153). Well-watered plants (WW) were exposed to SWD under an adequate temperature of 25/20°C (day/night), and thereafter submitted to a gradual increase up to 42/30°C, and a 14-d recovery period (Rec14). Greater protective response was found to single SWD than to single 37/28°C and/or 42/30°C (except for HSP70) in both cultivars, but CL153-SWD plants showed the larger variations of leaf thermal imaging crop water stress index (CWSI, 85% rise at 37/28°C) and stomatal conductance index (IG, 66% decline at 25/20°C). Both cultivars revealed great resilience to SWD and/or 37/28°C, but a tolerance limit was surpassed at 42/30°C. Under stress combination, Icatu usually displayed lower impacts on membrane permeability, and PSII function, likely associated with various responses, usually mostly driven by drought (but often kept or even strengthened under SWD and 42/30°C). These included the photoprotective zeaxanthin and lutein, antioxidant enzymes (superoxide dismutase, Cu,Zn-SOD; ascorbate peroxidase, APX), HSP70, arabinose and mannitol (involving de novo sugar synthesis), contributing to constrain lipoperoxidation. Also, only Icatu showed a strong reinforcement of glutathione reductase activity under stress combination. In general, the activities of antioxidative enzymes declined at 42/30°C (except Cu,Zn-SOD in Icatu and CAT in CL153), but HSP70 and raffinose were maintained higher in Icatu, whereas mannitol and arabinose markedly increased in CL153. Overall, a great leaf plasticity was found, especially in Icatu that revealed greater responsiveness of coordinated protection under all experimental conditions, justifying low PIChr and absence of lipoperoxidation increase at 42/30°C. Despite a clear recovery by Rec14, some aftereffects persisted especially in SWD plants (e.g., membranes), relevant in terms of repeated stress exposure and full plant recovery to stresses.

The yerba mate leaf metabolic composition depends mainly on genetics, sex, plant and leaf age, light intensity, harvest time, climate, and fertilization. In yerba mate, the secondary sexual dimorphism (SSD), the leaf metabolic SSD association with the frequency of leaf harvests, and the stability of the metabolites in the two genders over the years is not known. It was hypothesized that (1) the SSD in the metabolite segregation would differ among the winter and summer growth pauses, (2) females would show lower metabolite concentrations, and (3) the metabolic concentrations would show stability over the years on the same plants, not obligatorily associated with the SSD stability expression. Variations in theobromine, caffeine, chlorogenic and caffeic acids were correlated to the increasing time since the previous harvest, especially in females. However, the frequency of the metabolic SSD were associated with the studied growth pauses, rejecting the first hypothesis. No regular gender superiority was expressed in the yerba mate leaf secondary metabolites, rejecting our second hypothesis, even though more cases of superior female metabolite accumulation were identified. The stability of the leaf protein was preserved over the four years, with no SSD cases observed. The leaf methylxanthines were time stable, while the decrease in the phenolic content occurred with tree aging, which was not associated with the SSD expression, partially proving our third hypothesis. The novelty was related to the time stability of the leaf metabolic SSD observed over the winter and summer growth pauses, and over the four consecutive years without a regular expression of the male- or female-biased concentrations in the studied metabolites. To demystify the random metabolic gender responses in yerba mate, gender-orientated experiments with a high number of tree repetitions must be conducted, including clonal plants grown in various environments, such as monoculture and agroforestry, or on plantations in different climates and altitudes.

