Dry Matter Mass Research Articles

Amaranth Response to Water Stress

Amaranth is a species that has rapid growth, tolerates drought and produces grains of high food value. In this work the potential for dry season cropping in the Brazilian savannah of two amaranth species (Amaranthus caudatus e Amaranthus cruentus) was studied, subjecting them to three different periods of water availability at the beginning of the crop. Weekly data were collected on height, dry matter mass of shoot, panicle and roots, and at the end of the cultivation, yield, harvest index, thousand-grain weight, water-productivity. It was also determined the falling plant estimation. In the dry matter production evaluation, it was observed that the water deficit caused the reduction of the shoot, but significant increase of the root. The A. caudatus Inca did not show a significant productivity difference between the treatments, with a mean of 1,591.0 kg ha-1 and reached harvest point at 63 days. The A. cruentus BRS Alegria had better productivity in the treatment without water restriction, average of 2,008.6 kg ha-1 and reached harvest point at 86 days. Both species have potential for dry season cropping in the Brazilian savannah.

ПОРІВНЯЛЬНИЙ ВПЛИВ РЕГУЛЯТОРІВ РОСТУ АЗОТОФІТ, ЯНТАРНА КИСЛОТА ТА ВИМПЕЛ НА ДИНАМІКУ ПРОЦЕСІВ РОСТУ ТА ПРОДУКТИВНІСТЬ ОЗИМОЇ ПШЕНИЦІ СОРТУ ЮВІВАТА

Scientific research suggests that winter wheat cultivation technologies can be regulated by plant growth regulators. These substances have a complex effect on growth and development and facilitate plant growth and crop capacity.
 Three-year field studies were carried out using plant growth regulators of Azotophyte, Amber acid and Vympel to determine the dynamics of plant growth rates and their productivity. This made it possible to observe the influence of growth regulators before sewing and to establish their effectiveness at all stages of plant development. Seeds of winter wheat of the variety Jubiwata were treated with solutions of the substances under analysis. The experimental area was 40 m².
 The study demonstrated that the growth regulators do not influence the field germination rate of plants, but the percentage of germination was quite high in both control and experimental variants.
 As for the rates of plant height and root length, the first measurement of the average height of winter wheat plants in autumn demonstrated that Vympel was the most efficient. Its indicators exceeded the control variant by 3.4%. After the second measurement, the plant height increased in all variants. The fourth spring measurement showed that the most powerful was the effect by Amber acid. This compound significantly inhibited plant growth compared to other growth regulators and controls.
 The investigated plant growth regulators have a positive influence on the processes of root development of winter wheat plants in both autumn and spring time. This feature will provide a better nutrition of the plants.
 The weight of the dry matter after the first weighing was greater in the control and the variant treated with Nitrogen. The fourth weighing showed that the best effect on the dry matter mass was found by Azotophyte, which contributed to the increase of this indicator twice as much compared to the control. Amber acid, when used for pre-sowing seed treatment, exceeded the control value by 1.8 times.
 Stronger effect on the percentage of dry matter in the plant sample was found only by Vympel, under the influence of which this indicator was greater by 9 units compared to the control.
 The use of synthetic growth regulators significantly increases the productivity of winter wheat, namely the length of the complex ear, the number of grains and the weight of the compound ear.
 Thus, research has shown that plant growth regulators Azotophit, Amber acid and Vympel facilitate the growth and productivity of winter wheat plants of the Juvivat variety. Winter wheat crops can be treated with these substances before sowing. Determining the highest efficiency of each individual regulator, as well as the possibility of combining them to improve plant growth processes, requires further research.

Phosphate Fertilization in Amaranth Culture cv. BRS Alegria in Second Harvest in the Cerrado

