Semina: Ciências Agrárias ISSN: 1676-546X [email protected] Universidade Estadual de Londrina Brasil

da Conceição de Matos, Christiano; Teixeira da Silva, Cícero; Torres Cunha, Priscila; Martins Gandini, Elizzandra Marta; Valadão Silva, Daniel; Alves Barbosa, Edimilson; Barbosa dos Santos, José; Alves Ferreira, Evander physalodes growth at different concentrations of N, P and K Semina: Ciências Agrárias, vol. 36, núm. 3, mayo-junio, 2015, pp. 1307-1316 Universidade Estadual de Londrina Londrina, Brasil

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DOI: 10.5433/1679-0359.2015v36n3p1307 Nicandra physalodes growth at different concentrations of N, P and K

Crescimento de Nicandra physalodes em resposta à adubação com N, P e K

Christiano da Conceição de Matos1*; Cícero Teixeira da Silva2; Priscila Torres Cunha3; Elizzandra Marta Martins Gandini4; Daniel Valadão Silva5; Edimilson Alves Barbosa2; José Barbosa dos Santos6; Evander Alves Ferreira7

Abstract

Nicandra physalodes (L.) Gaertn. is a weed that frequently infests Brazilian agricultural areas. Knowledge of the ’s response to competition, in the form of nutrient availability in soil, is fundamental to management of agroecosystems. This study aimed to evaluate the effect of concentrations of N, P and K on the growth of N. physalodes. The experiment was carried out in greenhouse conditions, using a randomized complete block design with split-plot arrangement (4 x 10), with three replications. The main plots were four combinations of N, P and K: (L1) 0, 0.3 and 17.2 mg dm-3; (L2) 30, 450.3 and 75.4 mg dm-3; (L3) 60, 900.3 and 133.4 mg dm-3; and (L4) 120, 1800.3 and 249.68 mg dm-3. Subplots were used for 10 different harvest times: 26, 33, 40, 47, 54, 61, 76, 91, 106 and 121 days after emergence (DAE). The dry matter, dry matter partitioning, area, relative growth rate, height and photochemical efficiency of photosystem II were measured in N. physalodes at each harvest time. Overall, the showed higher total dry matter accumulation up to 61 DAE. After that, the reproductive organs showed higher accumulation. Increasing concentrations of N, P and K resulted in higher plant height and dry matter of N. physalodes. Moreover, doubling the nutrient levels resulted in a proportional increase in dry matter accumulation. However, N. physalodes showed lower growth under natural soil fertility conditions (L1 treatment). Thus, increasing concentrations of N, P, and K promoted higher growth of N. physalodes. Biomass distribution was not changed by fertilization. There is evidence that N. physalodes could adapt easily in fertile soil. Thus, this species has greater competitive potential in high fertility soils. Key words: Apple of , weed, plant nutrition

1 Engº Agrº, Discente do Curso de Doutorado em Fitotecnia, Deptº de Fitotecnia, Universidade Federal de Viçosa, Viçosa, MG, Brasil. E-mail: [email protected]; [email protected] 2 Engos Agros, Discente do Curso de Mestrado em Produção Vegetal, Deptº de Agronomia, Universidade Federal dos Vales do Jequitinhonha e Mucuri, UFVJM, Diamantina, MG, Brasil. E-mail: [email protected]; [email protected]. br 3 Discente do Curso de Agronomia, Deptº de Agronomia, UFVJM, Diamantina, MG, Brasil. E-mail: [email protected] 4 Engª Florestal, M.e, Deptº de Zootecnia, UFVJM, Diamantina, MG, Brasil. E-mail: [email protected] 5 Engº Agrº, Dr., Pós-Doutorado, Deptº de Produção Vegetal, UFV, Rio Paranaíba, MG, Brasil. E-mail: danielvaladaos@yahoo. com.br 6 Engº Agrº, Prof. Dr., Deptº de Agronomia, UFVJM, Diamantina, MG, Brasil. E-mail: [email protected] 7 Engº Agrº, Dr., Pós-Doutorado, Deptº de Agronomia, Universidade Federal dos Vales do Jequitinhonha e Mucuri, UFVJM, Diamantina, MG, Brasil. E-mail: [email protected] * Author for correspondence Recebido para publicação 24/11/13 Aprovado em 27/11/14 1307 Semina: Ciências Agrárias, Londrina, v. 36, n. 3, p. 1307-1316, maio/jun. 2015 Matos, C. C. de et al.

