Abnormal Seedlings Research Articles

Recovery of Bradyrhizobium cells and effects on the physiological quality of soybean seeds sown in dry soil

Abstract: Farmers sometimes sow soybean (Glycine max (L.) Merrill) in dry soil in the expectation of rain in the short time. However, the forecast may not confirm, letting the inoculated seeds in the dry soil indefinitely. We assessed the survival of inoculated Bradyrhizobium and physiological quality of soybean seeds sown in dry soil. In the first experiment, irrigation was applied with 2 h, 1, 4, 11, 18, or 21 days after sowing; in the second experiment, sowing was carried out 2 h, 1, 5, 12, 14, or 20 days before irrigation. Each time represented a treatment in a completely randomized design. Bradyrhizobium cells dropped from ~8-9 × 104 colony forming units per seed soon after inoculation to -60% at 2 h after sowing in dry soil, and decreased to close to zero with time in both experiments. Although there was no effect on germination (59% and 81% in the first and second experiments, respectively), the exposure to dry soil reduced the emergence speed index from 19.5 (2 h) to 12.0 (21 days) in the first experiment and from 37.8 (2 h) to 13.8 (21 days) in the second. In the first experiment, the number of abnormal seedlings increased from 7% (2 h) to 24% (21 days); in the second, cotyledons showed cracks, which increased from 1% (2 h) to ~50% (≥ 5 days). Sowing in dry soil negatively affects not only the inoculated Bradyrhizobium, but also the physiological quality of soybean seeds.

Reakcija parametara kvaliteta semena uljane repice na hemijski tretman

Rapeseed is a major oilseed crop that has various uses in the food, feed, and industrial sectors. The first condition for successful production and achieving high yields is to provide high-quality seeds, which, in addition to high seed vitality, also implies good seedling protection. The goal is to ensure an optimal number of plants per hectare, which is also a basic prerequisite for achieving high yields. Quality seed treatment has proven to be the best solution for plant protection in the initial stages of development. The seeds were treated with fungicides with the a.i. carboxin + thiram and fluopicolide + fluoxastrobin, as well as an insecticide with a.i. flupyradifuron, and the control was untreated seed. Treatments had a great influence on germination energy, seed germination, number of abnormal seedlings, length and weight of seedlings. The fungicidal fluopicolide + fluoxastrobin treatment had the greatest positive effect on most of the tested parameters, while the carboxin + thiram + flupyradifuron treatment had the greatest negative effect on the seed germination parameter.

Criopreservação de sementes de espécies brasileiras do gênero Dyckia (Bromeliaceae)

Cryopreservation of seeds of Brazilian species of the genus Dyckia (Bromeliaceae). The objective of this study was to evaluate different cryoprotectants in cryopreservation in liquid nitrogen (NL) of seeds of Dyckia dusenii, Dyckia kranziana and Dyckia walteriana and to quantify the lipid content of the seeds. The treatments were: control, immersion in NL, glycerol 1 mol.L-1, sucrose 0.4 mol.L-1, PVS1, PVS2, PVS2 + 1% floroglucinol and PVS3. From the seeds, the total lipid content was evaluated. The percentage of germination and abnormal seedlings, germination speed index, length and dry mass of the seedlings were evaluated. After 150 days, the length and dry mass of the aerial and root parts. The cryoprotectants were not effective in the seeds of D. dusenii and D. kranziana, however, for those of D. walteriana it is recommended to use the cryoprotectants glycerol 1 mol.L-1, sucrose 0.4 mol.L-1, PVS1, PVS2 , PVS2 + 1 % floroglucinol or PVS3. Studies of the composition of saturated and unsaturated fatty acids are necessary to establish a relationship with cryopreservation.

