Ronaldo do Nascimento

Clorofila e carotenoides em maracujazeiro-amarelo irrigado com águas salinas no solo com biofertilizante bovino

The deleterious effects caused by salt stress result in changes in the physiological and biochemical mechanisms of plants, changing, among others, the levels of chlorophyll and carotenoids, affecting the photosynthetic activity and hence growth, development, production and adaptability to adverse environments. The study aimed to evaluate the effects of irrigation water with increasing salinity levels and the application frequency of biofertilizer on the concentration of the photosynthetic pigments (chlorophyll a, b, total and carotenoids) of the yellow passion fruit. The experiment was designed in a 5 x 4 factorial corresponding to the levels of electrical conductivity (EC) of the irrigation water of 0.5; 1.5; 2.5; 3.5 and 4.5 dS m-1 and to four frequencies of the application of bovine biofertilizer: no biofertilizer (WB); application of bovine biofertilizer one week before transplanting (1WBT); bio-fertilizer application every 90 days after transplanting (90DAT); and bovine bio-fertilizer applied one week before and every 90 days after transplanting (1WBT+90DAT). Increased salinity of irrigation water reduced the photosynthetic efficiency in leaves of yellow passion fruit, being more drastic in the conductivity above 2.5 dS m-1. The frequency of application of biofertilizer did not influence the photosynthetic pigments content.

Fisiologia e produção de algodoeiro naturalmente colorido submetido a estratégias de irrigação com água salinizada

The objective of this work was to evaluate the effects of irrigation management strategies, using low (0.8 dS m-1) and high (9.0 dS m-1) salinity water, on the physiological processes, production variables, and fiber productivity of naturally-colored cotton (Gossypium hirsutum) genotypes during different phenological stages. Three naturally-colored cotton cultivars (BRS Rubi, BRS Topázio, and BRS Safira) were subjected to seven irrigation management strategies, in a 3x7 factorial arrangement, in a randomized complete block design with three replicates. Plants were cultivated in pots in a protected environment. Gas exchange, chlorophyll a fluorescence, fiber production, and productivity and yield variables were evaluated. Salt stress causes greater reductions in gas exchange in natural cotton plants during the production stage. Plume cotton production is not compromised by the use of highly salinized water during the initial developmental stages of naturallycolored cotton.

ACÚMULO DE FITOMASSA DE CULTIVARES DE ALFACE HIDROPÔNICA SUBMETIDAS À SALINIDADE

O objetivo deste estudo foi avaliar os efeitos de diferentes niveis de salinidade na acumulacao de fitomassa de duas cultivares de alface sob cultivo hidroponico. O experimento foi realizado em um ambiente protegido na Universidade Federal de Campina Grande (UFCG), Campus I, durante o periodo 01 a 22 de setembro de 2016. O delineamento experimental foi inteiramente casualizado (DIC), em esquema fatorial 2x4, duas variedades de alface, Valentina (C1) e Alcione (C2) e quatro niveis de condutividade eletrica da solucao nutritiva (CESN) (1,6, 3,6, 5,6 e 7,6 dS m-1), totalizando 8 tratamentos com 3 repeticoes cada, resultando em 24 unidades experimentais. As variaveis analisadas foram o numero de folhas, fitomassa fresca e seca de folhas, caule e raizes, e fitomassa total da parte aerea. Observou-se que as variaveis fitomassa fresca das folhas e do caule, e fitomassa seca das folhas foram significativamente afetadas pelos niveis de salinidade, apenas a fitomassa seca das folhas e a fitomassa fresca das raizes diferiram entre as cultivares. O ponto de maxima producao de materia fresca das folhas foi observado na CESN de 3,5 dS m-1, o acumulo de fitomassa decresceu 31,48% para CESN de 7,6 dS m-1. Houve interacao entre os fatores apenas para a massa seca da folha.

Vigor and tolerance of cowpea (Vigna unguiculata) genotypes under salt stress

Saline stress is a frequent phenomenon in the arid and semi-arid regions of the globe, affecting the agricultural production of these regions, and it is necessary to use strategies that minimize the impacts of saline stress under agriculture. This requires the incorporation of species, variety and genotypes tolerant to increase agricultural production in those regions. This study aimed to evaluate germination and initial growth of cowpea genotypes under salt stress. The experimental design was completely randomized in 19 x 3 factorial scheme, composed of nineteen cowpea cultivars and three osmotic potentials, with four replicates of 50 seeds each. The germination test lasted for eight days, when the seeds were evaluated for germination percentage, germination speed index, length of shoot and root, accumulation of dry mass of shoot and root. The increase in salinity affected germination and initial growth of the cowpea genotypes. The genotypes 6 MNCO2-689F-2-8, 10 MNCO2-675F-4-10, 12 MNCO3-737F-5-9, 16 MNCO2-677F-2, 18 BRS-Pajeú and 19 – Paulistinha exhibited higher tolerance to salt stress in the stage of germination and initial growth. The genotypes 11 MNCO2-675F-9-5, 13 BRS-Tumucumaque, 15 MNCO3-736F-7 and 17 BR17-Gurgueia were more susceptible to the effects of salt stress in the stage of germination and initial growth.