Low Physiological Quality Research Articles

Identification of Greenish Soybean Seeds through Image Processing, under Different Types of Lighting

A high occurrence of greenish soybean seeds in crops is an issue, these types of seeds have low physiological quality, which can generate seedlings with anomalies, if destined for processing in industries, the presence of chlorophyll is undesirable, requiring additional processes for its removal. This work aimed to evaluate the differentiation of mature and greenish soybean seeds, illuminated with red laser, green laser, red LED, and fluorescent lamp, using image processing. Images of mature and greenish soybean seeds were captured at a resolution of 340x480 pixels, illuminated with red laser, green laser, red LED, and fluorescent lamp. Subsequently, the averages of the gray levels of each image were obtained in the red, green, blue channels and in images converted to grayscale 8-bit. The data were submitted to tests of variance after gray level for image classification. And a validation presented results of 97% of hits for red laser, 94% for fluorescent light and 93.5% for red LED, all in red channel. Keywords: seed classification, agricultural automation, soybean seed quality, computer vision

The role of PME and ADH enzymes in seed deterioration and its implication for producing high quality soybean seed

Soybean seeds are member of the orthodox seeds group which suseptable to deterioration. The low quality of soybean seeds used by farmers is one of the causes of the low soybean productivity at the farmer level. Pectin methylesterase (PME) and alcohol dehydrogenase (ADH) enzymes have been studied in relation to seed deterioration. Increase in seed moisture content is strongly suspected to be the initial occurrence and increase in PME enzyme activity which then followed by ADH enzyme activity in a series of biochemical reactions leading to the accumulation of acetaldehyde-protein adducts (APA) in soybean seeds. The APA contributes to deterioration of seeds. Thus, the increase in APA in soybean seeds may be used as an indicator of the level of deterioration of soybean seeds. Since high seed moisture content contributes to the initiation of PME activity in seeds, soybean seed production in the rainy season is not recommended because it will produce seeds with low physiological quality due to high PME activity so that the seeds cannot be stored for long-term period.

Delinting and neutralizers residue effect on stored cotton seeds physiological quality determined by phenotyping image analysis

Abstract: The cottonseed delinting removes lint from the seed coat to improve plantability and maintain the seed’s physiological quality, therefore, this work aimed to determine the effect of delinting and neutralizers’ residual on the physiological quality of stored cottonseed by using image analysis phenotyping. The experiment was a randomized factorial design of 3 x 4 x 2 and two periods of storage evaluation (0 and 180 days). The cotton seeds were delinted at three different times (2, 4, and 10 minutes), neutralized using four distinct neutralizers (Quicklime, Hydrated lime, Filler lime, and NaOH), and there were seeds with and without neutralizer residue. The evaluations carried out were: water content, seed residual lint imaging, germination, seedling emergence, and seedling length imaging. The neutralizers Quicklime, Hydrated lime, and Filler lime do not need removal from the cotton seed coat. In storage, only the neutralizer NaOH has a high latent effect in lowering cottonseed quality, and the other neutralizers have lower physiological quality when the residue is removed. The image analysis phenotyping is efficient in identifying seedlings’ vigor.

Drying of arabica coffee and its effect on the gene expression and activity of enzymes linked to seed physiological quality

The reduced longevity of coffee seeds has been attributed to their sensitivity to desiccation. Studies related to gene expression and enzyme activity in coffee seeds under drying are important for understanding the effects of drying on their physiological quality. The aim of this study was to investigate the molecular aspects of seeds under different drying methods and associate them with physiological quality. Coffee seeds with different water contents were dried both slowly and rapidly. Enzymatic activity was analysed, as well as the expression of genes that encode the enzymes superoxide dismutase, catalase, peroxiredoxins, isocitrate lyase, and endo-ß-mannanase. There was a significant effect of drying speed and final water content on enzyme activity and on the expression of the different genes analysed. In seeds under rapid drying, there was greater expression of the genes that encode the enzymes catalase and endo-ß-mannanase. Greater expression of the 1 CYS PRX and SOD genes and greater activity of the ICL isoenzymes were found in seeds with superior physiological quality, but greater activity of the endo-β-mannanase and CAT enzymes occurred in seeds with lower physiological quality.

