scholarly journals Effect of Trinexapac-Ethyl, at Two Application Timings, on the Initial Development of Eucalyptus under Water Deficit

2019 ◽  
Vol 37 ◽  
Author(s):  
A.L. BACHA ◽  
P.F.R.B. MARTINS ◽  
P.L.C.A. ALVES ◽  
R.C. PAULA

ABSTRACT: Eucalyptus plants are sensitive to stress during their initial development, and water deficit is the most important one. Thus, the hormetic effect caused by the application of chemical products may be a factor that allows plants to tolerate such stresses. The objective of this study was to evaluate the effects of trinexapac-ethyl on the initial growth of Eucalyptus urophylla (Clone I-144), under water deficiency, at two application timings (before planting - BP; and after planting - AP). Two experiments were conducted simultaneously in a greenhouse for 74 days after planting (DAP) eucalyptus in 15 L pots. Treatments consisted of three trinexapac-ethyl doses (0.0, 30, and 60 g a.i. ha-1) and two water conditions (with and without water deficit). A complete randomized block design was used, in a 3 x 2 factorial arrangement, with five replications. At the BP application timing, trinexapac-ethyl was sprayed at 0 DAP, and at the AP timing, at 24 DAP. In both experiments, plant height, diameter, leaf area, dry matter, total relative chlorophyll content and gas-exchange were evaluated. There was a positive effect for the net CO2 assimilation rate at 27 and 40 DAP, for AP and BP, respectively. Eucalyptus plants, without water deficit, presented higher growth, regardless of the application timing. In conclusion, the application of trinexapac-ethyl before planting caused a positive effect on the height and diameter of eucalyptus; and the application timing influenced, in different ways, the evaluated characteristics, not having harmful effects on any of them.

2019 ◽  
Vol 32 (2) ◽  
pp. 318-328 ◽  
Author(s):  
MURILO MEIRA SOARES ◽  
CLÁUDIA DAIANNY MELO FREITAS ◽  
FERNANDO SARMENTO DE OLIVEIRA ◽  
HÉLIDA CAMPOS DE MESQUITA ◽  
TATIANE SEVERO SILVA ◽  
...  

ABSTRACT In the agricultural environment, the occurrence of biotic and abiotic stresses, such as weed interference and soil water deficit is common. However, little is known about the effects of the interaction of these stresses on the growth of cultivated crops and weed species. Thus, the objective of this study was to evaluate the effects of competition and water deficiency on the growth of sunflowers and weeds. The experiment was performed in a randomized block design with four replications. The treatments were arranged in a 5 × 2 factorial design, with the first factor corresponding to the competition arrangements between the species (sunflower + Waltheria indica; sunflower + Amaranthus spinosus; and sunflower, W. indica, and A. spinosus in monoculture without competition) and the second factor corresponding to water regimes (irrigated and water deficit). The water deficit regime was established when the sunflower plants had six expanded leaves (V6 stage) and was maintained until the rate of CO2 assimilation of the plants reached values close to zero (6 days), after which irrigation was resumed and maintained until 40 days after emergence, when the plants were collected and evaluated. The growth components evaluated were plant height, leaf area, dry leaf mass, dry stem mass, dry root mass, and total dry mass. Competition between plants decreased sunflower, W. indica, and A. spinosus growth. W. indica and A. spinosus aggravated the negative effects of water deficiency on sunflower growth. The water deficit regime did not affect the growth of W. indica. A. spinosus was more competitive with the sunflower than was W. indica.


2022 ◽  
Vol 43 (2) ◽  
pp. 751-774
Author(s):  
Francisco Thiago Coelho Bezerra ◽  
◽  
Marlene Alexandrina Ferreira Bezerra ◽  
Raiff Ramos Almeida Nascimento ◽  
Walter Esfrain Pereira ◽  
...  

