Germination Velocity Research Articles

Fast seed germination of the halophyte Suaeda physophora across a wide range of environmental conditions

Suaeda physophora, a succulent-leaf euhalophytic subshrub, is known for its unique adaptation to saline environ­ments. This study aimed to evaluate the germination performance of S. physophora seeds under various environmental conditions. The germination of 24-hour-imbibed S. physophora seeds reached 100% within 24 hours at 10/25°C with 12 hours light / 12 hours dark or continuous dark. Even at 5/15°C, the germination could still reach 55% within 24 hours. At a PEG concentration of 20%, the germination was also 60%. Under 200 mmol L-1 NaCl, the germination reached 67% within 24 hours. Germination velocity was affected by temperature, drought and salinity, with the fastest germination velocity observed at 10/25°C without PEG-simulated drought or salinity stress. These findings highlight very fast germination of S. physophora seeds across diverse environmental conditions, making it suitable for ecological research and application.

Breaking seed dormancy in Searsia pentaphylla(Anacardiaceae)

Seeds (true seed plus endocarp) of Searsia pentaphylla, a species with significant medicinal, ecological and horticultural importance, have an extremely hard and water impermeable endocarp. Hence, effective dormancy- breaking techniques are crucial for enhancing its cultivation and ensuring successful establishment in both natural and managed environments. This study evaluated the effects of mechanical scarification, chemical scarification (sulphuric acid soaking for 30, 60, 90 and 120 minutes, hydrogen peroxide soaking for 10 minutes), hot water soaking for 10 minutes, and heat treatment for three minutes at 200°C on final germination percentage (FGP), mean germination time (MGT), time to 50% germination (T50), coefficient of velocity of germination (CVG) and mean daily germination (MDG). Compared to the control group (untreated seeds), the most effective treatment was 120 minutes of sulphuric acid soaking, achieving a FGP of 92%, a MGT of 7.28 days, a CVG of 13.7%, a T50 of 6.67 days and a MDG of 6.57%. Mechanical scarification yielded a FGP of 36.5%, with poorer MGT, CVG, T50 and MDG values. Other methods, including hydrogen peroxide and heat, were less effective. These results highlight the importance of aggressive scarification techniques to enhance germination in S. pentaphylla.

Seed dormancy and germination in Sophora secundiflora (Fabaceae)

Given the ecological and horticultural significance of Sophora secundiflora (Ortega) DC., effective dormancy-breaking techniques are crucial for enhancing its cultivation and ensuring successful establishment in both natural and managed environments. Seeds have an extremely hard and water impermeable testa. This study evaluated the effects of mechanical scarification (MS), sulphuric acid (SA) soaking for 30, 60, and 90 minutes, and hydrogen peroxide (HP) soaking for 10 and 20 minutes on final germination percentage (FGP), mean germination time (MGT), time to 50% germination (T50), and coefficient of velocity of germination (CVG). Mechanical scarification and 60-minute sulphuric acid treatments were the most effective, achieving FGPs of 95% and 93%, respectively, and showing efficient germination processes as indicated by T50 and CVG metrics. Mechanical scarification resulted in the fastest and most consistent germination. Sulphuric acid treatments showed time-dependent efficacy, with the 60-min treatment optimizing both germination speed and percentage, whereas the 90-min treatment caused potential seed damage, reflected in a lower FGP. Hydrogen peroxide treatments were less effective overall, with a maximum FGP of 33% for the 20-minute soaking. Statistical analysis highlighted significant differences among treatments, particularly for FGP (p < 0.0001), T50 (p = 0.0020), and CVG (p = 0.0348). These findings align with existing research on Fabaceae species, supporting the importance of physical and chemical scarification methods in breaking seed dormancy. This study provides critical insights into optimizing germination protocols for S. secundiflora, with wider applications for other hard-seeded Fabaceae species.

Determination of Median Lethal Dose and Effects of Gamma Radiation on Seed Germination in Viola cornuta L.

