Germitest Paper Research Articles

Uni- and Multivariate Analyses for the Characterization of Popcorn Inbred Lines for Drought Tolerance at Seedling and Vegetative Stages

Water deficit is the main limiting factor in rainfed agricultural production, negatively affecting germination and vegetative development. The objectives of this work were to characterize inbred lines for drought tolerance, to identify the most important root and shoot morphological traits for discriminating genotypes, to compare the efficiency of identifying contrasting inbred lines using uni- and multivariate methods, and to evaluate the effectiveness of identifying drought-tolerant genotypes at seedling and vegetative stages. We assessed 28 popcorn inbred lines and three maize single crosses, two drought-tolerant and one drought-sensitive. At the seedling stage, drought was induced on germitest paper moistened with polyethylene glycol 6000. At the vegetative stage, we applied water stress using lysimeters. We measured root and shoot morphological traits under water stress and no stress and processed the relative values. Uni- and multivariate methods, alone or in combination, were equally efficient for identifying contrasting inbred lines for drought tolerance. The confidence interval and Dunnett’s test worked very well when contrasting controls were included. Principal component analysis allowed to discriminate genotypes and identify the most important traits for discriminating them. At the seedling stage, inbred line 22-1824-2 was the most drought-tolerant and 22-1877-3 the most sensitive. At the vegetative stage, inbred lines 22-1920-1 and 22-1867-4 were the most tolerant and 22-1860-5 was the most sensitive. Root length, volume, dry weight, and surface area, as well as water content, were the most important traits for discriminating genotypes. Due to distinct tolerance mechanisms, drought tolerance should be assessed at both stages.

Aluminum and UV-C light on seed germination and initial growth of white oats

ABSTRACT Aluminum (Al) may be beneficial to crops, but in excess becomes detrimental to the germination and initial development of seedlings. The main determining indicators are the type of crop and exposure duration. The aim of this study was to examine the influence of Al and of UV-C light on the germination and initial growth of white oats. Seeds were sown on germitest paper in a solution of 100, 200, 300, 400, or 500 mg/L of aluminum chloride and kept in a germination chamber at 20°C for a 12-hr photoperiod. Germination and seedling growth parameters were determined after 5 and 10 days. The seeds were also exposed to two doses of UV-C (0.85 and 3.42 kJ m−2) under aluminum chloride stress (200 mg/L). Data demonstrated that treatment with aluminum chloride significantly decrease in germination at 200 mg/L and total seedling length at 100 mg/L. Exposure of seeds to UV-C light under excess Al (200 mg/L) did not show a significant effect on germination and growth compared to control (non-irradiated). Results indicated that exposure to high concentration of Al in the medium adversely altered germination and initial growth of white oat seedlings. Although UV-C light alone was not detrimental to the germination process, treatment with UV-C light also failed to mitigate the toxic effects of Al.

INOCULAÇÃO COM AZOSPIRILLUM BRASILENSE, TRICHODERMA HARZIANUM, BACILLUS SUBTILIS E BACILLUS MEGATERIUM EM SEMENTES DE MILHO

The aim of this study was to evaluate the effects of inoculation and coinoculation with the microorganisms Azospirillum brasilense, Trichoderma harzianum, Bacillus subtilis, and Bacillus megaterium on seed germination and on maize production components. Two experiments were carried out, the first in the laboratory and the second in the field. Experiment 1 was carried out in a completely randomized design (DIC) with eight treatments and four replications of 20 seeds. Pioneer® cultivar 30F53 was used. For inoculation and co-oculation, BiomaMais®, StimuControl® and BiomaPhos® products were used, the seeds were placed in plastic bags and the doses of each treatment were added to it. The dose used was 80 ml ha-1 of Azospirillum brasilense; 92 ml ha-1 of Trichoderma harzianum and BiomaPhos® product. These were placed on moistened Germitest® paper 2.5 times the weight of the paper and kept in a germination chamber. After seven days, germination, shoot and root length were evaluated. To evaluate the emergence speed index (IVG), 50 corn seeds were sown with the treatments on three sheets of Germitest paper, the same procedures being carried out in the germination test. Experiment 2 was carried out in a randomized block design (DBC), with eight treatments and three replications of 40m². Corn sowing was carried out in the conventional system. A spacing of 45 cm was used, with 4 rows each 20 m long, sowing of 3 plants m-1. Inoculation and co-inoculation followed the same procedure as in experiment one. Productivity components were determined. Treatment T5 resulted in higher germination and root length. Inoculation with T3 resulted in greater development of the aerial part of the seedlings. The T8 treatment showed the highest grain yield.