Vegetable species, capable of diversifying production in the second crop of the Cerrado, producing grains rich in protein and providing dry matter for off-season, are most welcome. The amaranth presents these characteristics, however its cultivation is little known in Brazil. The adequate availability of nutrients for this plant, under cerrado conditions, has not yet been defined and these soils, in turn, are of low natural fertility, deficient, mainly, in phosphorus. Before this senary, the present work was developed with the objective of evaluating agronomic and productive aspects of amaranth cv. BRS Alegria, cultivated in succession to soybean, underwent increasing doses of phosphorus. The experimental design was a randomized complete block design with five levels of phosphorus (0, 30, 60, 100 and 150 kg.ha-1 of phosphorus - triple superphosphate) applied in the sowing furrow, with four replications. Plant height was evaluated; stem diameter; panicle length; final population of plants; phosphorus content in leaf tissue; mass of dry matter of panicle, stem, leaf and total and; grain yield. The model with higher R2 in the regression analysis was selected to express the behavior of the phosphorus doses on the evaluated characteristics. The phosphorus applied in the sowing furrow increases productivity and phosphorus content in the amaranth foliar tissue in succession to the soybean crop. The highest estimated productivity of amaranth grains was obtained with 98.7 kg ha-1 of P2O5, with values close to the level of economic response to the application of the input.

Growth of lettuce cultivars in beds covered with differing materials

In commercial lettuce growing, the intensive cultivation of the soil results in an increase in weed populations, making it difficult to fully exploit the area and increasing production costs. Under such
 circumstances, the use of soil covers can minimize this problem. Consequently, the objective of this study was to evaluate the effects of different materials as soil covers on the agronomic performance of three lettuce cultivars. The experiment was arranged in randomized blocks, with treatments set in a subdivided plot scheme. Five types of soil cover (plots) were tested: no cover, black plastic, double white faced plastic, straw mulching and kraft paper and three Lettuce cultivars (subplots): loose-crested leaf group, iceberg lettuce group, with four replicates. Number of leaves per plant, stem length and diameter, head diameter, mass of fresh and total dry matter, fresh matter mass of leaves and stem were evaluated. For the Lisa and Americana lettuce groups, bed soil cover materials were more efficient when compared to the uncovered beds. For economic and environmental reasons, kraft paper is recommended as a bedding cover material for these cultivars. Variation in growth occurred between the lettuce cultivars, independently of the use of bedding cover. This
 occurred in the sequence: loose leaf > iceberg lettuce> loose-crested leaf group.

Filling in sewage sludge biodrying gaps: Greenhouse gases, volatile organic compounds and odour emissions

In the present work, a complete study of the sewage sludge (SS) biodrying technology was conducted at bench-scale, aiming at assessing its performance and providing a valuable insight into the different gaseous emission patterns found for greenhouse gases (GHG) and odorant pollutants. As process key parameters, temperature, specific airflow, dynamic respiration index, final moisture content and Lower Calorific Value (LCV) were evaluated. At the end of the biodrying, a product with a 35.9% moisture content and a LCV of 7.1 MJ·kg−1product was obtained. GHGs emission factor was 28.22 kgCO2eq per Mg of initial mass of dry matter in the SS (DM0-SS). During the biodrying process, maximum odour concentration measured was 3043 ou·m−3 and the estimated odour emission factor of the biological treatment was 3.10E + 07 ou per Mg DM0-SS. Finally, VOCs were completely identified and quantified. The most abundant VOCs found in the biodrying gaseous emissions were terpenes, sulphur-compounds and ketones.

Physiological potential of Physalis peruviana L. seeds under different temperatures and light wavelengths

Physalis peruviana L. is a plant that produces small sweet berries of great nutritional and medicinal importance. This plant is propagated mainly through seeds, which requires information on germination response to temperature and light changes. Thus, the present study aimed to evaluate the use of different temperatures and light wavelengths on the physiological potential of P. peruviana seed batches. The experiment was conducted with seeds from plants cultivated in 2015/15 and 2016/16. The treatments applied were the following: two germination temperatures (constant temperature of 25 °C and alternated between 20/30 °C), two seed batches (2015/15 and 2016/16), and four forms of light exposure during germination (blue, red, white, and dark). The data were analyzed by principal component analysis using the correlation matrix obtained through the standardized mean equal to zero and variance 1 of the parameters evaluated for each treatment. The eigenvalues and eigenvectors of the matrix were obtained using the SAS University Edition® statistical software. The analyzed variables were: Germination test performed on the 7th and 28th day considering root protrusion, normal seedlings, shoot length, root length, and total dry matter mass. The data showed that the seed germination test of Physalis peruviana L. should be performed under a constant temperature of 25 °C, in the presence of light (white, blue, or red). When the option is the application of the test in the dark, it is necessary to use a thermoperiod of 20–30 °C to provide the expression of maximum physiological potential.

