The development of tissue cultured-based protocols applied to braúna, an endangeres species, would be though highly desirable. However, contamination-free explants are determinant for the success of this technique, which might be vulnerable to the toxicity of disinfectants. Here, we aimed at establishing an efficient protocol for in vitro production of axenic seedlings of braúna and to evaluate the toxicity of disinfectant agents in the Lactuca sativa model species. Experiments I and II: Seeds were treated with sodium hypochlorite (NaOCl) and fungicide captan, with and without residue, by different immersion times, respectively. The following were analyzed: contamination; germination and normal and abnormal seedlings. Experiment III: Lettuce seeds placed in Petri dishes were exposed to 2.5 mL captan at 0.5; 1; 2; 4 and 8%; 0.01% glyphosate and distilled water. The germination, length of seedlings, cell cycle, nuclear and chromosomal alterations of the cells of the root meristem were assesed. The isolated use of NaOCl was not efficient in the disinfestation of braúna seeds. However, the immersion of the seeds in captan, for 10 minutes with its residue, led to higher germination and vigor indexes; however, resulted in the formation of abnormal seedlings. This compound exhibited toxicity in the lettuce model seeds because affected the germination and the whole development of the seedlings, showing clastogenic and aneugenic action in the meristematic cell cycle.

The Atlantic Forest is a biome that has suffered anthropic actions, such as the extraction of hardwood, which can lead to the extinction of endemic species of great economic and ecological value, such as Dalbergia nigra. In this perspective, large-scale multiplication studies are necessary to contribute to the conservation of this species. The objective of this work was to establish a protocol for the in vitro production of axenic seedlings of D. nigra. Four experiments were performed: I. Immersion times in NaOCl. II. Disinfecting agents in seed germination of D. nigra. III. NaOCl toxicity in seeds of the model species Lactuca sativa L. IV. Culture media and glutamine in the germination and initial growth of D. nigra. All experiments were arranged in a completely randomized design. For a better disinfestation and less harmful effects to the seedlings, it is recommended that the seeds be treated with 70% alcohol (1 min) and NaOCl (14 min). NaOCl has a high phytotoxic, cytotoxic, and genotoxic effect, and its mechanism of action in the L. sativa cell cycle is clastogenic and aneugenic, suggesting the formation of abnormal seedlings in D. nigra. The WPM medium and its supplementation with glutamine (0.75 mg.L-1) are recommended.

The Amazon rainforest and the biodiversity hotspot of the Atlantic Forest are home to fruit trees that produce functional foods, which are still underutilized. The present study aimed to select potential functional nut donor trees from two Brazilian chestnuts, by evaluating the nutritional and antioxidant composition of the nuts and the fatty acid profile of the oil. The nutritional characteristics, antioxidants, oil fatty acid profile, and X-ray densitometry of the nuts were evaluated, as well as the characterization of leaf and soil nutrients for each parent tree. The nut oil was evaluated through Brix (%), mass (g), yield (%), and the fatty acid profile. For L. pisonis, the most nutritious nuts were produced by L. pisonis tree 4 (N > P > K > Mg > Ca > Zn > Fe) and L. pisonis tree 6 (P > Ca > Mg > Mn > Zn > Cu > Fe), and for the species L. lanceolata, L. lanceolata tree 6 (N > P > Ca > Mg > Zn > Fe > Cu) and L. lanceolata tree 2 (P > K > Mg > Zn > Cu). In L. pisonis, the highest production of anthocyanins, DPPH, total phenolics, and flavonoids was obtained from the nuts of L. pisonis tree 4 as well as for L. lanceolata, from L. lanceolata tree 1, except for flavonoids. The Brix of the oil from the nuts of both species showed no difference between the trees and the fatty acid profile with a similar amount between saturated (48–65%) and unsaturated (34–57%) fatty acids. Both species have nuts rich in nutrients and antioxidant compounds and can be considered unconventional functional foods. The data collected in the present study confirm that the nuts of these species can replace other foods as a source of selenium.

The jacaranda of Bahia (Dalbergia nigra (Vell.) Allemão ex Benth) is an endemic tree of a Brazilian neotropical biodiversity hotspot and is of great ecological and economic interest. Given the threat of extinction due to timber overexploitation and climate change, the present study aimed to analyze the physiological and biochemical quality of D. nigra seeds exposed to heat stress. The seeds were sown in a test tube containing woody plant culture medium, kept in a biochemical oxygen demand chamber at 45°C for 0, 24, 48, 72, and 96 hours, and then maintained in the same chamber at 25°C for 30 days. Physiological analyses of moisture, electrical conductivity, germination speed index, normal and abnormal seedlings, seedling length, root length, hypocotyl length, collar diameter, seedling and root dry mass, and Dickson quality index revealed a drop in germination and vigor with prolonged heat stress, dropping from 95% to 0% between 0 and 96 hours. This was accompanied by a reduction in the content of carbohydrates, lipids, and proteins. Therefore, the vigor and quality of seedlings is negatively influenced by exposure to heat stress at 45°C.