Overcoming dormancy in citrus rootstock seeds

Citrus is a fruit of great importance in Brazil, mainly in the socio-economic issue as it generates employment and income due to the production and export of concentrated orange juice, as well as other products. In view of the above, this work aimed to evaluate the dormancy overcoming of citrus seeds of the cultivars: Flying Dragon, San Diego, Índio, Cravo Santa Cruz, Riverside, BRS Sunki Tropical, Volkamerian, as well as the species Poncirus trifoliata. The seeds from Embrapa (Brazilian Agricultural Research Corporation) Clima Temperado, located in Pelotas-RS, as well as from Embrapa Cassava e Fruticultura, located in Cruz das Almas-BA, were submitted to the germination test as written in the Seed Analysis Rules and a germination test in which a small cut was made in the seed coat on the side of the embryo, around 0.1 mm with the help of a stylet, which was used 200 seeds (4 samples of 50 seeds per repetition) on germitest® paper, moistened with distilled water in an amount equivalent to 2.5 times its weight and kept inside a germinator at a constant temperature of 25 °C, photoperiod of 12 hours. The evaluations were carried out at the end of the 21 days after the installation of the test, providing data that were expressed in percentage of normal and abnormal seedlings and non-germinated seeds (hard, dormant or dead). of citrus seedlings at the end of the tests and the data obtained were submitted to analysis of variance and the means were compared by the Tukey test at a 5% significance level (p≤0.05), with the aid of the R- bio. It is concluded that, when evaluating germination and shoot and root length of seedlings cultivars Flying Dragon, Índio, Cravo Santa Cruz, BRS Sunki Tropical, Riverside and Volkameriano, San Diego and the species P. trifoliata, were satisfactory when submitted in the dormancy breaking process, but further studies are needed.

Seed Priming and Pericarp Removal Improve Germination in Low-Germinating Seed Lots of Industrial Hemp

Industrial hemp (Cannabis sativa L.) is experiencing a resurgence in North America as an agricultural commodity. Germplasm improvement for locally adapted and stable cannabinoid production is an industry priority. This study used seed priming and pericarp removal to recover seedlings in low-germinating seed lots that could prove important for plant breeding and germplasm conservation. Both seed priming and pericarp removal improved early seed germination, but pericarp removal was more effective in improving overall final germination percentages. On average, pericarp removal improved final germination in low-germinating seed lots by approximately 38% compared to intact seed germination. In seeds with the pericarp removed, the initial germination substrate had an impact on normal seedling development following transplanting: those germinated for 2 to 3 days on rolled towels produced more normal seedlings compared to those started in Petri dishes. There was a dramatic increase in abnormal seedlings produced in the low-germinating seed lot initially germinated in a Petri dish wetted with 6 mL water where nearly 80% never transitioned to normal actively growing seedlings.

Prediction of Germination Percentage Through Electrical Conductivity in White and Coloured Coated French Bean (Phaseolus vulgaris L.)

Background: Rapid detection of seed germination will be a valuable tool for seed testing laboratories and commercial seed companies. The EC test has been accepted into ISTA rules for beans. The potential of the electrical conductivity test (EC) readings in predicting total and normal germination of nine white coated and nine coloured coated French bean cultivar seeds was examined. Methods: Nine different white coated and nine coloured coated French bean (Phaseolus vulgaris L.) cultivars were obtained from different sources. EC measurements for predicting germination were carried out 2, 4, 6 and 8 h during soaking at 20°C. Germination test was conducted on three replicates of 50 seeds in between wet towel papers for 8 days at 25°C in the dark. Result: Regression models were developed between EC and percentages of normal and abnormal seedlings in the germination test. EC readings at 2, 4, 6 and 8 hours were negatively related to percentage of total (R2=0.717, 0.830 P less than 0.05) and normal germination percentages (R2=0.762, 0.897 P less than 0.05). Results suggested that EC measurements carried out in between 2 and 8 hours soaking can be used for the estimation of seed germination in beans.

Studies on the Quality and Health Status of T. Aman Rice Seeds Collected From Different Sources

