BACKGROUND: Elaeocarpus prunifolius Wall. ex Müll. Berol. is a threatened tree species of north-eastern India. The present study was undertaken to investigate the type of dormancy prevailing in seeds of E. prunifolius, explore seed dormancy breaking techniques and assess seedling fitness. METHODS: Ripe fruits of E. prunifolius were harvested from Jaintia hills, and seeds were subjected to various physical, manual and chemical treatments. The effect of plant growth regulators, viz gibberellic acid (GA₃) and potassium nitrate (KNO₃), were tested. Seedling vigour and survival based on seed weight were examined. RESULTS: Germination took 6 months to initiate after seed dispersal and natural germination percentage of fresh seeds was 24%. Physical pre-germination treatments such as surface and acid scarification failed to overcome dormancy. Cracked seeds promoted germination (46%) with a mean germination time of 146 days (time to 50% germination, T₅₀ = 144 days). Among the GA₃ treatments, split seeds treated with GA₃ (3000 mg/L⁻¹) yielded the highest germination (24%) with a T₅₀ of 55 days whereas KNO₃ did not promote germination. A combination of GA₃ and KNO₃, however, increased the germination to 31%. Between the seed weight classes, the highest percentage of germination was observed in heavy seeds (25%) and the lowest in light seeds (20%). There was no significant variation between seed weight and germination time (p > 0.05). Seed weight had a significant effect on the shoot height, number of leaves and dry weight of seedlings (p < 0.05). CONCLUSION: Based on the seed tests, E. prunifolius seeds exhibits ‘combined’ dormancy (physical and physiological) as splitting seed coat and application of GA₃ effectively broke dormancy. Splitting the seed coat is a cost-effective method for accelerating germination of seeds. Heavy-weight seeds produced better performing seedlings compared to their counterparts which may be viewed as an important reproductive strategy of the species.

Abstract Background Elaeocarpus prunifolius Wall. ex Müll. Berol. is a threatened tree species of north-eastern India. The present study was undertaken to investigate the type of dormancy prevailing in seeds of E. prunifolius, explore seed dormancy breaking techniques and assess seedling fitness. Methods Ripe fruits of E. prunifolius were harvested from Jaintia hills, and seeds were subjected to various physical, manual and chemical treatments. The effect of plant growth regulators, viz gibberellic acid (GA3) and potassium nitrate (KNO3), were tested. Seedling vigour and survival based on seed weight were examined. Results Germination took 6 months to initiate after seed dispersal and natural germination percentage of fresh seeds was 24%. Physical pre-germination treatments such as surface and acid scarification failed to overcome dormancy. Cracked seeds promoted germination (46%) with a mean germination time of 146 days (time to 50% germination, T 50 = 144 days). Among the GA3 treatments, split seeds treated with GA3 (3000 mg/L−1) yielded the highest germination (24%) with a T 50 of 55 days whereas KNO3 did not promote germination. A combination of GA3 and KNO3, however, increased the germination to 31%. Between the seed weight classes, the highest percentage of germination was observed in heavy seeds (25%) and the lowest in light seeds (20%). There was no significant variation between seed weight and germination time (p > 0.05). Seed weight had a significant effect on the shoot height, number of leaves and dry weight of seedlings (p < 0.05). Conclusion Based on the seed tests, E. prunifolius seeds exhibits ‘combined’ dormancy (physical and physiological) as splitting seed coat and application of GA3 effectively broke dormancy. Splitting the seed coat is a cost-effective method for accelerating germination of seeds. Heavy-weight seeds produced better performing seedlings compared to their counterparts which may be viewed as an important reproductive strategy of the species.

The germination of papaya seeds is slow and uneven, usually due to inhibitors present in the sarcotesta; however, some removal procedures may cause physical damage, negatively interfering in the physiological quality and field performance. This study aimed to evaluate the physical and physiological quality of papaya seeds submitted to methods of sarcotesta removal by image analysis. Papaya Formosa ‘Tainung 01' seeds were submitted to the following methods of sarcotesta removal: fermentation + sieve, sand + sieve, sieve and blender + sieve. After the sarcotesta removal, the seeds were submitted to tests of germination, first germination count, germination speed and seedling length. For the image analysis, the seeds without sarcotesta were submitted to the X-ray test and to a computerized analysis of seedling images by the SVIS® software. The methods used were only promising for the sarcotesta removal, while the blender + sieve method obtained the highest physical and physiological seed quality, in addition to performing the best sarcotesta removal. However, the image analysis using the SVIS® software allowed to identify the high physical and physiological seed quality using the blender + sieve method, which promoted the highest efficiency in removing the sarcotesta.