Salinity interferes in the physiology of seedlings from germination and seedling emergence, so it is necessary to adopt measures to mitigate its effects. The objectives of this research were to evaluate irrigation frequency, saline water, polymer, and container volume in the emergence and physiology of Talisia esculenta (A. St.-Hil.) Radlk. The treatments were obtained from the combination of polymer doses (0.0; 0.2; 0.6; 1.0; and 1.2 g dm-3), electrical conductivities of the irrigation water (0.3; 1, 1; 2.7; 4.3; and 5.0 dS m-1), and irrigation frequencies (daily and alternate), plus two additional treatments to assess the volume of the container. A randomized block design was used. Emergence and leaf indices of chlorophyll, fluorescence, and gas exchange were analyzed 100 days after sowing. The increase in electrical conductivity reduced and delayed seedling emergence. Decreasing irrigation frequency reduced the chlorophyll b index, stomatal conductance, transpiration, net CO2 assimilation, and carboxylation efficiency. The magnitude of the effects of electrical conductivity of water and polymer were associated with the frequency of irrigation. However, both salinity and polymer reduced practically all physiological variables. The reduction in container volume also affected the physiology of the seedlings, with more effects when irrigated on alternate days. The T. esculenta seedlings are considered sensitive to salinity, should be irrigated daily with water with less electrical conductivity than 1.0 dS m-1, as well as higher capacity containers used (0.75 vs 1.30 dm3).


2018 ◽  
Vol 53 (1) ◽  
pp. 10-21
Author(s):  
Gisele Pereira Domiciano ◽  
Adilson Kenji Kobayashi ◽  
Hugo Bruno Correa Molinari ◽  
Bruno Galveas Laviola ◽  
Alexandre Alonso Alves

Abstract: The objective of this work was to evaluate physiological processes in contrasting physic nut (Jatropha curcas) genotypes during the flowering and fruiting stages. Gas exchange parameters were measured using an infrared gas analyzer, and morphological traits were evaluated during each stage under natural conditions, in a randomized complete block design with five replicates. Differences in yield between J. curcas accessions were not related to photosynthetic performance, but rather to the number of inflorescences and female flowers, which are genetically determined. Moreover, the net CO2 assimilation was equivalent in both genotypes, although they produced different amount of fruit. The genotypes differed consistently in terms of carboxylation efficiency and ribulose bisphosphate regeneration. Finally, J. curcas branch growth is not impaired by the increased sink strength during fruiting, and fruit may have been actually exerting a positive effect on the net CO2 assimilation, which may have enabled plants to maintain growth while producing flowers and fruits.


Author(s):  
Amanda Cristina Esteves Amaro ◽  
Essione Ribeiro Souza ◽  
Laíse Sousa Santos ◽  
Daniel Baron ◽  
Elizabeth Orika Ono ◽  
...  

We hypothesized that phytohormones and essential mineral nutrients influence the duration of leaf photosynthetic activity, fruit production and quality. We used a randomized block design, with four treatments and six replicates. Two commercial products were studied: Stimulate® (Stim), which is composed of a mixture of 0.009% cytokinin [N6-furfuryladenine or kinetin (Kt)], 0.005% auxin [4-indole-3-butyric acid (IBA)], and 0.005% gibberellin [gibberellic acid (GA3)], and Hold® (CoMo), which is composed of 2% cobalt and 3% molybdenum. These products were applied alone or in combination at different concentrations as follows: T1 - control, T2 - 1.8 L ha-1 Stim, T3 - 1.8 L ha-1 Stim + 1.0 L ha-1 CoMo, and T4 - 1.8 L h-1 Stim + 1.5 L ha-1 CoMo. The treatments were applied via foliar spraying at three phases: the inflorescence primordial stage (19 days after pruning [DAP]), the point at which the berries were 6 to 8 mm in diameter (49 DAP), and the initiation of berry elongation (56 DAP). We revealed that in semiarid conditions, the grapevines were characterized by evergreen leaves (do not lose their leaves) that maintained their photosynthetic capacity throughout their lifecycles (133 days after sprouting). The application of Stim alone (T2) yielded the maximal net CO2 assimilation rates and increased the carboxylation efficiencies, which indicated that this treatment might improve the photosynthetic output. These effects led to increases in the average mass, total length and width of the clusters per plant and decreased acidity level. Thus, we recommend the application of T2 for grapevines.