A laboratory experiment was carried out at the Professor GAF Seed Pathology Centre and Laboratory of Department of Seed Science and Technology, Bangladesh Agricultural University (BAU), Mymensingh during the period of July 2018 to January 2019 to determine the effect of seed sources on quality and health status in some Transplanted Aman rice varieties in Bangladesh. Among the seed sources, the moisture content was recorded from 10.40% to 13.37%. In case of purity analysis of seed pure seed ranged from 39.23g to 39.94g. Germination test of rice seeds was recorded and the percentage of total number of germination ranged from 55.75% to 93.0%, normal seedling (51.50 % to 86.50%), abnormal seedling (4.75 % to 10.75%), fresh ingeminated seed (1.75% to15.0%), hard seed (0.0 % to 11.75%), dead seed (2.75% to 21.25%), respectively. Vigour index in the seed sources ranged from (1255.80 to 2089.86). In dry inspection test apparently healthy seeds (17.74gto 28.92g), spotted seeds (9.8g to 17.34g), deformed seeds (0.36g to 5.58g), discolored seeds (0.34g to 3.40g), inert mater (0.00g to 0.38g), insect damaged seeds (0.00g to 0.24g) and chaffy seeds (0.08 g to 1.14g) were recorded(2.75% to 21.25%), respectively. In the seed health study, seven species of fungi were recorded. In the seed health test Alternaria padwickii (1.25 % to 5.50%), Aspergilus niger (0.0% to 1.75%), Bipolaris oryzae (0.0% to 1.50%), Curvularia lunata (0.00% to 1.0%), Aspergillus flavus (0.00% to 1.25%), Penicillium sp. (0.00% to 1.50%) were recorded, respectively. Most of the farmers were failed to obtain the quality and good health status. In this study, BRRI dhan34 in farmer's seed recorded the highest performance in the seed sources and the lowest performance was recorded in BRRI dhan49 in farmer's seed. Among the seed sources BR22 of BADC seed (T8) performed the best in respect of seed quality and seed health.
 Vol. 9, No. 2, August 2022: 103-116

Acclimatization of coffee seedlings obtained from zygotic embryos of aged seeds

Coffee seeds rapidly lose viability during storage, which hinders the development of vigorous seedlings for crop establishment. There are reports that seed endosperm is more sensitive to deterioration than embryos, which can be excised and cultivated in vitro. However, a substantial number of plants grown in vitro do not survive during transfer to a greenhouse or field environment. The objective of this study was to evaluate the acclimatization of coffee seedlings of cultivar Catuaí Amarelo IAC 62, developed from zygotic embryos obtained from aged seeds in different substrates and environments, for the production of well-developed seedlings suitable for planting. For this purpose, seedlings were obtained from the in vitro cultivation of embryos obtained from seeds of two quality levels: freshly harvested seeds and artificially aged seeds. Zygotic embryos were extracted from the seeds and cultivated in MS medium. At 60 days, the percentages of normal and abnormal seedlings and dead seeds were evaluated. The good-quality seedlings grown in vitro for 60 days were transplanted into two different substrates (Tropstrato and coconut fiber) and acclimatized in two environments (growth room and greenhouse with a misting system). The plants were evaluated for height, stem diameter, number of leaves, chlorophyll content, and growth rate. The greenhouse environment was better for seedling growth, possibly due to its higher sunlight and temperature. The best substrate was coconut fiber, as it ensured better development of plants from freshly harvested seeds and those from aged seeds. It is possible to develop healthy seedlings from seeds with low viability

Reduction of Weed Growth under the Influence of Extracts and Metabolites Isolated from Miconia spp.

Weeds pose a problem, infesting areas and imposing competition and harvesting difficulties in agricultural systems. Studies that provide the use of alternative methods for weed control, in order to minimize negative impacts on the environment, have intensified. Native flora represents a source of unexplored metabolites with multiple applications, such as bioherbicides. Therefore, we aimed to carry out a preliminary phytochemical analysis of crude extracts and fractions of Miconia auricoma and M. ligustroides and to evaluate these and the isolated metabolites phytotoxicity on the growth of the target species. The growth bioassays were conducted with Petri dishes with lettuce, morning glory, and sourgrass seeds incubated in germination chambers. Phytochemical analysis revealed the presence of flavonoids, isolated myricetin, and a mixture of quercetin and myricetin. The results showed that seedling growth was affected in a dose-dependent manner, with the root most affected and the seedlings of the lettuce, morning glory, and sourgrass as the most sensitive species, respectively. Chloroform fractions and myricetin were the most inhibitory bioassays evaluated. The seedlings showed structural changes, such as yellowing, nonexpanded cotyledons, and less branched roots. These results indicate the phytotoxic potential of Miconia allelochemicals, since there was the appearance of abnormal seedlings and growth reduction.

