Relationship between different physiological processes of Tomato seedlings exposed to acid mine water Uncovered using correlation analysis.

This study was conducted to assess the correlation between growth response, phytoaccumulation factor of different tissues, and elemental composition in tomato seedlings exposed to acid mine water (AMW). In pairwise correlation determinations values of plant height, stem diameter, seed germination indices (radicle length, final germination percentage (FGP), emergency rate index (ERI), vigour index (VI), germination percentage (G%) and germination rate index (GRI)) and the elemental compositions (Cd, Cr, Cu, Ni and Zn) in the different plant tissues, root (root accumulation factor = RAF), stem (stem translocation factor = STF) and leaves (leaf translocation factor = LTF) were selected for the relationship determinations. Pearson correlation coefficients were calculated and revealed the relationships between the paired parameters. The study concluded that the strongly correlated physiological parameters were jointly co-ordinated in tomato seedlings exposed to AMW.

Accurate machine learning-based germination detection, prediction and quality assessment of three grain crops.

BACKGROUND: Assessment of seed germination is an essential task for seed researchers to measure the quality and performance of seeds. Usually, seed assessments are done manually, which is a cumbersome, time consuming and error-prone process. Classical image analyses methods are not well suited for large-scale germination experiments, because they often rely on manual adjustments of color-based thresholds. We here propose a machine learning approach using modern artificial neural networks with region proposals for accurate seed germination detection and high-throughput seed germination experiments. RESULTS: We generated labeled imaging data of the germination process of more than 2400 seeds for three different crops, Zea mays (maize), Secale cereale (rye) and Pennisetum glaucum (pearl millet), with a total of more than 23,000 images. Different state-of-the-art convolutional neural network (CNN) architectures with region proposals have been trained using transfer learning to automatically identify seeds within petri dishes and to predict whether the seeds germinated or not. Our proposed models achieved a high mean average precision (mAP) on a hold-out test data set of approximately 97.9%, 94.2% and 94.3% for Zea mays, Secale cereale and Pennisetum glaucum respectively. Further, various single-value germination indices, such as Mean Germination Time and Germination Uncertainty, can be computed more accurately with the predictions of our proposed model compared to manual countings. CONCLUSION: Our proposed machine learning-based method can help to speed up the assessment of seed germination experiments for different seed cultivars. It has lower error rates and a higher performance compared to conventional and manual methods, leading to more accurate germination indices and quality assessments of seeds.

Synthetic strigolactone (rac-GR24) alleviates the adverse effects of heat stress on seed germination and photosystem II function in lupine seedlings.

There is increasing experimental evidence that strigolactones, a class of carotenoid-derived sesquiterpenoid hormones, and their downstream signal components play a role in plant resilience to abiotic stress. Strigolactones positively influence plant coping mechanisms in response to abiotic stressors like drought and high salinity. In this study, we examined the effects of rac-GR24 (a synthetic strigolactone analog) and strigolactone inhibitors on the physiological and molecular responses associated with thermotolerance during seed germination and seedling development in Lupinus angustifolius under heat stress. Photosystem I & II functions were also evaluated via Chl a fluorescence transient analysis in heat stressed lupine seedlings. Our results suggest a putative role for GR24 in mediating tolerance to heat stress during seed germination and seedling development albeit these responses appeared independent of D14-mediated signalling. Seeds primed with GR24 had the highest of all germination indices, enhanced proline content and reduced peroxidation of lipids. GR24 also enhanced the activities of enzymes of the antioxidant and glyoxalase systems in lupine seedlings. The JIP-test indicated that GR24 conferred resistance to heat stress-induced damage to the oxygen evolution complex while also preventing the inactivation of PSII reaction centres thus ensuring PSII thermotolerance.

Phytotoxicity assessment of olive mill wastewater treated by different technologies: effect on seed germination of maize and tomato.

The phytotoxicity effect of olive mill wastewater (OMWW) treated in a combined system regrouping pretreatment by filtration on olive stones and coagulation-flocculation, and anaerobic digestion (AD) on seed germination of maize and tomato was evaluated through germination tests in petri dishes and growth tests in pots. Three samples, referenced as AD-40, AD-60, and AD-80, were collected from the anaerobic reactor operating with an influent at 40, 60, and 80% OMWW/water (% v/v). Concentrations between 25 and 100% were used for maize and between 5 and 25% were used for tomato using raw and pretreated samples, while anaerobic samples were used without dilution. For maize, 100% and 75% OMWW were very phytotoxic and completely prohibited seed germination, while phytotoxicity was decreased following dilution at 25% and 50% OMWW. Maize germinability was found highly enhanced when watered with anaerobic samples. For tomato, high dilution was required to reduce the phytotoxicity of raw and pretreated OMWW and a high relative germination percentage was registered at 5, 10, and 15% OMWW, while for samples anaerobically treated, a high phytotoxicity is still observed. Growth tests, showed more favorable results for maize watered with raw and pretreated samples at 25% OMWW and with biological samples. For tomato and with the exception of 25% OMWW and AD-80, seeds respond positively to all samples. It was concluded that if the OMWW will be used for irrigating maize, it could be directly used after anaerobic digestion, while for tomato further dilution is required. The phenolic profile analysis of the tested samples coupled with the results of the germination tests showed that the OMWW phytotoxicity appears to be determined by not only the monomeric phenols but also by other toxic components unaffected by the applied treatments.