2006 ◽  
Vol 18 (3) ◽  
pp. 407-411 ◽  
Author(s):  
Mauro G. dos Santos ◽  
Rafael V. Ribeiro ◽  
Marcelo G. Teixeira ◽  
Ricardo F. de Oliveira ◽  
Carlos Pimentel

Two common bean cultivars were grown in pots under greenhouse conditions. Plants were submitted to a foliar Pi spray two days before suspending irrigation, what enhanced net CO2 assimilation rate of Ouro Negro cultivar but did not change significantly the photosynthesis of Carioca cultivar under both water deficit and rehydration periods. The results revealed that a foliar Pi spray induced an up-regulation of photosynthesis in common bean under mild water deficit, with this effect being genotype-dependent.


Agronomy ◽  
2018 ◽  
Vol 8 (7) ◽  
pp. 122 ◽  
Author(s):  
Amanda Moreira Lopes ◽  
Pedro Schumacher ◽  
Aurora Terylene Pérez Martínez ◽  
Antônio Paulino da Costa Netto ◽  
Antonio Chalfun-Junior

Achieving high yields is a challenge for sugarcane producers due to the diverse environmental conditions to which the crop is subjected. In tropical and subtropical regions, where sugarcane is typically cultivated, crop diseases are common. This necessitates the development of disease management techniques. Among these techniques, chemical control is of particular significance due to the development of new antifungal agents, such as pyraclostrobin. For some crops, pyraclostrobin has a positive influence on yield due to its effects on plant physiology. The aim of this study was to evaluate the physiological responses and yield of three sugarcane cultivars treated with the fungicide, pyraclostrobin. The experiment was performed in a randomized block design (RBD) with a split-plot arrangement; the variables analyzed were the application or non-application of fungicide in the plots and, in the subplots, the evaluation times after fungicide application. Both the rate of photosynthesis and the antioxidant enzyme (Superoxide Dismutase, Catalase and Ascorbate Peroxidades) activity increased in plants treated with fungicide in comparison to untreated plants, and in the RB855156 cultivar the stomatal conductance, transpiration, and nocturnal respiratory rate were increased. Furthermore, application of pyraclostrobin increased stalk yield and the green biomass index in the RB855156 and RB86751 sugarcane cultivars. In certain cultivars of sugarcane, application of pyraclostrobin leads to an increased yield.


2012 ◽  
Vol 36 (5) ◽  
pp. 951-960
Author(s):  
Paulo Sérgio Lima e Silva ◽  
Alexandre Emanuel Régis Holanda ◽  
Haroldo Nogueira de Paiva ◽  
Fábio Henrique Tavares de Oliveira ◽  
Odaci Fernandes de Oliveira

Planting densities influence several aspects of forest formation, including management practices, timber yield, quality, and extraction, and consequently its production costs. The objective of this study was to evaluate Mimosa caesalpiinifolia and Gliricidia sepium growth as a function of planting density (400, 600, 800, 1000, and 1200 plants ha-1) and plant age. The species were evaluated every 90 days for plant height (PH), crown diameter (CD) and root collar diameter (RCD) (10 cm above the ground), with the first evaluation performed at 90 days and the last at 720 days. When plants were one year of age and beyond, evaluations were conducted also for stem diameter at breast height (DBH) (1.30 m above the ground). A randomized block design with split-plots and three replicates was adopted. Species were assigned to plots, planting densities were assigned to subplots, and evaluation ages were assigned to subsubplots. The four traits in both species had their values decreased as planting density increased, but continually increased as plant age increased. For PH and RCD there was an alternation between species superiority, with gliricidia being superior to sabiá at some ages, while the opposite occurred at other ages. As to CD the species only differed in the last measurement, gliricidia being superior. With regard to DBH, gliricidia was superior starting from the second measurement. There was an effect of the species × ages interaction for the four traits and also an effect of the densities × ages interaction for CD and DBH.


