Communications in Plant Sciences, vol 8, p. 112-115, 2018 (2018015)

DOI: http://dx.doi.org/10.26814/cps2018015

Authors: Gilberto Coutinho Machado Filho, Marcelo Almeida Mota, André Buarque Montelo, David Ingsson Oliveira Andrade de Farias, Ildon Rodrigues do Nascimento, and Manoel Mota dos Santos

Abstract: Weed chemical control in cassava crop is an alternative that contributes to increase productivity and costs reduction. However, there are few registered products, becoming a trouble for this crop exploration. Therefore, the present research had the objective evaluate selectivity of post-emergent herbicides applied in cassava in two plant development stages. The experiment was carried out in greenhouse at Federal University of Tocantins – UFT, Campus Gurupi, TO Brazil. The experiment design was completely randomized, arranged in factorial 6×2, combination of 5 herbicide molecules with different mechanisms of action (mesotrione, carfentrazone-ethyl, Chlorimuron-ethyl, nicosulfuron and imazethapyr) and a control with no application, applied in two stages, 30 and 45 days after plant emergence, with four replications. The results were submitted to analysis of variance by F test, and means were statistically analyzed by LSD test, at 5% probability. Mesotrione, and chlorimuron herbicides were not toxic for the crop, promoting results similar to those observed for control. Differences in tolerance level of herbicides studied was founded between application stages.

Highlighted Conclusions
1) The herbicides mesotrione, chlorimuron and carfentrazone-ethyl applied in post-emergence are highly selective to cassava.
2) The herbicides nicosulfuron and imazethapyr show differences in the level of toxicity to cassava, depending on the growth stage, being less selective at 30 days after emergence.

Keywords: Chemical control, Manihot esculenta, Weed control. (more…)

Communications in Plant Sciences, vol 8, p. 100-111, 2018 (2018014)

DOI: http://dx.doi.org/10.26814/cps2018014

Authors: Gabriela de Magalhães da Fonseca, Viviane Kopp da Luz, Maicon Nardino, Victoria Freitas de Oliveira, Juliana de Magalhães Bandeira, Ariano Martins de Magalhães Júnior, Luciano Carlos da Maia and Antonio Costa de Oliveira

Abstract: The use of nutrient solution combined with different herbicide concentrations allows the evaluation and discrimination of tolerant and non-tolerant genotypes to imidazolinone herbicides. The objectives of this research were to identify possible morphological characteristics to be used as markers of resistance to imidazolinones, as well as the identification of herbicide doses and evaluation time to discriminate sensitive and tolerant genotypes of rice under hydroponic systems. Six rice genotypes four characterized as sensitive, BRS Querência, BRS Border, BRS Atalanta and BRS Pampa and two as tolerant, BRS Sinuelo CL and PUITA INTA CL to imidazolinones were tested in a hydroponic system. Four doses of herbicide were tested, which were evaluated at 7, 14, 21 and 28 days after transplantation. The IFL was the most responsive variable and can be used as morphological marker in experiments for selecting rice genotypes tolerant to imidazolinones. The best time to discriminate genotypes is the 7th day of development. The concentration of herbicide that enables better discrimination between tolerant and sensitive genotypes is 25 µg L^-1, according to the methods described in this bioassay.

Highlighted Conclusion
The insertion of the first leaf can be used as morphological marker for selecting rice genotypes tolerant to imidazolinones at 7^th day of development.

Keywords: Oryza sativa L., Morphological marker, Sensitivity, Tolerance. (more…)

Communications in Plant Sciences, vol 8, p. 90-99, 2018 (2018013)

DOI: http://dx.doi.org/10.26814/cps2018013

Authors: Gabriela de Magalhães da Fonseca, Viviane Kopp da Luz, Maicon Nardino, Victoria Freitas de Oliveira, Marina de Magalhães da Fonseca, Camila Bedin Scalco, Juliana de Magalhães Bandeira, Rosa Maria Vargas Castilhos, Ariano Martins de Magalhães Júnior, Luciano Carlos da Maia and Antonio Costa de Oliveira

Abstract: Soils with high salt concentrations (NaCl) may affect plant development and nutrient uptake in rice. The objective of this experiment was to evaluate the response of rice cultivars released by Embrapa Clima Temperado to salt stress at the germination and seedling stages. Four NaCl concentrations (0, 40, 80 and 120 mM) and a random factorial design 4×6 (dose × genotype), the cultivars belonging to the Embrapa germplasm collection were evaluated, BRS Bojuru (the only tolerant variety), BRS Pampa, BRS 7 Taim, BRS Querência, BRS Atalanta and BRS Sinuelo CL, with three replicates. After 14 days, the levels of Na, K, Ca and Mg absorbed by the plant shoots and roots were determined. NaCl was not significantly present in the germination stage. In the first germination count, BRS Bojuru and BRS 7 Taim decreased the germination with the increase in salt. The length of the first leaf in the 40 mM dose at 14 days of development (vegetative stage) is indicated as morphological marker for discriminating sensitive and tolerant genotypes to salinity in hydroponic system. The cultivar BRS Pampa showed higher ability of leaf Ca and Mg translocation under salt stress conditions.