Increases in water use efficiency (WUE) and the reduction of negative impacts of high temperatures associated with high solar radiation are being achieved with the application of fine particle film of calcined and purified kaolin (KF) on the leaves and fruits of various plant species. KF was applied on young Coffea arabica and Coffea canephora plants before their transition from nursery to full sunlight during autumn and summer. The effects of KF were evaluated through the responses of leaf temperature (Tleaf), net CO2 assimilation rate (A), stomatal conductance (gs), transpiration (E), WUE, crop water stress index (CWSI), index of relative stomatal conductance (Ig), initial fluorescence (F0), and photosynthetic index (PI) in the first 2–3 weeks after the plant transitions to the full sun. All measurements were performed at midday. In Coffea plants, KF decreased the Tleaf up to 6.7°C/5.6°C and reduced the CWSI. The plants that were not protected with KF showed lower A, gs, E, and Ig than those protected with KF. C. canephora plants protected with KF achieved higher WUE compared with those not protected by 11.23% in autumn and 95.58% in summer. In both Coffea sp., KF application reduced F0, indicating reduced physical dissociation of the PSII reaction centers from the light-harvesting system, which was supported with increased PI. The use of KF can be recommended as a management strategy in the transition of Coffea seedlings from the nursery shade to the full sunlight, to protect leaves against the excessive solar radiation and high temperatures, especially in C. canephora during the summer.

Water availability, light, management practices, and harvest time impacts on Coffea arabica L. yield and bean quality remain uncertain. It was hypothesized that the soil water and light availability could impact berry distribution, yield, and bean chemical attributes within the plant canopy. Therefore, it was aimed to study berry yield, berry distribution, and bean chemical traits along the canopy strata of four coffee genotypes (Iapar 59, Catuaí 99 and two Ethiopian wild accessions, ‘E083’ and ‘E027’), cultivated with (IRR) and without irrigation (NI) in the two initial harvest years. The maximum height of berry occurrence was lower in NI than in IRR plants in both harvest years. In the 2nd harvest year, higher leaf-to-fruit ratio was found under NI than under IRR for all genotypes, except for Catuaí 99, while the most regular berry distribution among canopy strata was obtained in IRR ‘E083’, the highest bean yield in IRR ‘E083’ and Iapar 59, and the highest percent of useful bean biomass in NI Catuaí 99. The reduced lipid content under IRR was more important in the 1st (all genotypes) than in the 2nd harvest year (Iapar 59 and ‘E027’). As a novelty, chemical bean composition was additionally impacted by light availability along the canopy strata. Proteins declined from bottom (shaded) to upper (highly light exposed) strata, regardless of genotype and harvest year. Similar stratification was observed in caffeine in the 2nd year. Although some traits were somewhat changed among strata, no substantial quality changes occurred, thus allowing that harvest might include the entire plant and not only some specific strata. Iapar 59 and ‘E083’ showed chemical composition usually associated with high bean quality, with the highest lipid, sucrose, and soluble sugar contents, and the lowest caffeine, chlorogenic acids, and phenolic components among four genotypes, but Iapar 59 plants were less affected in their yield under NI. Based on additional responses from space occupation and yield only under IRR, the wild accession ‘E083’ must be considered in future breeding programs as promising material for intensive input conditions. High bean quality and the less variated yield under lower soil water availability qualified the Iapar 59 as the most prominent among the four genotypes.

The effects of hydric stress and sunlight access conditions on metabolic compounds in coffee leaves were investigated utilizing statistical mixture design extractor solvents. PCA and OSC–PLS–DA chemometric methods were used to analyze UV–visible spectra of irrigated and non-irrigated Coffea arabica L. leaves from low (80 cm, light exposed) strata. The first latent variable of the OSC–PLS–DA score plot perfectly discriminated extracts of 34 calibration and 14 validation samples of irrigated and non-irrigated leaves. Higher spectral signals observed at the 410, 505, 535, 607 and 665 nm wavelengths are attributed to conjugate double bond pigments, mainly pheophytin a, indicating that non-irrigated conditions are more stressful than irrigated ones for this species. No significant difference was found for leaf sample extracts with varying light access conditions. Keywords: Coffea arabica L. leaves, Hydric stress, Mixture design, PCA, OSC–PLS–DA