Irriga ◽  
2017 ◽  
Vol 22 (2) ◽  
pp. 288-300 ◽  
Author(s):  
Henrique Fonseca Elias de Oliveira ◽  
Cléber Luiz De Souza ◽  
Danilo Vieira Félix ◽  
Leandro Da Silva Fernandes ◽  
Polliany Santos Xavier ◽  
...  

DESENVOLVIMENTO INICIAL DE MUDAS DE BARUZEIRO (Dipteryx alata Vog) EM FUNÇÃO DE SUSBTRATOS E LÂMINAS DE IRRIGAÇÃO  HENRIQUE FONSECA ELIAS DE OLIVEIRA1; CLÉBER LUIZ DE SOUZA2; DANILO VIEIRA FÉLIX2; LEANDRO DA SILVA FERNANDES2; POLLIANY SANTOS XAVIER2 E LUCAS MAGALHÃES ALVES2 1Eng. Agrícola, Doutor, Instituto Federal Goiano, GO 154, km 03, CEP 76300-000, Ceres – GO, e-mail: [email protected]ônomo (a), Instituto Federal Goiano, GO 154, km 03, CEP 76300-000, Ceres – GO, e-mail: [email protected], [email protected], [email protected], [email protected], [email protected]  1 RESUMO O presente estudo objetivou avaliar o crescimento inicial de plantas de baruzeiro, sob substratos e lâminas de irrigação e identificar o manejo que resulte em condições ideais para a produção de mudas desta espécie. Foi implantado um experimento no delineamento em blocos ao acaso, com quatro repetições, em parcelas subdivididas no esquema 5 x 4, sendo as parcelas compostas por lâminas de irrigação diárias (6, 8, 10, 12 e 14 mm) e as subparcelas substratos: S1 - 100% Latossolo vermelho; S2 - 50% Latossolo vermelho e 50% Areia; S3 - 45% Latossolo vermelho, 45% Areia e 10% Esterco Bovino Curtido e S4 - Substrato comercial Basaplant®. As características avaliadas foram altura de planta, diâmetro de caule, número de folíolos, comprimento de raiz, massa seca de raiz, massa seca de parte aérea, massa seca de muda, relação das massas secas de raiz e parte aérea e índice de qualidade de Dickson. Aos 200 dias após a semeadura (DAS) o substrato S1 proporcionou maior crescimento e qualidade às plantas de baruzeiro, dado pelo Índice de Qualidade de Dickson (IQD) obtido de 1,05, assim como a lâmina de 14 mm dia-1, a qual obteve IQD igual 0,98, diferindo estatisticamente das demais lâminas avaliadas. Palavras-chave: gotejamento, características produtivas, Índice de Qualidade de Dickson.  OLIVEIRA, H. F. E.; SOUZA, C. L.; FÉLIX, D. V.; FERNANDES L. S.; XAVIER, P. S.; ALVES, L. M.INITIAL DEVELOPMENT OF BARUZEIRO (Dipteryx alata Vog) SEEDLING AS FUNCTION OF SUBSTRATES AND IRRIGATIONS LEVELS  2 ABSTRACT This study aimed to evaluate the initial growth of baruzeiro plants, under substrates and irrigation levels and identify the management that results in ideal conditions for the production of seedlings of this species. The experiment was installed in a randomized block design, with four replications, in split-plot, in the scheme 4 x 5, with plots composed of five daily irrigations levels and four subplots substrates: S1 - 100% OXISOL RED; S2 - 50% OXISOL RED and 50% sand; S3 - 45% OXISOL RED, 45% sand, and 10% of tanned manure and S4 - Commercial Substrate Basaplant. The five daily watering (6, 8, 10, 12 and 14 mm) make up the subplot. The characteristics assessed were plant height, stem diameter, number of leaflets, root system length, dry matter mass of roots, dry matter mass of aerial portion, dry matter  mass of seedling, ratio between roots dry matter mass and aerial portion and seedling quality. At 200 DAS substrate S1 provided greater growth and quality to baruzeiro plants, given by the Dickson Quality Index (DQI) obtained of 1.05, as well as the irrigation depth of 14 mm day-1, once it obtained DQI equal to 0.98, statistically differing from the other irrigation depths assessed. Keywords: drip irrigation, productive characteristics, Dickson Quality Index.


