ABSTRACT. In various parts of the world, agricultural exploitation faces saline soil or water, such that cultivable species tend to be limited regarding the establishment of seedlings, with effects on productivity. The objective of this study was to evaluate the effects of salinity levels associated with different temperatures on the germination, initial development, and oxidative damage indicators of purple corn seedlings. The experiment was completely randomized in a 5 × 2 factorial design (moistening of the germination paper with 0, 25, 50, 75, and 100 mM NaCl solutions at temperatures of 25 and 30°C). The parameters evaluated were germination, growth, and oxidative damage indicators at the seedling phase. The germinative decline and initial development of purple corn seedlings, regardless of the temperature (25 and 30°C), reflected oxidative damage resulting from saline stress. Although deleterious effects of salinity were observed, a temperature of 30°C provided greater length and accumulation of dry mass of purple corn seedlings compared to the effects at 25°C. Total chlorophyll, chlorophyll a, chlorophyll b, total carotenoids, and lipid peroxidation, regardless of the temperature (25 and 30°C), were identified as sensitive biochemical indicators for the detection of physiological quality of purple corn seedlings subjected to NaCl.

RESUMO O milho roxo é fonte de pigmentos naturais que podem ser utilizados para diversas finalidades industriais, no entanto a contaminação dos solos por alumínio afeta sua produção. Diante do exposto, o objetivo foi avaliar o efeito da toxidez por alumínio associado a diferentes temperaturas sobre a germinação das sementes e desenvolvimento inicial de plântulas de milho roxo, por meio da germinação, crescimento inicial das plântulas e indicadores de danos oxidativos. O delineamento utilizado foi inteiramente casualizado, com esquema fatorial 5×2 (concentrações × temperaturas). Os parâmetros avaliados foram porcentagem de germinação, comprimento e massa seca total, da parte aérea, do sistema radicular e indicadores de danos oxidativos (clorofilas totais, a, b, carotenoides totais e peroxidação de lipídeos) na fase de plântula. As concentrações de cloreto de alumínio não interferem na germinação de sementes de milho roxo. O comprimento, massa seca, clorofilas totais, a, b e carotenoides totais das plântulas normais de milho roxo sofrem redução e acréscimos na peroxidação lipídica com o aumento das concentrações de alumínio. O estresse por toxidez do alumínio em plântulas de milho roxo é detectado pelos indicadores bioquímicos (clorofilas totais, a, b, carotenoides totais e peroxidação de lipídeos).

ABSTRACT Purple maize is a source of natural pigments that can be used for various industrial purposes; however, soil contamination from aluminium affects production. The aim of this study was to evaluate the effect of aluminium toxicity associated with different temperatures on seed germination and initial development in purple maize seedlings, through germination, initial seedling growth and indicators of oxidative damage. The experimental design was completely randomised in a 5×2 factorial scheme (concentrations × temperatures). The parameters under evaluation were germination percentage, length and total dry weight of the root system and shoots, and indicators of oxidative damage (chlorophyll a, chlorophyll b and total chlorophyll, total carotenoids and lipid peroxidation) at the seedling stage. Aluminium chloride concentrations have no effect on seed germination in purple maize. With increasing aluminium concentrations, the length, dry weight, chlorophyll a, chlorophyll b, total chlorophyll and total carotenoids of normal purple maize seedlings are reduced, while lipid peroxidation increases. Aluminium toxicity stress in purple maize seedlings can be detected using biochemical indicators (chlorophyll a, chlorophyll b and total chlorophyll, total carotenoids and lipid peroxidation).

ABSTRACT The determination of leaf area is fundamental for studies related to plant growth and physiology. Thus, non-destructive methods allow an accurate estimate of the leaf area through linear dimensions of the leaves. The research objective was to construct allometric equations to estimate the leaflet area of peanut cultivars. Then, 2,605 leaflets were collected from six peanut cultivars (IAC Caiapó, IAC 8112, Runner IAC 886, BRS Havana, BRS 151 L7, and IAC Tatuí), with more than 400 leaflets sampled for each cultivar. We measured the length, width, product between length and width, and leaflet area. Linear and non-linear models (linear, linear without intercept, power, and exponential) were built, and the best equation was chosen using the statistical criteria: highest coefficient of determination (R2), Pearson’s linear correlation coefficient (r), Willmott’s agreement index (d), lowest Akaike information criterion (AIC), and root mean square of the error (RMSE). It was found that the models that used the product between length and width were the most suitable for estimating the leaflet area of peanut cultivars. Given the little intraspecific morphological variability, it was possible to group the cultivars, and model y ^ = 0.875 * LW0.929 was indicated to estimate the peanut leaflet area accurately, regardless of the cultivar.

Resumo: O processo de deterioração das sementes é tido como irreversível, mas técnicas como o priming são realizadas após o armazenamento visando atenuar os efeitos deletérios do envelhecimento. Objetivou-se avaliar o desempenho fisiológico de diásporos de A. urundeuva quando armazenados e, posteriormente, submetidos ao priming e à secagem, testando-se, assim, a hipótese de que o hidrocondicionamento funcionaria como um atenuador da deterioração. Adotou-se o delineamento inteiramente casualizado em esquema fatorial triplo 2x4x4, sendo dois ambientes (laboratório e câmara refrigerada), quatro tempos de armazenamento (0, 45, 90 e 180 dias) e quatro períodos de hidratação (0 h/diásporos secos, 5 h, 14 h 30 min e 23 h 30 min). Avaliou-se emergência, índice de velocidade e número de dias para a ocorrência de 50% de emergência, assim como o comprimento e a massa seca da parte aérea e do sistema radicular. O armazenamento de diásporos de A. urundeuva por 180 dias acarreta a redução do desempenho fisiológico, independente do ambiente. Os períodos de hidrocondicionamento não são eficientes para atenuar os efeitos deletérios da deterioração. O hidrocondicionamento por 23 h e 30 min proporciona um estabelecimento mais rápido das plântulas.

Abstract: Seed deterioration is an irreversible process. However, techniques such as priming have been used after storage, in order to mitigate the harmful effects of aging. This study aimed to evaluate the physiological performance of A. urundeuva diaspores when stored and, subsequently, subjected to priming and drying, thus testing the hypothesis that hydropriming would mitigate deterioration. A completely randomized design was adopted, in a triple factorial scheme 2x4x4, considering two environments (laboratory and refrigerated chamber), four storage times (0, 45, 90, and 180 days), and four hydration times (0 h/dry diaspores, 5 h, 14 h 30 min, and 23 h 30 min). Emergence, speed index, and the number of days to 50% emergence were assessed, as well as length and dry mass of both shoot and root systems. The storage of A. urundeuva diaspores for 180 days leads to a reduction in their physiological performance, regardless of the environment. The hydropriming times are not effective in attenuating the harmful effects of deterioration. Nevertheless, hydropriming for 23 h 30 min provides a faster seedling establishment.