Zinc and methyl jasmonate modulate the growth and the volatile compounds of the 'Albahaca Dante' basil cultivated in vitro

The species Ocimum basilicum has many cultivars with different chemotypes. The basil cultivar ‘Albahaca Dante’ has great economic potential. Nevertheless, there is little data about the production of volatiles and the growth using elicitors. This study aims to evaluate growth, physiological disorders, enzymatic activity, biochemistry, stomatal analysis, and the volatile compounds of Ocimum basilicum L.' Albahaca Dante' cultivated in vitro under different concentrations of zinc sulfate (ZnSO4) and methyl jasmonate (MeJa). The experiment was conducted in a completely randomized design (CRD). Five treatments were evaluated based on the combination of MeJa x Zinc Sulfate, using a Murashige and Skoog medium. The results demonstrate that MeJa reduced the formation of abnormal seedlings. Nevertheless, the growth and the number of leaves were not incremented compared in half without elicitors. The number of volatile compounds was lower in the treatment without elicitors and with 25µM ZnSO4 + 1µMMeja. Methyl chavicol was the main compound in both treatments. In this case, the seedlings had smaller stomata with higher density. The seedlings that were developed under unfavorable conditions (75µM ZnSO4 + 1µM MeJa and 75µM ZnSO4 + 5µM MeJa) produced compounds such as Eugenol, Linalool, Methyleugenol, α-Bergamotene, and showed a reduction in the stomatal density, but larger size. The elicitors influenced the activity of antioxidant enzymes, except for 75µM ZnSO4 + 1µM MeJa, which occasioned an acute decrease of all enzymes. The elicitors altered the volatile composition of this basil cultivar and its biochemical responses

Seed quality of Brachiaria brizantha by X-ray image analysis using a Bayesian approach

Brachiaria brizantha is the most economically important forage grass in Brazil and is propagated through sowing. Producing high-quality seeds has been a constant challenge due to their uneven maturation. The development and application of precise and non-destructive methods for identifying internal damages to seeds, such as the X-ray test, which quickly indicates the quality of the lots, is of fundamental importance for the seed industry. In this work, the quality of Brachiaria brizantha seeds was analyzed based on the morphological characteristics observed in X-ray images that were related to viability using a mixture model under a Bayesian approach, with the following objectives: i) verify the adequacy of the Bayesian modeling used in the data analysis; ii) associate the efficiency of using radiographs as a way to assess the viability of the seeds; and iii) relate the classifications carried out by evaluators with the probability of originating normal or abnormal seedlings. The methodology applied for the analysis proved to be adequate. Further, the Bayesian estimates for parameters related to internal morphology were established with associated levels of uncertainty, which represents an advantage over usual frequentist methods. Based on the model's estimates, seeds evaluated as potentially unviable by three evaluators had practically no probability of germination and did not germinate in the test applied later. Seeds classified as potentially viable had a high probability of developing into normal seedlings, while 73.27% showed this property in the germination test.

Phytotoxicity evaluation of poly (ɛ-caprolactone) nanocapsules prepared using different methods and compositions in Brassica juncea seeds

The objective of this study was to analyze the phytotoxic effects of poly (ɛ-caprolactone) (PCL) nanocapsules on mustard ( Brassica juncea ) seeds. The nanoformulations were prepared using two protocols: PCL nanocapsules containing Tween as a stabilizer (NC TW) and PCL nanocapsules containing poly(vinyl alcohol) (PVA), a polymer that has emulsifying properties (NC PVA). Two experimental systems were used (nanoformulations sprayed on the substrate and as seed treatment), each one in a factorial scheme with two formulations (NC TW and NC PVA) and five dilutions (0%, 25%, 50%, 75%, and 100% of the stock formulation). In general, intermediary concentrations of NC TW showed higher phytotoxicity than NC PVA, as indicated by sharper reductions in germination and increases in the percentage of abnormal seedlings. However, in the substrate treatment, NC PVA (100%) led to a sharper reduction in germination than NC TW in the same dilution. NC TW-treated seeds presented greater water absorption. In an additional assay with nanocapsules labeled with a fluorescent probe (rhodamine B), NC PVA-treated seeds showed higher fluorescence intensity in the seed coat. In the case of NC TW-treated seeds, the fluorescence signal tended to move to the seed interior as the nanocapsule levels increased. Moreover, the seed treatment with this formulation induced sharper increases in water uptake by the seeds than NC PVA. The different effects induced by NC TW and NC PVA could be related to the different characteristics of the nanocapsules, as the lower size and more negative charge of NC TW might have favored their entrance into the seeds. • The nanocapsules led to some negative effects on seed germination. • They did not affect shoot and root length of mustard seedlings. • The nanocapsules altered the water uptake by the seeds. • The effects were dependent on the nanocapsules’ characteristics. • The effects were relatively low given the potential benefits of nanoencapsulation.