RESUMO A germinação de sementes de mamão é lenta e desuniforme, normalmente em função de inibidores presentes na sarcotesta; no entanto, alguns procedimentos de retirada podem acarretar danos físicos, interferindo, de forma negativa, na qualidade fisiológica e no desempenho em campo. Objetivou-se avaliar a qualidade física e fisiológica de sementes de mamão, submetidas a métodos de remoção da sarcotesta, por meio de análise de imagens. Sementes de mamão Formosa ‘Tainung 01' foram submetidas aos seguintes métodos de remoção da sarcotesta: fermentação + peneira, areia + peneira, peneira e liquidificador + peneira. Após a retirada da sarcotesta, as sementes foram submetidas a testes de geminação, primeira contagem de germinação, velocidade de germinação e comprimento de plântula. Para a análise de imagem, as sementes sem sarcotesta foram submetidas ao teste de raios X e à análise computadorizada de imagens de plântulas pelo software SVIS®. Os métodos utilizados mostraram-se promissores somente para a retirada da sarcotesta, enquanto o método peneira + liquidificador, além da melhor retirada, obteve alta qualidade física e fisiológica das sementes. Entretanto, a utilização do software SVIS® permitiu identificar a alta qualidade física e fisiológica das sementes com a utilização do método liquidificador + peneira, que promoveu maior eficiência na remoção da sarcotesta. | ABSTRACT The germination of papaya seeds is slow and uneven, usually due to inhibitors present in the sarcotesta; however, some removal procedures may cause physical damage, negatively interfering in the physiological quality and field performance. This study aimed to evaluate the physical and physiological quality of papaya seeds submitted to methods of sarcotesta removal by image analysis. Papaya Formosa ‘Tainung 01' seeds were submitted to the following methods of sarcotesta removal: fermentation + sieve, sand + sieve, sieve and blender + sieve. After the sarcotesta removal, the seeds were submitted to tests of germination, first germination count, germination speed and seedling length. For the image analysis, the seeds without sarcotesta were submitted to the X-ray test and to a computerized analysis of seedling images by the SVIS® software. The methods used were only promising for the sarcotesta removal, while the blender + sieve method obtained the highest physical and physiological seed quality, in addition to performing the best sarcotesta removal. However, the image analysis using the SVIS® software allowed to identify the high physical and physiological seed quality using the blender + sieve method, which promoted the highest efficiency in removing the sarcotesta.

ABSTRACT: Our knowledge about seed dormancy breaking and environmental factors affecting seed germination of greater bur-parsley (Turgenia latifolia) is restricted. This study has addressed some seed dormancy breaking techniques, including different concentrations of gibberellic acid (GA3) and potassium nitrate (KNO3), leaching duration, physical scarification as well as some environmental factors effective on seed germination such as salt and drought stresses, pH and seed planting depth. Seed germination was promoted with lower concentrations of KNO3 (0.01 to 0.02 g L-1), while higher concentrations reduced germination percentage. Seed dormancy was declined by low concentrations of GA3 up to 100 ppm. Seeds of greater bur-parsley germinated in a range of pH from 3 to 7. With enhancement of drought and salt stresses, seed germination decreased. Also, there was no seed germination in a high level of stresses. Seedling emergence reduced as planting depth increased. Use of GA3, KNO3, leaching and physical scarification had a positive effect on seed dormancy breaking of greater bur-parsley. The information from the study increases our knowledge about seed dormancy breaking techniques, response of germination to drought and salt stresses and also determination of distribution regions of greater bur-parsley in the future.

