Pretreatment and storage effects on seed germination of Adenia viridiflora Craib.

Factors affecting the germination of doum palm ( Hyphaene thebaica Mart.) seeds from the semi-arid zone of Niger, West Africa

Background and Aim: Osyris lanceolata (Hochst. & Steud) is an evergreen shrub or small tree of the Santalaceae family, valued for its fragrant heartwood and essential oils used in perfumery and traditional medicine. However, its propagation is limited due to poor seed germination and challenges in vegetative methods. This study aimed to evaluate the effects of different pre-sowing seed treatments, germination substrates, and fruit maturity stages on the germination and early growth performance of O. lanceolata from naturally growing populations in Tehri Garhwal, Uttarakhand. Study Design: The study was conducted through two separate experimental setups using a completely randomized design (CRD) to evaluate the effects of fruit maturity stages, germination substrates, and various pre-sowing treatments on the seed germination and early growth of Osyris lanceolata. In the first experiment, conducted at the Forest Tree Seed Laboratory, ICFRE-FRI, seeds collected at three different maturity stages (green, light orange, and bright red) were subjected to mechanical scarification followed by soaking in boiling water for 12 hours. The seeds were then sown on two different substrates: sand and vermiculite, incubated under controlled laboratory conditions at 25 ± 1 °C, >90% relative humidity, and a 24-hour photoperiod. Each treatment included four replicates of 20 seeds.The second experiment was carried out in the nursery of Jakh-Koti Botanical Garden, Tehri, Uttarakhand where seeds were subjected to eight different pre-sowing treatments: T1 – Control, T2 – Mechanical scarification + 500 ppm GA₃ (24 h), T3 – Mechanical scarification + 1000 ppm GA₃ (24 h), T4 – 30% Hydrogen peroxide (24 h), T5 – 0.2% Potassium nitrate (24 h), T6 – 2% Thiourea (24 h), T7 – 20% Sulfuric acid (1 min), and T8 – Hot water (1 min). Each treatment included four replicates of 80 seeds. Across both experiments, germination performance was evaluated using key parameters: Germination Percentage (GP), Mean Germination Time (MGT), Germination Value (GV), Peak Value (PV), Germination Index (GI), Seedling Vigor Index (SVI), Sturdiness Quotient (SQ), Vigor Index (VI) and Quality Index (QI). Results: In the laboratory experiment, substrate and fruit maturity stage had a significant impact on germination parameters. Seeds sown on vermiculite showed a significantly higher germination percentage (46.66 ± 7.63%) compared to those sown on sand (33.33 ± 7.63%). Pretreatment improved all germination parameters, while fruit maturity stage played a critical role. Seeds collected at the bright red maturity stage (moisture content: 52.62 ± 2.51%) recorded the highest germination percentage and germination value, along with a low mean germination time (MGT), indicating their physiological readiness for germination. In the nursery experiment, the highest germination percentage (66.66 ± 8.32%) was observed in T3 – Mechanical scarification followed by soaking in 1000 ppm GA₃ for 24 hours, which was significantly superior to all other treatments. This was followed by T2 (Mechanical scarification + 500 ppm GA₃; 49.33 ± 4.61%) and T7 (20% Sulphuric acid for 1 min; 41.33 ± 2.30%). The lowest germination percentages were recorded in T4 (30% Hydrogen peroxide; 18.66 ± 2.30%), T8 (Hot water; 18.66 ± 6.11%), and the untreated control T1 (13.33 ± 2.30%), with significant differences among them. Among all treatments, T3 proved to be the most effective for enhancing seed germination. Conclusion: The study highlights effective strategies for improving the germination and early growth of Osyris lanceolata. Vermiculite was identified as the optimal germination medium, while seeds collected at the bright red maturity stage (~52% moisture content) exhibited the highest germination performance, including superior germination percentage (GP), germination value (GV), and reduced mean germination time (MGT). Among pre-sowing treatments, mechanical scarification followed by soaking in 1000 ppm GA₃ for 24 hours (T3) resulted in the highest germination percentage and significantly enhanced seedling vigor. These findings provide valuable guidance for optimizing seed propagation and support the domestication and conservation of O. lanceolata.