Fluoride effect indicators in Phaseolus vulgaris seeds and seedlings.

BackgroundFluoride (F) is one of the main environmental pollutants, and high concentrations are commonly detected in the air and in both surface and groundwater. However, the effects of this pollutant on seed germination and on the initial growth of crop seedlings are still poorly understood. In this context, the aim of this study was to assess morphoanatomical, physiological and biochemical fluoride effect indicators in Phaseolus vulgaris L. seeds and seedlings.MethodsP. vulgaris seeds were exposed to a liquid potassium fluoride solution (KF, pH 6.0) at concentrations of 0 (control), 10, 20, 30 mg L−1 for 7 days. A completely randomized experimental design was applied, consisting of four treatments with four replications each. During the experimental period, physiological (7 days) anatomical and histochemical (2 days), biochemical and chemical (4 days) assessments. An analysis of variance was performed followed by Dunnett’s test. to determine significant differences between the KF-exposed groups and control seeds; and a multivariate analysis was performed.ResultsThe germination parameters, and anatomical, morphological, physiological, biochemical and nutritional characteristics of the seedlings did not show negative effects from exposure to KF at the lowest doses evaluated. On the other hand, treatment with the highest dose of KF (30 mg L−1) resulted in a lower germination rate index and increase in abnormal seedlings, and higher electrical conductivity. A lower root length, magnesium content and photochemical efficiency were also observed. The exposure of P. vulgaris to KF, regardless the dose did not affect seeds anatomy and the accumulation of starch and proteins, in relation to the control group.ConclusionsOur findings demonstrated that P. vulgaris seedlings were tolerant to KF solutions up to 20 mg L−1, and sensitive when exposed to 30 mg KF L−1.

Influence of Biopolymer Synthesized from Tamarind Seed Polysaccharide (TSP) on Physiological and Biochemical Parameters of Maize Hybrid COH(M) 8 Seeds

The experiment was conducted in Department of Seed Science and Technology, Tamil Nadu Agricultural University, Coimbatore, Tamil Nadu during 2021. Biopolymer was synthesized from Tamarind Seed Polysaccharide (TSP) and added with different additives and coated maize seeds to know how they effect their physiological and biochemical parameters. The seeds were given with four treatments viz., T0- control (untreated seed), T1- biopolymer (B.P) - 10g kg-1, T2- B.P (10g) + Humic acid (0.3g) + Zimmu (Allium cepa × Allium sativum) leaf extract (0.5 ml) and T3- T2+ Ascorbic acid (0.2 g) and evaluated for seed quality parameters. The results of the present investigation revealed that T3 was significantly superior viz., higher percentage of germination (95%), rate of germination (31.64), seed metabolic efficiency (2.78), seedling root length (25.92 cm), seedling shoot length (15.57 cm), total biomass production (9.41 g), vigour index I (3942), vigour Index-II (94.15). This treatment also recorded highest value of biochemical parameters such as α-amylase (2.23), dehydrogenase (1.87 OD value), catalase (29.94) and peroxidase (7.00) activities. It reduced the abnormal seedlings (2%), dead seeds (3%), days to 50% germination (2.54), mean emergence time (3.02) and pathogen infection (0.25%). We concluded that maize seeds coated with T3 had better seedling establishment and may be recommended as pre sowing seed treatment under organic agriculture.