Resumo

A Nicandra physalodes (L.) Gaertn. é uma planta daninha que infesta com frequência áreas agrícolas brasileiras. O conhecimento do comportamento das plantas frente aos fatores de competição, como a disponibilidade de nutrientes no solo, é fundamental para direcionar o manejo dos agroecossistemas. Nesse contexto, objetivou-se avaliar o efeito de doses de N, P e K no crescimento de N. physalodes. O experimento foi conduzido em casa de vegetação, em delineamento de blocos casualizados arranjado em parcelas subdivididas, com três repetições. Nas parcelas foram aplicadas as doses de N, P e K: 0, 0,3 e 17,2 (D1); 30, 450,3 e 75,4 (D2); 60, 900,3 e 133,4 (D3); 120, 1800,3 e 249,68 mg dm-3 (D4) e nas subparcelas as épocas de colheita (26, 33, 40, 47, 54, 61, 76, 91, 106 e 121 dias após emergência (DAE)). Avaliou-se a matéria seca, área foliar, distribuição da matéria seca, taxa de crescimento relativo, altura e a eficiência fotoquímica do fotossistema II das plantas de N. physalodes. De maneira geral, as folhas apresentaram maior participação no acúmulo de matéria seca total até os 61 DAE; posteriormente, órgãos reprodutivos apresentaram maior participação. O aumento das doses de N, P e K proporcionou maior altura e produção de matéria seca da planta daninha, sendo que quando se dobrou as doses dos nutrientes aplicados observou-se aumento proporcional em acúmulo da matéria seca. Porém, ao ser cultivada nas condições de fertilidade natural do solo (tratamento D1), N. physalodes apresentou baixas taxas de crescimento. Conclui-se que o aumento das doses de N, P e K promove aumento do crescimento de N. physalodes, no entanto, o padrão de distribuição de biomassa não é alterado pela adubação. Essa espécie adapta-se bem a solos férteis, assim, pode-se considerar que a mesma tem maior potencial competitivo em solos de alta fertilidade. Palavras-chave: Joá-de-capote, planta daninha, nutrição de plantas

Nicandra physalodes (L.) Gaertn. is a South to plant growth, since it is applicable in the study American weed known popularly as apple of Peru of variations between genetically different plants or shoo-fly plant that frequently infests Brazilian or plants subjected to different environmental agricultural areas. It is an annual shrub, 1.0 to 2.0 conditions (CAMPOS et al., 2012). m high (KISSMANN; GROTH, 2000). The plant Weeds are known to be efficient in the extraction, is able to produce large amounts of , which use and accumulation of soil nutrients but vary increases its dispersal and makes it difficult to by species and local environmental conditions control. It commonly infests crops such as soybean (CURY et al., 2012). Plant development is subject (NEPOMUCENO et al., 2007), cotton (BRAZ et al., to availability of resources in the environment 2011) and okra (BACHEGA et al., 2013), and also and the ability of plants to extract and use pastures (KISSMANN; GROTH, 2000). However, resources; competition for nutrients is one of the there is little information available on the biology main ecological factors that reduce crop yields. and management of N. physalodes. Thus, knowledge of plant behavior in response to The survivability and reproduction of a biotype in growth factors such as the availability of nutrients a population determines its ecological adaptability, in the soil is essential to management of plants in which depends on biological characteristics such agroecosystems. Therefore, this work aimed to as germination rate, growth and seed production evaluate the effect of different concentrations of N, (CHRISTOFFOLETI, 2001). The growth potential P and K on growth of N. physalodes. of each individual is determined mainly by the The experiment was carried out in a greenhouse availability of resources and the adaptability of the of the Department of Agronomy of the Universidade plant in the environment (OBARA; BEZUTTE; Federal dos Vales do Jequitinhonha e Mucuri ALVES, 1994). The analysis of plant growth is still (UFVJM), Diamantina-MG, in May and September the simplest and most accurate way to quantify the 2012. contribution of different physiological processes

1308 Semina: Ciências Agrárias, Londrina, v. 36, n. 3, p. 1307-1316, maio/jun. 2015 Nicandra physalodes growth at different concentrations of N, P and K