Effects of cobalt-60 gamma irradiation on seed germination and seedling survival of 7 cultivars of Viola cornuta L. were investigated. The results revealed that low doses of gamma radiation at 100 Gray (Gy) significantly stimulated germination in ‘Deep Blue Blotch’ and ‘Clear Purple’ and slightly enhanced germination in ‘Clear Yellow’ and ‘Victoriana’. In contrast, higher doses (> 400 Gy) significantly decreased germination across all cultivars. No germination was observed at 1,000 Gy in the ‘Deep Blue Blotch’ cultivar. Analysis of mean germination time (MGT) and coefficient of velocity of germination (CVG) showed delays in germination and decreased germination velocity with increasing irradiation dose. The seedling survival percentage also decreased with higher radiation doses, indicating sublethal effects on seedling establishment. The lethal dose for 50 % mortality (LD50) values ranged from 320 to 495 Gy for the Bel Viso series and from 430 to 640 Gy for the Grandissimo series. Our findings highlight the dose-dependent effects of gamma irradiation on seed germination and seedling survival and provide insights into irradiation tolerance and susceptibility among cultivars. Understanding these responses is crucial for optimizing irradiation-induced mutagenesis strategies and developing plant selection plans for crop improvement. HIGHLIGHTS Low cobalt-60 gamma radiation doses at 100 Gray (Gy) stimulated seed germination in Viola for ‘Victoriana’, ‘Deep Blue Blotch’, ‘Clear Yellow’ and ‘Clear Purple’ cultivars whereas higher doses (> 400 Gy) decreased germination across all 7 cultivars. Mean germination time (MGT) increases and coefficient of velocity of germination (CVG) decreases with higher gamma radiation doses, indicating delayed and slower germination. Seedling survival percentages decline significantly with increasing radiation dose, highlighting sublethal effects on seedling development. GRAPHICAL ABSTRACT

NaCl salt stress and PEG water stress differentially affect germination and early seedling growth of two sesame (Sesamum indicum L.) cultivars

Drought stress and salt stress are serious challenges to crop productivity in the arid lands. This work investigates the impact of NaCl-salt stress and PEG-water stress on germination and embryo growth of two sesame (Sesamum indicum L.) cultivars: Sohag 1 (Sohg) and Shandaweel 3 (Shnd). Seed dimensions, volume and weight were measured. The red Sohg seeds were larger with oblong appearance and lower density relative to the white Shnd seeds. Seeds were germinated in isosmotic solutions of NaCl and PEG-6000 at 0, − 0.103, − 0.205, − 0.410 and − 0.615 MPa. The time-based parameters (velocity, uniformity and synchrony of germination) were more reliable measures of germination efficiency than the final germination percentage. The impact of PEG was more severe than that of NaCl particularly on Sohg. The peak of daily germination was lowered and delayed under stress. The genotypic variability in germinability became evident under stress in favor of Shnd. Radicle length–a reliable measure of seedling growth–was subjected to stronger impact of NaCl than PEG. Although Na+ mobilization from seeds to embryos was indifferent in the two cultivars in PEG solutions, Shnd seedlings exhibited higher Na+ uptake from NaCl solutions. Whereas K+ mobilization was restricted by NaCl only in Sohg, it was hastened by PEG equally in the two cultivars. The stress-vulnerable Sohg recovered from stress with higher magnitude than did Shnd, particularly from the more stressing osmoticum (PEG). The indices of germination recovery were highest in PEG-pretreated Sohg while the biomass of recovered seedlings was highest in NaCl-pretreated Sohg.

Effect of Different Seed Treatment on Germination of Fishtail Palm (Caryota urens) under Naturally Ventilated Poly-house Conditions

An investigation was conducted to study the effect of different seed treatments comprising of mechanical scarification, chemical and plant growth regulator on germination of Fishtail palm (Caryota urens) seeds under naturally ventilated poly-house at sheth D. M. Polytechnic in Horticulture College, Anand Agricultural University, Vadodara during 2021 to 2023. There were total 12 treatments under study which was replicated trice and statistically analysed by completely randomized design at 90 days after sowing. The results revealed that treatment T12 i.e. seeds treated with GA3 1000 ppm for one day recorded significantly lesser days to initiation of germination (46.33 days) along with higher germination percentage (86.67 % and 85.00 %), germination rate index (5.90 %/day and 5.70 %/day) and germination index (255 and 243.67), coefficient of velocity of germination (6.18 and 6.02), timpson’s germination index (1275 and 1218), modified timpson germination index (42.50 and 40.61) and survival percentage (88.33 and 86.67) at 90 days after sowing during first and second year respectively. While, seed without any treatment kept in open condition treatment T1 showed poor performance in germination percentage as well as survival percentage. Thus, Fishtail palm (Caryota urens) seeds soaked in solution of 1000 ppm GA3 along with sowing them in polybags and kept under NVPH condition provides better germination and survival.