Defense response-like reaction associated with an anomaly in Eucalyptus grandis

Key messageBased on transcriptome and qPCR analysis, a phenotypic abnormality resulting from a Eucalyptus crossing is associated with overexpression of metabolic pathways related to defense responses against biotic and abiotic stress.Genetic recombination by outcrossing, a strategy used in improvement programs, can present a low frequency of individuals within progeny with morphological and physiological abnormalities. An abnormality was identified in progeny from a controlled cross of Eucalyptus grandis. Applying RNA-Seq technology to leaf, stem, and root tissue of normal and abnormal seedlings grown under the same greenhouse conditions, we examined global gene expression changes and compared the transcriptional profiles of the two contrasting phenotypes. We also conducted functional enrichment and metabolic pathway analyses. Among the identified differentially expressed genes, most were upregulated in leaf and stem tissues of abnormal plants, with gene ontology (GO) terms associated with 'response to stress', 'response to stimulus', and 'immune system process' categories. Further, in differential gene expression and functional enrichment analyses, we observed overexpression of metabolic pathways related to defense response processes in abnormal plants. Our results suggest that the anomaly is associated with changes in the defense response to biotic and abiotic stresses. As all progeny were grown in a controlled environment and there was no evidence of pathogenic attacks, the defense response in abnormal plants may be due to an autoimmune mechanism caused by genetic incompatibility.

A Novel Endophytic Trichoderma longibrachiatum WKA55 With Biologically Active Metabolites for Promoting Germination and Reducing Mycotoxinogenic Fungi of Peanut.

Plant residuals comprise the natural habitat of the plant pathogen; therefore, attention is currently focusing on biological-based bioprocessing of biomass residuals into benefit substances. The current study focused on the biodegradation of peanut plant residual (PNR) into citric acid (CA) through a mathematical modeling strategy. Novel endophytic Trichoderma longibrachiatum WKA55 (GenBank accession number: MZ014020.1), having lytic (cellulase, protease, and polygalacturonase) activity, and tricalcium phosphate (TCP) solubilization ability were isolated from peanut seeds and used during the fermentation process. As reported by HPLC, the maximum CA (5505.1 μg/g PNR) was obtained after 9 days in the presence of 15.49 mg TCP, and 15.68 mg glucose. GC–MS analysis showed other bioactive metabolites in the filtrate of the fermented PNR. Practically, the crude product (40%) fully inhibited (100%) the growth and spore germination of three mycotoxinogenic fungi. On peanuts, it improved the seed germination (91%), seedling features, and vigor index (70.45%) with a reduction of abnormal seedlings (9.33%). The current study presents the fundamentals for large-scale production in the industry for the sustainable development of PNR biomass as a natural source of bioactive metabolites, and safe consumption of lignocellulosic-proteinaceous biomass, as well. T. longibrachiatum WKA55 was also introduced as a novel CA producer specified on PNR. Application of the resulting metabolite is encouraged on a large scale.

Toxicogenetic effects are involved in the occurrence of imbibitional damage in soybean seeds

Soybean represents a valuable source of food for humans and animals and the quality of the seeds has great importance for the establishment and high productivity of this crop. Soybean seeds require continuous improvement, which is dependent on a better understanding of the regulatory mechanisms that coordinate seed germination. To investigate whether the method of water absorption into soybean seeds could lead to abnormal seedlings, and if this could be associated with cytogenetical consequences, we premoistened the seeds of three cultivars; M 6410 IPRO, M6210 IPRO, and BMX Potência RR by direct immersion (fast method), use of a wet substrate (intermediate method), and by moist atmosphere (slow method) with distilled water at 25ºC for 24 hours. We investigated the normal and abnormal seedlings, electrical conductivity, mitosis, cell death, and the chromosomal abnormalities index. The comet assay was applied to investigate DNA fragmentation. Direct immersion in water induced seedling growth inhibition and caused cytological alterations associated with genotoxicity effects in the studied soybean genotypes. Slow premoistening of the seeds increased seedling performance as a result of higher final germination percentage (above 85%), reduced abnormal seedlings (below 5%, on average), and reduced the electrical conductivity of seeds. All three genotypes of soybean seeds lost their ability to withstand the imbibitional damage induced by direct immersion as abnormal seedlings increased. We concluded that the fast water absorption by seeds poses a threat to genomic integrity owing to its potential for genotoxicity to DNA, manifesting as breaks or loss of whole chromosomes. Slow premoistening of the seeds resulted in a longer time period to deal with damage. Stabilized seedling growth was provided by altering cytogenetic responses during uptake of water by soybean seeds through the maintenance of cell viability.