Effect of Priming on Vigor of Germinated Chili (Capsicum annum L.) Seeds in Aluminium Stress Conditions

Seed germination in ultisol is a problem. Ultisol has a low pH, poor in nutrients and organic matter, and high Al content. The low physiological quality of seeds is also a limiting factor. The purpose of this study was to determine the effect of priming on the seed vigor of two chili varieties whose seeds have expired and have not expired. This experiment consisted of 2 experiments, namely Experiment 1, which used seeds that had expired (deteriorating), and Experiment II, which used seeds that had not expired (non-deteriorating). This study was structured using a completely randomized design (CRD) which was repeated three times. This experiment is factorial. The first factor is priming, consisting of five levels: control, immersion in water, 30% PEG, 50 ppm GA3, and 1% KNO3. At the same time, the second factor in the first experiment was the seeds of the Tanjung 2 and Kencana varieties that had expired (deteriorating). In the second experiment, the second factor was the seeds of the Tanjung 2 and Kencana varieties that had not expired (non-deteriorating). The data obtained were analyzed using the R statistic program with a 5% HSD test. The results showed that priming with 50 ppm GA3 and 1% KNO3 increased the vigor of seeds that had expired (deteriorating). Meanwhile, priming with water and 1% KNO3 increased the vigor of seeds that had not yet expired (deterioration). The Kencana variety has a higher vigor than the Tanjung 2 variety on expired seeds. In seeds that have not yet expired, both varieties have the same good vigor.

Physical integrity of endive and chicory seeds determined by automated analysis of radiographic images

Seeds are commercialized in Brazil after rigorous quality control, which is performed by mandatory tests that are time consuming and frequently destructive. X-ray image analysis has been highlighted as it has the advantage of being fast, nondestructive, can be automated, and for some species, has high correlation with the physiological quality of the seeds. This study aimed to investigate the efficiency of the X-ray test, combined with digital image processing techniques, to evaluate the characteristics of the internal structures of endive (Cichorium endivia L.) and chicory (Cichorium intybus L.) seeds, as well as to relate these characteristics to the physical integrity and physiological potential of the seeds. Four commercial chicory seed lots and six commercial endive seed lots were submitted to the X-ray test and subsequent germination test. By visual analysis of the images, cracks, embryo malformation, and empty spaces in the seeds were identified. The seeds presented high physiological quality, which agrees with the data obtained in the radiographic image analysis. The physical parameters evaluated through image analysis inferred the seed integrity and seed filling. Although a low correlation between physical and physiological parameters was observed, the analysis of the radiographic images allowed the identification of seeds with low physical and physiological quality. Thus, X-ray analysis is efficient in evaluating the physical integrity of chicory and endive seeds and has the potential to infer their physiological quality.

Physiological Quality of Corn Seeds Treated with Gaseous Ozone

ABSTRACT The objective of this study was to evaluate the effect of gaseous ozone on the physiological quality of corn seeds with different initial germination percentages. Seeds with initial germination percentages of 54.0% (low physiological quality) and 86.0% (high physiological quality) were used. Samples of 0.12 kg of seeds were exposed to different combinations of inlet ozone concentrations (10 and 30 mg L−1) and exposure times (0, 30, 60, 90, and 120 min). A flow rate of 1.0 L min−1 was used at a temperature of 25 °C. The percentage of germination, shoot, root, and seedling lengths, germination velocity index, and electrical conductivity were analyzed. Univariate and multivariate analysis were used for data analysis. Seeds with low initial germination percentage showed increase of 1.6 to 1.8 times in germination percentage and approximately 1.2 times in length of the seedlings when the inlet ozone concentration was 10 mg L−1 and the exposure times were 30 and 120 min. Regarding seeds of high physiological quality, there was an increase in the germination velocity index of 1.1 to 1.2 times in ozonated seeds at 10 mg L−1, compared to the non-ozonated seeds. According to the multivariate analysis, the inlet ozone concentration of 10 mg L−1 associated with exposure times of 30 and 120 min showed similar results for seeds with low initial germination percentage. Based on the obtained results, we concluded that regardless the initial corn seeds quality, the recommended treatment is made by the combination of inlet ozone concentration of 10 mg L−1 and exposure time of 30 min. Also, greater benefits are obtained from the application of ozone gas in corn seeds of low initial physiological quality. The ozonation proved to be a promising technique for seed treatment since it increased germination percentage and shoot and seedling lengths.