Despite the negative impacts of increased ultraviolet radiation intensity on plants, these organisms continue to grow and produce under the increased environmental UV levels. We hypothesized that ambient UV intensity can generate acclimations in plant growth, leaf morphology, and photochemical functioning in modern genotypes of Coffea arabica and C. canephora. Coffee plants were cultivated for ca. six months in a mini greenhouse under either near ambient (UVam) or reduced (UVre) ultraviolet regimes. At the plant scale, C. canephora was substantially more impacted by UVam when compared to C. arabica, investing more carbon in all juvenile plant components than under UVre. When subjected to UVam, both species showed anatomic adjustments at the leaf scale, such as increases in stomatal density in C. canephora, at the abaxial and adaxial cuticles in both species, and abaxial epidermal thickening in C. arabica, although without apparent impact on the thickness of palisade and spongy parenchyma. Surprisingly, C. arabica showed more efficient energy dissipation mechanism under UVam than C. canephora. UVam promoted elevated protective carotenoid content and a greater use of energy through photochemistry in both species, as reflected in the photochemical quenching increases. This was associated with an altered chlorophyll a/b ratio (significantly only in C. arabica) that likely promoted a greater capability to light energy capture. Therefore, UV levels promoted different modifications between the two Coffea sp. regarding plant biomass production and leaf morphology, including a few photochemical differences between species, suggesting that modifications at plant and leaf scale acted as an acclimation response to actual UV intensity.

The objectives of this work were to determine the heliotropic movements of the upper trifoliates for two soybean cultivars, BR 16 and Embrapa 48, during a daily cycle, in three phenological stages and two water regimes, and to estimate the impact of irrigation and daily leaflet movements on agronomic characteristics and grain yield. Heliotropic movements were studied in three phenological stages: V4-V6, V7-V10, and R5 in irrigated and non-irrigated plots. For each stage, the leaflet elevation and azimuth were measured hourly. Under a low (V4-V6 stage) and mid (V7-V10 stage) leaf area index (LAI) the diaheliotropism was slightly more frequent and intensive in non-irrigated than in irrigated plants, only at early morning and late afternoon hours. At R5 stage (high LAI) the paraheliotropism of superior trifoliates was predominant and more intensive in non-irrigated plants. The heliotropic movements are correlated to carbon gain, but not to environment (light intensity or temperature), for measurements at 11h. 'Embrapa 48' expresses greater paraheliotropism than 'BR 16' at high LAI, while 'BR 16' displays lower heliotropic plasticity under irrigation. In spite of significant heliotropic differences, genotype and water availability treatments did not influence the final grain yield.Os objetivos deste trabalho foram determinar o movimento heliotrópico dos trifólios superiores de duas cultivares de soja, BR 16 e Embrapa 48, durante o dia, em três estádios fenológicos e em dois regimes hídricos e determinar o impacto da irrigação e do movimento foliar diário nas características agronômicas e na produção de grãos. Movimentos heliotrópicos foram determinados a cada hora, em três estádios fenológicos: V4-V6, V7-V10 e R5, em parcelas irrigadas e não irrigadas. Para cada estágio, a elevação do folíolo e o azimute foram medidos por hora. Em índices de área foliar (IAF) baixo e médio (V4-V6 e V7-V10), o diaheliotropismo foi levemente mais intenso e frequente nas plantas sem irrigação do que nas irrigadas, e somente nas primeiras horas matinais e últimas horas da tarde. Em R5 (alto IAF), o paraheliotropismo dos trifólios superiores foi predominante e mais intenso em plantas não irrigadas. Os movimentos heliotrópicos se correlacionaram com o ganho de carbono mas não com o ambiente (intensidade de luz ou temperatura), para medidas às 11 horas. 'Embrapa 48' apresenta maior paraheliotropismo do que 'BR 16', em plantas com alto IAF enquanto 'BR 16' apresenta menor plasticidade nas respostas heliotrópicas nas parcelas irrigadas. Apesar de diferenças no heliotropismo, o genótipo e disponibilidade de água não influenciaram a produção de grãos.