Seeds of N. physalodes were collected from the They were then weighed on a digital scale with a experimental field of UFVJM Diamantina-MG. precision of 0.0001 g. Dormancy was broken by pulverising fruit briefly in Relative growth rate (RGR) was determined for a blender to separate the from the fruit, Seeds each time of assessment based on the results of leaf were subsequently immersed in water at room area and dry matter accumulation according to the temperature. The water was exchanged at two-hour method proposed by Benincasa (2003). intervals. This process was repeated six times then the seeds were placed to dry in a ventilated and The distribution of dry matter in each plant part shaded environment. was calculated using percentage of dry matter of each part related to the total during the evaluation Dry seeds were germinated on a plastic platter period, which allowed the interpretation of organic containing soil (red-yellow latosol). At 25 days translocation (BENINCASA, 2003). after sowing, each seedling was transplanted to a 8 dm3 plastic plot containing soil with the following At 46 and 86 DAE, we measured the physical and chemical characteristics: pH (water) photochemical efficiency of photosystem II from of 6.1; organic matter content of 1000 mg dm-3; leaves using a fluorometer (Junior-Pam Teaching clay content of 110 000 mg dm-3; P and K, 0.3 and Chlorophyll Fluorometer – Walz, Effeltrich, 17.2 mg dm-3, respectively; and Ca, Mg, Al, Al and Germany). Chlorophyll a fluorescence was measured cation-exchange capacity of 13, 3, 0.2, 19 and 16.6 in the middle third of the first fully expanded leaves mmol dm-3, respectively. of plants after 60 minutes of dark adaptation. Assessments were done at night, with emission of The treatments were arranged in a randomized a pulse of saturating light for 0.3 s, at a frequency block design with three replications in a split-plot of 0.6 kHz to determine initial fluorescence (Fo), arrangement (4 x 10). NPK treatments were applied maximal fluorescence (Fm) and the ratio between in each experimental plot in four levels: 0, 0.5, 1 fluorescence and maximal fluorescence (Fv/Fm) and 2 times the dose recommended by Cantarutti (GENTY; BRIANTAIS; BAKER, 1989). et al. (2007), corresponding to NPK of: (L1) 0, 0.3, 17.2 mg dm-3; (L2) 30, 450.3, 75.4 mg dm- Fv/Fm data subjected to analysis of variance and 3; (L3) 60, 900.3, 133.4 mg dm-3; and (L4) 120, expressed as mean and standard deviation for each 1800.3, 249.68 mg dm-3. The subplots were for 10 treatment at different sampling times. The remaining harvest times (26, 33, 40, 47, 54, 61, 76, 91, 106 data were subjected to regression analysis and the and 121 days after emergence (DAE)). We used model was chosen taking into account the statistical ammonium sulfate (N), simple superphosphate (P) significance (F test), the coefficient of determination and potassium chloride (K) applied one day before (R²) and the biological significance of the model transplanting the weeds. (PIMENTEL-GOMES, 2009). At each harvest, height and leaf area of plants Inflorescence of N. physalodes began before the were measured and the plants were separated first harvest (between 21 and 25 DAE), with 20%, into root, stem, leaves and reproductive organs. 47% and 57% of plants flowering in L2, L3 and Leaves were digitally photographed and the images L4 treatments, respectively. Inflorescence in the processed in the software Image-Pro PlusTM to treatment without fertilization (L1) began between obtain the leaf area. All plant material was placed 33 and 45 DAE. Kissmann and Groth (2000) suggest in paper bags, keeping different parts of the plant that early flowering in this plant is influenced by separate, and put in a fan-forced oven at 65°C where photoperiod. they remained until hey reached constant weight.

1309 Semina: Ciências Agrárias, Londrina, v. 36, n. 3, p. 1307-1316, maio/jun. 2015 Matos, C. C. de et al.

There were significant interactions between treatment L1 (Figure 1). This treatment resulted in nutrient doses and harvesting times in dry matter of total dry matter around 168 times greater than plants leaf, stem, root and reproductive organs, leaf area, grown in fertilized soil. height and relative growth rate of plants. Unpacking according to harvesting time for plants of N. physalodes N.in physalodes the treatment plants L1 grown (Figure in fertilizer1). This treatmentstreatment these interactions allowed regression equations for resulted in total dry matter around 168 times greater thanL2, plants L3 grownand L4 in fertilizedshowed rapidsoil. initial growth up to harvesting time to be adjusted at each level of N, P N. physalodes plants grown in fertilizer treatmentsnear L2,61 DAEL3 and (Figure L4 showed 1). From rapid that initial point, growth there up wasto and K (Figures 1, 2 and 3). near 61 DAE (Figure 1). From that point, there was a pronounceda pronounced decrease decrease in dry inmatter dry matterof leaves of dueleaves to leaf due Low dry matter accumulation of leaves, stem, root to leaf senescence (Figure 1A). In the same period, senescence (Figure 1A). In the same period, the accumulation of stem and root dry matter tended to stabilize and reproductive organs was observed according to the accumulation of stem and root dry matter tended harvesting(Figures 1B time and for 1C). plants of N. physalodes in the to stabilize (Figures 1B and 1C).

Figure 1. Measures of dry matter in Nicandra physalodes plants over the life cycle in four treatments of N, P Figure 1. Measures of dry matter in Nicandra physalodes plants over the life cycle in four treatments of N, P and K. and K. (A) Leaf dry matter - LDM, (B) stem dry matter - SDM, (C) roots dry matter, (D) reproductive organs (A) Leaf dry matter – LDM, (B) stem dry matter – SDM, (C) roots-3 dry matter, (D) reproductive organs dry-3 matter – dry matter - RODM. Treatments are: (L1) 0,-3 0.3, 17.2 mg dm N, P, K; (L2) 30,‑3 450.3, 75.4 mg dm N, P, RODM. Treatments are: (L1) 0, 0.3,-3 17.2 mg dm N, P, K; (L2) 30, 450.3, 75.4 mg dm-3 N, P, K; (L3) 60, 900.3, 133.4 K; (L3)-3 60, 900.3, 133.4 mg dm N, P, K; and (L4)-3 120, 1800.3, 249.68 mg dm N, P, K. Data are the mean mgof dm three N, replications P, K; and (L4) ± standard 120, 1800.3, deviation. 249.68 mg dm N, P, K. Data are the mean of three replications ± standard deviation.