ABSTRACT: Our knowledge about seed dormancy breaking and environmental factors affecting seed germination of greater bur-parsley (Turgenia latifolia) is restricted. This study has addressed some seed dormancy breaking techniques, including different concentrations of gibberellic acid (GA3) and potassium nitrate (KNO3), leaching duration, physical scarification as well as some environmental factors effective on seed germination such as salt and drought stresses, pH and seed planting depth. Seed germination was promoted with lower concentrations of KNO3 (0.01 to 0.02 g L-1), while higher concentrations reduced germination percentage. Seed dormancy was declined by low concentrations of GA3 up to 100 ppm. Seeds of greater bur-parsley germinated in a range of pH from 3 to 7. With enhancement of drought and salt stresses, seed germination decreased. Also, there was no seed germination in a high level of stresses. Seedling emergence reduced as planting depth increased. Use of GA3, KNO3, leaching and physical scarification had a positive effect on seed dormancy breaking of greater bur-parsley. The information from the study increases our knowledge about seed dormancy breaking techniques, response of germination to drought and salt stresses and also determination of distribution regions of greater bur-parsley in the future. | RESUMO: O conhecimento sobre a quebra da dormência de sementes e fatores ambientais que afetam a germinação de sementes de Grande Bur-Parsley (Turgenia latifolia) é restrito. Neste estudo, foram investigadas algumas técnicas de quebra da dormência de sementes, incluindo diferentes concentrações de ácido giberélico (GA3) e nitrato de potássio (KNO3), durações de lixiviação, escarificação física, bem como alguns fatores ambientais efetivos na germinação de sementes, como estresse salino e seca, pH e profundidade de plantio semente. A germinação de sementes foi promovida com as menores concentrações de KNO3 (0,01 a 0,02 g L-1), enquanto as maiores concentrações reduziram a porcentagem de germinação. A dormência da semente foi diminuída por baixas concentrações de GA3 até 100 ppm. As sementes de Grande Bur-Parsley germinaram em pH na faixa de 3 a 7. Com o aumento dos estresses de seca e sal, a germinação de sementes diminuiu. Além disso, não houve germinação de sementes em alto nível de estresse. A emergência de plântulas se reduziu à medida que se aumentou a profundidade de plantio. O uso de GA3, KNO3, a lixiviação e a escarificação física afetaram positivamente a quebra de dormência de sementes de Grande Bur-Parsley. Os resultados deste estudo aumentam nosso conhecimento sobre técnicas de quebra de dormência de sementes, resposta de germinação à seca e estresses de sal e também sobre a determinação de regiões de distribuição de Grande Bur-Parsley no futuro.

This research aimed to improve selection of pepper seeds for separating high-quality seeds from low-quality seeds. Past research has shown that seed vigor is significantly related to the seed color and size, thus several physical features were identified as candidate predictors of high seed quality. Image recognition software was used to automate recognition of seed feature quality using 400 kernels of pepper cultivar 101. In addition, binary logistic regression and a neural network were applied to determine models with high predictive value of seed germination. Single-kernel germination tests were conducted to validate the predictive value of the identified features. The best predictors of seed vigor were determined by the highest correlation observed between the physical features and the subsequent fresh weight of seedlings that germinated from the 400 seeds. Correlation analysis showed that fresh weight was significantly positively correlated with eight physical features: three color features (R, a*, brightness), width, length, projected area, and single-kernel density, and weight. In contrast, fresh weight significantly negatively correlated with the feature of hue. In analyses of two of the highest correlating single features, germination percentage increased from 59.3 to 71.8% when a*≥3, and selection rate peaked at 57.8%. Germination percentage increased from 59.3 to 79.4%, and the selection rate reached 76.8%, when single-kernel weight ≥0.0064 g. The most effective model was based on a multilayer perceptron (MLP) neural network, consisting of 15 physical traits as variables, and a stability calculated as 99.4%. Germination percentage in a calibration set of seeds was 79.1% and the selection rate was 90.0%. These results indicated that the model was effective in predicting seed germination based on physical features and could be used as a guide for quality control in seed selection. Automated systems based on machine vision and model classifiers can contribute to reducing the costs and labor required in the selection of pepper seeds.