Contribution to the allelopathic study of Melia azedarach L. on the germination and initial growth of Fagopyrum esculentum Moench and Cyperus iria L. seeds

Allelopathy can be considered a chemical interference of one or more substances from a plant species in the development of another species, encompassing both inhibition and stimulation effects. In this context, the goal of the current research was to evaluate the allelopathic effect of Melia azedarach (chinaberry) leaf extracts on the germination of Fagopyrum esculentum (buckwheat) and Cyperus iria seeds. The experiment was conducted in a completely randomized design where the seeds were placed on germitest paper containing an aqueous extract of M. azedarach leaves at concentrations corresponding to 0, 25, 50, 75, and 100% and kept in a germination chamber in the presence of light. The analyzed variables were: first germination count, germination, length, and dry mass of seedlings. The results showed that, for both species, aqueous extracts at a concentration of 25% affected germination and initial seedling growth differently. The inhibition or stimulation of seed germination and initial growth depended on the extract concentration and varied in different species. M. azedarach extracts are not indicated for the control of C. iria. Therefore, it recommends removing M. azedarach leaves from the fields before sowing to prevent a negative impact on the early development of buckwheat and to stimulate the growth of C. iria.

Thermal optima for seed germination of 30 tree species from Central Amazonia: a comparison of approaches and a new proposal

This study compared the seed germination of 30 tree species from Central Amazonia using a wide temperature range (5-40°C with 12 hours of light daily). Seeds were submitted to pre-germination treatments, whenever necessary, sown on vermiculite or germitest paper, and normal seedling development was assessed until stabilisation. With the same data set, seeds' optimal germination temperature (Topt ) was determined by comparing the following approaches: (i) 2-step, the temperature with the highest germination and the shortest time to seed population reach 50% of germination was chosen; (ii) the highest Germination Speed Index (GSI); (iii) using the formula developed by Olff and collaborators (Olff's approach); (iv) three species were evaluated with Covell's approach; and (v) new formulas for Topt calculation are proposed, based on germination success and five different variables of germination rate (Cipriani's approach). Comparing the results, Topt differed between 0.6-10.0°C. GSI and 2-step indicated generally higher values than Olff's formula. The minimum and maximum Topt differences between Cipriani's approaches were between 0.1-2.2°C. Our study showed that Toptshould be determined for each species as, even the 30 Amazonian tree species of the same habitat, Topt ranged between 22.5 and 32.5°C.

Physiological quality of ‘BRS’ passion fruit seeds grown at different altitudes and storage environments

