Gas exchange rates, plant height, yield components, and productivity of upland rice as affected by plant regulators

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Rooting of healthy and CVC-affected 'Valência' sweet orange stem cuttings, through the use of plant regulators

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Effects of plant regulators and potassium nitrate, on Rangpur lime seeds germination

The effects of plant regulators and potassium nitrate were studied on 'Rangpur' lime (Citrus limonia Osbeck) seeds germination. The seeds were removed from ripe fruits, washed, dried and stored at 4 - 5 degrees C, and treated for 24 hours before sowing and the treatments were: KNO3 0,1% and 0,2%; GA(3) 50 ppm, 100 ppm and 250 ppm; GA(4+7)+phenylmethylaminepurine 100 ppm; phenylmethylaminepurine 20 ppm and control. The germination was evaluated begining 13 days after sowing. Best results were obtained with KNO3 0,2%, which proved most beneficial in enhancing percentage and germination rate.

Plant regulators on vegetative growth of 'Tommy Atkins' mangoes

Paclobutrazol applied to the soil is used for the production management of mango in most of orchards on the semiarid region. However, it is necessary to identify other plant growth regulators that might be applied to the leaves, so as to minimize the risk of residues in the soil and plant. The present paper has the purpose to evaluate the effect of plant regulators in the management of vegetative growth on mangoes 'Tommy Atkins'. Three plant growth regulators, sprayed to the leaves, were evaluated: prohexadione-Ca, ethyl-trinexapac and chlormequat chloride, applied in two dosages, and compared to paclobutrazol applied to the soil. In order to compare the effects of the treatment, data were recorded on the vegetative growth (number and length of the shoots). Furthermore, the levels of gibberellins in the apical area of the shoots of 'Tommy Atkins' were quantified, from the beginning of the experiment until the beginning of floral induction. The results showed that sprayings with prohexadione-Ca, trinexapac-ethyl and chlormequat chloride in a dosage of 1.5 g a.i. plant-1 plant was as efficient as a dose of 4.0 g a.i. plant-1 of paclobutrazol applied to the soil, regarding the regulation of vegetative growth of 'Tommy Atkins'. © ISHS 2013.

Effect of plant regulators on growth and flowering of 'Meyer' zoysiagrass

This trial aimed to evaluate the effect of sequential applications of different plant regulators over growth and flower rachis emission of 'Meyer' zoysiagrass (Zoysia japonica). The study was conducted on 15-month old green turfgrass under a randomized complete block design with four replications. The following plant regulator and doses were tested: trinexapac-ethyl (113+113, 226+113, 226+226, 452+113, 452+226, 452+452, 678+339 e 904+452 g a.i./ha-1), prohexadione-calcium (100+100 e 200+200 g a.i. ha-1) and bispyribac-sodium (40+40 e 60+60 g a.i. ha-1), as well as an untreated control. The turfgrass was mowed again at 3.0 cm aboveground and the second plant regulator was applied when 'Meyer' zoysiagrass was between 5.0 and 6.0 cm high. The effect of the treatments was visually rated for visual injury, plant height, height and number of flower rachis, and total dry mass production of clippings. Only bispyribac-sodium had visual symptoms of injury on 'Meyer' zoysiagrass, and no intoxication was observed at 28 days after the second application (DAAB). The sequential applications of trinexapac-ethyl, prohexadione-calcium and bispyribac-sodium reduced by more than 80% the total clipping dry mass produced by 'Meyer' zoysiagrass. All the plant regulators tested also showed promising results in reducing the height and emission of rachis, especially when trinexapac-ethyl was applied at the doses 452+452, 678+339 and 904+452 g a.i. ha-1. 'Meyer' zoysiagrass turfgrass can be handled with the sequential application of a plant regulator, which reduces the need for mowing over a period up to 110 days after the application of the second plant regulator, and it also avoids deleterious visual effects over turfgrass.