The objective of this work was to build mock-ups of complete yerba mate plants in several stages of development, using the InterpolMate software, and to compute photosynthesis on the interpolated structure. The mock-ups of yerba-mate were first built in the VPlants software for three growth stages. Male and female plants grown in two contrasting environments (monoculture and forest understory) were considered. To model the dynamic 3D architecture of yerba-mate plants during the biennial growth interval between two subsequent prunings, data sets of branch development collected in 38 dates were used. The estimated values obtained from the mock-ups, including leaf photosynthesis and sexual dimorphism, are very close to those observed in the field. However, this similarity was limited to reconstructions that included growth units from original data sets. The modeling of growth dynamics enables the estimation of photosynthesis for the entire yerba mate plant, which is not easily measurable in the field. The InterpolMate software is efficient for building yerba mate mock-ups.O objetivo deste trabalho foi construir maquetes de plantas de erva-mate em vários estágios de desenvolvimento com o uso do programa InterpolMate, e de computar a fotossíntese a partir de estrutura interpolada. Maquetes de erva-mate foram construídas com o software VPlants para três estágios de crescimento. Foram consideradas plantas do sexo masculino e feminino, cultivadas em dois ambientes distintos: monocultura e sub-bosque. Para modelar a arquitetura dinâmica 3D, de plantas individuais de erva-mate, durante o período bienal de crescimento entre duas podas, foram utilizadas informações coletadas em 38 datas do desenvolvimento dos galhos. Os valores estimados a partir das maquetes, incluindo dimorfismo sexual e fotossíntese foliar, são muito próximos aos observados em campo. Contudo, essa semelhança foi limitada às reconstruções que incluíram unidades de crescimento de conjuntos de dados originais. A modelagem da dinâmica de crescimento possibilita estimativas de fotossíntese de plantas inteiras da erva-mate, o que é dificilmente mensurável no campo. O software InterpolMate é eficiente na construção de maquetes de erva-mate.

Este trabalho teve como objetivo indicar algumas possíveis manipulações ecofisiológicas, com base em experimentos de arquitetura de plantas. Plantas de erva-mate, seringueira e videira foram caracterizadas no campo e no laboratório, e suas maquetes 3D foram reconstruídas com os programas V-Plants e PlantGLViewer. Indicações sobre a análise de crescimento e impactos ambientais, com a aplicação de diversas simulações, foram discutidas.The objective of this work was to indicate some possible ecophysiological manipulations, based on experiments of plant architectural traits. Yerbamate, rubber tree and grapevine plants were measured in field and laboratory, and their 3D mockups were constructed using V-Plants and PlantGLViewer softwares. Indications about growth and environmental impact analysis were discussed, applying diverse simulations in modeling process.

The bitterness intensity of beverage prepared from the leaves produced on the males and females of yerba mate (Ilex paraguariensis), grown in the forest understory and monoculture, was evaluated. The leaves were grouped by their position (in the crown and on the branch tips) and by the leaf age. The leaf gas exchange, leaf temperature and photosynthetic photon flux density were observed. Inter and intra-specific competition for light and self-shading showed the same effect on yerba mate beverage taste. All the shading types resulted in bitterer taste of the processed yerba mate leaves compared to the leaves originated under the direct sun exposure. The leaves from the plants grown in the monoculture showed less bitterness than those grown in the forest understory. This conclusion was completely opposite to the conventionally accepted paradigm of the yerba mate industries. The leaves from the tips (younger leaves) of the plants grown in the monoculture resulted a beverage of softer taste; the males produced less bitter leaves in any light environment (forest understory or in the crown in monoculture). The taste was related to the photosynthetic and transpiration rate, and leaf temperature. Stronger bitterness of the leaves provided from the shade conditions was related to the decreased leaf temperature and transpiration in the diurnal scale.Mediu-se a intensidade de amargor da bebida preparada a partir de folhas da erva-mate (Ilex paraguariensis) de diversas idades, situadas em duas posições na copa (interior e ponteiras), produzidas por plantas masculinas e femininas cultivadas na floresta antropizada e em monocultura. As trocas gasosas foliares, a temperatura de folhas e a densidade de fluxo de fótons fotossinteticamente ativos também foram medidas. Com isso verificou-se que a idéia corrente de que o sombreamento está diretamente relacionado ao sabor suave do chimarrão é completamente equivocada, já que as competições inter- e intra-específicas por luz e auto-sombreamento provocaram o mesmo efeito no sabor do chimarrão, isto é, todos os tipos de sombreamento resultaram em sabor mais amargo de folhas processadas do de pleno sol. Assim, as folhas de plantas cultivadas em monocultura mostraram-se menos amargas do que aquelas de plantas manejadas sob a floresta. Além disso, as folhas de ponteiras (mais jovens) da monocultura originaram o chimarrão mais suave e os machos produziram folhas menos amargas que as fêmeas em ambos ambientes luminosos (floresta e monocultura). O sabor mostrou-se relacionado à fotossíntese, à transpiração e à temperatura de folha. Em sombreamento a modificação de sabor foi direcionada ao aumento de amargor e, aparentemente, relacionada ao decréscimo da temperatura de folhas e da transpiração na escala diurna.