The aim of this work was to study the physiological quality of ‘BRS’ passion fruit seeds grown at different altitudes stored in cold chamber and in natural environment for six months. Hybrid passion fruit seeds (BRS Gigante Amarelo, BRS Sol do Cerrado and BRS Rubi do Cerrado) grown at three altitudes (104; 711; 1016 meters) in the southern region of the state of Espírito Santo were used. Germination was carried out in germitest paper rolls, placed in BOD-type germination chambers at temperature of 20-30 ºC. The following parameters were analyzed: germination, germination speed index, shoot and root length and dry mass of seedlings. The experimental design used was completely randomized in a factorial scheme with split plot in time 4x(3x3) (four bimonthly analyses x three hybrids x three altitudes), with two independent storage environments and three replicates of 100 seeds. Hybrid Passiflora edulis f. flavicarpa seeds can be stored in natural environment or cold chamber. Hybrid yellow passion fruit seeds grown at altitudes of 104 and 711 meters show higher germination and vigor percentages. Hybrid ‘Gigante Amarelo’ seeds had lower averages for variables under study, regardless of altitude. Hybrid ‘Rubi do Cerrado’ seeds grown at altitude of 1016 meters and hybrid ‘Sol do Cerrado’ seeds grown at altitudes of 104 and 711 meters have higher germination and vigor percentages and can be stored for 180 days in natural environment or cold chamber without viability loss. Flavicarpa can be stored in natural environment or cold chamber. Hybrid yellow passion fruit seeds grown at altitudes of 104 and 711 meters show higher germination and vigor percentages. Hybrid ‘Gigante Amarelo’ seeds had lower averages for variables under study, regardless of altitude. Hybrid ‘Rubi do Cerrado’ seeds grown at altitude of 1016 meters and hybrid ‘Sol do Cerrado’ seeds grown at altitudes of 104 and 711 meters have higher germination and vigor percentages and can be stored for 180 days in natural environment or cold chamber without viability loss. Passiflora edulis f. flavicarpa can be stored in natural environment or cold chamber. Hybrid yellow passion fruit seeds grown at altitudes of 104 and 711 meters show higher germination and vigor percentages. Hybrid ‘Gigante Amarelo’ seeds had lower averages for variables under study, regardless of altitude. Hybrid ‘Rubi do Cerrado’ seeds grown at altitude of 1016 meters and hybrid ‘Sol do Cerrado’ seeds grown at altitudes of 104 and 711 meters have higher germination and vigor percentages and can be stored for 180 days in natural environment or cold chamber without viability loss. Hybrid ‘Gigante Amarelo’ seeds had lower averages for variables under study, regardless of altitude. Hybrid ‘Rubi do Cerrado’ seeds grown at altitude of 1016 meters and hybrid ‘Sol do Cerrado’ seeds grown at altitudes of 104 and 711 meters have higher germination and vigor percentages and can be stored for 180 days in natural environment or cold chamber without viability loss. Hybrid ‘Gigante Amarelo’ seeds had lower averages for variables under study, regardless of altitude. Hybrid ‘Rubi do Cerrado’ seeds grown at altitude of 1016 meters and hybrid ‘Sol do Cerrado’ seeds grown at altitudes of 104 and 711 meters have higher germination and vigor percentages and can be stored for 180 days in natural environment or cold chamber without viability loss.

Constituent content and allelopathic potential of eighteen extracts for the control of Urochloa decumbens under laboratory conditions

Invasive grasses, those of the genus Urochloa act aggressively, thereby inhibiting the germination and growth of native species. We investigated the allelopathic potential and constituent content of different plant species to determine their effect on the germination of Urochloa decumbens (Stapf) R.D. Webster. Eighteen (18) species from the families Anacardiaceae (1), Annonaceae (6), Euphorbiaceae (1), Fabaceae (2), Myrtaceae (1), Rubiaceae (4), Sapindaceae (2), and Tropaeolaceae (1) were selected to obtain methanolic extracts at 1% (m/v). The total phenols, flavonoids, condensed tannins, flavonols, and saponins were evaluated by colorimetric methods. To evaluate the allelopathic effect of methanolic extracts 25 seeds from U. decumbens were distributed in Petri dishes containing two sheets of germitest paper and 2 mL of extract, and they were maintained at 25 °C under white light. All methanolic extracts showed total phenols, flavonoids, flavonols, and condensed tannins; however, saponin was identified in A. coriacea, A. crassiflora, A. sylvatica, Psychotria carthagenensis, P. leiocarpa, and Tropaeolum majus. Annona dioica (Annonaceae), Stryphnodendron adstringens (Fabaceae), and Palicourea crocea (Rubiaceae) have allelopathic potential and showed decelerated U. decumbens seed germination and inhibited hypocotyl and radicle growth. These findings provide insights into alternative methods for controlling U. decumbens in areas of ecological restoration.