ENHANCING GERMINATION AND SEEDLING VIGOR IN NIGELLA SATIVA: THE IMPACT OF NANO IRON OXIDE AND PHOSPHORUS PRIMING

Nigella sativa, commonly known as black cumin, is known for its health benefits due to its rich content of compounds like thymoquinone. This study explored the effects of various seed priming methods on Nigella sativa seeds, including control (unprimed), distilled water, nano iron oxide (Fe₂O₃), phosphorus (P), and a combination of Fe₂O₃ and P. We assessed how these treatments influenced several key aspects of seed germination: germination rate (GR), mean germination time (MGT), germination index (GI), coefficient of velocity of germination (CVG), and vigor index (VI).Our results showed that seeds treated with Fe₂O₃ nanoparticles had the highest germination rate at 93.5% and germinated faster than seeds from other treatments. This suggests that Fe₂O₃ nanoparticles effectively speed up the germination process. However, despite the improved germination rate, the seeds treated with Fe₂O₃ did not exhibit the highest seedling vigor; the control seeds had the highest vigor index, indicating that while Fe₂O₃ accelerates germination, it does not enhance seedling health as much as the untreated seeds. Additionally, there were no significant differences in the germination index and coefficient of velocity of germination between the treatments, suggesting these parameters were less influenced by the priming methods.In summary, nano-priming with Fe₂O₃ is effective for speeding up seed germination but does not necessarily improve seedling vigor. These findings provide valuable insights into how different priming techniques can be optimized to enhance seed performance and plant growth under various conditions.

Hydrolysates from cauliflower and artichoke industrial wastes as biostimulants on seed germination and seedling growth: a chemical and biological characterization.

Cauliflower (Brassica oleracea L.) and globe artichoke (Cynara scolymus L.) are vegetables with a high waste index mainly related to stems and leaves. In this study, enzymatic hydrolysates obtained from these wastes were proposed to be used as plant biostimulants. Life cycle assessment methodology was also applied to evaluate environmental performances related to cauliflower and artichoke byproducts. Hydrolysates (HYs) were chemically and biologically characterized. Amino acids, organic acids, amines, polyols, mineral elements, phenols, tannins, flavonoids and sulfur compounds were identified and quantified by means of NMR, inductively coupled plasma mass spectrometry and UV-visible analyses. Cauliflower leaf and flower HYs showed the highest concentration of free amino acids, whereas stems showed the highest concentration of Ca. Regarding artichoke, asparagine, glutamine and aspartic acid were exclusively detected in stems, whereas artichoke leaves showed the highest Mg and Mn levels together with the highest antioxidant activity. The HYs diluted in water were tested as biostimulants. The impacts of five concentrations of HYs (0.00, 0.28, 0.84, 2.52 and 7.56 g L-1) on seed germination and early seedling growth of crimson clover, alfalfa, durum wheat and corn were investigated. The application of artichoke biostimulant (0.28 g L-1) positively influenced the coefficient of velocity of germination in alfalfa, crimson clover and durum wheat, whereas cauliflower biostimulant significantly improved corn germination speed. © 2024 The Author(s). Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

The effect of activated water on lentil seed germination utilizing several plasma reactors and a hydrogen injection system

As a threat to meeting the global demand for food created by the continued growth of population, different methods are being applied to enhance seed germination and plant growth. This study investigates the effect of hydrogen-rich water (HRW) and different plasma-activated waters (PAW) and their combinations including HRW, PAW1, PAW2, HPAW1, and HPAW2 on the seed germination of lentils. Different arc discharge reactors are generated under atmospheric pressure in the air. Optical emission spectroscopy was used to detect the radiative species formed in the plasma zone. Raman spectra and physicochemical properties of different waters were investigated. The results demonstrated significant differences in the properties of different activated waters compared to control water. On day 3 after treatment, the fraction and length of germinated seeds were evaluated. During germination, treated water significantly increased germination parameters such as final germination percentage, mean germination time, germination index, and coefficient of germination velocity. HPAW2 exhibited the highest germination index (GI), which combines germination percentage and speed. The plasma systems also effectively reduced the pH of PAW1 and PAW2, with a greater decrease observed in HPAW1 and HPAW1. Analysis of nitrite and nitrate levels revealed that HPAW2 had the highest concentrations, indicating more reactive processes in the presence of hydrogen. Based on our results, it can be concluded that lentil seed germination can be increased using PAW and hydrogenated PAW combined.

