Moadir de Sousa Leite

Classification of Sorghum bicolor (L.) Moench Seed Vigor by Respiratory Activity

Seeds are one of the main inputs used in agriculture, and their quality is directly related to the success of the field crop. Thus, seed companies increasingly need to obtain fast and reliable seed quality results, making it easier to make decisions regarding the use of seed batches. In this sense, the objective was to evaluate the CO2 measurement efficiency in the classification of S. bicolor seed vigor. For this, six batches of cv. Ponta Negra seeds were used, from different national producers. The physiological quality of the seeds was evaluated by means of the following tests: germination, first germination count, germination speed index, accelerated aging, total dry matter of seedlings, electrical conductivity and respiratory activity. The experimental design was completely randomized, with four replications. The Pearson correlation coefficient between the respiratory activity and the germination and vigor tests was determined. The respiratory activity test on S. bicolor seeds was shown to be promising for the identification of differences in vigor between seed batches.

The use of saline aquaculture effluent for production of Enterolobium contortisiliquum seedlings

The use of aquaculture effluent for irrigation of field crops has been suggested as the most appropriate biological method for treatment of this effluent. However, using it for irrigation of tree species in seedling nurseries might be a better alternative to avoid soil salinization and groundwater contamination in agricultural fields. This paper aimed at assessing the production of Enterolobium contortisiliquum seedlings under irrigation with saline aquaculture effluent. The experiment was carried out in a randomized complete block design with four replicates and four seedlings per experimental unit. Each replicate was daily irrigated with five solutions containing different concentrations of saline aquaculture effluent diluted with freshwater (0, 25, 50, 75 and 100% effluent). Despite increasing substrate salinity, the dilution of saline aquaculture effluent in the irrigation water promoted greater shoot growth and higher total dry weight in E. contortisiliquum. Moreover, seedlings treated with low concentrations of this effluent increased their leaf area expansion and chlorophyll content. Therefore, the use of solutions containing 25 and 50% effluent allowed the production of high-quality seedlings. These results suggest that saline aquaculture effluent can be reused to irrigate tree species, enabling a successful integration of aquaculture and agriculture and reducing environmental impacts of improper effluent disposal.

PRODUÇÃO DE MUDAS DE Enterolobium contortisiliquum E PARTIÇÃO DE ASSIMILADOS EM RESPOSTA À ADUBAÇÃO FOSFATADA E INOCULAÇÃO COM FUNGOS MICORRÍZICOS

This study aimed to evaluate the production of Enterolobium contortisiliquum (Vell.) Morong seedlings and assimilate partitioning under different levels of phosphorus, in the presence and absence of arbuscular mycorrhizal fungi. The experiment was conducted in randomized blocks in a 5x2 factorial design, with four replications represented by three plants each. The first factor consisted of P levels (0, 50, 100, 150 and 200 mg.Kg soil -1 ), using superphosphate fertilizer (P 2 O 5 ) as the phosphorus source. The second factor consisted of the presence or absence of arbuscular mycorrhizal fungi. At 98 days after sowing (DAS), plants were evaluated by non-destructive assessments of shoot height (APA), leaf number (NF) and stem diameter (DC). Then, chlorophyll content index (ICC), leaf dry matter (MSF), stem dry matter (MSC), shoot dry matter (MSPA) and root dry matter (MSR) analyses were conducted. Leaf area (AF), leaf weight ratio (RPF), specific leaf area (AFE), Dickson quality index (IQD) and shoot/root dry matter ratio (MSPA/R) were also determined. The P level of 100 mg.Kg -1 proved to be the most efficient one for the production of Enterolobium contortisiliquum seedlings in Mossoro, Rio Grande do Norte state, with no benefits in the use of mycorrhizal fungi until 98 DAS, promoting photoassimilate distribution between the organs of young seedlings favorable to the establishment in the field.