Catingueira (Poincianella pyramidalis Tul. L. P. Queiroz) is an endemic species of the Caatinga, with great economic potential. Research on the development of this species under conditions of water restriction, common in the Northeastern semi-arid region, is still scarce. This study evaluated the effects of water restriction on the morphological and biochemical characteristics of catingueira seedlings subjected to water restriction. The experimental design was a randomized complete block design, with five treatments and four replicates. The treatments consisted of periods of water restriction (0, 6, 12, 18 and 24 days without irrigation). The characters evaluated were shoot height, leaf diameter, number of leaves, leaf area, total dry mass, ratio between shoot height and dry mass, Dickson quality index, chlorophylls a and b content, total soluble sugars and free proline. Periods of water restriction longer than six days caused damage to the seedlings development, with reduced growth and quality.

The viability of T. aurea seeds is evaluated through the germination test, taking 21 days, which makes it difficult to obtain quick information about the viability of its seeds. In this context, using the tetrazolium test as an evaluation method would be appropriate because it provides faster and more reliable information for several species. In view of the above, the objective of this study was to adapt the tetrazolium test methodology to evaluate the viability of T. aurea seeds. Initially, the imbibition curve was constructed to determine the appropriate hydration period for the seeds and the germination test was conducted, both for evaluating the initial quality and for comparison with the tetrazolium test results. For the tetrazolium test, the seeds were hydrated for 24 hours, then their coats were removed and the seeds were immersed in tetrazolium solutions. The concentrations used were 0.05, 0.075 and 0.1% for three staining periods 2, 4 and 6 hours, at 35 and 40 °C, in the absence of light. The experimental design was completely randomized in a 3 x 3 + 1 factorial scheme (three concentrations of tetrazolium solution x three staining periods + one control = germination test) with four replicates of 25 seeds. Tetrazolium test was adequate to evaluate the viability of T. aurea seeds using the concentration of 0.05% for four hours at 40 °C.

A cenoura é uma hortaliça com papel socioeconômico importante, tanto pelo elevado emprego de mão-de-obra, quanto por sua alta comercialização. Para otimizar o estabelecimento dessa cultura em campo se torna imprescindível sementes com germinação rápida e uniforme. Por isso, tem-se utilizado o tratamento de sementes como técnica para viabilizar o desempenho germinativo e expressão de vigor. Desse modo, objetivou-se avaliar os efeitos do tiametoxam no desempenho fisiológico de sementes de cenoura durante a germinação e desenvolvimento inicial de plântulas. O delineamento experimental foi o inteiramente casualizado, em esquema fatorial 5 x 4, sendo cinco cultivares de cenoura e quatro dosagens de tiametoxam (0; 0,4; 0,8 e 1,2 mL). Avaliaram-se a germinação, primeira contagem de germinação, comprimento e massa seca de plântula, além de análises bioquímicas do conteúdo de açúcares totais, aminoácidos totais e prolina. Os dados coletados foram submetidos à análise de variância (p ≤ 0,05) seguido do teste de Tukey e análise de regressão. O tratamento de sementes de cenoura com tiametoxam, no geral, influenciou positivamente a germinação das sementes das cultivares estudadas. No entanto, as dosagens de 0,4 e 0,8 mL de tiametoxam para cultivar Tropical não houve influência positivamente o desenvolvimento de plântulas. A dose de 1,2 mL do bioativador, para a cultivar Alvorada, foi benéfico ao desenvolvimento de plântulas e acúmulo de metabólitos.