EFFECT OF PHITOREGULATOR DOSES ON GERMINATION AND VEGETATIVE PHASE OF SOYBEAN WITH LOW PHYSIOLOGICAL QUALITY SEEDS

The objective of this work was to evaluate seed germination and the initial development of soybean plants with low physiological quality seeds submitted to different doses of phytoregulator. The experiment was carried out from March to April 2018 in Campo Novo do Parecis, MT, Brazil. The experimental design was of completely randomized blocks, in a 3x4 factorial scheme, being three soybean cultivars: Monsoy 7739, Desafio and Monsoy 8372, and four doses of phytoregulator: 0.0; 0.5; 0.75 and 1.0 L ha-1 of Stimulate® composed of cytokinin, indole butyl acid and giberelic acid. Totaling 12 treatments with four replicates. The evaluated variables were: initial germination, final germination, plant height, dry shoot mass, dry root mass and total dry mass. The cultivars responded differently to the phytoregulator doses. The cultivar Monsoy 7739 responded positively to the use of phytoregulator, as it increased germination, presented higher plant height, dry root mass and total dry mass, at the maximum dose of 1.0 L ha-1.The cultivar Desafio responded negatively to the phytoregulator, as germination presented significant differences compared the other evaluated variables. Monsoy 8372 did not conclusively respond to the use of the phytoregulator conclusively.

Qualidade de sementes de soja após a inoculação de biológicos em campo

A combinação de bactérias fixadoras de nitrogênio e fungos biocontroladores que interferem no desenvolvimento de plantas pode constituir uma ferramenta que permita promover uma melhor qualidade de sementes obtidas sob estas combinações. O objetivo deste trabalho foi verificar a interação de bioprodutos a base de Bradyrhizobium japonicum, Azospirillum brasilense, Trichoderma asperrellum e BioAx aplicados no solo visando melhorar a qualidade de sementes em cultivares de soja. O delineamento experimental utilizado foi inteiramente casualizado em esquema fatorial 3 × 4, com três repetições. Os tratamentos consistiram em três cultivares de soja [Brasmax Foco IPRO, Brasmax Desafio IPRO e Brasmax Bônus IPRO] e quatro biológicos [T1- Azospirillum brasilense + Bradyrhizobium japonicum, T2- BioAx, T3- Trichoderma asperrellum, e T4- a combinação dos três biológicos]. Avaliou-se: a primeira contagem de germinação, germinação, condutividade elétrica, massa seca da parte área e de raízes de plântulas e teste de tetrazólio (vigor e viabilidade). Os resultados mostraram que as respostas obtidas foram dependentes das cultivares avaliadas, e que Brasmax Foco IPRO e Brasmax Desafio IPRO apresentaram maior qualidade fisiológica das sementes. O efeito dos biológicos dependem da cultivar da soja; em cultivares com maior qualidade fisiológica o efeito do biológico não é evidente. Entretanto, em cultivares com menor qualidade fisiológica (Brasmax Bônus IPRO), o efeito dos biológicos é mais evidente, constituindo assim uma excelente alternativa de se melhorar a qualidade das sementes de soja com o uso combinado de biológicos.

Physical and physiological quality of Jatropha curcas L. seeds at different maturity stages using image analysis

Aim of study: To assess the potential of automated X-ray image analysis to evaluate the physical characteristics of Jatropha curcas seeds, and to relate the parameters obtained with the physiological quality of the seeds harvested at different maturity stages.Area of study: Experimental area of Agronomy Department, Federal University of Viçosa (UFV), Brazil.Material and methods: The fruits were harvested from 20 plants, based on the external skin color (green, yellow, brownish-yellow and brown). The study was performed by automated and visual analysis of radiographic images of the seeds, in which measurements of tissue integrity, density and seed filling were performed. Seed dry matter, germination and seedling growth were also analysed.Main results: Variables obtained through automated analysis of radiographic images correlated significantly with all physiological variables (r > 0.9), as well as visual image evaluations (r > 0.75). The seeds extracted from green fruits presented lower tissue integrity and lower physiological quality. Radiographic analysis was efficient for monitoring J. curcas seed quality at different maturity stages. Morpho-anatomical parameters obtained from X-ray analysis were highly correlated with seed physiological attributes.Research highlights: It is important to develop and improve methodologies based on lower-cost techniques, such as X-ray analysis. In this context, we verified that X-ray images can be used for monitoring J. curcas seed filling and maturation. Radiographic images of seeds can be analyzed automatically with ImageJ software. Internal morphology and physical characteristics of seeds have relationship with their physiological quality.