ˆ L1 Y = 0.0059exp(0.0194x) R² = 0.71 B L1 Yˆ = 0.0008exp( 0.0275x) R² = 0.96 A L2 Yˆ = 9.95exp(-0.5((x - 61.68)/11.37)2 ) R² = 0.94 L2 Yˆ = 4.86/(1 + exp(-(x - 53.43)/3.4 1)) R² = 0.92 2 ˆ 30 L3 Yˆ =18.06exp(-0.5((x - 63.11)/11.48) ) R² = 0.95 25 L3 Y = 12.41/(1 + exp(-(x - 53.47)/4.1 8)) R² = 0.99 L4 Yˆ = 20.73/(1 + exp(-(x - 55.59)/2.6 6)) R² = 0.99 L4 Yˆ = 25.63exp(-0.5((x - 68.59)/13.76)2 ) R² = 0.94 25 20 ) ) 20 -1 -1 15

15

10 SDM (g plant (g SDM LDM (g plantLDM 10

5 5

0 0 26 33 40 47 54 61 76 91 106 121 26 33 40 47 54 61 76 91 106 121 Days after emergence Days after emergence ˆ L1 Y = - 0.0045+ 0.0002x R² = 0.76 L1 Yˆ = 0.04/(1+ exp(-(x- 92.69)/14.70)) R² = 0.94 C D L2 Yˆ = 4.09/(1+ exp(-(x- 47.88)/2.94)) R² = 0.92 L2 Yˆ = 8.69/(1+ exp(-(x- 69.91)/7.98)) R² = 0.99 15 L3 Yˆ = 7.16/(1+ exp(-(x- 48.48)/2.48)) R² = 0.96 50 L3 Yˆ = 20.55/(1+ exp(-(x- 71.21)/7.93)) R² = 0.99 L4 Yˆ =11.19/(1+ exp(-(x- 54.06)/4.33)) R² = 0.97 L4 Yˆ = 41.45/(1+ exp(-(x- 76.97)/8.99)) R² = 0.99

12 40 ) ) -1 -1 9 30

6 20 RDM (g plant RODM (g plant

3 10

0 0 26 33 40 47 54 61 76 91 106 121 26 33 40 47 54 61 76 91 106 121 Days after emergence Days after emergence

Source:Source: Elaboration ofof thethe authors. authors.

1310 The initial growth of reproductive organs of N. physalodes in fertilizer treatments was slow up to Semina: Ciências Agrárias, Londrina, v. 36, n. 3, p. 1307-1316, maio/jun. 2015 61 DAE, independent of levels of N, P and K (Figure 1D). After this period, reproductive dry matter rapidly increased up to 91 DAE on plants subjected to the L2 and L3 treatments, and up to 106 DAE in plants grown in conditions of greater fertility (L4 treatment), then there was pronounced reduction in the rate of dry matter Nicandra physalodes growth at different concentrations of N, P and K

The initial growth of reproductive organs of N. of species that compete with crops and can rapidly physalodes in fertilizer treatments was slow up to 61 cover the ground in areas of crop rotation (CAMPOS DAE,accumulation independent in reproductive of levels of organs. N, P andThus, K there(Figure was almostet al., no 2012). increase Therefore, in the accumulation as a result and of allocation high growth 1D).of Afterassimilates this betweenperiod, 91reproductive and 106 DAE, dry at whichmatter time ratesaccumulation and dry of matterdry matter production in stem andof rootsshoots was of N. rapidlystabilizing. increased Therefore, up to 91 after DAE 91-106 on plantsDAE, thesubjected plant dras ticallyphysalodes reduced, mainly growth whenand enhanced grown theon fertileprocess soils,of it to thefruit L2 ripening. and L3 treatments, and up to 106 DAE in can be inferred that this weed has high competitive plants grownRapid in conditions growth and ofhigh greater dry matter fertility production (L4 ofpotential shoots are and important ability to biological cover the characteristics ground. of treatment), then there was pronounced reduction in species that compete with crops and can rapidly cover the groundN. physalodes in areas of crop grown rotation without (CAMPOS fertilization et al., the rate of dry matter accumulation in reproductive 2012). Therefore, as a result of high growth rates and produceddry matter aproduction higher proportion of shoots ofof N.leaf physalodes dry matter, at organs. Thus, there was almost no increase in the mainly when grown on fertile soils, it can be inferred allthat harvest this weed times has in high this competitiveexperiment. potential However, and there accumulation and allocation of assimilates between was an increase in the proportion of dry matter in 91 andability 106 to DAE, cover theat which ground. time accumulation of dry reproductive organs 47 DAE, indicating that the matter in stemN. andphysalodes roots was grown stabilizing. without fertilization Therefore, produced a higher proportion of leaf dry matter at all plants invest in the continuation of the species under afterharvest 91-106 times DAE, in thisthe experiment.plant drastically However, reduced there was an increase in the proportion of dry matter in adverse conditions such as the L1 treatment (Figure growth and enhanced the process of fruit ripening. reproductive organs 47 DAE, indicating that the plants invest2). The in the percentage continuation of of dry the matterspecies inunder stem adverse and roots Rapidconditions growth such asand the high L1 treatment dry matter (Figure production 2). The per centagevaried oflittle dry duringmatter inthe stem experiment and roots variedwith valueslittle of of shootsduring theare experiment important with biological values of 6-17%characteristics and 16-27%, 6-17% respectively. and 16-27%, respectively.