Highlighted Conclusions
1) The genotypes have contrasting responses in relation to the increase of NaCl doses, due to the interaction G x D for all evaluated variables.
2) The length of the first leaf in the 40 mM dose at 14 days of development (vegetative stage) is indicated as morphological marker for discriminating sensitive and tolerant genotypes to salinity in hydroponic system.

Keywords: Oryza sativa L., Salinity, Abiotic stress, Morphological marker, Germination. (more…)

Communications in Plant Sciences, vol 8, p. 82-89, 2018 (2018012)

DOI: http://dx.doi.org/10.26814/cps2018012

Authors: Tauane Santos Brito, Renan Pan, Elisiane Inês Dall’Oglio Chaves, and Vandeir Francisco Guimarães

Abstract: The objective of the present research was to evaluate the initial development of maize (Zea mays) inoculated with plant growth-promoting diazotrophic bacteria Azospirillum brasilense, Burkholderia ambifaria and Herbaspirillum seropedicae in vitro and in protected culture. The experiment in protected culture consisted in the comparison of four methods of nitrogen fertilizations in maize crop (absence, broadcast, placement, broadcast and placement) associated or not to inoculation with growth-promoting bacteria. Morphological parameters, foliar nitrogen content and bacterial population were evaluated at 30 and 45 days after sowing.  The in vitro essay consisted in the cultivation of inoculated plants in culture medium, with and without nitrogen and then, at seven days after seeding, evaluated morphological parameters, foliar nitrogen content and bacterial population. A. brasilense was more responsive to placement fertilization, while H. seropedicae for the association between placement and broadcast fertilization, or else the absence of fertilization. Yet, B. ambifaria was responsible to the absence of fertilization. Bacterial populations in protected culture varied according to the fertilization used and the period of collection. In vitro, the bacterial population was higher epiphytically.

Highlighted Conclusions
1) A. brasilense is more responsive to placement fertilization, and B. ambifaria to the absence of fertilization. H. seropedicae is more responsive the association between placement and broadcast fertilization, or else the absence of fertilization.
2) Bacterial populations vary according to the fertilization and the period of collection in protected culture, and they are higher epiphytically in vitro.

Keywords: Zea mays, Azospirillum brasilense, Burkholderia ambifaria, Herbaspirillum seropedicae, Diazotrophic bacteria. (more…)

Communications in Plant Sciences, vol 8, p. 75-81, 2018 (2018011)

DOI: http://dx.doi.org/10.26814/cps2018011

Authors: Mayeve Didomenico Melo, William Gustavo Sganzerla, Guilherme Cruz Duarte, Jocleita Peruzzo Ferrareze, Ana Paula de Lima Veeck, and Paula Iaschitzki Ferreira

Abstract: The growing concern about food safety makes necessary to search for alternative methods of food conservation. The objective of this work was to evaluate postharvest conservation of kale leaf using aqueous vegetal extracts. The experimental design was completely randomized, with the concentrations of 5, 10, 15, 20 and 25% of Rosmarinus officinalis, Allium sativum, Capsicum baccatum, Cymbopogon citratus and the control treatment using deionized water. The extracts were sprayed on kale leaves with manual spray over the entire adaxial and abaxial epidermis. The evaluated parameters were chlorophyll a and b, weight loss, total phenolics compounds, antioxidant activity and a visual analysis. The leaves remained at ambient temperature for six days. The results indicate that there was no significant conservation in the content of chlorophyll a, b and visual analysis when compared to the control, and the extracts did not have influence in the weight loss. There was an increase of total phenolic content and antioxidant activity with rosemary, lemongrass and pepper extracts, the garlic extract reduced the concentration of these bioactive compounds when compared to the control. In general, the application of the vegetal extracts did not influence in the postharvest conservation of kale leaves.

Highlighted Conclusion
The application of aqueous extracts in general does not influence positively postharvest conservation of kale leaves.