Ozonized Water in the Preconditioning of Corn Seeds: Physiological Quality and Field Performance

ABSTRACT Corn is a cereal of great economic and social importance worldwide. The objective of the present work was to evaluate the effects on the physiological quality and the performance in the field of corn seeds with different quality standards before and after hydropriming with ozone. To evaluate the effects on the physiological quality, two batches (one with high physiological quality and the other with low physiological quality) of corn seeds were used. Seeds from both batches were immersed in distilled water and bubbled with atmospheric air (control - 0 mg L-1) or ozone. Three inlet concentrations of ozone (0, 10, and 20 mg L−1) and five periods of preconditioning (0, 30, 60, 90, and 120 min) were used. To evaluate the physiological quality of the seeds, different tests were carried out both in the laboratory and in the field. The use of the corn seed hydropriming with atmospheric air or ozone favored the physiological quality of the corn seeds when considering laboratory and field variables. There was an increase of emergence in the field of seeds not submitted to aging (high physiological quality) only due to the preconditioning period. The use of ozone was positive in lowering the loss of cellular solutes in seeds submitted to aging. Ozonation also caused significant increases in the plant heights and in the first ear insertion height. The binomial 20 mg L−1/60 min is the most suitable for preconditioning corn seeds in ozonated water.

Production fields and physiological quality of Panicum maximum jacq. cv. mombasa seeds

The physiological quality of seeds is influenced by the climatic factors of production fields. The identification of the best conditions of P. maximum cv. Mombasa production fields allows the improvement of the seed sector. The aim of this work was to identify which climatic conditions of production fields can affect the physiological quality of P. maximum cv. Mombasa seeds. Nineteen plots from states of São Paulo (six from municipalities of Auriflama and three from Guzolândia) and Goiás (eight from Quirinópolis and two from Serranópolis), were collected by soil sweeping. The following parameters were evaluated: water content, germination rate, first germination count and germination rate index, seedling emergence in sand and field. Completely randomized design was used for all variables, with the exception of seedling emergence in field, since this variable required block design. Means were compared by the Scott-Knott test, at 5% probability. For the identification of the influence of climatic conditions on the physiological quality of seeds, multivariate statistical analysis was applied through Group and Principal Component Analysis. Production fields of Panicum maximum cv. Mombasa seeds presenting maximum temperatures above 32 ºC at flowering and natural fall stages produce seeds of low physiological quality. Production fields in which precipitation and high temperatures occur during natural fall and harvest of P. maximum cv. Mombasa seeds are not favorable to the production of seeds with high physiological quality.

The Application of Coconut Water at Various Levels of Robustness for Improving The Physiological Quality of Onion True Shallot Seed

Shallots are one of vegetable that can be cultivated with bulb or seeds. Shallot seeds better known as True Shallot Seed (TSS). Shallot cultivation using TSS still encounters several obstacles including low physiological quality of seeds. Physiological quality of seeds can be improved by plant growth regulators (PGR) application both natural or artificial. One of popular natural PGR is coconut water. The goal of this experiment was to determinate the effectiveness of various types of coconut water at freshness various levels toimprove TSS physiological quality. This experiment use factorial completely randomized design with 3 replications. First factor is 3 types of coconut water that are Gading Coconut, Hijau Coconut and Dalam Coconut. Second factor is 4 levels of water coconut freshness that are fresh coconut water, coconut water stored for 1 day, coconut water strored for 2 days and coconut water stored for 3 days. TSS used in this experient was Tisula variety. The result showed that various types of coconut water could improve physiological quality of TSS. Maksimum results obtained in HijauCoconut water with fresh, stored 1 day and strored 2 days treatment. Also Dalam Coconut water in fresh and stored 1 day. Gading Coconut water is also able to improve TSS physiological quality although the result as not as good Hijau Coconut and Dalam Coconut.