Identificação de genótipos de soja tolerantes a diferentes concentrações de NaCl

Soybean is the main product of Brazilian agriculture, strengthening the country's position as one of the most important commodities in world agricultural trade. However, the salinity present in soils and irrigation waters can hinder the production process and generate economic damage. With the aim of selecting soybean genotypes tolerant to different sodium chloride (NaCl) conditions, 5 soybean genotypes were sown in rolls germitest paper with NaCl solutions at concentrations of 00, 40 and 80 mM. The evaluated characteristics were: final seedling stand, length of root and aerial part of the plant, fresh weight, dry weight of cotyledons, root and aerial part, percentage of germination, index of speed of germination and average time of germination. The design used was completely randomized, in a 3x5 factorial arrangement. The TMG 2383 genotype stood out from the others in the presence of salinity with a greater growth compared to the tested genotypes. The soybean varieties SYN 16861 IPRO, M8644 IPRO, TMG 2383 IPRO and NS8383 RR showed a certain level of resistance to saline stress. The genotypes resistant to saline stress can be used in genetic improvement programs in order to develop new cultivars with greater resistance to saline stress.

Temperatures and substrates on the germination and vigor of seeds of Pilosocereus catingicola subsp. salvadorensis in the Caatinga biome of Paraíba

The Caatinga biome is presented in the vegetation where the Brazilian semiarid region predominates, with a great variety of native species, and facheiro is one of the most important species because of its wide range in the semiarid region in northeastern Brazil. Therefore, the knowledge of the germinative behavior of the Caatinga species is essential to subsidize conservationist actions in this ecosystem. This study aimed to determine the effect of temperature and substrate on the germination and vigor of facheiro’s seeds. These seeds were obtained from ripe fruits collected in three localities of the Agreste of Paraíba: Arara, Bananeiras, and Boa Vista. After extraction, the seeds were placed to dry on paper for one week in a laboratory environment. Subsequently, the experiment was started by testing four temperatures: 20, 25, 30, and 20-30 °C. The germination test was conducted with four replications of 50 seeds distributed in “gerbox” boxes and placed in bio-oxygen demand (BOD) chambers using as a substrate the germitest paper, with a photoperiod of 12 hours. The statistical design was randomized in a 3 × 4 factorial arrangement (3 localities and 4 temperatures). A significant effect was observed for populations and substrates. The best substrate for germination was the germitest, while the substrate vermiculite presented a good performance, and the substrate soil presented low germination. Therefore, seeds presented the best vigor in the germitest paper, mainly with a temperature of 25 °C where the best performance for all localities was found. The vigor of seeds in the localities of Bananeiras and Boa Vista, temperatures of 25, 30, and 20-30 °C, and substrate germitest paper provided the highest vigor. The germitest substrate is the recommended substrate for the germination of the species, maximizing its physiological potential and being able to accelerate conservation projects for the species.

USE OF UNICONAZOLE IN GROWTH REGULATION AND BIOCHEMICAL CHANGES IN MAIZE

The current paper evaluated the incubation time, and doses of Uniconazole (UCZ) applied to maize seeds to verify the plants’ response at different phenological stages. MSG1001 hybrid seeds were treated with UCZ (0, 50, and 100 mg.kg-1 of seed) with different incubation times (IT – 1 min and 12 h). In the lab experiment, the treated seeds were displaced in rolls of the previously moistened Germitest paper and incubated for a week in a BOD chamber at 25ºC with a 12-hour photoperiod. In the greenhouse experiments, sowing was carried out in pots with sand, and supplementary irrigation was applied for ten days. In the field experiment, sowing was performed with 0.5 m spacing between rows in densities of 75,000 and 65,000 plants.ha-1. In the BOD and the greenhouse, the design of both experiments was entirely randomized in a double-factor scheme (IT x UCZ). A randomized block design in a triple-factor scheme (IT x UCZ x Population) was used in the field experiment. Seed treatment with UCZ did not promote germination inhibition. The concentration of 100 mg UCZ kg-1 of seed in the 12-hour IT resulted in a more significant accumulation of root mass in seedlings after one week in the BOD. In the greenhouse, plants in the V1 stage presented longer shoot lengths for the treatments that received UCZ. Incubation time influenced root length, and IT = 12 h at a concentration of 50 mg UCZ kg-1 of seed was more efficient than IT = 1 min. Application of 100 mg UCZ kg-1 of seed was more effective for accumulating chlorophylls A and B in IT = 1 min. In the field, seeds treated with UCZ changed plants for female flowering and the number of green leaves below the ear. The population of 75,000 plants.ha-1 was more productive, with UCZ contributing to the hybrid’s yield. Incubation of the seeds with 50 or 100 mg UCZ kg-1 of seed in IT = 1 min contributed to more productivity than IT = 12 h. The grains’ starch content increased with the application of UCZ at a dose of 100 mg kg-1 of seed, and the starch percentage was modified according to population density and incubation time.