This research was carried out in the laboratory according to the factorial experimental design in completely randomized with 4 replications in order to determine the germination temperatures and appropriate dormancy breaking methods of birdsfoot trefoil seeds collected in 3 (three) locations in Suveren (A), Melekli (B) and Aşağı Çamurlu (C) regions of Iğdır province. The germination rates of normal, abnormal and dormant seeds were determined in birdsfoot trefoil seeds at 5 different constant (15, 20, 25, 30 and 35 °C) and 4 variable (15/25, 15/30, 20/30 and 20/35 °C) temperatures. The highest normal germination rates were determined at (20/30 °C). Even at the highest normal germination temperature, it was determined that there was a dormancy rate of 85.0% in the birds of birdsfoot trefoil collected in natural areas. There was no significant difference between the abnormal germination of birdsfoot trefoil seeds at different locations. In addition, there was no significant difference between the abnormal germination at different temperatures. Dormant seed rates were higher at locations B and C. The highest dormant seed rate was seen in birdsfoot trefoil seeds germinated at the lowest temperature (15 °C). In order to break the dormancy, gibberellic acid, potassium nitrate, sulfuric acid, hydrochloric acid, salicylic acid, soaking in warm water, mechanical scarification and soaking in hot water were applied to the birdsfoot trefoil seeds. Compared to the control treatment, sulfuric acid and potassium nitrate increased normal germination rates, gibberellic acid and mechanical scarification did not affect on normal germination rates, and hydrochloric acid and salicylic acid decreased germination rates. According to the research results, it was determined that dormancy was high in seeds collected in natural environments and that the seeds needed to be kept in 95-98% sulfuric acid for 12 minutes to break the dormancy. Soaking Lotus corniculatus seeds in sulfuric acid for 12 minutes increased the normal germination rate to 79%. Sulfuric acid application also caused an increase in the abnormal germination rate.

South Brazil has a great diversity of alimentary fruit species. The uvaia (Eugenia pyriformis Cambess), along with other nativespecies, has great economic potential due to its fruits and as a feedstock for the food industry. However, there is little information on seed dormancy for this species and neither a defined official protocol regarding dormancy overcoming, a necessary requisite for large-scale production. This work aimed to verify the presence of dormancy in E. pyriformis seeds, also proposing a possible method to overcome it. The applied seed breaking treatments were: mechanical scarification with sandpaper, chemical scarification using concentrated sulfuric acid, thermal shock using hot water, chemically induced germination using gibberellic acid, a combination of sulfuric acid and gibberellic acid treatments, a combination of hot water and gibberellic acid treatments, and a control (seed without treatment). The seeds were kept incubated in a BOD incubator for 60 days at 25±5 °C and a photoperiod of 8:16 h (light:dark). The percentage of germination and germination speed index (GSI) were evaluated. The results indicated that mechanical scarification induced faster germination (GSI values of 0.637 for mechanical scarification and 0.187 for the control) and germination percentages of 77%, while the control treatment presented 36%. The fresh collected E. pyriformis seeds may present dormancy, which was overcome by mechanical scarification.

SUMMARY Seeds of M. esculenta exhibit dormancy that hampers, rapid and uniform germination. To overcome this dormancy, seeds of this species were pretreated with mechanical scarification by slicing off the end of the seed, soaking in sulphuric acid for 4, 8 and 12 minutes and soaking in hot water for 24, 48 and 72 hours. Some scarified seeds were treated with two concentrations of GA3: 50 and 100 ppm. All pretreatments improved the germination capacity of seeds, the highest being after mechanical scarification with soaking in GA3 100 ppm (85.00%); next highest germination was with the sulphuric acid and hot water soaking treatments. The maximum survival percent (60.00%) of seedling was associated with 48 hrs hot water soaking. The maximum shoot length (9.50 cm) occurred with GA3 50 ppm treatment of scarified seeds, whereas maximum root length (14.68 cm), number of leaves (11.50), shoot dry weight (0.19 g) and root dry weight (0.26 g) were found with GA3 100 ppm. Soaking in hot water for 48 hours is the treatment recommended as being cheap and easy to apply as scarification results in a high level of damage to the seeds.

