Toxicological effects of comercial formulations of fungicides based on procymidone and iprodione in seedlings and root tip cells of Allium cepa.

In this study the phytotoxic, cytotoxic, genotoxic and mutagenic effects of two commercial fungicide-active compounds, procymidone (PR) and iprodione (IP), were determined. The parameters evaluated were germination and root growth, mitotic index, chromosomal and nuclear aberrations, and molecular analyses were also performed in the model plant Allium cepa L. The results demonstrated that the active compounds PR and IP were phytotoxic, delaying germination and slowing the development of A. cepa seedlings. Moreover, PR and IP showed cytogenotoxicity towards A. cepa meristematic cells, inducing chromosomal changes and cell death. The mutagenic activity of the active compounds was demonstrated by the detection of DNA changes in simple sequence repeat (SSR) and inter-simple sequence repeat (ISSR) markers in the treated cells compared to the negative control. Together, these results contribute to a better understanding of the damage caused by these substances in living organisms and reveal a promising strategy for prospective studies of the toxic effects of environmental pollutants.

Mutagenic effects of spent potliner and derivatives on Allium cepa L. and Lactuca sativa L.: A molecular approach.

Spent potliner (SPL) is a solid residue generated by the aluminum industry. Its composition is variable and complex, containing fluoride and cyanide salts as well as aluminum, which contributes to its toxicity. SPL is sometimes released directly into the soil, where it is prone to leaching and has the potential to cause alterations and damage to DNA. Considering that polymorphism analysis of simple sequence repeat (SSR) and inter-simple sequence repeat (ISSR) DNA markers is an interesting tool to determine the mutagenicity of an environmental pollutant, the present study adopted this approach to verify the mutagenic potential of SPL and its main toxic components (aluminum, fluoride, and cyanide) on root tip cells of Lactuca sativa and Allium cepa. Alterations in ISSR and SSR regions were identified by DNA fingerprinting (gain and loss of bands and changes in band intensity). The estimated dissimilarities indicated differences between treatments and the negative control. Furthermore, the relationship between the amplification profile of the markers and alterations in cell mitosis was discussed.

Cryostorage of sunflower seeds / Crioarmazenamento de sementes de girassol

Sunflower seeds present a great economic importance due to the high oil content. The aim of this study to evaluate the effect of storage sub-zero temperatures and the quick and slow thawing methods on the physiologic quality of seeds of Helianthus annuus, cultivars BRS 122 and BRS 324. The experiment was set up in a randomized complete design, in a factorial 2x6 (cultivars x procedures) with four replications; means were compared by the Tukey test at 5%. Were evaluated: first count and percentage of germination, mean time of germination, germination speed index, dry mass seedling, root and shoot length and stability of membranes, through electrical conductivity test solution soaking of seed. Sunflower seeds tolerate storage in sub zero temperatures up to six months; the seeds of cultivars BRS and BRS 324 122 present different answers in relation to the type of freezing and thawing.

As sementes de girassol apresentam grande importância econômica devido ao grande conteúdo de óleo. Objetivou-se neste trabalho avaliar o efeito do armazenamento em temperaturas sub-zero e os métodos de descongelamento rápido e lento sob a qualidade fisiológica de sementes de Helianthus annuus cultivares BRS 122 e BRS 324. Utilizou-se o delineamento experimental inteiramente casualizado, num fatorial 2x6 (cultivares x procedimentos), com quatro repetições; as médias foram comparadas pelo teste de Tukey em nível de 5%. Foram avaliados: primeira contagem e porcentagem de germinação, tempo médio de germinação, índice de velocidade de germinação, massa seca de plântulas, comprimento de raiz e parte aérea e estabilidade das membranas, através de teste de condutividade elétrica da solução de embebição das sementes. As sementes de girassol toleram o armazenamento em temperaturas sub-zero até seis meses; as sementes dos cultivares BRS 122 e BRS 324 apresentam respostas diferentes em relação ao tipo de congelamento e descongelamento.