Comparative seed germination, morphology and post-seminal development of two Bromeliaceae species with ornamental potential

Knowledge about the behavior of seeds is important to support studies to minimize the effects of predatory extractivism on ornamental bromeliads. The aim of this study was to evaluate the germination, seed morphology and post-seminal development of Hohenbergia belemii and Neoregelia compacta (Bromeliaceae) in different substrates. Seeds were disinfested with a sodium hypochlorite solution and germinated in four substrates: germitest paper; washed sand; vermiculite; and the commercial substrate Plantmax®. The experimental design was completely randomized in a 2 x 4 factorial scheme, with four repetitions and 50 seeds per repetition. The seeds were sown on the substrates and stored in plastic Gerbox® boxes, which were kept in BOD chambers with 12 hours photoperiod at constant temperature of 30ºC. Data were collected daily to calculate germination percentage and growth performance. The germination started on the 4th day after sowing (DAS) for H. belemii, with stabilization on the 11th DAS, while this occurred from the 5th DAS for N. compacta with stabilization on the 21st DAS. Germination was classified as development of epigeal and cryptocotylar seedlings for both species. The vermiculite substrate had a significant effect on seed germination, GSI (germination speed index) and growth of seedlings of both species. Our findings can support future research on seed technology and also contribute to better knowledge of the evolution of morphological characters of these bromeliad species.

Germination of radish seeds (Raphanus sativus) treated with homeopathic drugs

The radish is a short cycle crop, since it is harvested at 25-30 days after direct sowing. Under the economic point of view it is an important species, but there are few studies on germination of radish seeds. The objective of this study was to evaluate the effect of high diluted substances on the germination of radish seeds. The trial was conducted at the Agricultural Research Institute of Paraná (IAPAR) in Londrina / Paraná. It was used a pesticide free cultivar named Cometa. The treatments were: Bryonia, hydroalcoholic solution, Arnica montana, Cina and Lupine + Oat, all of them diluted and agitated at 9x; distilled water and agitated distilled water were used as controls. The mother tincture of Lupine + Oat was prepared from plants collected at the experimental station of IAPAR in Londrina. The mother tincture and all treatments were prepared according to the guidelines in the Brazilian Homeopathic Pharmacopeia, Part I [1]. The agitations of the treatments were made by a mechanical equipment, model Denise 10-50 manufactured by Autic. The water was distilled the day before preparing the treatments. The experiment was performed with 300 seeds per treatment. The seeds were placed in gerbox with germitest paper, and 50 gerbox were used per treatment, with six seeds in each gerbox. The germitest papers were moistened with the treatments and the seeds were soaked for 2 hours previously set up the experiment. The substances in high dilutions were agitated 100 times on the machine before soaking the seeds and moistening the germitest paper. The experimental design was entirely randomized and the gerbox were kept at the bench at the Laboratory of Plant Protection of IAPAR. A person not involved in conduct of the experiment coded (blinded) the treatments solutions with a random letter code. The code was kept secret until all measurements and data processing were finished. Seeds were observed daily for germination and counted only those considered germinated. Seeds were considered germinated when the radicle was at least two millimeters length. Arnica montana 9x increased 5.9% the seed germination when compared with distilled water.

