) e quatro doses de bioestimulante aplicado via tratamento de sementes (0; 5; 10 e 20 mL kg -1 de sementes), com cinco repetições. Utilizou-se o bioestimulante comercial Stimulate ® (0,009% citocinina, 0,005% giberelina e 0,005% de auxina) e as plantas foram coletadas aos 50 dias após a semeadura. Foram avaliadas as seguintes variáveis: altura de plantas, diâmetro do colmo, número de folhas, área foliar, massa seca de colmo, massa seca de folhas, massa seca de raiz, massa seca de pendão, massa seca total e área foliar específica. O uso de água salina na irrigação provocou redução na maioria das variáveis de crescimento do milho doce, independentemente do tratamento de sementes com bioestimulante. O tratamento de sementes com Stimulate ® promove o desenvolvimento de plantas de milho pipoca, mais não inibiu nem amenizou o efeito da salinidade sobre as plantas. Palavras-chave: Zea mays. Fitorregulador. Qualidade da água.ABSTRACT -The use of biostimulants has become widespread in Brazilian agriculture, promoting growth and increased crop yields. However, studies on the use of these substances in plants under stress are still being developed, especially for salt stress. The aim was to evaluate the use of bio-stimulants to relieve salt stress in popcorn. The experiment was carried out in a greenhouse on the campus of the Federal Rural University of the Semi-Arid in Mossoró, in the State of Rio Grande do Norte, Brazil. A completely randomised design was used, with treatments distributed in 2 x 4 factorial scheme, representing two levels of salinity of the irrigation water (0.5 and 4.5 dS m -1 ) and four levels of biostimulant, applied by seed treatment (0, 5, 10 and 20 ml kg -1 seed), with five replications. The commercial biostimulant Stimulate® was used (0.009% cytokinin, 0.005% gibberellin and 0.005% auxin), with the plants being harvested 50 days after sowing. The following variables were evaluated: plant height, stem diameter, number of leaves, leaf area, stem dry weight, leaf dry weight, root dry weight, tassel dry weight, total dry weight and specific leaf area. The use of saline water for irrigation caused a reduction in most growth variables in the sweet corn, regardless of seed treatment with biostimulants. Seed treatment with Stimulate® promotes development in popcorn, but did not inhibit or lessen the effect of salinity on the plants.

AÇÃO DE BIOESTIMULANTE NO DESENVOLVIMENTO INICIAL DO MILHO DOCE SUBMETIDO AO ESTRESSE SALINO  RAFAELA CRISTINA DA CUNHA1; FRANCISCO DE ASSIS DE OLIVEIRA1; MARIA WILLIANE DE LIMA SOUZA1; JOSÉ FRANCISMAR DE MEDEIROS1; LUAN ALVES LIMA1; MYCHELLE KARLA TEIXEIRA DE OLIVEIRA1 1 Departamento de Ciências Ambientais e Tecnológicas, UFERSA; Avenida Francisco Mota, 572, 59625-900, Bairro Costa e Silva, Mossoró, RN, Brasil, e-mail: rafacris_dantas@hotmail.com; thikaoamigao@ufersa.edu.br; williane-lima@hotmail.com; jfmedeir@ufersa.edu.br; luanefa2@yahoo.com.br; mymykar@gmail.com  1   RESUMO A utilização de água salina na agricultura é um grande desafio para pesquisadores e agricultores, pois sua utilização está condicionada a adoção de tecnologias que minimizem o efeito do estresse salino sobre as plantas. Neste contexto, o presente trabalho foi desenvolvido com o objetivo de avaliar o uso de bioestimulante como agente amenizador do estresse salino na cultura do milho doce. O delineamento experimental utilizado foi inteiramente casualizado, em esquema fatorial 2 x 4, sendo dois níveis de salinidade da água de irrigação (0,5 e 4,5 dS m-1) e quatro doses de bioestimulante aplicado via tratamento de sementes (0, 5, 10 e 20 mL kg-1 de sementes). A avaliação das plantas foi realizada aos 45 dias após a semeadura, analisado as seguintes variáveis: altura de plantas, diâmetro do colmo, número de folhas, área foliar, massa seca de colmo, massa seca de folhas, massa seca de raiz, massa seca de pendão e massa seca total. A utilização de água salina na irrigação provocou redução na maioria das variáveis de crescimento do milho doce, sendo o efeito mais expressivo sobre o desenvolvimento foliar. O tratamento de sementes com Stimulate® promove o desenvolvimento de plantas de milho doce apenas na ausência de estresse salino, não sendo eficiente como agente atenuador do efeito da salinidade, além disto, o uso de água salina na irrigação do milho inibiu o efeito benéfico do Stimulate® no desenvolvimento do milho doce. Palavras-chave: Zea mays, fitorregulador, qualidade de água  CUNHA, R. C; OLIVEIRA, F. A.; SOUZA, M. W. L.; MEDEIROS, J. F.; LIMA, L. A.; OLIVEIRA, M. K. T.ACTION BIOSTIMULANT NO INITIAL DEVELOPMENT OF SWEET CORN UNDER SALT STRESS  2   ABSTRACT The use of saline water in agriculture is a major challenge for researchers and farmers, because its use is subject to the adoption of technologies that minimize the effect of salt stress on plants. In this context, the present work was intended to evaluate the use of plant growth regulator as softening agent of salinity stress on the sweet corn crop. The experimental design was completely randomized, factorial 2 x 4, with two salinity levels of irrigation water (0.5 and 4.5 dS m-1) and four doses of plant growth regulator applied as seed treatment (0, 5, 10 and 20 ml kg-1 seed). The evaluation of the plants was carried out 45 days after sowing, and the following variables were analyzed: plant height, stem diameter, number of leaves, leaf area, dry weight of stem, leaf dry weight, root dry weight, dry weight tassel and total dry mass. The use of saline irrigation water caused a reduction in most growth variables of sweet corn, the most significant effect being on leaf development. The seed treatment Stimulate® promotes the development of sweet corn plants only in the absence of salt stress, there being effective for diminishing the effect of salinity agent, moreover, the use of saline irrigation water in maize inhibit the beneficial effect of Stimulate® in the development of sweet corn. Keywords: Zea mays, plant regulators, water quality