Keywords: Aqueous vegetal extracts, Postharvest, Storage, Kale. (more…)

Communications in Plant Sciences, vol 8, p. 69-74, 2018 (2018010)

DOI: http://dx.doi.org/10.26814/cps2018010

Authors: Ana Kelly Chornobay, Luiz Antonio Odenath Penha, and Renato Yagi

Abstract: In soybean production in Brazil, the ends often justify the means. The high marketing prices of grains have motivated producers to adopt new techniques for cultivation of the legume in an empirical way or without adequate scientific support. Thus, we hypothesized that soybean cross-sowing in equal populations or twice (as used in conventional sowing in parallel rows) may increase soybean yield and decrease weed infestation in crops. In this study, we aimed to evaluate the spatial arrangements of plants associated with the presence or absence of chemical treatment for weed control in the soybean crop. A randomized block design was used with five treatments (four replicates per treatment): 1) uncrossed with the recommended plant population; 2) crossed with the recommended plant population; 3) crossed with double the plant population; 4) crossed with the same plant population and without herbicide; and 5) crossed with double the plant population and without herbicide. Soybeans cross-sowed with the recommended plant population had the same growth as uncrossed soybeans in terms of height and dry matter of shoot and roots, but had a higher leaf area index. Moreover, root nodulation increased in number with soybeans cross-sowed with the recommended plant population and in mass for soybeans cross-sowed with double the plant population, without differences in indirect measures of chlorophyll. Thus, our findings suggested that cross-sowing with the recommended plant population or double the recommended plant population did not aid in weed control and did not increase the yield of soybean grains.

Highlighted Conclusion
Soybean cross-sowing with the recommended or double the recommended plant population does not aid in weed control or increase soybean grain yields.

Keywords: Glycine max (L.) Merr., Spatial arrangement, Plasticity. (more…)

Communications in Plant Sciences, vol 8, p. 62-68, 2018 (2018009)

DOI: http://dx.doi.org/10.26814/cps2018009

Authors: Paula Porrelli Moreira da Silva, Renata Cristina Casemiro, José Guilherme Prado Martin, Leandro Francisco Carmo, Vanessa Groppo-Ortiz, and Marta Helena Fillet Spoto

Abstract: There are no studies regarding the irradiation of juçara pulp with a view to their conservation. Therefore, this study pursued to test the conservation of juçara pulp submitted to gamma radiation at the doses 0.0 (control), 2.5, 5.0; 7.5 and 10.0 kGy, and analyzed in 1, 7, 14, 21 and 28 days post irradiation. The samples were kept at 6 °C. We evaluate the bioactive compounds (anthocyanin and total phenolic), the enzymatic activity polyphenol oxidase and peroxidase, and the sensorial quality (acceptance test with hedonic scale) of the samples. The results of the biochemical analyses were submitted to the regression test and the sensorial analysis to the Tukey’s test at p<0.05. The samples remained within the prevailing legal standards regarding the microbiological quality. The anthocyanin levels decreased during the first week and its reduction was inversely proportional to the dose increments. The phenolic compounds showed high values in the first day, with a reduction in the later period and a constant average to the end. The activity of PPO and POD enzymes decreased in all periods, regardless of the radiation dose applied. The gamma radiation did not affect juçara pulp sensorial quality.

Highlighted Conclusion
The gamma radiation affects the conservation and biochemical characteristics of juçara pulp under refrigeration, but it does not affect its sensorial quality.

Keywords: Euterpe edulis, Irradiation, Biochemical analyzes, Sensory quality, Shelf life. (more…)

Communications in Plant Sciences, vol 8, p. 55-61, 2018 (2018008)

DOI: http://dx.doi.org/10.26814/cps2018008

Authors: Ayslan Trindade Lima, Daianne Maria de Oliveira, and Marcos Vinicius Meiado

Abstract: The imbibition process, which is essential for seed germination, can be interrupted due to lack of water in the environment. Once this occurs, seeds have its germination process interrupted and loses the water absorbed to the environment. The objective of this study was to evaluate the effects of hydration and dehydration cycles (HD cycles) on seed germination of Macroptilium atropurpureum under water deficit conditions. Seeds of M. atropurpureum were submitted to 0 (control), 1, 2 and 3 HD cycles at different hydration times. In addition, the seeds were also submitted to osmotic potentials of 0.0, -0.1, -0.3, -0.6 and -0.9 MPa for water deficit simulation. Although the seeds germinated in all of the osmotic potentials used, the seeds presented a reduction in the percentage of germination, independently of the number of HD cycles and the hydration time between each cycle. In addition, HD cycles also negatively affected the mean germination rate, promoting a reduction of this parameter as seeds were submitted to HD cycles and osmotic potentials. Thus, the results demonstrated that HD cycles did not provide an increase in water stress tolerance in M. atropurpureum seeds during germination.

