The germination response of seeds under artificial stress conditions is a tool for better understanding of the survival and adaptation ability of species under natural stress conditions. The aims of this study were to evaluate the protective effect of nitric oxide during germination as well as seed vigor and seedling development of Eucalyptus urophylla under salt stress conditions. The experimental design was completely randomized, with five replications, in a 3 × 3 + 1 factorial arrangement, with three priming factors [water, sodium nitroprusside (SNP), and potassium nitrate (KNO3)], three germination conditions (distilled water, and the water potentials of -0.6 and -1.2 MPa), and an additional control treatment (unprimed seeds). The following determinations were made: germination count at seven and fourteen days, germination speed index, primary root length, shoot length, and total length. SNP protects seeds, leading to a higher percentage of germination, as well as greater root growth and total seedling size, whereas KNO3 is not effective in protecting seeds that suffer from salt stress, which affects their physiological and morphological characteristics. E. urophylla seeds are sensitive to salt stress, and physiological priming with SNP leads to an increase in the percentage of germination, vigor, and seedling development under salinity conditions.

In order to understand the allelochemical action of Byrsonima intermedia A. Juss. and B. verbascifolia Rich. ex A. Juss., the effects on germination, initial growth and cell cycle of Lactuca sativa L., exposed to leaves and fruits of this species, were evaluated using the sandwich method. Data were subjected to analysis of variance and means were compared by the Scott-Knott test (p < 0.05). For the parameters germination percentage and germination rate index, no difference between Byrsonima spp. was observed, and B. intermedia fruits were responsible for the highest inhibition of lettuce germination, compared to the leaves. Root elongation in lettuce exposed to B. verbascifolia organs showed stimulatory effects and B. intermedia organs showed inhibitory effects on root growth. The mitotic index showed the allelopathic effect of Byrsonima spp. by the reduction in cell division in lettuce root meristem, and the stimulus in root elongation was caused by B. verbascifolia, understood as a consequence of cell expansion, not mitotic activity. An aneugenic effect of Byrsonima spp. was observed, and the highest frequency of C-metaphase and stickness was found in B. verbascifolia fruits and B. intermedia leaves.

HIGHLIGHTS In general, toxic metals cause negative effects on plants' physiology. Lead reduces chlorophyll B, negatively impacting photosynthesis and the photosystem II. Aluminum acts negatively specially in chloroplast pigments. Fabaceae family do not present changes in physiology when exposed to those Toxic Metals.

ECOPHYSIOLOGY OF THE TREE SPECIESCedrela fi ssilis Vell. (Meliaceae) SUBMITTED TO FLOODING ROCHA, G. A.; ROMANATTI, P. V.; OLIVEIRA, F. M.; CUNHA NETO, A. R.; PEREIRA, F. J.; POLO, M. Ecophysiology of the tree species Cedrela fi ssilis Vell. (Meliaceae) submitted to fl ooding. CERNE, v. 24, n. 4, p. 323-333, 2018. HIGHLIGHTSCedrela fi ssilis trees survived in all treatments due to a marked development of cortical intercellular spaces in fl ooded plants The stem periderm thickness was reduced by fl oodingThe superoxide dismutase activity was decreased, but the activities of the ascorbate perioxidases and catalase in the leaves were increased.Young Cedrela fi ssilis trees partially tolerate fl ooding since they developed ecophysiological changes in order to survive in this condition. ABSTRACTSoil water saturation requires different adaptative strategies by tree species that live under such conditions. We aimed to study the responses that ensure fl ooding tolerance by tree species and so provide support for recovery projects with degraded areas subject to fl ooding. We evaluated the ecophysiology of Cedrela fi ssilis under different water saturations, including anatomical traits, gas exchange parameters, antioxidant system analysis and growth. We subjected 100 day-old plants to three treatments: Control (FC) where the substrate was kept at fi eld capacity; Flooded Roots (FR), where the substrate remained submerged but with no surface layer of water, and Flooded Stem (FS), with a water layer accumulation of around 3.0 cm over the substrate, fl ooding part of the stems. The plants were kept under such conditions for 90 days. Plants survived in all treatments due to a marked development of cortical intercellular spaces in fl ooded plants. However, photosynthesis and other gaseous exchange were limited under FR and FS treatments. In addition, the periderm thickness was reduce by fl ooding and there was an accumulation of starch grains in the parenchyma cells of the xylem, cortex and pith of the stem. There was also a signifi cant lipid peroxidation on the leaves under FR and FS treatments. The superoxide dismutase activity was decreased, but the activities of the ascorbate perioxidases and catalase in the leaves were increased. We concluded that young Cedrela fi ssilis plants partially tolerate fl ooding since they developed ecophysiological changes in order to survive in this condition. Consequently, this species is a good candidate for the reforestation projects in environments where intermittent fl ooding occurs, such as riverside and riparian forests. v.24 n.4 2018 ECOPHYSIOLOGY OF THE TREE SPECIES Cedrela fissilis VELL. (MELIACEAE) SUBMITTED TO FLOODING 324 CERNE ROCHA et al.