Effects of plant regulators on the growth and flowering of Saint Augustine grass plants

The objective of this work was to evaluate the effects of three plant growth inhibitors on the development and emission of floral rachis of Saint Augustine grass [Stenotaphrum secundatum (Walt.) Kuntzel] plants. The study was carried out in a 15 month old lawn with the experimental plots being distributed in accordance with a complete randomized block design with four replications. The treatments consisted of sole application of trinexapac-ethyl (113, 226, 452, 678, and 904 g ai ha(-1)), prohexadione-calcium (100 and 200 g ai ha(-1)), and bispyribac-sodium (40 and 60 g ai ha(-1)) plus a check treatment in which the plants were not submitted to any of the plant growth inhibitors. The effects of those products were evaluated in terms of visual signs of plant intoxication, plant height, emission and height of floral rachises, and chip total dry matter production. All the plant growth inhibitors resulted in visible injury to the plants but these intoxication signs practically disappeared 28 days after the application. Trinexapac-ethyl at the dose of 904 g ai ha(-1) reduced plant height by 59.7%, the emission of floral rachis by 96.4%, and the amount of chip dry matter production by 87.7%. Plant growth inhibitors may reduce the number of times of lawn plants cutting up to 119 days after their application with no harmful effects on the plants visual aspect.

Efeito de giberelina (GA3) e do bioestimulante 'Stimulate' na indução floral e produtividade do maracujazeiro-amarelo em condições de safra normal

O objetivo do trabalho foi avaliar os efeitos de GA3, nas concentrações de 100; 200 e 300mg L-1 e do bioestimulante Stimulate®, em doses de 2,08; 4,17 e 6,25mL L-1, em duas aplicações via foliar, acrescidas de espalhante adesivo Silwett® a 0,05% e a exposição dos ramos à luminosidade, na indução floral e produtividade do maracujazeiro-amarelo, em condições de safra normal, em Araguari-MG. Aos 30 dias após a primeira aplicação dos tratamentos, iniciaram-se as avaliações do número de flores, com contagens diárias, nos dois lados da espaldeira, nos meses de setembro de 2002 a março de 2003. As colheitas dos frutos foram realizadas semanalmente, no período de novembro de 2002 a abril de 2003, observando-se a produção. O GA3 e o Stimulate não proporcionaram efeito significativo no número de flores, nas sete épocas, assim como no número total de flores. Não houve efeito dos tratamentos para a produtividade e produção total de frutos. Os ramos sob luminosidade pela tarde apresentaram maior número de flores, nos meses de setembro, dezembro, fevereiro e março. A interação entre os tratamentos e a exposição dos ramos à luminosidade não foi significativa para o número de flores, nas épocas avaliadas.

Qualidade tecnológica da cana-de-açúcar em função da aplicação de maturadores em meio de safra

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Reguladores vegetais e atividade de invertases em cana-de-açúcar em meio de safra

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Crescimento aéreo e radicular de arroz de terras altas em função da adubação fosfatada e bioestimulante

The use of plant regulators that stimulate root growth can increase phosphorus uptake by upland rice. The objective of this study was to evaluate shoot and root growth of upland rice fertilized with different phosphorus doses with and without biostimulant. The experiment was carried out in greenhouse in the Faculdade de Ciencias Agronomicas-UNESP, in Botucatu-SP. The treatments consisted of six phosphorus doses applied in sowing (0, 12,5, 25, 50, 100 and 200 mg dm(-3)), with and without Stimulate (R) applied in the seeds (cv. Primavera). The plants were grown for 78 days and then cut at soil level to evaluate leaf area and leaves and collar dry matter. Root samples that were harvested on the same day had their root diameter and dry matter evaluated. The experimental design was the completely randomized, with three replications, arranged as a factorial 2x6. Variance analysis and regression were used to data evaluation. Linear and quadratic equations were adjusted at a probability level of 5%, using those with higher determination coefficient (R(2)). The increase on the phosphorus dose contributed to the lower matter production and leaf area of the plants when the biostimulant was applied. For shoot phosphorus accumulation and root evaluations, the same behavior was observed. It was concluded that the use of Stimulate (R) in seeds, for fitomass production or root system evaluation, was only efficient in low phosphorus doses.