Physiological quality of cucurbits in spectral qualities

The objective of this work was to evaluate the influence of spectral qualities on the germination and vigor of cucurbit seeds. This experiment was a completely randomized design, in a factorial scheme 3 x 6, with three species of cucurbitaceae: cucumber, melon and watermelon. Six spectral qualities were used: blue LED, white LED, red LED, blue + red LED, fluorescent and dark (no light). Variables related to germination and vigor were analyzed. The cucurbitaceae presented differentiated responses when submitted to the different spectral qualities. For cucumber seeds, the luminous spectra increased root length, compared to the dark treatment. The melon seeds had low physiological quality; for these, the dark promoted a higher percentage of germinated and normal seeds. For watermelon seeds, the white LED conditions led to a higher percentage of normal seedlings, high rate of germination (IVG) and lower percentage of dead seeds. Red LED conditioned high IVG in watermelon. In general, fluorescent light favors carotenoid content and the dark condition favors shoot length in cucurbit seeds.

Sowing depth of annual ryegrass seed on different substrates as a vigor test

Abstract: Annual ryegrass seeds having low physiological quality can lead to the formation of pastures with undesirable plant stands for soil cover and forage utilization pastures. Thus, the objective of this study was proposing a vigor test to classify annual ryegrass seeds. For that, different sowing depths (0.5, 1.0, 1.5, 2.0, 2.5 and 3.0 cm) over three substrates (sand, coconut fiber, and carbonized rice husk) were tested to differentiate the physiological quality of four seed lots of annual ryegrass cv. BRS Ponteio having similarities in germination and moisture. The seed lots were classified according to vigor through the field seedling emergence (FSE), 1,000-seeds weight, saturated salt accelerated aging, and germination first count. The 2.5 cm of sand sowing depth and 3.0 cm of coconut fiber sowing depth provided separation of seed lots in similar groups of those reported to FSE test through the seedling emergence and speed of seedling emergence tests.

Gene Expression Related to Physiological Quality of Soybean Seeds

Production of soybeans with high physiological quality is important to ensure the productivity of improved plant populations. The objective of this work was to select soybean genotypes for high physiological quality of seeds, through germination and vigor tests, and to study gene expression by transcripts and proteins. In a first trial, seeds of 12 soybean cultivars were evaluated and selected six cultivars with contrasting physiological quality levels. At the protein level, the isoenzyme systems alcohol dehydrogenase (ADH), malate dehydrogenase (MDH), phosphoglucose isomerase (PGI), sorbitol dehydrogenase (SDH), superoxide dismutase (SOD), catalase (CAT), isocitrate lyase (ICL), esterase (EST), glutamate oxaloacetate transferase (GOT), and heat-resistant proteins were evaluated. For the transcript levels, the real-time PCR technique (qRT-PCR) was used, and the genes coding for the SOD, CAT, MDH, PGI, ICL and PRX enzymes were studied. The germination and vigor tests classified the seeds of cultivars CD201, CA115 and MS8400 as high quality, while the cultivars Syn1263, Syn1279 and CD202 were classified as of low quality. The enzymes involved in the process such as dehydrogenase and phosphoglucose isomerase, are promising markers for assessing the physiological quality of soybean seeds. Higher expression of peroxiredoxin enzyme is related to the low physiological quality of soybean seeds.

Glyphosate Resistance Affect the Physiological Quality of Conyza bonariensis seeds

ABSTRACT: High seed production and dispersal capacity and glyphosate resistance are among the main factors that have made hairy fleabane (Conyza bonariensis) one of the most important and dispersed weeds in the world. Herbicide-resistant weeds populations may have fitness cost due to molecular, physiological, and biochemical changes. This study aimed to evaluate the physiological quality of seeds of Conyza spp. and determine whether glyphosate resistance causes fitness costs for resistant biotypes. Seeds from six hairy fleabane biotypes, three glyphosate-resistant and three -sensitive, with a resistance factor average of 11.7 were studied. Among the studied biotypes, five were identified as C. bonariensis and one as C. blakei. Seed analyses were performed in a completely randomized design with ten replications of 100 seeds each (1,000 seeds per biotype). The analyzed seeds were originated from second-generation self-pollinating plants with known segregation rate. The mean results indicate that, in relation to sglyphosate-sensitive biotypes of C. bonariensis, seeds from -resistant biotypes showed a 16% reduction in vigor and 13% in germination, a 44% increase in the number of empty seeds and approximately five times more viable dormant seeds. The lower physiological quality of glyphosate-resistant hairy fleabane seeds regarding to -sensitive indicates that resistance affect the seed’s physiology and causes a fitness costs. It implies a reduction of invasive potential and persistence in the environment of resistant biotypes. Therefore, in the absence of glyphosate as a selective factor, the frequency of resistant biotypes tends to decrease and increase the predominancy of glyphosate-sensitivre biotypes. However, the highest number of viable dormant seeds of resistant biotypes supplies the soil seed bank. All biotypes of C. bonariensis showed higher physiological quality of seeds when compared to C. blakei, indicating that the first species is more adaptably evolved for survival in agricultural and disturbed areas.