Highlighted Conclusions
1) Macroptilium atropurpureum seeds can germinate even in low osmotic potentials conditions.
2) Discontinuous hydration confers a negative effect on M. atropurpureum germination and does not provide a greater tolerance to water deficit.

Keywords: Siratro, Abiotic stress, Hydration and dehydration cycles, Semi-arid ecosystem, Caatinga. (more…)

Communications in Plant Sciences, vol 8, p. 48-54, 2018 (2018007)

DOI: http://dx.doi.org/10.26814/cps2018007

Authors: Fernando Scarati Frandoloso, Leandro Galon, André Dalponte Menegat, Felipe Bianchessi, Leonardo Chechi, César Tiago Forte, Altemir José Mossi and Ubirajara Russi Nunes

Abstract: The seeds physiological quality is a fundamental characteristic to obtain competitive and productive plants, where seeds treatment is an important tool to keep seeds physiological high-quality. The present study aimed to evaluate chemical treatments and storage period influence on seeds physiological quality. It was used a factorial (4 x12) randomized complete block design, with eight replications. In factor A, the chemicals (thiametoxan, metalaxyl + fludioxonil + thiabendazole and pyraclostrobin + methyl thiophanate + fipronil) and control. In the factor B, the treated seeds storage periods (0, 3, 7, 14, 21, 28, 35, 42, 49, 56, 63 and 90 days). The variables evaluated were vigor and germination, and the tests were performed at p≤0.05. The results indicate that the maize seeds vigor is maintained with the fungicide application, regardless of the vigor test used. As the treated seeds storage period increases, their vigor was reduced by the first count test. However, maize seeds germination was not influenced by seed treatment or storage period.

Highlighted Conclusions
1) The maize seeds vigor is maintained applying fungicides, regardless of the vigor test used.
2) The first count test indicates that the longer the untreated or treated maize seeds with thiametoxan are stored the lower the seed vigor.
3) Maize seeds germination is not influenced by the thiametoxan, metalaxyl + fludioxonil + thiabendazole and pyraclostrobin + methyl thiophanate + fipronil chemicals, not even by the storage period up to 90 days of treated seeds.

Keywords: Zea mays L., Germination, Vigor, Storage period. (more…)

Communications in Plant Sciences, vol 8, p. 40-47, 2018 (2018006)

DOI: http://dx.doi.org/10.26814/cps2018006

Authors: William Gustavo Sganzerla, Mayeve Didomenico Melo, Jocleita Peruzzo Ferrareze, Ana Paula de Lima Veeck, Paula Iaschitzki Ferreira, and César Luis Girardi

Abstract: The aim of this study was to evaluate the application of 1-MCP on physicochemical characterization and antioxidant activity of ‘Gala’ apples mutants, harvested at two different times and maintained in refrigerated atmosphere (0 °C) during 90 days. ‘Mondial Gala’, ‘Imperial Gala’ and ‘Galaxy’ were obtained from commercial orchards. After harvesting, half of the fruits were treated with 1-MCP, and control fruits were maintained in the same condition, but without the treatment. Skin color, pulp firmness, titratable acidity, total soluble solids, total phenolic compounds, anthocyanin and antioxidant activity were evaluated in peel and pulp. The results show that using 1-MCP, pulp firmness was higher than the control. Titratable acidity analysis showed statistical differences for apple clones, harvest point and treatment with 1-MCP. Total soluble solids content was not influenced by the treatments. Epidermis color was statistically influenced by clone (a*, L* and C*), and by harvest point (L*), but 1-MCP did not affect this parameter. The content of total polyphenols and antioxidant activity was higher in the peel when compared to the pulp. 1-MCP proved to be effective in maintaining postharvest quality in all clones and at two harvest points tested.

Highlighted Conclusions
1) Refrigerated atmosphere during 90 days maintained the fruit quality.
2) Total phenolic compounds are higher in apple peel.
3) 1-MCP proved to be effective in maintaining postharvest quality.

Keywords: 1-methylcyclopropene, Total phenolic compounds, Refrigerated atmosphere, Mondial Gala, Imperial Gala, Galaxy. (more…)