The influence of different N sources on the growth of maté (Ilex paragurariensis St.Hil.) seedlings grown in greenhouse was studied. All seedlings received a base fertilization of 10 mg N.kg-1 soil as NH4NO3, 60 mg P2O5.and 40 mg K2O.kg-1 soil as KH2PO4 15 days before treatments application. Treatments were as follow: Control, with no extra N added; Urea = 100 mg N.kg-1 soil as Urea; NO3- = 100 mg N.kg-1 soil as Ca(NO3)2; and NH4+ = 100 mg N.kg-1 soil as (NH4)2SO4. It was concluded that: 1) increasing N content in leaves alone was not able to promote gain in biomass production of maté seedlings; 2) seedlings receiving N-NH4 showed a higher accumulation of P and Mg on shoot biomass; and 3) an increase in leaf area, leaf number and net photosynthesis observed at the N-NH4 treatment was coincident with an increasing absorption of P and Mg.A influência de diferentes fontes de N sobre o crescimento de mudas de erva-mate (Ilex paraguariensis St.Hil.) foi estudada, em casa de vegetação. Todas as mudas receberam uma fertilização base de 10 mg N.kg-1 de solo na forma de NH4NO3, 60 mg P2O5.kg-1 e 40 mg K2O.kg-1 de solo na forma de KH2PO4 quinze dias antes da aplicação dos tratamentos. Os tratamentos foram os seguintes: Controle, sem adição extra de N; Uréia = 100 mg N.kg-1 de solo como Uréia; NO3- = 100 mg N.kg-1 de solo como Ca(NO3)2; e NH4+ = 100 mg N.kg-1 de solo como (NH4)2SO4. Concluiu-se que: 1) o aumento do conteúdo de N nas folhas, por si, não é capaz de promover ganhos na produção de biomassa em mudas de erva-mate; 2) mudas que receberam N-NH4 apresentaram maior acumulo de P e Mg na biomassa aérea; e 3) o aumento na absorção de P e Mg coincidiu com um aumento na área foliar, no número de folhas e na fotossíntese liquida na fonte N-NH4.

Seeds of Cedrela fissilis Vellozo were planted and maintained under two distinct conditions: at east border of a forest with red: far-red ratio of 1.15 and under canopy with photosynthetic photon flux density of 0.22-7% of full sun radiation and red: far-red ratio of 0.21-0.36. Seedling growth (height and stem diameter) was faster under sun, the development of roots more continuous and the number of leaves almost twice of that of shade plants. The leaf area was 10 times greater in sun plants with 15-25 leaflets per leaf while under shade only 5 to 10 leaflets were found per leaf. In shade plants, a higher proportion of dry mass was found in aerial parts. Leaves of sun plants had the capacity of gas exchange to respond to high light radiation, but leaves adapted to shade presented a lower response to light changes. When shade plants were transferred and maintained under the sun for 15 days, only the young leaves were adapted to increased light radiation, reaching the same photosynthetic rate as sun plants, while old leaves were shed. Sun plants transferred to shade conditions did not lose leaves, but did not reach the same photosynthetic rate attained by shade plants.Cedrela fissilis foi semeada e mantida em dois ambientes de luz: na margem leste (tratamento sol - razão vermelho: vermelho extremo da radiação solar direta foi 1,15) e sob dossel de floresta (tratamento sombra - radiação fotossinteticamente ativa reduzida de 0.22 a 7% da radiação direta e razão vermelho:vermelho extremo de 0,21 a 0,36). O crescimento em altura e diâmetro do caule no sol foi mais rápido, o desenvolvimento do sistema radicular continua, o número de folhas foi em média o dobro das de sombra, quanto à área foliar foi 10 vezes maior em plantas de sol com 15-25 folíolos por folha, enquanto as plantas da sombra desenvolveram de 5 a 10. Nas plantas de sombra, as maiores proporções de matéria seca foram investidas em parte aérea. A capacidade de troca de gases das plantas da sombra expostas na radiação alta não aumentou. Quando plantas de sombra foram transferidas ao sol e mantidas por 15 dias, apenas as folhas jovens se adaptaram às condições de radiação aumentada, atingindo a capacidade de resposta das folhas das plantas de sol, enquanto as folhas mais velhas caíram. As plantas de sol transferidas para a sombra não perderam as folhas, mas não atingiram a resposta das plantas de sombra.