As forage production increase, high-quality seeds demand follows. Priming have been reported as a technique for improve seed quality and stress tolerance. The aim of this study was to evaluate the priming agents effect on Urochloa ruziziensis seed germination and seedling establishment under water deficit and salt stress. A completely randomized experiment assessing six priming agents and three germination conditions were established. We evaluated: seed water content; germination percentage and speed index; viability of seeds remaining from the germination test; seedling length; antioxidant enzymatic activity; and malondialdehyde quantity. Seeds primed under water deficit and salt stress showed better physiological performance than dry seeds. There was a significant increase in seed germination percentage and speed and in seedling roots and shoots length. Sodium Nitroprusside shows significant potential for use in the physiological priming of U. ruziziensis seeds.

Different products have been tested to increase the vase life of cut flowers after harvest such as the biodegradable films. These products have been used in fruits since the application on the surface may provide the modification of the atmosphere around it, although, there is no information for flowers. The objective was to evaluate the effectiveness of cassava starch films as a postharvest product for Red Torch Ginger inflorescences. On the first experiment, different starch concentrations in the solution were tested and in the second experiment starch, concentrations with plasticizers and adjuvants were evaluated. The application of the biodegradable film in Red Torch stems acted as a barrier to the gases, as observed by their water absorption rate and the maintenance of fresh weight, maintaining postharvest quality up to Day 6. The visual quality was better in the inflorescences treated with 6% starch and in the films without additives. The use of 6% starch films led to lower contents of hydrogen peroxide and lipid peroxidation and higher levels of primary-metabolism macromolecules up to Day 6, delaying senescence and increasing postharvest durability. The addition of glycerol plasticizer to the different film concentrations improved the film resistance characteristics. It is recommended the use of films based on cassava starch at a concentration of 6%. The use of the adjuvant is not essential since it changed the film’s characteristics, leaving it less transparent and more viscous, hindering drying.

Aesthetic attributes and easy-to-grow nature of tropical cut flowers (TCFs) have contributedto their potential for increased production. The dearth of information regarding agronomic practices and lack of planting materials are the key hindrances against their fast expansion. Unconventional high-temperature storage requirements and the anatomy of the peduncle contribute topoor vase life performance, while troublesome packaging and transport due to unusual size and structureprimarily cause post-harvest quality deterioration. Nonetheless, the exotic floral structuresconsequently increase market demand, particularly in temperate countries. This boosts studies aimed at overcoming post-harvest hindrances. While a few TCFs (Anthurium, Strelitzia, Alpinia, and a few orchids) are under the spotlight, many others remain behind the veil. Heliconia, an emerging specialty TCF (False Bird-of-Paradise, family Heliconiaceae), is one of them. The structural uniquenessand dazzling hues of Heliconia genotypes facilitate shifting its position from the back to the forefrontof the world floriculture trade. The unsatisfactory state-of-the-art of Heliconia research and the absence of any review exclusively on it are the key impetus for structuring this review. In addition to the aforementioned setbacks, impaired water uptake capacity after harvest, high chilling sensitivity, and the proneness of xylem ducts to microbial occlusion may be counted as a few additional factors that hinder its commercialization. This review demonstrates the state-of-the-art of post-harvest research while also conceptualizing the implementation of advanced biotechnological aid to alleviate the challenges, primarily focusing on Heliconia (the model crop here) along with some relevant literature on its other allied members. Standard harvesting indices, grading, and packaging are also part of the entire post-harvest operational chain, but since these phases are barely considered in Heliconia and the majority of tropical ornamentals except a few, a comprehensive account of these aspects has also been given. The hypothesized cues to nip chilling injury, resorting to different bio-chemical treatments, nano-based technology, and advanced packaging techniques, may help overcome preservation difficulties and propel its transition from niche to the commercial flower market. In a nutshell, readers will gain a comprehensive overview of how optimum post-harvest handling practices can rewardingly characterize this unique group of TCFs as the most remunerative component.

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