Performance of Chia on Different Sowing Dates: Characteristics of Growth Rate, Leaf Area Index, Shoot Dry Matter Partitioning and Grain Yield

The objective of this study was to comparatively determine the characteristics of growth rate, leaf area index, shoot dry mass partitioning and grain yield of chia plants (Salvia hispanica L.) on different sowing dates. A field experiment was conducted in the crop year of 2016/2017 in five sowing dates (09/22/16, 10/28/16, 01/03/17, 02/08/17 and 03/24/17) with a randomized complete block design and four replicates. Plant growth was determined through field samplings to determine the dry matter mass and leaf area performed every 15 days. The following physiological indexes were calculated: relative growth rate, absolute growth rate, net assimilation rate, leaf area ratio, specific leaf area and leaf mass ratio. To weekly evaluate plant height, ten plants per plot were marked after emergence, and the final height was considered when plants reached physiological maturity. A useful area of 2.10 m² per plot was collected for evaluating grain yield. The physiological indexes indicated that at earlier sowing dates there is a greater plant growth, either in shoot dry matter mass, height and leaf area index. The leaf area index of branches is progressively increased with plant development and contributes significantly to total leaf area index of chia plants in all studied sowing dates. The main stem represents between 60 and 70% of the shoot dry matter accumulated in the early sowing dates, and between 40 and 50% in late sowing. The best sowing date in terms of grain yield is 01/03/17.

DESENVOLVIMENTO DA CULTURA E PRESENÇA DE E. COLI NA SALSA IRRIGADA COM ÁGUA RESIDUÁRIA TRATADA POR RADIAÇÃO SOLAR

DESENVOLVIMENTO DA CULTURA E PRESENÇA DE E. COLI NA SALSA IRRIGADA COM ÁGUA RESIDUÁRIA TRATADA POR RADIAÇÃO SOLAR
 
 
 MARIANA ALEXANDRE DE LIMA SALES1 E RODRIGO MÁXIMO SÁNCHEZ ROMÁN2
 
 1 Doutora em Agronomia: Irrigação e Drenagem. Rua Heleni de Souza Costa, 41 – Jardim Ypê, 18.608-710, Botucatu-SP, Brasil. mal_sales@hotmail.com
 2 Departamento de Engenharia Rural, Faculdade de Ciências Agronômicas, Universidade Estadual Paulista (UNESP) Campus de Botucatu. Fazenda Experimental Lageado, Avenida Universitária, nº 3780, Altos do Paraíso, CEP: 18610-034, Botucatu – SP. Brasil. rodrigo.roman@unesp.br
 
 
 1 RESUMO
 
 O objetivo deste trabalho foi avaliar a influência da água residuária doméstica tratada por radiação solar (ARD-TRS) no desenvolvimento da salsa (graúda portuguesa), além de verificar e quantificar a presença de Escherichia coli na cultura. O experimento foi realizado na FCA/UNESP no município de Botucatu - São Paulo, o qual consistiu na aplicação de diferentes porcentagens (0, 25, 50, 75 e 100%) de ARD-TRS na lâmina total de irrigação. Os resultados obtidos foram satisfatórios, visto que no geral houve um aumento nos valores de altura da planta, número de talos, diâmetro do maior talo, diâmetro da touceira e massa da matéria fresca e seca, observando-se diferenças significativas em função da porcentagem de ARD-TRS na lâmina total de irrigação. Assim conclui-se que, a utilização de diferentes porcentagens de ARD-TRS na lâmina total de irrigação influenciou positivamente no desenvolvimento da cultura estudada, apresentando uma população de E. coli na água de irrigação < 100 NMP 100 mL-1 e nas culturas ≤ 1.000 NMP 100 mL-1.
 
 Palavras-chave: reuso da água, SODIS, Petroselinum Crispum, coliformes, produtividade.
 
