The objective of this work was to evaluate the effects of drought stress in the reproductive stage (R3) on the physiological parameters and grain yield of two soybean (Glycine max) lines. The Vx-08-10819 and Vx-08-11614 soybean lines were grown in a greenhouse, where they were irrigated until they reached the R3 development stage. During three days, the weight of the pots was monitored daily in order to maintain 100, 60, and 40% field capacity (control and moderate and severe stress, respectively). The parameters gas exchange and chlorophyll a fluorescence, as well as chloroplast pigments, osmoregulatory solutes and antioxidant enzymes, were determined. After stress, the plants were rehydrated until the end of the reproductive stage (R8), to evaluate grain yield. Vx-08-10819 showed traits that contributed to drought tolerance, such as better water-use efficiency, modulation of leaf area, and enzymatic activity, as well as a more efficient photosynthetic apparatus and a lower lipid peroxidation rate than Vx-08-11614. In addition, Vx-08-10819 maintained its productivity even after the severe water deficit. By contrast, water limitations affected negatively the productivity of Vx-08-11614. The Vx-08-10819 soybean line can efficiently withstand drought periods during the reproductive stage, without any interferences on final grain yield.

Acid soils with elevated aluminum (Al) saturations are worldwide distributed and harm the crop production in most of the tropical and subtropical regions. The initial and most dramatic symptoms of Al toxicity are changes on the external morphology and inhibition of elongation of roots. These changes have served as a marker for level of Al toxicity and the ability of plants tolerate this metal. Therefore, the goal of this study was to evaluate the Al effects on the growth root and the external morphology of root tips in two rice genotypes: Fernandes (CNA-1158) and Maravilha (CNA-6843-1), tolerant and sensitive to Al, respectively. The genotypes were treated with 0 and 1 mM of Al in Clark’s solution for different times (3, 6 and 9 days). The contents and the distribution of Al in root tips, as well as its morphology, were analyzed. After Al exposure, the content of this metal was higher in Al-sensitive genotype leading to inhibition of root length and decrease in root dry matter production, after the sixth day of treatment. Additionally, Al accumulation in the root tips (0–3 mm) of both genotypes was detected mainly in root cap cells. We also observed damage in the external micromorphology of the root tips, especially in the Al-sensitive Maravilha genotype. Al accumulation in root tips of this genotype induced cellular disorganization in the root cap cells, resulting in the peeling of the superficial layers. Overall, our findings evidenced the higher tolerance of one of genotypes (genotype Fernandes) to Al.

Seed germination studies provide essential information for biodiversity conservation and ecological restoration programs. This work aimed to investigate the relationship between the substrates and the mobilization of reserves during germination of Ormosia coarctata seeds under different temperatures. Samples were collected every 48 h for up to 240 h for quantification of lipids, soluble sugars, starch, and soluble proteins. The optimum temperature range for germination was 25 to 35 °C. The highest germination percentages were obtained using sand or paper roll. Carbohydrate, lipid, and protein contents decreased during germination, regardless of temperature.

Toxic levels of aluminum (Al) in the soil can reduce the growth of different grain crops. To understand the effects of Al in soybean (Glycine max L.) seedlings Al accumulation and its effect on anatomy, morphology, and metabolism in roots of two soybean genotypes were evaluated: Suprema and A7002. For this, soybean plants were grown in nutrient Clark solution, pH 4.0, without Al (control) and with 100 µM of Al for 72 hours. Both genotypes accumulated Al in the roots, however, Suprema showed a higher Al accumulation than A7002. The latter genotype showed Al accumulated only in the cell walls of the epidermis and root cap, which did not affect root growth. On the other hand, in Suprema, Al accumulated in the cells of the root cap, epidermis, and the nucleus of the ground meristem cells, which resulted in inhibited root growth and structural damage in the root epidermis cells. Al modulated the primary metabolism with increases in the levels of glucose, fructose, sucrose, and malate in the roots of the genotype A7002 and reduced the starch levels in the Suprema genotype. The findings of this study suggest the A7002 genotype seems to be more resistant to Al than Suprema, mainly by the use of two important mechanisms: an increase in malate content and Al immobilization in the external cells of the root.