Seed Gamma Irradiation of Arabidopsis thaliana ABA-Mutant Lines Alters Germination and Does Not Inhibit the Photosynthetic Efficiency of Juvenile Plants.

Plant growth response to γ-irradiation includes stimulating or inhibitory effects depending on plant species, dose applied, stage of ontogeny and other factors. Previous studies showed that responses to irradiation could depend on ABA accumulation and signaling. To elucidate the role of ABA in growth and photosynthetic responses to irradiation, lines Col-8, abi3-8 and aba3 -1 of Arabidopsis thaliana were used. Seeds were γ-irradiated using 60Co in the dose range 50-150 Gy. It was revealed that the dose of 150 Gy affected germination parameters of aba3 -1 and Col-8 lines, while abi3-8 line was the most resistant to the studied doses and even showed faster germination at early hours after γ-irradiation at 50 Gy. These results suggest that susceptibility to ABA is probably more important for growth response to γ-irradiation than ABA synthesis. The photosynthetic functioning of 16-day-old plants mainly was not disturbed by γ-irradiation of seeds, and no indication of photosystem II photoinhibition was noticed, revealing the robustness of the photosynthetic system of A. thaliana. Glutathione peroxidase activity and ABA concentrations in plant tissues were not affected in the studied dose range. These results contribute to the understanding of germination and photosynthesis fine-tuning and of mechanisms of plant tolerance to ionizing radiation.

Zero-valent silver nanoparticles attenuate Cd and Pb toxicities on Moringa oleifera via immobilization and induction of phytochemicals.

Potentials of zero-valent extract of cocoa pod mediated silver nanoparticles (AgNPs) for heavy metals (cadmium and lead) immobilization, attenuation of induced toxicities and influence on phytochemical contents in Moringa oleifera were investigated. M. oleifera seeds were planted in soil spiked and watered with water (control), 0.2 mg AgNPs, 0.5 mg CdCl2, 0.5 mg PbCl2, 0.2 mg AgNPs + 0.5 mg CdCl2, 0.2 mg AgNPs + 0.5 mg PbCl2, 0.2 mg AgNPs + 0.75 mg CdCl2 and 0.2 mg AgNPs + 0.75 mg PbCl2 per g soil designated as groups A, B, C, D, E, F, G and H respectively. Significant (p < 0.05) repression in shoot and root lengths, percentage germination, number of leaves, vigour and growth tolerance indices, relative water contents with attendant inhibition of photosynthetic pigments, total carotenoid contents, total flavonoid contents and total phenolic contents were obtained for M. oleifera planted on Cd and Pb spiked soil. There were marked decrease in ferric reducing, hydrogen peroxide scavenging and free radical scavenging activities with resultant significant increase in lipid peroxidation (MDA) levels for M. oleifera grown on Cd and Pb treated soil compared to control with Pb having more deleterious effects. Conversely, AgNPs significantly enhanced both physiological and biochemical parameters in M. oleifera over control and considerably attenuated suppressions of these parameters in M. oleifera induced by Cd and Pb. Results in this study have shown AgNPs as excellent immobilizing agents and outstanding modulators of heavy metal induced toxicities.

Data collection and advanced statistical analysis in phytotoxic activity of aerial parts exudates of Salvia spp

In order to define the phytotoxic potential of Salvia species a database was developed for fast and efficient data collection in screening studies of the inhibitory activity of Salvia exudates on the germination of Papaver rhoeas L. and Avena sativa L.. The structure of the database is associated with the use of algorithms for calculating the usual germination indices reported in the literature, plus the newly defined indices (Weighted Average Damage, Differential Weighted Average Damage, Germination Weighted Average Velocity) and other variables usually recorded in experiments of phytotoxicity (LC50, LC90). Furthermore, other algorithms were designed to calculate the one-way ANOVA followed by Duncan's multiple range test to highlight automatically significant differences between the species. The database model was designed in order to be suitable also for the development of further analysis based on the artificial neural network approach, using Self-Organising Maps (SOM).