ResumoO mulungu (Erythrina vellutina Willd) é uma espécie nativa que ocorre em diversas regiões do país, com potencial para uso madeireiro, arborização urbana e para recomposição de vegetação em áreas degradadas. Contudo, ainda é uma espécie pouco estudada. O presente trabalho foi desenvolvido com o objetivo de avaliar o efeito de seis concentrações de nutrientes na solução de fertirrigação (0, 25, 50, 75, 100 e 125%), dispostos em delineamento experimental inteiramente casualizado, com três repetições. Foram realizados dois experimentos independentes, sendo um para cada acesso. As mudas foram avaliadas para as seguintes variáveis: altura, diâmetro do caule, número de folhas, área foliar, massa seca da parte aérea, massa seca da raiz e massa seca total, área foliar específica, razão de área foliar, relação altura/diâmetro e índice de qualidade de Dickson. Com exceção das variáveis área foliar específica e razão de área foliar, todas as demais foram afetadas pelos tratamentos aplicados para os dois acessos. Para ambos os acessos, mudas de melhor qualidade podem ser produzidas utilizando-se fertirrigação com solução nutritiva variando de 70 a 80% da solução padrão. Palavras-chave: Erythrina vellutina Willd; viveiro florestal; nutrição mineral; índice de qualidade de Dickson. Abstract Development of seedlings mulungu fertigated with different nutrient solutions.The mulungu (Erythrina vellutina Willd) is a native species that occurs in various regions of the country, with potential for timber use, urban tree planting and restoration of vegetation in degraded areas, however, is still a little studied species. This work was to evaluate the effect of six nutrient concentrations in fertigation solution (0, 25, 50, 75, 100 and 125%), arranged in a completely randomized design with three replications. Two independent experiments were performed, one for each access. The seedlings were evaluated for the following variables: height, stem diameter, number of leaves, leaf area, shoot dry weight, root dry mass and dry mass of the total, specific leaf area, leaf area ratio, height/diameter ratio and Dickson quality index. With the exception of the variables specific leaf area and leaf area ratio, all other were affected by the treatments applied to the two hits. For both access, better quality seedlings can be produced using fertigation with nutrient solution ranging from 70 to 80% of the standard solution Keywords: Erythrina vellutina Willd; forest nursery; mineral nutrition; index of Dickson quality . INTRODUÇÃOA Caatinga é um ecossistema exclusivamente brasileiro, representando 11% do território nacional e 54% da região Nordeste (ALVES et al., 2009). Atualmente, a Caatinga vem sofrendo o efeito da antropização, em razão do desmatamento, idealizado pela prática extrativ ista, agricultura de "sequeiro" e pecuária extensiva. A combinação dessas ações antrópicas com os fenômenos naturais ligados às mudanças climáticas expõe o semiárido a u ma ameaça ainda maior, a desertificação (LEA L et al., 2005).Nesse cenário, a intervenção h...

This study aimed to evaluate lettuce production in different pot volumes and different irrigation frequency under saline stress. The experiment was carried out at the Department of Environmental and Technological Sciences of the Federal Rural University of the Semi-Arid, in Mossoró, RN, Brazil. Randomized block experimental design was used in factorial scheme of 2 × 3 × 3, with 3 replicates. Treatments were consisted of 2 water’s salinity levels (0.5 and 2.0 dS m-1), 3 frequencies of irrigation (6, 9, and 12 daily events), and 3 different pots (0.5, 1.0, and 3.0 L). Data from parameters evaluated at harvest were submitted to variance analysis and means were compared. We verified that when the lower saline water (0.5 dS m-1) was used lettuce production increased when cultivated in pots of 3.0 L and submitted to 6 daily events of irrigation. When 3.0 dS m-1 water was used the best results were obtained in 0.5 L and nine daily events of irrigation. The combination of 0.5 L pot and six or nine daily events of irrigation better inhibited the damaging effects of salinity.

The objective of this study was to evaluate the effect of a plant growth regulator (PGR; Stimulate®) on the yield and quality of zucchini fruits from plants of the cultivar Caserta-Italiana grown under different salinity levels of the irrigation water (SLIW). A randomized block design was used, in a 2 × 6 factorial arrangement consisted of two SLIW (0.5 and 5.0 dS m-1) and six PGR application modes: imbibition of seeds for 8 h in distilled water (PGR-T1; Control); imbibition of seeds for 8 h in PGR at 10 mL L-1 (PGR-T2); imbibition of seeds for 8 h in PGR at 10 mL L-1 plus foliar application at 10 mL L-1 at the flowering stage (PGR-T3); imbibition of seeds for 8 h in PGR at 10 mL L-1 plus two foliar applications at the flowering stage and at 20 and 30 days after sowing (PGR-T4); foliar application at 10 mL L-1 at the flowering stage (PGR-T5); and two foliar applications at 10 mL L-1 at 20 and 30 days after sowing (PGR-T6). The SLIW affected differently the variables of the zucchini crops evaluated. The PGR application to plants under no salt stress (0.5 dS m-1) increased the solid soluble concentration and biomass accumulation of zucchini fruits. The PGR application as seed treatment and foliar application at the flowering stage increased the fruit yield of zucchini plants irrigated with saline water.