Physiological response of sorghum seeds treated with Arsenicum album submitted to low temperature

Introduction: Temperature is one of the main environmental factors that act on plants, affecting physiological processes such as germination and vigor, growth, photosynthesis, water and nutrients uptake, among others [1]. When seeds are exposed to temperature stress during imbibition process occur dramatic changes in the reorganization and function of the plasma membrane impairing the stability and functional structure of the membrane resulting in the decrease on germination and embryo death [2][3]. In plant, stress triggers wide response that extends from the change of gene expression and cell metabolism to changes in growth rate and productivity. The organism’s reaction is a function of plant capacity to produce effects opposite to the action of stressors [4].
 
 Aim: the purpose of this study was to evaluate high dilution effect of Arsenicum album on physiological variables of germination and growth of sorghum.
 
 Material and Methods: The experiment was conducted at the Laboratory of Physiology and Homeopathy at Universidade Estadual de Maringá - UEM. Arsenicum album 6x matrix was acquired in homeopathic laboratory. From matrix, other dilutions were prepared according to Brazilian Homeopathic Pharmacopoeia [5] with the homeopathic remedies prepared in distilled water (1/10) and succussed by 100 times in mechanical arm (50-Denise Model Autic). For cold test, 50 seeds were distributed on germitest paper moistened to 2.5 times the weight of paper under different dilutions of A. album (9, 12, 18, 24 and 30x) with four replications. The control consisted of distilled water. After sowing, the rolls were placed in plastic bags and sealed, and lead in BOD-chamber at 10°C for 7 days. After this period, the rolls were removed from plastic bags and transferred to BOD-chamber at (25 ± 2)°C, arranged at random where they remained for seven days. Germination percentage (GP%) were evaluated according to Rules for Seed Analysis [6]. The length of primary roots (LPR) and length of hypocotyl (LH) were determined only for seedlings. The total length seedlings (TLS) was calculated as the sum of the lengths of hypocotyl (LH) and primary root (LPR). The fresh biomass (FB) of the seedlings were obtained by removing from their cotyledons, and then weighed on an analytical balance. The dry biomass (DB) was obtained after drying at (80 ± 1)°C for 72h. The experimental design was completely randomized. We adopted the double-blind procedure, thereby avoiding possible researcher interference. Data were subjected to analysis of variance and means compared by Scott-Knott (P≤ 0.05).
 
 Results: Seed exposure for seven days to cold stress at 10º C inhibited the germination percentage (GP%). Dilutions 9 and 18x showed the lowest germination percentage (Figure 1A). The cold inhibited the total length of hypocotyls (LH) the length of the seedlings (TLS), with the lowest values ​​observed in seeds treated with dilution 24x (Figures 1B and 1C). Fresh biomass production of seedlings (FB) also was reduced the dilutions 9, 12 and 24x (Figure 1D). Seedlings treated with the dilution 24x reduced the dry biomass production (DB) (Figure 1E).
 
 Conclusions: We can conclude that homeopathy Arsenicum album 24x reduced the germination percentage, the length, fresh and dry biomass of sorghum. Probably the cause of this reduction is the lower absorption/water content in the system. The reduction in water content can be the cause lower values ​​for the variables mentioned. However, the inhibitory action of the 24x dilution in water content is not yet known and will be one of the goals of future work.

Germination of Corymbia citriodora on different substracts

The objective of the present work was to evaluate the germination of lemon-scented gum (Corymbia citriodora) on different substrates. The following were tested: 1) commercial substrate, 2) sand, 3) sand + coconut fiber (2: 1), 4) coconut fiber, 5) substrate + coconut fiber (2: 1), 6) sand + substrate (2: 1) and the control treatment (germitest paper). Based on the experiment, it was observed that germination varied between 57 and 74%, although there was no significant difference between treatments. The treatments that led to a higher germination speed were the control (germitest paper), followed by the commercial substrate, coconut fiber, sand + substrate and substrate + fiber, with no significant difference, indicating that they are the best for the germination of C. citriodora seeds. The substrate based on coconut fiber is promising, as it can be considered an alternative and low-cost substrate.