Physiological and biochemical performance of lettuce (Lactuca sativa L.) seeds treated with essential oils used to control phytopathogens

This work aimed to evaluate the physiological and biochemical performance of lettuce (Lactuca sativa L.) seeds treated with essential oils (EOs) of citronella (Cymbopogon sp.), guaçatonga (Casearia sylvestris Sw.), melaleuca (Melaleuca sp. L.), patchouli (Pogostemon sp. Benth), and pitangueira (Eugenia uniflora L.). The experimental design was completely randomized in double factorials (5 oils × 4 doses) at different doses (10, 20, 30, and 40 μL), with an additional treatment that served as growth control (without EOs, 0 μL). In other words, the experimental design entails 5 oils × 4 doses + 1 control, with 4 replicates of 100 Grand Rapid lettuce seeds without industrial chemical treatment. The response variables were: first germination count (FGC, %), last germination count (LGC, %), germination rate (GR), normal seedlings (NS, %), abnormal seedlings (AS, %), aerial part length (APL, cm), fresh mass (mf, g), total soluble proteins content (mg•g-1), and enzyme activities of β-1,3-glucanase (UA•mg-1) and phenylalanine ammonia-lyase (PAL, UA•mg-1). The lettuce plant proved to be a good reference plant for evaluations related to physiological and biochemical performance when treated with EOs. However, although treatment of lettuce seeds with EOs did not cause undesirable damages, it positively altered the physiological parameters APL and mf. All EOs affected the total proteins content and enzyme activities of PAL and β-1,3-glucanase. Therefore, EOs demonstrated the potential to activate the plant's defense mechanism to control phytopathogens. More specifically, 10 μL of citronella EO activated two plant defense mechanisms: PAL and β-1,3-glucanase activities. In addition, EOs of melaleuca (10 and 40 μL) and patchouli (20 and 30 μL) also activated PAL enzyme activity.

SOYBEAN GENERATIONS UNDER GAMMA RAYS AND EFFECTS ON SEED QUALITY

Mutation induction is used to improve existing or generate new varieties. The objective of this study was to evaluate the effect of gamma radiation doses under successive generations of cultivation on seed quality of two soybean lines (VX04-6828 and VX04-5692). Different gamma-ray doses (60Co) were evaluated (0; 50; 150 and 250 Gray) in the M0 (first sowing) generation, and analyzed for water content, germination, vigor, abnormal seedlings, dead seeds, and hilum color. Then, sowing (M0) was carried out to obtain plants and seeds of the first production cycle (M1 generation), and then those of the subsequent cycle (M2 generation). The same analyses of M0 were performed for M2 and M3 generations, with the addition of germination rate and emergence speed index in the field. The data were submitted to analysis of variance in a factorial arrangement. The generations were compared using Tukey’s test, while doses were evaluated by regression analysis. Seeds of the two soybean lines showed significant interaction for the different generations and gamma-ray doses in all the variables analyzed, except for water content. The application of gamma rays in soybean seeds showed effects on successive generations of cultivation, with better physiological quality up to the dose of 150 Gy (Gray) and greater sensitivity to gamma radiation for the VX04-5692 line.

ENHANCEMENT THE SEEDLING QUALITY OF OKRA THROUGH PRIMING WITH H2O2

The experiment was conducted to evaluate the physiological fluctuations in the seeds of okra seeds primed with the aqueous solutions of H2O2 and to find the suitable strength(s) of H2O2 as the priming material for their highest seedling quality. The experiment had eight treatments: T1 (control/no priming), T2 (hydro-priming in plain H2O) and other six aquatic solutions of H2O2: T3 (0.5%), T4 (1.0%), T5 (1.5%), T6 (2.0%), T7 (2.5%) and T8 (3.0%). The seeds were soaked for six hours in those seven media (T2 toT8). The seeds were dibbled in wooden seed flats filled-in with coarse sand. The experiment was laid-out in the RCBD with three replications. Data collected for the 13 traits were: % germination, % abnormal seedlings, shoot length, root length, seedling length, shoot dry matter, root dry matter, seedling dry matter, number of secondary roots (>1cm) per seedling, number of true leaves per seedling, relative growth rate, seedling vigor index, and root: shoot ratio (dry weight basis). Except the first two traits, the rest 11 were collected at three stages: 10, 20 and 30 days after dibbling (DAD). It was lucid that H2O2 was significantly (P≤0.05%) effective to improve most of the traits noted. But 1% concentration was utmost helpful for both okra and others were toxic and hindered the maximum parameters for all the three species. Nevertheless, further studies with different varieties of those three vegetables species with variable doses of H2O2, priming time and temperature could be explored before drawing valid conclusions.