Specific knowledge on dormancy and germination patterns of weed species aids the development of integrated management strategies. This study aimed to evaluate and select effective methods for overcoming dormancy in B. latifolia seeds, as well as determining their influence on the germination process. A completely randomized experimental design was used, with four replications and 20 seeds per repetition. Seven tests were conducted, with the corresponding B. latifolia seed treatments: Test 1- mechanical scarification (EM), sulfuric acid (H2SO4), hot water (IAQ) and running water (LAC); Test 2- pre-cooling at 4 °C (PE) and dry heat (CS) at 60 °C. Test 3- gibberellic acid (AG) at concentrations of 0, 50, 100, 200 and 400 ppm; Test 4- acetic acid (AC) and KNO3 2%; Test 5- dual combinations of the three best treatments observed in the first four tests. Test 6- pre-soaking in a sandbox (EST) and in germination paper (PE) and; Test 7- imbibition curve. The seeds were submitted to the germination test in BOD at 25 °C with a photoperiod of 12h, in transparent polypropylene boxes. Germination percentage (GP), mean germination time (MGT) and relative frequency of germination (RFG) were determined and the weight of the seeds after soaking in Test 7 was measured. The best treatments for overcoming seed dormancy were CS, AG 283 ppm and KNO3 3h. The association of CS+KNO3 and KNO3+AG increased GP by 25% compared to isolated treatments.

The effect of seed presowing treatment on Guibortia coleosperma and Amblygonocarpus andongensis was investigated. Seeds of both species were subjected to four experiments, containing 10 levels of presowing treatments: mechanical scarification, soaking in concentrated sulphuric acid (for 15, 30, 45 and 60 min), immersion in boiling water (for 1, 3 and 5 min), and soaking in boiling water (and cooling down for 24 h) and the control. The germination data were subjected to ANOVA followed by Tukey’s HSD test to separate significantly different treatment means. The highest germination in G. coleosperma was recorded: mechanical scarified seeds, those soaked in sulphuric acid (15, 30, 45 and 60 min), hot water (and cooling down for 24 h) and the control seeds. For A. andongensis, seeds treated with mechanical scarification, exposure to sulphuric acid (15, 30, 45 and 60 min) and boiling water (1 min) had higher percent germination than the controls. Key words: Germination mean time, germination percentage, pre-treatment, scarification.

Germination ecology of twelve indigenous and eight exotic multipurpose leguminous species from Ethiopia

Botanical yam (Dioscorea rotundata) seeds are currently used by yam breeders to generate and conserve new varieties of yam instead of seed yams (vegetative propagule). Yam seed treatment through scarification is one of the most effective methods of improving seed germination and seedling establishment. This study was carried out under greenhouse condition to determine the best seed treatment for the germination and establishment of botanical yam seeds. The set up involved a soil mixed with carbonized rice husk using five different seed treatments; dry heating (DHS) at 60 0C, mechanical scarification + gibberellic acid (MSS + GA), mechanical scarification (MSS), acid scarification with sulphuric acid (ASS) and soaking in hot water at 80 0C (SOS). The findings showed that the treatment, MSS + GA and MSS only, had significant (P<0.05) positive effect on the seed emergence and seedling establishment compared to the untreated control (COS) and other treatments. ASS caused seed damage resulting to no emergence. The findings showed that carbonized grain waste (rice husk) enhanced soil fertility and seed treatment (MSS + GA) was the best to improve yam seed germination and seedling establishment. These treatments can be efficiently applied to reduce the long gestation periods and increase yield in yam breeding programmes.

Malvella sherardiana (L.) Jaub & Spach (Malvaceae) is a perennial herbaceous plant listed as Vulnerable in the Red List of threatened plant species for Spain. The germination characteristics under controlled conditions of light and temperature of M. sherardiana seeds were studied. Mechanical scarification, cold stratification, liquid nitrogen, freezing, hot water, dry heat, sulphuric acid, soaking in distilled water and soaking in gibberellic acid were used as pre-sowing treatments applied for enhancing germination. The untreated seeds showed a high dormancy at all temperature regimens tested and sulphuric acid scarification drastically improved final germination percentage and germination rate. Germination of seeds soaked in concentrated sulphuric acid arithmetically increased as soaking time increased (from 5 min to 3 h), but seeds soaked in acid for more than 4 h failed to germinate. The application of a gibberellic acid solution (1000 mg l−1) increased the germination percentages for all tested soaking times in sulphuric acid. However, it was only significantly effective for the soaking time of 3 h. The other pre-sowing treatments resulted in some germination, but none resulted in greater germination than sulphuric acid. As embryos are fully developed and the seed coat is water permeable, we conclude that M. sherardiana seeds present physiological dormancy. The main conclusion of the study is that dormancy of M. sherardiana seeds is attributed to mechanical restriction of the embryo caused by the tough seed coat. This is the first report on germination requirements of the Malvella genus.