Figure 2. Dry matter partitioning (%) in different organs of Nicandra physalodes plants over the life cycle at Figure 2. Dry matter partitioning (%) in different organs of -3Nicandra physalodes plants over the life-3 cycle at four differentfour differentlevels of levelsfertilizer: of fertilizer: (L1) 0, 0.3, (L1) 17.2 0, 0.3,mg dm17.2-3 N,mg P, dm K; (L2)N, P, 30, K; 450.3, (L2) 30, 75.4 450.3, mg dm 75.4‑3 N, mg P, dm K; (L3) N, P, 60, K; 900.3, (L3) 60, 900.3, 133.4 mg dm-3 N, P, K; and (L4) 120, 1800.3, 249.68 mg dm-3 N, P, K. 133.4 mg dm-3 N, P, K; and (L4) 120, 1800.3, 249.68 mg dm-3 N, P, K.

Source: Elaboration of the authors. Source: Elaboration of the authors. 1311 Semina: Ciências Agrárias, Londrina, v. 36, n. 3, p. 1307-1316, maio/jun. 2015 Matos, C. C. de et al.

In plants grown in soil with fertilizers (L2, in a time and no during a long time (BIANCO et L3 and L4), similar dry matter partitioning was al., 2012). Although N. physalodes accumulates dry observed regardless of treatment (Figure 2). matter in fruit in a similar way to that commonly Overall, the leaves had higher dry matter content observed in some crops, the maturation of fruit in in relation to other parts of the plant in the first this species is not uniform, which contributes to the 61 DAE, with values varying between 44% and production of seeds over the full life cycle, although 85% of the total. In the same period, the stem seed dispersal must occur in a shorter period of time showed accumulation between 6% and 26% and for most non-crop species. reproductive organs between 0% and 11%. After Studies have shown differential uptake and the initial period of 61 days the reverse occurred: utilization of N, P and K between species or among the proportion of dry matter in leaves became lower, cultivars of the same species (FAGERIA, 1998). representing between 3% and 23% of the total, the According to Weiss (1983) plant growth and yield stems represented between 27% and 31%, and respond differently when subjected to different reproductive organs 30-51% of total dry matter. The levels of nutrition, so that plants selected to grow proportion of dry matter in roots was less variable at a particular fertility level can be adjusted to during plant growth, representing between 8% and produce maximally at this level. Despite the use of 11% up to 40 DAE and 15-25% in the remaining high doses of N, P and K in the soil, N physalodes period of plant growth, probably due to the limiting showed similar behavior in relation to dry matter effect of the capacity of the plot. partitioning; there were no differences among A pronounced decrease in the percentage of treatments in the proportion of dry matter allocated dry matter accumulated in leaves of N. physalodes to vegetative growth relative to reproductive organs. from early fruiting is due to changes in the main The maximum photochemical quantum yield drain from leaves to reproductive structures (TAIZ; of photosystem II of N. physalodes was estimated ZEIGER, 2009). by the ratio Fv/Fm, which has an optimal range At the beginning of growth, regardless of the of 0.75-0.85 (Figure 3A). Data within this range treatment, a higher proportion of dry matter is found indicate that the photosynthetic apparatus of the in leaves in N. physalodes, because this plant quickly plant is intact (BOLHÀR-NORDENKAMPF et al., develops its photosynthetic system (Figure 2). The 1989), whereas smaller values of this ratio reflect rapid development of leaf structure with subsequent the presence of some stress on the photosynthetic formation of the root system favors domination of apparatus (BJÖRKMAN; DEMMING, 1987). We the space in which the plant is developing, mainly found that plants of N. physalodes when grown in due to higher interception of incident radiation. soil that received no fertilizer (L1) presented an average Fv/Fm of 0.66 at 46 DAE, indicating that the Dry matter accumulation in reproductive organs photosystem was compromised. By 86 DAE, there of N. physalodes grown in fertilized soil intensified is evidence of plant adaptation to the environment, after 61 DAE, representing around 50% of the total with consequent recovery of the photosystem, dry matter at the end of the growth assessment. A key illustrated by the average increase in the ratio Fv/ feature for the success of a weed in agricultural areas Fm to 0.77 (Figure 3A). is related to the ability of these plants to produce and disperse seeds throughout its development At 46 DAE, N. physalodes plants grown in cycle (BAKER, 1974). Domesticated plants such soil with fertilizer had an average Fv/Fm of 0.83, as soybeans, corn, beans, and others, during the regardless of the levels of N, P and K in the treatments process of selection and breeding have lost the (Figure 3A). By 86 DAE, fertilizer treatments ability to disperse seeds and the seed production is resulted in decrease of quantum photosynthesis of 1312 Semina: Ciências Agrárias, Londrina, v. 36, n. 3, p. 1307-1316, maio/jun. 2015 compromised. By 86 DAE, there is evidence of plant adaptation to the environment, with consequent recovery of the photosystem, illustrated by the average increase in the ratio Fv/Fm to 0.77 (Figure 3A). At 46 DAE, N. physalodes plants grown in soil with fertilizer had an average Fv/Fm of 0.83, regardless of the levelsNicandra of N, physalodesP and K ingrowth the treatmentsat different concentrations(Figure 3A). ofBy N, 86P and DAE, K fertilizer treatments resulted in decrease of quantum photosynthesis of plants due to leaf senescence. The photosynthetic activity plants due to leaf senescence. The photosynthetic time, leaf scenescence begins and photosynthetic of the plant per leaf area increased with leaf age, up to full expansion of leaves; after this time, leaf activity of the plant per leaf area increased with capacity gradually declines (TAIZ; ZEIGER, 2009). scenescence begins and photosynthetic capacity gradually declines (TAIZ; ZEIGER, 2009). leaf age, up to full expansion of leaves; after this