O trabalho teve por objetivos estimar parâmetros genéticos para 59 progênies de meios-irmãos de erva-mate, por ocasião da poda de formação, bem como avaliar propriedades ecofisiológicas para quatro progênies (P15, P18, P41 e P47) e duas testemunhas (P61 e P62) componentes de um teste combinado de procedências e progênies em Erechim, RS. As propriedades ecofisiológicas (condutância estomática (gs) – mol m-2s-1, fotossíntese liquida (A) - μmol CO2 m- 2s- e transpiração (E) –mmol H2O m-2s-1) foram medidas durante um ano (de setembro de 2002 a agosto de 2003) em cinco épocas. Os componentes de variâncias, parâmetros genéticos e fenotípicos e valores genéticos (para dados de massa foliar coletados em poda de formação) foram obtidos através do programa genético - estatístico “SELEGEN – REML/BLUP”. A análise de parâmetros ecofisiológicos mostrou a sazonalidade de respostas, tornando-a importante na avaliação. A sazonalidade de troca gasosa acompanha a ocorrência de paradas e ondas de crescimento da erva-mate. As progênies P18 e P47, classificadas quanto ao valor genético, em quinto e 23o lugar, respectivamente, apresentaram maior A, maior economia de água (menor E com maior A) e maior sobrevivência, quando comparadas com P15 e P41, que ocuparam a 23a e a 40a posição, respectivamente. Com herdabilidade individual no sentido restrito de 22,7%, é necessário recorrer a métodos de seleção que utilizem, simultaneamente, as informações do indivíduo e da média de sua família, para melhorar o peso de massa foliar em planta de erva-mate. Houve coerência entre respostas genéticas na análise de massa foliar e análise ecofisiológica, o que sugere avaliar componentes ecofisiológicos acompanhando a avaliação de massa foliar ou/e massa total, no processo de seleção e melhoramento genético da erva-mate.

Neste estudo preliminar foram determinadas as propriedades ecofisiológicas de plantas femininas e masculinas da erva-mate (Ilex paraguariensis St.Hil.) cultivadas no campo. Fluxo de fótons ativo na fotossíntese (PPFD), condutância estomática (gs), fotossíntese liquida (A), transpiração (E) e temperatura foliar (Tl) foram avaliados em um ciclo bienal de produção: no verão (janeiro e fevereiro) durante o período de maturação dos frutos quando ocorre pausa no crescimento; na primavera (novembro) e no outono (março a junho) durante emissão de novas brotações. As medições foram efetuadas em diferentes posições na copa (interior, exterior e ponteiras). Resultados indicam existência de dimorfismo sexual fisiológico na espécie. A condutância foi superior nas plantas femininas, exceto nas ponteiras. A e E foram superiores na parte exterior do terço médio das copas das plantas femininas. Foi detectada sazonalidade na troca gasosa, com os maiores valores registrados na época de emissão de novas brotações e menores durante a fase de maturação dos frutos. Observaram-se correlações positivas entre trocas gasosas e PPFD. A e E correlacionaram-se positivamente com a gs, tanto para plantas masculinas quanto femininas. A estratégia funcional das plantas fêmeas, com o propósito de finalização do processo de reprodução, é de proporcionar o aumento relativo da fotossíntese e da transpiração das folhas sombreadas por intermédio de um maior valor de gs, quando comparado com indivíduos masculinos.