The species Cochlospermum regium is a shrub that disseminates by seed, but with extremely low germination even under ideal conditions, that is a response to physical dormancy imposed by the seed coat. Thus, we aimed to evaluate the efficacy of dimethyl sulphoxide (DMSO) in overcoming dormancy in Cerrado ‘algodãozinho’ seeds compared to other traditional methods, in combination with growth analysis to assess seedling normality. The seeds in experiment I were submitted to the following treatments: (1) control: soaking in distilled water for 24h; (2) mechanical scarification: rubbing with sandpaper for 1min and soaking in distilled water for 24h; (3) acid scarification: immersion in sulphuric acid for 2h followed by soaking in distilled water for 24h; (4) immersion in DMSO at 65°C for 24h followed by soaking in distilled water for 24h; and (5) soaking in distilled water for 24h and immersion in sodium hypochlorite (NaOCl), 12% active chlorine, for 5h. The volume of solution used in all treatments was sufficient to completely submerge the seeds. Initial seed moisture content, seed dry mass, germination percentage, and germination speed index (GSI) were measured. In experiment II, seeds were immersed in DMSO at 65°C for 24h followed by soaking in distilled water for 24h or distilled water at 65°C for 24h and evaluated by the standard germination test and GSI. Shortly after germination, seeds from both treatments were transferred to trays containing sand as a substrate for subsequent seedling morphological and growth evaluation. Overall, the results show that mechanical scarification with sandpaper for 1min and seed immersion in DMSO were the best treatments for overcoming dormancy in seeds of C. regium, and DMSO caused no morphological abnormality in the seedlings.

Juniperus oxycedrus L. and Pistacia lentiscus L. are two taxa with a rigid or rigid enough structure caused by a solid pericarp resulting in a strong inhibition of the germination. The objective of this work was to test the effectiveness of certain pre-germinative treatments on the germination rate of the Juniperus oxycedrus and Pistacia lentiscus seeds with the aim of restoring perturbed ecosystems. In this context 180 seeds from each of the 2 examined species were tested in the laboratory (the number of repetitions is 5, to reach the degree of freedom 'ddl'). The seeds were divided into 4 groups of 20 seeds of each species and were treated as follows: 1) Immersion in the concentrated (95%) sulphuric acid (H2SO4) for 10, 30 and 60 minutes; 2) Mechanical scarification with a scalpel; 3) Soaking in hot water (at 100°C) for 30 seconds, 60 seconds and 2 minutes; 4) Cold stratification at 5°C for 24 hours. There is also a control group of 20 seeds representing each of the two species, which remained neutral. In the case of the Juniperus oxycedrus seeds the results showed that the germination rate improves after the mechanical scarification with a scalpel (92%), followed by the cold stratification with water (86%) and a treatment with a concentrated sulphuric acid for 60 minutes (82%). The seeds were treated with H2SO4 for 10 and 30 minutes, respectively, soaked in hot water; the control lot did not germinate. The germination rate for the Pistacia lentiscus seeds is 88% after the mechanical scarification and 84% after the cold water stratification. On the other hand, the treatment with H2SO4 or after soaking in hot water does not allow for the germination of these seeds. The same result is observed on the control group (0% for 30 days).