Salt stress effects in the physiological quality of Cajanus cajan (L.) millspaugh seeds at different temperatures

Cajanus cajan (L.) Millspaugh, known as pigeon pea, is considered a rustic legume, high-temperature tolerant, well adapted to environments with low water availability, saline, and low fertility soils. This study aimed to evaluate the germination and vigor of Cajanus cajan seeds under conditions of salt stress and different temperatures. A completely randomized experimental design was used, with treatments distributed in a 6 x 3 factorial scheme (salinity levels and temperatures), with four replications of 50 seeds. After determining the seed water content, the seeds were placed on germitest paper moistened with sodium chloride (NaCl) solutions in concentrations of 0.0 (control); 2.0; 4.0; 6.0; 8.0 and 10.0 dS m-1; Seeds were incubated in a B.O.D, at constant temperatures of 25 and 30 °C and alternating 20-30 ºC. The germination and vigor tests (first germination count, germination speed index, length and dry mass of roots and shots) were evaluated. An interaction between the salt concentration and temperature for all variables analyzed was observed, with a negative effect on the germination and vigor of Cajanus cajan seeds as the salinity levels increased. Salt stress simulated with NaCl reduced the germination and vigor of Cajanus cajan seeds, mainly when submitted to the temperature of 25 °C. However, the increase in NaCl concentration, up to the potential 10.0 dS m-1, was not high enough to impair seed germination.

Application of vigor indexes to evaluate the cold tolerance in rice seeds germination conditioned in plant extract

Rice is a crop that presents sensitivity to cold, especially in the germination phase, which leads to high economic losses. Alternative management forms are essential to increase tolerance to low temperatures, and seed priming represents a promising tool. The objective of this study was to investigate the priming effect of the aqueous extract of carrot roots on rice seeds to increase tolerance to low temperatures during germination. Seeds from cultivars BRS Querência (cold-susceptible) and Brilhante (cold-tolerant) were soaked for 24 h in concentrations of 0, 25, 50, and 100% carrot extract, sown on germitest paper and conditioned in BOD for 21 days at 15 °C. As a control, the seeds soaked in water were also germinated at 25 °C. They were evaluated for germination, first germination count, and germination speed index to calculate the stress indices: tolerance index, susceptibility index, and harmonic mean. They were also evaluated for the length and dry mass of shoot and root. The results showed that the rice seeds conditioning in carrot extract effectively reduces the damage caused by cold, significantly increasing the germination speed and the percentage of final germination and the growth evaluations, more expressive at 100% concentration. The stress indexes are efficient in estimating the tolerance of the cultivars and the effect of the different conditions in low-temperature conditions, highlighting the superiority of the Brilhante cultivar.

Cadmium-induced transgenerational effects on tomato plants: A gift from parents to progenies

The present study aimed to investigate the Cd-induced transgenerational effects on plants. Grafted tomato plants, which exhibited the same cultivar as scion and distinct cultivars with contrasting Cd-tolerance as rootstocks, were grown in soil without and with artificial addition of Cd (less than 2.0, and 6.9 mg kg−1 of Cd, respectively) in a pot experiment carried out in a greenhouse. Their fruits were harvested to extract seeds (i.e., the progenies), which were sown over either Cd-free (control) or Cd-containing germitest paper (germination testing paper with 0 and 35 μM of CdCl2, respectively) and grown in a growth chamber. The immediate progeny of all grafting combinations from stressed plants presented an elevated germinability, despite high internal Cd concentration. When sown in Cd-containing germitest paper, the immediate progeny of plants grown in soil with no Cd addition was generally able to maintain or even increase the content of carotenoids and chlorophylls a and b (up to 93.3, 62.8 and 76.1%, respectively), indicating a Cd-induced hormetic effect on photosynthetic pigments. Two of the grafting combinations from stressed plants yielded seeds that generated seedlings with enhanced dry mass when they were sown in Cd-free media (~41%), suggesting a Cd-induced transgenerational enhancement of biomass production. Because only one tomato cultivar was used as scion, data indicated that type and degree of Cd-induced transgenerational effects depend strongly on signals generated and/or processed in roots of the parental plants. When sown in Cd-contaminated germitest paper, the immediate progeny of Cd-treated plants presented major reductions in the leaf area (35–69%) and content of photosynthetic pigments (57–93%) in comparison to the progeny from control plants. However, one of the grafting combinations exhibited satisfactory performance after “double” exposure to Cd, showing 91% of the biomass that was produced in the seedlings of control seeds from control plants. Further investigation indicated that adjustments in the chlorophyll fluorescence behavior might counterbalance losses in leaf pigments and area. Taken together, our data provide new insights on the origin, outcomes and mode of action of the Cd-induced transgenerational effects.