 SALES, M. A. L.; SÁNCHEZ-ROMÁN, R. M.
 DEVELOPMENT AND PRESENCE OF E. COLI IN PARSLEY IRRIGATED WITH DOMESTIC WASTE WATER TREATED WITH SOLAR RADIATION 
 
 
 2 ABSTRACT
 
 The objective of this study was to evaluate the influence of solar-treated domestic wastewater (ARD-TRS) on the development of parsley (Portuguese coarse), and to verify and quantify the presence of Escherichia coli in the crop. The experiment, carried out at FCA / UNESP, in Botucatu - São Paulo, consisted of the application of different percentages (0, 25, 50, 75 and 100%) of ARD-TRS in the total irrigation depth. The results obtained were satisfactory, since in general there was an increase in values ​​of plant height, number of stalks, diameter of the largest stalk, clump diameter and mass of fresh and dry matter, and significant differences were observed as function of the percent of ARD-TRS in the total irrigation depth. Thus, it was concluded that the use of different percentages of ARD-TRS in the total irrigation depth had a positive influence on the development of the studied culture, presenting a population of E. coli in irrigation water <100 NMP 100 mL-1 and in cultures ≤ 1,000 NMP 100 mL -1.
 
 Keywords: water reuse, SODIS, Petroselinum crispum, coliforms, productivity.

Reconstruction of bovine spermatozoa substances distribution and morphological differences between Holstein and Korean native cattle using three-dimensional refractive index tomography

Measurements of the three-dimensional (3D) structure of spermatozoon are crucial for the study of developmental biology and for the evaluation of in vitro fertilization. Here, we present 3D label-free imaging of individual spermatozoon and perform quantitative analysis of bovine, porcine, and mouse spermatozoa morphologies using refractive index tomography. Various morphological and biophysical properties were determined, including the internal structure, volume, surface area, concentration, and dry matter mass of individual spermatozoon. Furthermore, Holstein cows and Korean native cattle spermatozoa were systematically analyzed and revealed significant differences in spermatozoa head length, head width, midpiece length, and tail length between the two breeds. This label-free imaging approach provides a new technique for understanding the physiology of spermatozoa.

Complementary Application of Inoculant in Post-emergence on Soybean Crop

Objective: Inoculation is an important agricultural practice in soybean cultivation that guarantees high productivity without the external input of nitrogen. The objective of this study was to evaluate if the complementary of liquid inoculant (Bradyrhizobium japonicum), via leaf, in different times and different application rates, affects the nodulation, plant growth and soybean productivity.
 Study design: A randomized complete block design (RCBD) was used, with four replications, in a 5x3 factorial scheme, evaluating the complementary inoculant application, via foliar (0; 75; 150; 225 e 300 mL ha-1), in three stages of vegetative development of the crop (V2, V4 e V6).
 Location and duration of the study: The study was performed in a commercial area, in the municipality of Sinop, in the northern of Mato Grosso State, between October 2017 and February 2018.
 Methodology: The cultivation was in soil classified as Red-yellow Latosol with of clayey texture, was in a direct seeding system, using the cultivar NS7901RR. The seeds used were treated and inoculated at sowing, with turfous inoculant and liquid. The experimental units received the complementary applications of inoculant, via pulverization, at 15, 21 and 28 days after emergence, according to the treatment.
 Results: It was verify that the different times of application of foliar inoculant, does not condition significant differences to the parameters measured in this study. The complementary inoculant application affected, significantly, the leaf chlorophyll index (P <0.05), as well as the dry matter mass of the plants (P <0.001). Up to 300 mL ha-1, a gradual increase in grain yield was verified.
 Conclusion: The complementary supply of liquid inoculant (B. japonicum), via foliar, in different rates application, affects the nodulation and development of the plants and the productive yield of the crop.

Depositing ability of stem of winter wheat varieties of different periods of selection

