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Abstract: Handroanthus spongiosus (Rizzini) S. Grose is an endangered tree species. However, its seed quality, storage, and conservation strategies are issues still unexplored. This study aimed to evaluate the physiological quality of H. spongiosus seeds subjected to different storage times, packaging, and environments for their conservation. A completely randomized experimental design was used, in a double factorial arrangement with an additional treatment (recently-harvested seeds), consisted of five storage times (up to 24 months) and six storage conditions, combining packaging types (permeable and impermeable) and environments (room, cold chamber, freezer, and liquid nitrogen conditions). Seed germination percentage and normal seedling percentage, shoot length, root length, and root to shoot dry weight ratio were evaluated. The seed germination and normal seedling percentages of H. spongiosus seeds conserved under room conditions decreased over the storage time. Normal seedling percentages decreased from the 12th month of storage onwards. Low and ultralow temperatures are recommended for short and medium-term conservation of H. spongiosus seeds, since they did not affect the growth of seedlings.

Biosaline agriculture has been a viable alternative for agricultural production in regions with lack of good quality water. To enable the cultivation of vegetables in high electrical conductivities, seed priming has been used to increase tolerance to stress caused by use of brackish water. We aimed to evaluate the efficiency of osmo and hydropriming in cucumber seeds cv. Caipira germinated biosaline in water, regarding germination and biochemical changes during the germinative process. The experimental design was totally randomized, with four replications of 50 seeds or 10 seedlings, in a factorial scheme 6x3; with six priming conditions (control, osmopriming during 24 and 48 hours, hydropriming with 1, 2 and 3 cycles of hydration-dehydration) and three biosaline water (fish farming biosaline wastewater) concentrations in distilled water (0, 50 e 100%). We evaluated the kinetics and percentage of germination; germinative metabolism and activity of antioxidant enzymes. According to the results, one hydropriming cycle is faster and more efficient to improve the performance of cucumber seedling in biosaline water and this can be used in substrate for germinating seeds of cucumber cv. Caipira.

Abstract: Myracrodruon urundeuva, a native species from the Brazilian Caatinga, is widely distributed across its endemic region, where it also plays an essential socioeconomic role. The objective of this study was to evaluate the influence of environmental stress on the germination of M. urundeuva seeds harvested in different years (2010 to 2013). Seeds were germinated at constant temperatures between 10 to 40 °C, osmotic potentials from 0 to -0.8 MPa (in polyethylene glycol 6000 solutions), and from 0 to -0.5 MPa (in NaCl solutions). The experiment was conducted according to a completely randomized design, with three replicates of 50 seeds, in a factorial scheme (harvest year x stress intensity) for each environmental stress. Germination data were then analysed using thermal, hydro and halo time models, and future germination responses projected according to climate change scenarios. The germination thermal thresholds ranged from 7.4 to 53.3 oC. The germination base osmotic threshold (using polyethylene glycol) was -0.6 MPa and the base osmotic threshold in NaCl was -0.43MPa. Seeds from different harvest years showed distinct tolerance to environmental stresses. The thermal, hydro and halo-time models were efficient to describe the germinative response of seeds, and the climate models allowed to identify the germination responses of M. urundeuva in future climate. According to the models for future climate (RCP 8.5), the reduction of rainfall by 2100 will directly affect seed germination and seedling recruitment of M. urundeuva.

Abstract: Angico is a species found in several environments in Brazil, with several applications. It is used in the timber industry and mainly in folk medicine. In order to verify a variation in the biometric characteristics and the quality of seeds from different mother-plants in different harvesting years, the following variables were studied: moisture content, diameter, density, electrical conductivity, fresh and dry matter of seedlings, germination percentage and kinetics, in a completely randomized design with a 2x3 factorial arrangement (lots x size). The obtained results showed that angico seeds from different lots showed different physiological quality, possibly due to the climate variations to which mother-plants were submitted in the different years. Seed size directly interferes with seedling growth under both controlled and greenhouse conditions, and it can be used as a vigor indicator for angico seeds.

The production of seeds and seedlings by these species is of utmost importance to prevent a loss of biodiversity of the Caatinga, a unique and exclusively Brazilian biome. Biosaline agriculture is conducted over a range of salinity levels in groundwater and/or in soils. The current study evaluated the application of biosaline agriculture to Anadenanthera macrocarpa, Myracrodruon urundeuva, Aspidosperma pyrifolium and Erythrina velutina by examining the germinative metabolism of seeds subjected to different electrical conductivities (ECs) of NaCl solutions and biosaline water. The seeds were germinated in biosaline water (4.94 dS.m-1) and in NaCl solutions with ECs of 0, 2, 4, 6, 8, 10, 12, 14, 16 and 18 dS.m-1 at 25 ºC, 12-h photoperiod. The kinetic variables of germination were assessed, and the seeds and seedlings were assayed for reserve biomolecules, proline content and antioxidant enzyme activity. The seeds were highly tolerant to salinity, with germination-limiting ECs above 12 dS.m-1. Although high EC promoted alterations in seed metabolism that enabled salinity tolerance, seedling production was indicated with ECs no higher than 6 dS.m-1. These results demonstrated that Caatinga seedling production is viable through biosaline agriculture beucause the groundwater salinity of this region is within the tolerance levels of the seeds.

The aim of this study was to evaluate the effect of different abiotic stresses on the activity of antioxidant enzymes and on accumulation of proline in Erythrina velutina Willd. seeds during germination. Mulungu seeds were scarified and placed to germinate at constant temperatures of 15, 25, and 35 ºC, moistened with distilled water, and exposed to 12 h of light. Other seeds were exposed to solutions of NaCl (EC of 0, 4, and 8 dS.m-1) and polyethylene glycol (osmotic potentials of 0.0, -0.2, and - 0.6 MPa) and maintained in a germination chamber set at 25 ºC and 12 h photoperiod for seven days. At the end of each period of imbibition, the embryonic axis and cotyledons of the seedlings were collected separately and used to quantify proline content and the activity of antioxidant enzymes. These were detected in both the cotyledons and embryonic axis of the mulungu seeds. Antioxidant activity varied depending upon the type and degree of stress applied. It was concluded that under the aspect of the detoxification process, the mechanism found in mulungu seeds is more efficient when subjected to different temperatures followed by salt stress and water stress.