Effects of heat stress and seaweed-derived biostimulants on the germination of Comanthera mucugensis, an endemic plant of fire-prone Campos rupestres of Chapada Diamantina (Brazil)

Fires are common in Chapada Diamantina and reach large extensions of Campos rupestres, where there is a high number of endemic species, among which Comanthera mucugensis stands out. However, the effect of high temperatures on the seeds of this species is unknown (or alternatives to mitigate thermal stress). The present study evaluated the effects of heat stress and the effect of aqueous and polysaccharide extracts from seaweeds Agardhiella subulata and Hypnea pseudomusciformis, and κ-carrageenan on germination and post-seminal development of C. mucugensis seeds. The seeds were exposed to four high-temperature levels: 40, 45, 50, and 55 °C. Subsequently, they were germinated in germitest paper moistened with distilled water, aqueous and polysaccharide extracts from seaweeds and κ-carrageenan in different concentrations: 10, 1 and 0.1 mg ml−1. The seeds of C. mucugensis were heat tolerant up to 50 °C. The high concentration of aqueous and polysaccharide extracts was efficient in mitigating the thermal stress on seeds stressed at 45 and 50 °C. In a condition of non-stress and low thermal stress (40 °C), the low concentration of extracts and κ-carrageenan improved the frequency of germination and post-seminal development of the seeds. It is the first report on the effects of heat on seeds of Eriocaulaceae species from Chapada Diamantina.

Utilização de Stimulate® para germinação de sementes de porta-enxerto de Poncirus trifoliata, variedade Flying dragon

An experiment was carried out with the objective of evaluating the germination of seeds of Poncirus trifoliata var. monstrous ‘Flying dragon’. The seeds were soaked for 24 hours in a solution containing 0, 100, 150 and 200 mL L-1 of Stimulate®. After the imbibition period, the seeds were placed to germinate in two types of substrate, and germitest paper and sand. The counts were performed from the seventh to thirtieth days after sowing. The analyzes performed were germination %, Germination Speed Index, Radicle Length and Plumule Length. Stimulate® doses did not represent a reduction in germination time.

Cryopreservation and low-temperature storage of seeds of Tillandsia species (Bromeliaceae) with ornamental potential.

Tillandsia (Bromeliaceae) species have high endemism, and due to their strong ornamental potential, predatory extraction is threatening the extinction or drastic population reduction of many of them. In light of this scenario, it is necessary to find strategies for the conservation of these endangered species. The objective of this study was to evaluate two seed preservation strategies (freezing at - 5°C and cryopreservation at - 196°C) for 20 Tillandsia species occurring in the state of Bahia. We initially evaluated the morphometry, thousand-seed weight, and water content, followed by tests of germination and desiccation. After selecting the best result of the germination test (Germitest paper and incubation at 30°C) and desiccation (3h on silica gel), we established conservation tests utilizing two temperatures (freezing at - 5°C and liquid nitrogen at - 196°C), with storage times of 1, 7, 30, 180 and 450days. Analysis of variance indicated that the 20 species had different behaviors when submitted to the two temperatures and different storage times. After 450days there was a reduction in the germination percentage and germination speed index (GSI) of all the species studied when the seeds were preserved in the freezer. The storage in liquid nitrogen was efficient for the preservation of Tillandsia seeds when dried to a moisture content of approximately 7%. Our results support the establishment of a cryobank for Tillandsia to conserve these endemic species.