Adaptation of high-yielding winter wheat crops to changes in climatic conditions has great importance for food security of countries. The remobilization of stem assimilates for grain filling is one of the possible ways of increasing wheat yield in unfavourable environmental conditions. Field experiments in natural conditions with three old and three modern varieties of winter wheat were performed to compare depositing abilities of their stems. The objective of this study was a comparative analysis of the parameters of depositing capacity of stems of the main shoots for identification of the criteria for assessing grain productivity of winter wheat. The parameters of depositing capacity of the stem of the main shoots of three old winter wheat varieties (1997, 2003, and 2008) and three modern ones (2013, 2014 and 2016) were studied in field conditions with natural conditions of water supply (Kyiv Oblast, Ukraine). During the period of formation of reproductive organs (April and May), the amount of precipitation, respectively, was only 17% and 68% of long-term values and average monthly air temperature was 3–4 ºС higher than the climatic norm. We analyzed the variability of the parameters of depositing capacity of the stem of the main shoot and grain productivity of the ear of six wheat winter varieties which differed by time of selection. In unfavourable conditions during the period of formation of reproductive organs the modern winter wheat varieties had an 11% higher yield on average compared to the older ones. It was determined that the highest mass of grain from the ear of the main shoots (1.9–2.1 g) belonged to Odeska 267 variety, a drought-tolerant variety from earlier selection, and three modern varieties – Raihorodka, Prydniprovska and Darunok Podillia. It is demonstrated that these varieties also exceeded two old varieties (Podolianka and Yednist) by stem dry matter weight of main shoot at anthesis by 0.3–0.6 g. The highest content of non-structural carbohydrates at this phase was observed in Odeska 267, Raihorodka and Darunok Podillia varieties (273–307 mg/stem). Correlation analysis revealed the significant correlation between mass of grain from ear and dry matter of stem at anthesis and full ripeness, as well mass of grain from ear and the amount of non-structural carbohydrates at anthesis. Therefore, modern varieties of winter wheat and the drought-tolerant variety have higher yield, weight of dry matter of stem of the main shoot at anthesis and grain productivity of the ear, compared to old varieties. The results of this study indicate that the mass of dry matter of the stem of the main shoot at anthesis can be used as a marker of the grain productivity of winter wheat.

Efficiency and Carbon Footprint of the German Meat Supply Chain.

Meat production and consumption contribute significantly to environmental impacts such as greenhouse gas (GHG) emissions. These emissions can be reduced via various strategies ranging from production efficiency improvement to process optimization, food waste reduction, trade pattern change, and diet structure change. On the basis of a material flow analysis approach, we mapped the dry matter mass and energy balance of the meat (including beef, pork, and poultry) supply chain in Germany and discussed the emission reduction potential of different mitigation strategies in an integrated and mass-balance consistent framework. Our results reaffirmed the low energy conversion efficiency of the meat supply chain (among which beef was the least efficient) and the high GHG emissions at the meat production stage. While diet structure change (either reducing the meat consumption or substituting meat by edible offal) showed the highest emissions reduction potential, eliminating meat waste in retailing and consumption and byproducts generation in slaughtering and processing were found to have profound effect on emissions reduction as well. The rendering of meat byproducts and waste treatment were modeled in detail, adding up to a net environmental benefit of about 5% of the entire supply chain GHG emissions. The combined effects based on assumed high levels of changes of important mitigation strategies, in a rank order considering the level of difficulty of implementation, showed that the total emission could be reduced by 43% comparing to the current level, implying a tremendous opportunity for sustainably feeding the planet by 2050.

Assessment of Gaseous Emissions from Cattle Abattoir Wastes in Cameroon

Abattoirs are potentially a significant source of greenhouse gas (GHG) methane (CH4) and nitrous oxide (N2O) emissions. Measurements were conducted in a beef cattle abattoir located in Bamenda, Cameroon, to characterise waste production and quantify GHG emissions. A male and female cattle were randomly selected on each day for waste measurement over a period of two weeks. Waste from each cattle was quantified by collecting all the intestinal/stomach contents after slaughtering and determining the mass of dry matter (DM) and volatile solids (VS). Emissions from the outdoor solid waste storage heap was measured using flux chambers. The average cattle weight was 420 kg and the average intestinal/stomach waste was 37 ± 6 kg cattle−1, half of which was dumped outdoor in a heap, while the rest was discarded with wastewater into a stream. The DM produced was 4.19 ± 0.85 kg cattle−1, representing 11% of the wastes, and the VS produced was 3.42 ± 0.82 kg cattle−1. The average ratio of waste DM to cattle weight was 1.0%, while the ratio of waste VS to cattle weight was 0.8%. Modelled CH4 emissions from the total waste was estimated at 37.84 ± 8 g CH4 cattle−1 with a range of 27.57–56.03 g CH4 cattle−1. Measured GHG emission from the outdoor heap was 5.89 ± 4.78 mg CH4 m−2 min−1, 0.137 ± 0.151 mg N2O m−2 min−1, and 95 ± 83 mg CO2 m−2 min−1. The total GHG (CH4 + N2O) emission rate was 229 mg CO2e m−2 min−1, indicating that CH4 contributes 82% of the total GHG. Improved waste management strategies, such as anaerobic digestion for biogas production or using covers over waste heaps, would help abattoirs mitigate GHG emissions.

Effect of Preharvest Application of Silicon and Saline Water on Postharvest Quality of Beet (Beta vulgaris L.)