<p>A germination experiment of <em>Vachellia karroo</em> seeds was conducted at the Botswana University of Agriculture and Natural Resources, Department of Crop and Soil Sciences laboratory, from September to October 2018. Seeds were collected along the Segoditshane River in Gaborone to investigate the effect of different pre-sowing treatment methods on their germination. The experiment was laid out in a completely randomized design (CRD) with five treatments (control, mechanical scarification, boiling water, hot water and concentrated sulphuric acid (98.8%). Boiling water (30, 60, 180 and 300 seconds) and concentrated sulphuric acid (15, 30, 45 and 60 minutes) had four levels of exposure time. The highest significant (p < 0.01) cumulative germination percentages were recorded in seeds subjected to sulphuric acid for 45 and 60 minutes, mechanical scarification (shortest germination mean time of 2.0<strong>-</strong>2.3) and boiling water at 30 and 60 seconds (moderate germination mean time of 5<strong>-</strong>5.9) whereas, the control treatment had the least cumulative germination percentage of 2%. As expected, the same trend was revealed for germination index. The seeds possess seed coat imposed dormancy, which requires sowing treatments. The best treatments for releasing dormancy in <em>V. karroo</em> were sulphuric acid and mechanical scarification and because of the risks associated with the use of sulphuric acid, the researchers recommend mechanical scarification as the suitable treatment method in tree nurseries.</p>

Bowdichia virgilioides Kunth is a tree species of the family Fabaceae. The species is well adapted to dry and poor lands, being indicated for reforesting activities, being widely used on wood structures for civil construction, and also as a species with high medicinal potential. This study aimed to evaluate methods for overcoming dormancy of B. virgilioides seeds through different types of scarification and water submersion. To do so, four treatments and control were used: T1 - seeds with no treatment, T2 – mechanical scarification with # 120 sandpaper; T3 – chemical scarification with concentrated sulfuric acid (98%) for 10 minutes; T4 – submersion in hot water (80°C) for 5 minutes; T5 – submersion in water at room temperature (approximately 30°C) for 48h. The experiment was conducted in a Completely Randomized Design (CRD) and the analyzed variables were: germination percentage (%G), average germination speed (VMG) and average germination time (TMG). Data was analyzed using the “GerminaQuant” software and results compared using Tukey’s test at 5% probability. Germination percentage was higher for treatments 3 and 4, with the decreasing sequence: T3 – 82%, T4 – 64%, T2 – 9%, T1 – 4% and T5 – 2%. Regarding average germination time, only T2 and T1 were statistically different from each other, T2 had the shortest time (10.33) and T1 the longest time (30.33). For VMG, T2 and T3 presented the best results, being statistically different from the other treatments, with 0.093 and 0.085 as respective results of T2 and T3. It could be concluded that treatments with immersion in sulfuric acid for 10 minutes (T3) and immersion in water at temperature of 80°C for five minutes (T4) are more efficient for improving germination percentage of B.virgilioides seeds, being the recommended methods for overcoming seed dormancy.

The experiments were conducted in the Forestry laboratory of Kebbi State University of Science and Technology, Aliero, Kebbi State. The studies were conducted from February 2020− March 2020 to assess the most effective method of breaking seed dormancy in Dialium guineense seeds. The seeds were subjected to four (4) pre-treatment methods (sulphuric acid, hot water, cold water and mechanical scarification) with untreated seeds as control, the experiment was laid out in completely randomized design (CRD) and replicated three (3) times. Final germination percentage (FGP), germination mean time (GMT), germination index (GRI), Coefficient Velocity of Germination (CVG) and Germination rate index (GRI) were calculated and the data was subjected to the analysis of the variance (ANOVA). Seed treated with cold water for 48 hours (Trt 1) started germination at two (2) days after sowing (DAS) and ended germination at 5 DAS, control and three of the treatments (Trt 2, Trt 5& Trt 7) started germination at 3 DAS while Trt 4 and Trt 8 started at 4 and 5 DAS respectively. FGP 100% was obtained from Control and Trt 5 and they finished Germination at 9 and 21 DAS respectively. Highest GI, GRI and CVG and lowest MGT were recorded from Trt 1. The result analysis of findings at 5% level of statistics showed that there is nosignificant difference between the treatments. Similarly, no germination on seeds in Trt 3 and Trt 6. Seeds of Dialium guineense are not limited by dormancy therefore can be sown without any pre-treatment, but for large scale production of Dialium seedlings it can be treated in cold water at room temperature for 48 hours due to availability and low cost with less risks.