Este estudo teve por objetivo avaliar o sabor da bebida preparada a partir de folhas de erva-mate, de plantas masculinas e femininas . As propriedades ecofisiológicas, químicas e sensoriais foram avaliadas em uma das fases de brotação e em duas fases de frutificação. As plantas masculinas e femininas não diferiram em produção de matéria fresca e seca, nem nos teores de macro-e-micro-elementos. Mas, as plantas femininas apresentaram maior fotossíntese líquida (A) e condutância estomática (gs). A bebida preparada com folhas oriundas de plantas masculinas foi menos amarga do que das femininas, particularmente quando coletadas das ponteiras dos ramos. A intensidade de amargor apresentou correlação positiva com o teor de Zn e Mg nas plantas femininas e com gs e teor de Mn nas plantas masculinas. O amargor da bebida preparada de plantas masculinas mostrou-se negativamente correlacionada com teor de K. A "masculinização" de eral pode ser uma solução para se produzir erva-mate de sabor normal a suave.

The aim of this study was to assess the taste of beverage prepared from yerba-mate (Ilex paraguariensis) leaves, originated from male and female plants, by taking into account leaf gas exchange and the content of macro-and-trace-elements. Ecophysiological, chemical and sensorial properties were evaluated in one of the sprouting phases and in two fruit ripening phases. Male and female plants did not differ in fresh and dry matter production per plant, nor in the content of micro- and trace elements. However, female plants showed higher leaf net photosynthesis (A) and stomatal conductance (gs) than male plants. The beverage prepared with male plant leaves was less bitter than that prepared with female plant leaves, especially when leaves from the branch tips were used. The intensity of bitterness was positively correlated with Zn and Mg contents in female plants and with Mn content and gs in male plants. The bitterness of the beverage prepared with male plant leaves was negatively correlated with K content. The idea about "masculinization" of yerba-mate stands appeared as a possible solution for the production of yerba-mate of normal to soft taste.Este estudo teve por objetivo avaliar o sabor da bebida preparada a partir de folhas de erva-mate, de plantas masculinas e femininas . As propriedades ecofisiológicas, químicas e sensoriais foram avaliadas em uma das fases de brotação e em duas fases de frutificação. As plantas masculinas e femininas não diferiram em produção de matéria fresca e seca, nem nos teores de macro-e-micro-elementos. Mas, as plantas femininas apresentaram maior fotossíntese líquida (A) e condutância estomática (gs). A bebida preparada com folhas oriundas de plantas masculinas foi menos amarga do que das femininas, particularmente quando coletadas das ponteiras dos ramos. A intensidade de amargor apresentou correlação positiva com o teor de Zn e Mg nas plantas femininas e com gs e teor de Mn nas plantas masculinas. O amargor da bebida preparada de plantasmasculinas mostrou-se negativamente correlacionada com teor de K. A "masculinização" de eral pode ser uma solução para se produzir erva-mate de sabor normal a suave.