Beet is one of the vegetables richest in nutrient (bioactive compounds, folic acid and potassium). However, there are few studies on postharvest quality from the crop under irrigation conditions with saline waters, and because of that, the objective of this study was to evaluate effect of saline waters and silicon application in the preharvest on physicochemical quality of the beet. Two experiments were conducted with the objective of evaluating two forms of silicon application: via foliar (experiment 1) and via soil (experiment 2) about its influence in mitigating salt stress. In both experiments was adopted a randomized design with blocks in a 5 x 5 factorial, referring to five levels of electrical conductivity of the irrigation water (ECw): (0.5, 1.3, 3.25, 5.2 and 6.0 dS m-1) five doses of silicon (0.00; 2.64; 9.08; 15.52 and 18.16 mL L-1), they were combined according to the experimental matrix Central composite of Box totaling 10 treatments, with four replicates and three plants per plot. After harvesting, 70 days after transplanting, the following characteristics were evaluated: bulb dry mass, pH, titratable acidity (TA), total soluble solids (TSS), TSS/TA ratio and ash. There was a significant effect for the salinity x silicon (Si) interaction applied via soil to the dry matter mass and titratable acidity. The electrical conductivities of irrigation water (ECw) and Si doses via leaf and soil influenced significantly for analyzed variables, except pH, total soluble solids, TSS/TA ratio, ash and titratable acidity, which were not influenced by ECw and nor by the doses of Si via soil and foliage. Irrigation with water of 6.0 dS m-1 promotes better quality beet tuber. The fertilization on preharvest with silicon via soil or foliage improved postharvest quality of beet.

Fitness of Echinochloa crusgalli var. mitis biotypes susceptible and resistant to imazapyr + imazapic herbicide

The continuous use of herbicides with the same mechanism of action has caused the selection of resistant weed biotype that may present differences in fitness when compared with susceptible biotype. The objective of the present study was to identify and distinguish the fitness of barnyardgrass biotypes resistant and susceptible to imazapyr + imazapic herbicide under controlled and noncompetitive conditions. For that, there were used barnyardgrass biotype susceptible (ECH1 and ECH38) and resistant (ECH14 and ECH44) to ALS inhibitors, collected at Pelotas/RS and Rio Grande/RS cities, respectively, in experiment installed in a greenhouse in a completely randomized experimental design during the months from October to December 2015. The biotype were evaluated during the period of 15 to 120 days after the emergence related to plant height, foliar area, shoot dry matter mass and root dry matter mass. The results showed insignificant differences between the biotypes during the development of the plants. The susceptible biotype ECH44 showed a higher number of panicles per plant and seeds along with the resistant ECH1. There is variability among Echinochloa crusgalli var. mitis biotypes resistant and susceptible to ALS inhibitors, indicating an absence in fitness penalty caused by resistance when cultivated without the selection of pressure (herbicide).

CONSERVATION OF SEEDS OF Myrcianthes pungens (Berg) Legr. IN DIFFERENT PACKAGING IN A CONTROLLED ENVIRONMENT1

ABSTRACT Studying the physiological and biochemical behavior of Myrcianthes pungens seeds stored in different packages for up to ten months was the objective of this work. Seeds were collected in Toledo, Pato Bragado, and Marechal Cândido Rondon and stored in a cold and dry chamber (11 ºC and 6,3% RH) for ten months. The germination test and the germination speed index (GSI), the seedling length (SL), the seedling dry matter mass (DMS), and the tetrazolium (ZT) test were performed and, for each evaluation, the water content was determined. Non-parametric analysis was used. During storage, the water content of the seeds in the plastic and glass containers varied little, but decreased in the paper packaging. The germination was maintained for ten months when the seeds were stored in plastic containers and for two months in the glass and paper ones. The variables GSI, SL, and DMS presented upwards and downwards variations during the storage period. The ZT revealed that, in the plastic packaging, the seeds remained viable for up to ten months, in glass, up to two months, and in paper, up to four months. Therefore, seeds of Myrcianthes pungens with high initial quality can be stored in a cold and dry chamber in plastic bags, maintaining viability and vigor for a period of ten months