Estudio de la propagación sexual del arboloco Montanoa quadrangularis Schultz Bipontianus Asteraceae / Sexual propagation of arboloco Montanoa quadrangularis Schultz Bipontianus (Asteraceae) / Estudo da propagação sexual do "arboloco" Montanoa quadrangularis Schultz Bipontianus Asteraceae

Objetivo. Desarrollar metodologías para la propagación sexual Montanoa quadrangularis Schultz Bipontianus ("Arboloco"). Materiales y métodos. Las semillas se colectaron de árboles establecidos en La Estación Ambiental de Chilaca (Geoambiente Ltda) localizada en el municipio de Pacho-Cundinamarca (Colombia). Se establecieron dos etapas de estudio: en semillero, se evalúo el efecto de los sustratos suelo local, mezcla suelo local con humus de lombriz y turba y dos arreglos espaciales: siembra directa al azar y a 0,5 cm de profundidad sobre la respuesta germinativa de las semillas. En vivero, se evaluó el efecto de los sustratos: suelo local y suelo local mezclado con humus de lombriz y turba, los estados de desarrollo de las plantas: dos hojas, cuatro hojas y seis hojas sobre el crecimiento y desarrollo vegetal. Resultados. En semillero, la turba determinó la mayor capacidad germinativa con 83,67%, mientras que en el suelo local, se obtuvo la menor capacidad germinativa con un 40,83%. En vivero, las plantas con 6 hojas y trasplantadas en el sustrato suelo local con humus de lombriz, presentaron las mejores respuestas en parámetros como longitud total por planta (9,51 cm), área foliar (36,69 cm²), el peso seco total de la planta (0,10 g). Conclusiones. El tipo de sustrato utilizado en semillero, afectó la capacidad germinativa de semillas de M. quadrangularis. El tipo de sustrato utilizado en vivero y el estado de desarrollo, incidieron significativamente en el crecimiento y desarrollo del arboloco.

Objective. To develop sexual propagation methodologies for Montanoa quadrangularis Schultz Bipontianus (arboloco). Materials and methods. Seeds were harvested from trees grown at the Chilaca environmental station (Geoambiente Ltda.) located in Pacho, Cundinamarca, Colombia. The study was carried out in two phases: firstly, substrate effect on germination responses was evaluated in seedbed conditions. Substrates evaluated were: local soil, local soil mixed with worm humus, and peat. Additionally, two spatial arrangements were assessed: seeds sown at random and at 0.5 cm in depth. Secondly, in nursery conditions the effect of the substrates local soil, local soil mixed with worm humus and peat, as well as the effect of developmental stages of the plants (with 2, 4, and 6 leaves) on their further growth and development were evaluated. Results. In seedbed conditions, the germination capacity was highly influenced by peat substrate (83.67%) whereas in local soil the germination capacity was 40.83%. In nursery conditions, 6-leaf plants grown in local soil mixed with worm humus showed the best responses on parameters such as plant total length (9.51 cm), leaf area (36.69 cm²), and total dry weight (0.10 g). Conclusions. The type of substrate used in seedbed conditions influenced the germination capacity of M. quadrangularis seeds. The substrate and the developmental stage of the plant had a significant influence on the growth and development of arboloco plants.

Objetivo. Desenvolver metodologias para a propagação sexual da especie Montanoa quadrangularis Schultz Bipontianus ("Arboloco"). Materiais e métodos. As sementes foram coletadas de árvores localizadas na "La Estación Ambiental de Chilaca (Geoambiente Ltda), município de Pacho, Cundinamarca (Colômbia). Houve duas etapas de estudo: em sementeira, onde foi avaliado o efeito de substratos do solo local, mistura de solo local com húmus de minhoca e turfa e dois arranjos espaciais: plantio direito aleatório e a 0,5 cm de profundidade, sobre a resposta germinativa das sementes. No viveiro, foi avaliado o efeito dos substratos: solo local e solo local misturado com húmus de minhoca e turfa, e os estágios de desenvolvimento das plantas: duas folhas, quatro folhas e seis folhas no crescimento e desenvolvimento das plantas. Resultados. Na sementeira, a turfa determinou a maior capacidade germinativa com 83,67%, enquanto que o solo local apresentou a menor capacidade germinativa com 40,83%. No viveiro, as plantas com 6 folhas e transplantadas para o substrato de solo local com húmus de minhoca, apresentaram as melhores respostas em parâmetros como o comprimento total por planta (9,51 cm), área folhar (36,69 cm²), e peso da matéria seca total da planta (0,10 g). Conclusões. O tipo de substrato utilizado na sementeira afetou a capacidade germinativa das sementes de M. quadrangularis. O tipo de substrato utilizado no viveiro e o estado de desenvolvimento, influenciaram significativamente no crescimento e desenvolvimento do "Arboloco".