Influência do etil-trinexapac no acúmulo, na distribuição de nitrogênio (15N) e na massa de grãos de arroz de terras altas

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Reguladores vegetais no desenvolvimento e produtividade da cana-de-açúcar

O objetivo deste trabalho foi avaliar o desenvolvimento e a produtividade de colmos de cana-de-açúcar, resultantes da aplicação de reguladores vegetais no iníco da safra. Ostratamentos consistiram na aplicação de três reguladores vegetais inibidores de crescimento - sulfometuron metil, glifosato e compostos de radicais carboxílicos orgânicos + glifosato - e na maturação natural como testemunha, em delineamento experimental em blocos ao acaso, com cinco repetições. Os maturadores retardam o processo de crescimento em altura das plantas, sem afetar o número e o diâmetro de colmos na colheita, e influenciam de forma e intensidade distintas a ocorrência do florescimento e chochamento. O glifosato proporciona elevados índices de brotação lateral e prejudica a rebrota da soqueira. Os maturadores induzem o aumento do teor de açúcares redutores totais, o que contribui para a melhoria da qualidade tecnológica da cana-de-açúcar.

Enraizamento de estacas semilenhosas de lichieira utilizando ácido indolbutírico

O objetivo deste trabalho foi estudar o enraizamento de estacas semilenhosas de lichieira ( Litchi chinensis Sonn.) da cultivar Bengal, empregando ácido indolbutírico (AIB) e sistema de nebulização intermitente. As estacas apicais foram coletadas nos meses de outubro (Primavera), janeiro (Verão) e abril (Outono), acondicionadas adequadamente e transferidas para uma estufa com nebulização intermitente, onde receberam as aplicações de : 0; 1.000; 2.000; 3.000 e 4.000 mg L-1 de AIB, com imersão da base das estacas, durante 10 segundos, e de 200 mg L-1 de AIB, com imersão das bases por 24 horas, em aeração. em seguida, foram colocadas para enraizar em substrato de vermiculita, com casca de arroz carbonizada, na proporção de 1:1. Após 100 dias, foram obtidos os dados referentes à porcentagem de estacas vivas com folhas, porcentagem de estacas enraizadas por parcela, comprimento médio de raiz por estaca enraizada (cm), número médio de raízes formadas por estaca enraizada, massa média da matéria fresca das raízes (g), massa média da matéria seca das raízes(g). Pelos resultados, concluiu-se que não há necessidade da aplicação do AIB para o enraizamento de estacas de lichieira, cultivar Bengal, e que a melhor época de coleta das mesmas é o verão.

Desenvolvimento e produtividade da cana-de-açúcar após aplicação de reguladores vegetais em meio de safra

The supply of technological quality raw material for providing economical return is the most important necessity of sugar and alcohol industry. The objective of this work was to evaluate the development and productivity of sugarcane stalks due to plant regulators application at half crop. The experiment was carried out in a randomized block design with five replications. The treatments consisted of four plant regulators of the class of the growth retainers (Ethephon, Ehyl-trinexapac, Potassium nitrate, Potassium nitrate + Boron) application and a control (natural ripening). Ethyl-trinexapac and Ethephon treatments were efficient to hold up growth process regarding height of plants, but had no effect on diameter of stalks. The maintenance of bud top integrity made possible the increase in diameter of stalks, without interrupting the growth process regarding height of plants. According to application time the ripeners provided improvement on technological quality of raw material. The ripeners did not affect the number of plants per meter at harvest and did not cause quantitative alterations in the mass of stalks per hectare. The ripeners did not affect the regrowth of the ratoon cane.

Cultura de embrião e indução de brotos in vitro para micropropagação do pinhão-manso

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)