A preliminary study was developed on leaf gas exchange properties of males and females in yerbamate (Ilex paraguariensis St. Hil.), planted in open growth conditions. The photosynthesic photon flux density (PPFD) on leaf level, stomatal conductance (gs), net photosynthesis (A), transpiration (E), and leaf temperature (Tl) was measured during the biennial production period: in the summer during the fruit ripening when there is a pause in its growth (January, February), spring sprouting (November) and autumn sprouting (March, Jun). The measurements have been taken in different tree crown positions (inside, exterior and tips). First indications of sex physiological dimorphism in yerba-mate have been shown. Conductance was superior on female plants, with exception on tips, whereas the A and E were superior on females, on the exterior of the third medium of the tree crown. Positive correlations among gas exchange properties and PPFD were established. The seasonality in gas exchange was observed. The maximum gas exchange values were registered in active sprouting whereas the minimum values were registered during fruit ripening, in full summer. A and E were positively correlated with gs for both males and females. The functional strategy of females, aiming to finish the reproductive process, is to proportionate the relative increase of A and E on self-shaded leaves, through the superior gs compared to males. Neste estudo preliminar foram determinadas as propriedades ecofisiológicas de plantas femininas e masculinas da erva-mate (Ilex paraguariensis St.Hil.) cultivadas no campo. Fluxo de fótons ativo na fotossíntese (PPFD), condutância estomática (gs), fotossíntese liquida (A), transpiração (E) e temperatura foliar (Tl) foram avaliados em um ciclo bienal de produção: no verão (janeiro e fevereiro) durante o período de maturação dos frutos quando ocorre pausa no crescimento; na primavera (novembro) e no outono (março a junho) durante emissão de novas brotações. As medições foram efetuadas em diferentes posições na copa (interior, exterior e ponteiras). Resultados indicam existência de dimorfismo sexual fisiológico na espécie. A condutância foi superior nas plantas femininas, exceto nas ponteiras. A e E foram superiores na parte exterior do terço médio das copasdas plantas femininas. Foi detectada sazonalidade na troca gasosa, com os maiores valores registrados na época de emissão de novas brotações e menores durante a fase de maturação dos frutos. Observaram-se correlações positivas entre trocas gasosas e PPFD. A e E correlacionaram-se positivamente com a gs, tanto para plantas masculinas quanto femininas. A estratégia funcional das plantas fêmeas, com o propósito de finalização do processo de reprodução, é de proporcionar o aumento relativo da fotossíntese e da transpiração das folhas sombreadas por intermédio de um maior valor de gs, quando comparado com indivíduos masculinos.

Understanding the dynamics of physiological changes involved in the acclimation responses of plants after their exposure to repeated cycles of water stress is crucial to selecting resilient genotypes for regions with recurrent drought episodes. Under such background, we tried to respond to questions as: (1) Are there differences in the stomatal-related and non-stomatal responses during water stress cycles in different clones of Coffea canephora Pierre ex A. Froehner? (2) Do these C. canephora clones show a different response in each of the two sequential water stress events? (3) Is one previous drought stress event sufficient to induce a kind of “memory” in C. canephora? Seven-month-old plants of two clones (’3V’ and ‘A1’, previously characterized as deeper and lesser deep root growth, respectively) were maintained well-watered (WW) or fully withholding the irrigation, inducing soil water stress (WS) until the soil matric water potential (Ψmsoil) reached ≅ −0.5 MPa (−500 kPa) at a soil depth of 500 mm. Two sequential drought events (drought-1 and drought-2) attained this Ψmsoil after 19 days and were followed by soil rewatering until a complete recovery of leaf net CO2 assimilation rate (Anet) during the recovery-1 and recovery-2 events. The leaf gas exchange, chlorophyll a fluorescence, and leaf reflectance parameters were measured in six-day frequency, while the leaf anatomy was examined only at the end of the second drought cycle. In both drought events, the WS plants showed reduction in stomatal conductance and leaf transpiration. The reduction in internal CO2 diffusion was observed in the second drought cycle, expressed by increased thickness of spongy parenchyma in both clones. Those stomatal and anatomical traits impacted decreasing the Anet in both drought events. The ‘3V’ was less influenced by water stress than the ‘A1’ genotype in Anet, effective quantum yield in PSII photochemistry, photochemical quenching, linear electron transport rate, and photochemical reflectance index during the drought-1, but during the drought-2 event such an advantage disappeared. Such physiological genotype differences were supported by the medium xylem vessel area diminished only in ‘3V’ under WS. In both drought cycles, the recovery of all observed stomatal and non-stomatal responses was usually complete after 12 days of rewatering. The absence of photochemical impacts, namely in the maximum quantum yield of primary photochemical reactions, photosynthetic performance index, and density of reaction centers capable of QA reduction during the drought-2 event, might result from an acclimation response of the clones to WS. In the second drought cycle, the plants showed some improved responses to stress, suggesting “memory” effects as drought acclimation at a recurrent drought.