Figure 3. Measure of fluorescence in Nicandra physalodes subjected to different N, P and K levels, at 46 Figureand 863. Measuredays after of emergencefluorescence (A) in Maximal Nicandra quantumphysalodes yields subjected (Fv/Fm), to different and measures N, P and of growthK levels, in atNicandra 46 and 86 daysphysalodes after emergence plants over(A) Maximal the life cycle quantum in four yields treatments (Fv/Fm), of andN, P measures and K. (B) of Leafgrowth area, in Nicandra(C) Relative physalodes growth rateplants over- RGR,the life (D) cycle height in four of treatmentsN. physalodes of N,. TreatmentsP and K. (B) are: Leaf (L1) area, 0, (C) 0.3, Relative 17.2 mg growth dm-3 rateN, P, – RGR,K; (L2) (D) 30, height 450.3, of N. physalodes75.4 mg. dmTreatments-3 N, P, K; are: (L3) (L1) 60, 0, 900.3,0.3, 17.2 133.4 mg dmmg-3 dm N,-3 P, N, K; P, (L2) K; and30, 450.3,(L4) 120, 75.4 1800.3, mg dm ‑3249.68 N, P, K; mg (L3) dm -360, N, 900.3, P, 133.4K. Datamg dm are-3 theN, meanP, K; andof three (L4) replications 120, 1800.3, ± standard249.68 mg deviation. dm-3 N, P, K. Data are the mean of three replications ± standard deviation.

L1 Yˆ  0.932exp(0 .02x) R²  0.86 A 46 DAE B 86 DAE ˆ  2  1.0 L2 Y 1513.06exp (-0.5((x -56.44)/12.54) ) R² 0.88 5000 L3 Yˆ  2656.24exp(-0.5((x - 61.58)/15.83)2) R²  0.91 L4 Yˆ  4364.45exp(-0.5((x - 69.23)/17.22)2) R²  0.97 0.8 4000

0.6 3000 Fv/Fm 0.4

2000 Leafarea (cm²) 0.2

1000 0.0 N 0 30 60 120 P 0.3 450.3 900.3 1800.3 0 K 17.2 75.4 133.4 249.7 26 33 40 47 54 61 76 91 106 121 -3 Fertilizer levels (mg dm ) Days after emergence C L1 Y  0.0247 L1 Yˆ  0.46  0.029x R²  0.78 L2 Yˆ  2.87exp(-0.0629x) R²  0.95 D ˆ 0.4 L2 Y  42.39 /(1 exp(-(x - 46.47)/ 6.50)) R²  0.96 100 L3 Yˆ  2.40exp(-0.0587x) R²  0.96 L3 Yˆ  62.38/(1 exp(-(x - 46.64)/6.84)) R²  0.99 L4 Yˆ 1.13exp(-0.0403x) R²  0.94 L4 Yˆ  76.27/(1+ exp(-(x - 50.70)/5.98)) R² = 0.98 0.3 80 ) -1 0.2 days 60 -1

0.1 40 Height (cm) RGR (g g RGR (g

0.0 20

0 33 40 47 54 61 76 91 106 121 26 33 40 47 54 61 76 91 106 121 Days after emergence Days after emergence Source: Elaboration of the authors. Source: Elaboration of the authors.