This research aimed to improve selection of pepper seeds for separating high-quality seeds from low-quality seeds. Past research has shown that seed vigor is significantly related to the seed color and size, thus several physical features were identified as candidate predictors of high seed quality. Image recognition software was used to automate recognition of seed feature quality using 400 kernels of pepper cultivar 101. In addition, binary logistic regression and a neural network were applied to determine models with high predictive value of seed germination. Single-kernel germination tests were conducted to validate the predictive value of the identified features. The best predictors of seed vigor were determined by the highest correlation observed between the physical features and the subsequent fresh weight of seedlings that germinated from the 400 seeds. Correlation analysis showed that fresh weight was significantly positively correlated with eight physical features: three color features (R, a*, brightness), width, length, projected area, and single-kernel density, and weight. In contrast, fresh weight significantly negatively correlated with the feature of hue. In analyses of two of the highest correlating single features, germination percentage increased from 59.3 to 71.8% when a*≥3, and selection rate peaked at 57.8%. Germination percentage increased from 59.3 to 79.4%, and the selection rate reached 76.8%, when single-kernel weight ≥0.0064 g. The most effective model was based on a multilayer perceptron (MLP) neural network, consisting of 15 physical traits as variables, and a stability calculated as 99.4%. Germination percentage in a calibration set of seeds was 79.1% and the selection rate was 90.0%. These results indicated that the model was effective in predicting seed germination based on physical features and could be used as a guide for quality control in seed selection. Automated systems based on machine vision and model classifiers can contribute to reducing the costs and labor required in the selection of pepper seeds.

In order to investigate different treatment effects on germination in Gundelia tournefortii, three factorial experiments were carried out in the completely randomized design with three replications. The first factor was stratification at 4oC in three levels including 0, 3 and 6 weeks, the second factor was mechanical scarification in two levels including seeds with/without scarification and the third factor was chemical treatments of seed dormancy breaking in three levels including distilled water and gibberellic acid at concentrations of 1000 and 1500 mg/l and Thiourea 0.1%. The results showed that the effects of stratification, scarification and chemical treatments of dormancy breaking and their interactions were significant on all studied parameters (p<0.01). Mean comparison values were significant for the effects of spate treatments together with mechanical scarification for the improvement of all traits. The results also revealed that treatment of mechanical scarification treatment together with gibberellic acid 1000 mg/l in six weeks stratification, due to maximum germination speed, seedling dry weight, seedling length, large-scale germination percentage and seedling vigor index and modest average germination period, was the most influential treatment for seed dormancy breaking of this plant. Correlation between germination percentage with germination rate, dry weight and seedling length was significant. It seems that seed dormancy type in Gundelia tournefortii is physiological and physical, as eliminating physiological and physical factors leads to its germination improvement.

In order to investigate different treatment effects on germination in Gundelia tournefortii, three factorial experiments were carried out in the completely randomized design with three replications. The first factor was stratification at 4oC in three levels including 0, 3 and 6 weeks, the second factor was mechanical scarification in two levels including seeds with/without scarification and the third factor was chemical treatments of seed dormancy breaking in three levels including distilled water and gibberellic acid at concentrations of 1000 and 1500 mg/l and Thiourea 0.1%. The results showed that the effects of stratification, scarification and chemical treatments of dormancy breaking and their interactions were significant on all studied parameters (p<0.01). Mean comparison values were significant for the effects of spate treatments together with mechanical scarification for the improvement of all traits. The results also revealed that treatment of mechanical scarification treatment together with gibberellic acid 1000 mg/l in six weeks stratification, due to maximum germination speed, seedling dry weight, seedling length, large-scale germination percentage and seedling vigor index and modest average germination period, was the most influential treatment for seed dormancy breaking of this plant. Correlation between germination percentage with germination rate, dry weight and seedling length was significant. It seems that seed dormancy type in Gundelia tournefortii is physiological and physical, as eliminating physiological and physical factors leads to its germination improvement.

In order to investigate different treatment effects on germination in Gundelia tournefortii, three factorial experiments were carried out in the completely randomized design with three replications. The first factor was stratification at 4oC in three levels including 0, 3 and 6 weeks, the second factor was mechanical scarification in two levels including seeds with/without scarification and the third factor was chemical treatments of seed dormancy breaking in three levels including distilled water and gibberellic acid at concentrations of 1000 and 1500 mg/l and Thiourea 0.1%. The results showed that the effects of stratification, scarification and chemical treatments of dormancy breaking and their interactions were significant on all studied parameters (p<0.01). Mean comparison values were significant for the effects of spate treatments together with mechanical scarification for the improvement of all traits. The results also revealed that treatment of mechanical scarification treatment together with gibberellic acid 1000 mg/l in six weeks stratification, due to maximum germination speed, seedling dry weight, seedling length, large-scale germination percentage and seedling vigor index and modest average germination period, was the most influential treatment for seed dormancy breaking of this plant. Correlation between germination percentage with germination rate, dry weight and seedling length was significant. It seems that seed dormancy type in Gundelia tournefortii is physiological and physical, as eliminating physiological and physical factors leads to its germination improvement.