Seeds of Peltophorum dubium submitted to osmotic conditioning increases germination and vigor

Peltophorum dubium (Spreng.) Taub. é uma espécie florestal nativa do Brasil utilizada em programas de restauração ambiental, paisagismo e construção civil. Sua propagação ocorre de forma seminal, porém, problemas na qualidade fisiológica das sementes aliados a ação de fatores bióticos e abióticos podem reduzir os percentuais de germinação e emergência. Neste contexto, técnicas que permitam a expressão do potencial fisiológico das sementes podem melhorar a germinação e o vigor em menor espaço de tempo. Uma destas técnicas é o condicionamento osmótico das sementes, o qual visa proporcionar a germinação mais rápida e uniforme, especialmente sob condições de estresse. O objetivo deste trabalho foi estudar se o condicionamento osmótico aumenta a germinação e o vigor de sementes de P. dubium. O estudo constituiu-se de três etapas: I – seleção do potencial osmótico ideal para a embebição; II - vigor e germinação de sementes osmocondicionadas e com diferentes teores de água; III - osmocondicionamento de quatro lotes de sementes com diferenças no vigor. A solução de PEG 6000 com -0,6 MPa é recomendada para o condicionamento osmótico de sementes de P. dubium com o objetivo de melhorar a germinação e o vigor. Sementes com teor de água próximo a 10% para o condicionamento osmótico influenciam positivamente o vigor. O condicionamento osmótico pode melhorar os aspectos fisiológicos de sementes de P. dubium com boa qualidade fisiológica, podendo reduzir o tempo de germinação e emergência e favorecendo os talhões com maior uniformidade e menor probabilidade de influência dos fatores bióticos e abióticos.

Treatment of soybean seeds of different levels of physiological quality with amino acids

Abstract: The aim of this study was to assess the effect of seed treatment at different levels of physiological quality with amino acids on the performance of seeds and plants in the field. The experimental design was a randomized complete block design with four replications involving a combination of two factors. Factor A consisted of seed lots of three levels of physiological quality (high, intermediate, and low) and factor B consisted of five doses of a commercial product based on amino acids used in seed treatment.Seeds of different levels of physiological quality were treated with a commercial product (C.P.) at doses of 0, 200, 400, 600, and 800 mL C.P. 100 kg−1 of seeds. After seed treatment, the physiological performance was assessed in the laboratory and then the seeds were sowed in the field aiming at assessing plant performance, yield components, and productivity. Seed treatment with amino acids does not promote the physiological performance of seeds and plants in the field. The productivity of isolated soybean plants from seed lots of a high physiological quality is 15% higher than that of plants from seed lots of a low physiological quality.

Qualidade fisiológica de sementes de mamona crioula var. Carrapatinho em função da posição do rácemo

The castor culture (Ricinus communis L.) is one of the most important crops for the semi-arid region of Brazil. Cultivation mainly relies on landraces, without breeding and low physiological quality. The objective of this study was to evaluate the physiological quality of Creole castor seeds var. Carrapatinho depending on the position of the raceme. The experiment was conducted at the State University of Southwest Bahia. The statistical analysis included a completely randomized design in a 2x3 factorial, corresponding to 2 morphological situations of castor seeds (presence and absence of wattle) from the racemes located in 3 different branches of the plant (primary branch, secondary and tertiary). Data were collected in laboratory conditions and in a greenhouse. At the end of the experiment the data were submitted to variance homogeneity and normality tests, and the averages were compared by Tukey test at 5%. It was concluded that the quality of Creole seeds variety Carrapatinho was affected by the racemes position in the plant, and that removal of caruncles positively affected most of the characteristics evaluated in the physiological quality tests on seeds, especially the electric conductivity.