N. physalodesN. physalodes grown ingrown treatments in treatments L2, L3 L2, and L3 andclose L4 toshow 61 edDAE. high However,initial increments when thisof leaf weed area, was L4 reachingshowed maximumhigh initial increment increments close ofto 61leaf DAE, area, when grown this variablein the absence began toof declinefertilizer (Figure (L1) the 3B). leaf The area reaching maximum increment close to 61 DAE, increased exponentially with time, but was a low when this variable began to decline (Figure 3B). increasing during the harvesting time similar to the The increase in leaf area was similar to the increase dry matter in the leaves (Figure 3B). in dry matter accumulation in the leaves of N. Leaf area is one of the most important indices physalodes, with the point of inflection occurring of plant growth because it represents the size of its 1313 Semina: Ciências Agrárias, Londrina, v. 36, n. 3, p. 1307-1316, maio/jun. 2015 Matos, C. C. de et al.

assimilatory apparatus, which is directly related The initial decrease of RGR at the beginning of to plant physiological processes (TAIZ; ZEIGER, plant development is probably due to the stress of 2009). Fast-growing species are possibly more transplantation of seedlings, since the seed-raising competitive than slow-growing species due to their substrate was more fertile than the experimental rapid production of greater leaf area which shades substrate. This stress is evidenced in Figure the soil. This study shows that increasing soil 3A, showing evidence that the photosynthetic fertility favors growth of N. physalodes, since the apparatus was compromised due to the lower Fv/ species is more competitive when grown in fertile Fm. However, at 86 DAE, the plants adapted to the soil. environment, promoting physiological recovery and, consequently, RGR increased, corroborated by Plants of N. physalodes grown in soil with the higher Fv/Fm. fertilizer, regardless of soil fertility level, showed decreasing RGR, with an average of 0.184 g g-1 day- As observed for dry matter accumulation, 1, 0.153 g g-1 day-1 and 0.123 g g-1 day-1 for L2, L3 increasing N, P and K levels in the soil promoted and L4 treatments, respectively, considering only the height of N. physalodes (Figure 3D). When in positive growth rate (Figure 3C). L1 soil conditions, the plants showed the same low increment in height over time. With the addition When the plant is growing there must be sufficient of macronutrients to the soil the plants reached photoassimilates for the metabolic demands of maximum size of 42.39 cm, 62.38 cm and 76.27 cm the plant, and also to store nutrients or build new in L2, L3 and L4, respectively, close to 76 DAE with structural organs. Thus, increasing accumulation subsequent stabilization of growth. N. physalodes of dry matter results in smaller amounts of decreased the rate of growth in height at 61 DAE, photoassimilates available for growth, and after which dry matter accumulation in reproductive consequently, the RGR decreases (BENINCASA, organs intensified (Figure 1D). At the beginning of 2003). the reproductive period, assimilates are diverted to RGR is considered an index of efficiency of the productive organs with fruits becoming a drain on plant, because it represents the daily yield capacity assimilates, thus reducing the vegetative growth rate of dry matter produced per gram of plant dry (TAIZ; ZEIGER, 2009). Growth analysis is used to matter (CHRISTOFFOLETI, 2001). Species with detect functional and structural differences among higher RGR have an ecological advantage due to individuals estimating their ecological adaptation rapid space occupation and rapid growth, which (HOLT; RADOSEVICH, 1983). Even though N. are essential to ruderal species (VIDAL; TREZZI, physalodes grown in different soil fertility regimes 2000). Thus, comparing N. physalodes in treatments responds to increased N, P and K levels, reproductive L2, L3 and L4, increasing N, P and K levels in the behavior and photoassimilate distribution were not soil did not affect growth efficiency, since growth altered by the availability of these macronutrients. behavior was similar in all treatments, with reduced Weeds that have rapid initial growth require that RGR during the growth cycle, although the total dry management measures be applied to young plants matter accumulation was limited by the levels of for best results, since the development of the plant these macronutrients in soil (Figure 3C). is difficult to control and to avoid competition Grown in low fertility soil (L1), N. physalodes between weeds and crops (Campos et al., 2012). showed reduction in RGR until 47 DAE, when Thus, control measures should be adopted in the negative values of RGR were observed. After 47 early development of N. physalodes. DAE, there was a tendency to increase RGR, which In