Abstract Salinity, of both soil and water, is one of the main causes of crop yield decline. Within this context, the objective of this study was to evaluate the influence of different salts on the germination of chia seeds. The experiment was conducted in a BOD chamber at a constant temperature of 20 °C and in the presence of light. The seeds were placed on paper soaked with aqueous solutions of calcium chloride (CaCl2), sodium chloride (NaCl), potassium chloride (KCl), and magnesium chloride (MgCl2), at the osmotic potentials zero, -0.10, -0.20, -0.30, and -0.40 MPa. The effect of the salinity was evaluated using a germination test, with counts on days 7 and 14 after sowing. Based on the results, chia seeds tolerate concentrations of NaCl to -0.4 MPa and KCl to -0.20 MPa. The salts CaCl2 and MgCl2 had a negative effect on the germination and vigor of the chia seeds for the osmotic potentials -0.30 MPa and -0.20 MPa, respectively.

The objective of this study was to comparatively determine the characteristics of growth rate, leaf area index, shoot dry mass partitioning and grain yield of chia plants (Salvia hispanica L.) on different sowing dates. A field experiment was conducted in the crop year of 2016/2017 in five sowing dates (09/22/16, 10/28/16, 01/03/17, 02/08/17 and 03/24/17) with a randomized complete block design and four replicates. Plant growth was determined through field samplings to determine the dry matter mass and leaf area performed every 15 days. The following physiological indexes were calculated: relative growth rate, absolute growth rate, net assimilation rate, leaf area ratio, specific leaf area and leaf mass ratio. To weekly evaluate plant height, ten plants per plot were marked after emergence, and the final height was considered when plants reached physiological maturity. A useful area of 2.10 m² per plot was collected for evaluating grain yield. The physiological indexes indicated that at earlier sowing dates there is a greater plant growth, either in shoot dry matter mass, height and leaf area index. The leaf area index of branches is progressively increased with plant development and contributes significantly to total leaf area index of chia plants in all studied sowing dates. The main stem represents between 60 and 70% of the shoot dry matter accumulated in the early sowing dates, and between 40 and 50% in late sowing. The best sowing date in terms of grain yield is 01/03/17.

This study aimed to obtain equations to estimate leaf area from linear leaf dimensions and establish the allometric relationship between leaf area and the number of leaves on the main stem of chia (Salvia hispanica L.) at different sowing times. The experiment was conducted in the agricultural year 2016/2017 on five sowing times in Santa Maria, RS, Brazil, in a randomized block design with four repetitions. In each plot, ten random plants were marked weekly during the vegetative phase to determine the number of leaves (NL) in the main stem, and three of these for the determination of leaf area (LA). A total of 70 leaves of different sizes were used to calibrate the model. Another 106 leaves were used to test the predictive capacity of the equations by various statistical indices. The length (L) and the largest leaf width (W) were measured. Leaf collection was carried out during the cycle, in all sowing times to represent all leaf sizes. The linear, quadratic, exponential, and potential models were adjusted. The non-destructive method, through the linear dimensions of the leaf, is appropriate for estimating the leaf area in chia. The general equation LA = 0.642 (L x W) can be used to estimate the leaf area of the chia plants without loss of precision. The potential model is appropriate to characterize the allometric relationship between leaf area evolution and the number of leaves accumulated in the main stem of chia at different sowing times.

A contaminação da água e dos solos com elementos tóxicos consiste em um grande problema ambiental com implicações para a saúde humana e animal. Entre os metais tóxicos, o alumínio (Al) representa um entrave para a agricultura, podendo causar diversos danos às plantas diminuindo sua produtividade. Assim, objetivou-se com este trabalho avaliar a tolerância ao Al no processo germinativo das sementes de alcachofra. Para tal, as sementes foram colocadas sobre papel embebido em solução aquosa de cloreto de alumínio nas concentrações correspondentes a zero; 30, 60, 90 e 120 mg L-1. Os parâmetros avaliados foram: percentagem de germinação, primeira contagem, comprimento e massa seca de plântulas. Os resultados obtidos indicam que concentrações de Al acima de 30 mg L-1 ocasionam redução do comprimento total das plântulas de alcachofra, não influenciando na percentagem de germinação das sementes. Conclui-se, portanto, que as sementes de alcachofra toleram moderadamente o Al nos níveis propostos neste trabalho.

Environmental contamination by toxic metals has become a serious problem to plants, animals, and humans. Among the toxic metals in the environment, copper (Cu) is the most important contaminant and, when in excess in water and soil, can disturb the growth and development of plants, decreasing the productivity of crops. Thus, the objective of this study was to evaluate the tolerance of chia seeds to copper. The seeds were place on paper soaked in aqueous solutions of copper at concentrations of zero (distilled water), 60, 120, 180, and 240 mg L-1. The parameters evaluated were percentage of germination, primary count, total, shoot and root length, and dry mass of the seedlings. An increase in concentration of copper in the substrate promoted a significant decrease in seed germination, growth, and dry mass of the chia seedlings. It is concluded that, during the germination phase, chia seeds moderately tolerate exposure to Cu, up to 180 mg L-1, but can be intolerant at higher concentrations.