Effect of cadmium on germination and growth of wheat

In this study, the effect of Cd on the germination, growth of seedlings and composition of plants deriving from contaminated grains, grown in the field, was ex?amined. Wheat grains were soaked in Cd-containing solutions: 0 (control, deionized water), 10-5, 10-4, 10-3, and 10-2 M CdCl2 during 24h. One portion of grains was used to test germi?nation and seedling growth, while the other was sown in the field. The concentration of Cd in the grains almost linearly increased with the increase in the applied concentrations of Cd, which reduced the germination and energy of germination and increased the proportion of atypical seedlings. Larger concentrations of Cd significantly impaired the growth of seedlings (length of the shoots and roots, dry matter mass). In the grains of the field-grown plants the concentrations of N, P, and K were not affected by Cd, but their concentrations in the straw declined (especially of N). These results suggest that the emergence and development of plants on the soil polluted by Cd are likely to be significantly limited and yield reduced.

Root growth and carbohydrate partitioning in cotton subjected to shading in the initial phase

ABSTRACT: Cotton cultivation in Brazil tends to occur mostly in the rainy season, and at the time of developing the crop there are often prolonged periods of low solar radiation. The objective of this work was to evaluate the root development of cotton cultivars subjected to shading in the initial phase. The experiment was carried out in a greenhouse, using rhizotrons. The experimental design was a 2x2 factorial in randomized blocks with five replications. The treatments were composed of cotton cultivars TMG 1WS (early) and TMG 8WS (late) and luminosity conditions: non-shaded and shaded (50% reduction of luminosity). There were no interactions between the factors “shading” and “cultivars” for any parameter evaluated. Shading reduced total and lateral root growth from the 21 days after emergence (DAE) and the main root at 24DAE. Shading caused reductions in length (60%), surface (65%), mean diameter (15%), root volume (69%), root dry matter mass (83%) and shoot (64%), as well as decreasing the content (36%) and the accumulation of carbohydrates in the shoot (73%). Shading at early cotton development reduces the shoot carbohydrates production, affecting dry matter accumulation and root growth, and this response is independent of the cultivar.

Leaching of Imidazolinones in Irrigation Systems in Rice Cultivation: Sprinkling and Flooding

ABSTRACT: Herbicides of the imidazolinone group have been used in irrigated rice and presented a long persistence in the soil, especially in floodplain areas with a low drainage, and could cause environmental contamination. This study aims to evaluate the leaching and residual of herbicides belonging to the imidazolinone group in sprinkler and flood irrigation systems. The experiment was carried out under greenhouse conditions, with the application of the herbicides imazethapyr, imazethapyr + imazapic, and imazapyr + imazapic in soil irrigated by flooding and sprinkling. Subsequently, the soil was collected from the layers of 0-5, 5-10, 10-15, 15-20, and 20-25 cm and packed in 500 mL capacity plastic pots in order to sow tomato as a bioindicator plant of the presence of the herbicides belonging to the imidazolinones. Phytotoxicity, length, and shoot dry matter mass of tomato plants were evaluated at 10 and 20 days after emergence. The herbicides of the imidazolinone chemical group presented a high potential for leaching and persistence with effects for more than 180 days after application. Based on the symptoms presented by the sensitive crop, the degradation of imazethapyr, imazethapyr + imazapic, and imazapyr + imazapic in the 0-15 cm layers was higher in soil with sprinkler irrigation when compared to flood irrigation. Thus, non-flooded soils present a greater capacity to degrade the herbicides belonging to the imidazolinone chemical group.

LONGITUDINAL DATA ANALYSIS OF STEVIA REBAUDIANA EVAPOTRANSPIRATION ACCORDING TO WATER LEVELS

The purpose of this work was to evaluate the accumulated evapotranspiration of stevia, planted in 40 pots, over a period of 27 days according to four irrigation levels through a nonlinear mixed eects model and, with this model, to verify if we can maximize the stevia's evapotranspiration with a lower than usual water level. When the humidity of the substrate reached 50% of its maximum capacity retention, we added water to raise the humidity according to the four treatments: W1 = 62:5%; W2 = 75:0%; W3 = 87:5%; W4 = 100:0%. Although the crop production depends on the availability of water in the soil, there is a limit for the total yield. The water levels, W3 and W4, resulted in similar total accumulated evapotranspiration, while all the last three water levels, W2, W3 and W4 had close shoot dry matter masses at the end of the experiment. We showed that is possible to nd an optimal level of crop production with a rational use of the available water resources.