general, greater effects of added N, P and K in again decreased close to 76 DAE (Figure 3C). soil on the growth of N. physalodes were observed 1314 Semina: Ciências Agrárias, Londrina, v. 36, n. 3, p. 1307-1316, maio/jun. 2015 Nicandra physalodes growth at different concentrations of N, P and K after 54 DAE, since up to that time the rates of 77 k among vascular plants of diverse origins. Planta, growth and dry matter accumulation were similar New York, v. 170, n. 4, p. 61-66, 1987. across the four treatments. After 54 DAE growth of BOLHÀR-NORDENKAMPF, H. R.; LONG, S. P.; this weed was limited by the amount of nutrients BAKER, N. R.; OQUIST, G.; SCHREIBER, U.; LECHNER, E. G. Chlorophyll fluorescence as probe available in the soil, since higher concentrations of the photosynthetic competence of leaves in the field: promoted dry matter, leaf area and accumulation of a review of current instrument. Functional Ecology, plant height. Dry matter distribution and the RGR Oxford, v. 3, n. 4, p. 497-514, 1989. of N. physalodes grown in fertilized soil, regardless BRAZ, G. B. P.; CONSTANTIN, J.; OLIVEIRA of concentration, were similar throughout the period JÚNIOR, R. S.; GUERRA, N.; OLIVEIRA NETO, A. of the experiment. M.; SANTOS, G.; ARANTES, J. G. Z.; DAN, H. A. Revista Brasileira de Herbicidas, Maringá, v. 10, n. 3, p. This study showed that under our experimental 190-199, 2011. conditions N. physalodes was well adapted to CAMPOS, L. H. F.; MELLO, M. S. C.; CARVALHO, fertilized soils, and had fast initial growth. Thus, S. J. P.; NICOLAI, M.; CHRISTOFFOLETI, P. J. this species has greater competitive potential in high Crescimento inicial de Merremia cissoides, Neonotonia wightii e Stizolobium aterrimum. Planta Daninha, fertility soils, which could be a problem in culture Viçosa, v. 30, n. 3, p. 497-504, 2012. of highly fertilized crops. CANTARUTTI, R. B.; BARROS, N. F.; PRIETO, H. E.; NOVAIS, R. F. Avaliação da fertilidade do solo e recomendação de fertilizantes. In: NOVAIS, R. F.; Acknowledgements ALVAREZ V.; V. H.; BARROS, N. F.; FONTES, R. L. F.; CANTARUTTI, R. B.; NEVES, J. C. L. Fertilidade The authors would like to thank CNPq do solo. Viçosa: Sociedade Brasileira da Ciência do Solo, (Conselho Nacional de Desenvolvimento Científico 2007. p. 769-850. e Tecnológico), FAPEMIG (Fundação de Amparo à CHRISTOFFOLETI, P. J. Análise comparativa do Pesquisa do Estado de Minas Gerais) and CAPES crescimento de biótipos de picão-preto (Bidens pilosa) (Coordenação de Aperfeiçoamento de Pessoal resistente e suscetível aos herbicidas inibidores da ALS. de Nível Superior) for financial support for this Planta Daninha, Viçosa, v. 19, n. 1, p.75-83, 2001. research. CURY, J. P.; SANTOS, J. B.; SILVA, E. B.; BYRRO, E. C. M.; BRAGA, R. R.; CARVALHO, F. P.; VALADÃO SILVA, D. Acúmulo e partição de nutrientes de cultivares de milho em competição com plantas daninhas. Planta References Daninha, Viçosa, v. 30, n. 2, p. 287-296, 2012. BACHEGA, L. P. S.; CARVALHO, L. B.; BIANCO, FAGERIA, N. K. Otimização da eficiência nutricional na S.; CECILIO FILHO, A. B. Períodos de interferência de produção das culturas. Revista Brasileira de Engenharia plantas daninhas na cultura do quiabo. Planta Daninha, Agrícola e Ambiental, Campina Grande, v. 2, n. 1, p. Viçosa, v. 31, n. 1, p. 63-70, 2013. 6-16, 1998. BAKER, H. The evolution of weeds. Economic Botany, GENTY, B.; BRIANTAIS, J. M.; BAKER, N. R. The New York, v. 37, n. 2, p. 255-282, 1974. relationship between the quantum yield of photosynthetic BENINCASA, M. M. P. Análise de crescimento de electron transport and quenching of chlorophyll plantas: noções básicas. Jaboticabal: FUNEP, 2003. 41 p. fluorescence. Biochimica et Biophysica Acta, Nijmegen, v. 990, n. 1, p. 87-92, 1989. BIANCO, S.; CARVALHO, L. B.; BIANCO, M. S.; PITELLI, R. A. Acúmulo de massa seca e de HOLT, J. S.; RADOSEVICH, S. R. 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NEPOMUCENO, M.; ALVES, P. L. C. A.; DIAS, T. TAIZ, L.; ZEIGER, E. Fisiologia vegetal. 4. ed. Porto C. S.; PAVANI, M. C. M. D. Períodos de interferência Alegre: Artmed, 2009. 819 p. das plantas daninhas na cultura da soja nos sistemas VIDAL, R. A.; TREZZI, M. M. Análise de crescimento de de semeadura direta e convencional. Planta Daninha, biótipos de leiteira (Euphorbia heterophylla) resistentes Viçosa, v. 25, n. 1, p. 43-50, 2007. e suscetível aos herbicidas inibidores da ALS. Planta OBARA, S. Y.; BEZUTTE, A. J.; ALVES, P. L. C. A. Daninha, Viçosa, v. 18, n. 3, p. 427-433, 2000. Desenvolvimento e composição mineral do picão-preto WEISS, E. A. Oilseed crops. London: Longman, 1983. sob diferentes níveis de pH. Planta Daninha, Viçosa, v. 659 p. 12, n. 1, p. 52-56, 1994. PIMENTEL-GOMES, P. Curso de estatística experimental. 15. ed. Piracicaba: FEALQ, 2009. 451 p.

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