2020 ◽  
Vol 1 (1) ◽  
pp. 21
Author(s):  
Dentin Queentiara Moelyaandani ◽  
S Setiyono

Sugarcane (Sacharum officinarum L.) is a sugar-producing plant and is a food commodity that is needed by the people of Indonesia. National sugar demands are increasing every year. The low productivity of sugarcane is due to the competition of weeds which can reduce sugarcane production. To achieve high productivity, it is necessary to pay attention to the varieties used because they require certain conditions in their management. The purpose of this study was to determine the effect of varieties and types of weeds on the initial growth of sugarcane. The study was conducted from September 2018 to December 2018. The study used factorial Randomized Block Design (RBD) with two factors and four replications. The first factor consists of 4 sugarcane varieties, namely: Bululawang (V1), Red HW (V2), VMC (V3) and PS 862 (V4). The second factor type of weed consists of 2 types, namely Cyperus rotundus (N1) and Amaranthus spinosus L. (N2). The results showed that (1) There was interaction between the varieties (V) and the weed types (N) in stem diameter parameters and number of tillers, the treatment V4N1 gives the best response to stem diameter 1,31 cm and 4,25 number of tillers; (2) The treatment of varieties (V) gives affects to stem diameter and number of leaves, the treatment V4 gives the best response 5,38 to number of leaves; (3) Types of thorn spinach weeds can reduce the initial growth of sugarcane. Keywords: Varieties; weed; sugarcane


2020 ◽  
Vol 33 (1) ◽  
pp. 184-194
Author(s):  
GEOVANI SOARES DE LIMA ◽  
COSMO GUSTAVO JACOME FERNANDES ◽  
LAURIANE ALMEIDA DOS ANJOS SOARES ◽  
HANS RAJ GHEYI ◽  
PEDRO DANTAS FERNANDES

ABSTRACT The objective of this study was to evaluate the gas exchange, chloroplast pigments and growth of ‘BRS Rubi do Cerrado’ passion fruit as a function of irrigation with saline water and potassium fertilization in the seedling formation stage. The experiment was conducted under greenhouse conditions in the municipality of Pombal-PB, Brazil. A randomized block design was used in 5 x 2 factorial scheme, corresponding to five levels of water electrical conductivity - ECw (0.3, 1.1, 1.9, 2.7 and 3.5 dS m-1) and two doses of potassium - KD (50 and 100% of the recommendation), with four replicates and two plants per plot. Water salinity from 0.3 dS m-1 reduced the stomatal opening, transpiration, CO2 assimilation and inhibited the growth of ‘BRS Rubi do Cerrado’ passion fruit plants, at 40 days after sowing. There was no CO2 restriction in the substomatal cavity of passion fruit plants grown under water salinity from 0.3 dS m-1. Potassium dose of 150 mg kg-1 of soil, corresponding to 100%, intensified the effect of salt stress on the assimilation rate and instantaneous carboxylation efficiency in 'BRS Rubi do Cerrado' passion fruit. There was interaction between water salinity levels and potassium doses for the chlorophyll a and b contents of 'BRS Rubi do Cerrado' passion fruit.


Sign in / Sign up

Export Citation Format

Share Document