Germination and early seedling growth of a medicinal plant giant milkweed (Calotropis gigantea) under salinity stress

Giant milkweed (Calotropis gigantea L.) is a salinity and drought-resistant xerophyte that is widespread around the world and serves significant ecological and medicinal purposes. The research aimed to evaluate the influence of saline stress on germination characteristics and prompt growth attributes of seedlings of C. gigantea. Seeds were germinated under five salinity levels viz. 0, 6, 8, 10 and 12 dS m-1 and allowed to grow for 30 days for traits assessment. Germination percentage (GP), germination rate index (GRI), co-efficient of the velocity of germination (CVG), mean germination time (MGT), Timson germination index (TGI), shoot length (SL), root length (RL), seedling dry weight (SDW) and healthy seedling number at 30 days were found lower in the salt solution compared to the control condition. Mean germination time was expanded with the increment of salinity levels. TGI of C. gigantea sustained a significant positive linear regression with GP (r = 0.9881), GRI (r = 0.9923) and CVG (r = 0.7887) at P < 0.001, but MGT (r = 0.7855) at P = 0.005. The correlation coefficient among the germination traits revealed insignificant between RL and other germination traits (GP, CVG, MGT, and TGI) except GRI (r = 0.499*) and SL (r = 0.541*). It is recommended that, as an emerging medicinal and fiber resource plant, C. gigantea can be cultured productively in coastal saline areas. Int. J. Agril. Res. Innov. Tech. 14(1): 10-17, June 2024

Application of chitosan nanopriming on plant growth and secondary metabolites of Pancratium maritimum L

BackgroundNanotechnology has demonstrated its vital significance in all aspects of daily life. Our research was conducted to estimate the potential of primed seed with chitosan nanoparticles in seed growth and yield by inducing plant secondary metabolism of Pancratium maritimum L. one of the important medicinal plants. Petri dish and pot experiments were carried out. Seeds of Pancratium maritimum L. were soaked in Nano solution (0.1, 0.5, 1 mg/ ml) for 4, 8, 12 h. Germination parameters (germination percentage, germination velocity, speed of germination, germination energy, germination index, mean germination time, seedling shoot and root length, shoot root ratio, seedling vigor index, plant biomass and water content), alkaloids and antioxidant activity of Pancratium maritimum L. were recorded and compared between coated and uncoated seeds.ResultsOur results exhibited that chitosan nanopriming had a positive effect on some growth parameters, while it fluctuated on others. However, the data showed that most germination parameters were significantly affected in coated seeds compared to uncoated seeds. GC-MS analysis of Pancratium maritimum L. with different nanopriming treatments showed that the quantity of alkaloids decreased, but the amount of pancratistatin, lycorine and antioxidant content increased compared with the control.ConclusionsApplying chitosan nanoparticles in priming seeds might be a simple and effective way to improve the quantity of secondary metabolites of Pancratium maritimum L. valuable medicinal plant.

Salinity tolerance at the germination stage of Senegalese varieties of peanut, cowpea, millet and sorghum

Salinization continues to increase in semi-arid areas like Senegal where it limits seed germination, a crucial phase in a plant's cycle. Adaptation to salinization, one of the great challenges of modern agriculture, is possible through the use of halotolerant varieties which could be selected early during seed germination. The general objective of this study is to evaluate the effect of salinity on the germination of peanut, cowpea, millet and sorghum. The effect of NaCl (0, 40, 80 and 120 mM) was tested on seed germination for one week at 30°C in a culture chamber. The parameters evaluated are: the final percentage of germination (FG), the germination vigor index (GVI), the coefficient of velocity of germination (CVG), the percentage reduction in germination compared to the control (PRG) and the daily average germination (DAG). The FG, GVI and CVG of millet, cowpea, sorghum and peanut show significant differences (p<0.01) for each NaCl concentration. On the other hand, DAG and PRG give significant differences only at 80 mM and/or 120 mM NaCl. FG, CVG, DAG and GVI decreased with increasing salinity for all varieties unlike PRG. Cowpea (V4) are less sensitive to salinity than peanut (V3), which tolerate NaCl better than cereals. Millet (V5) is more resistant than sorghum (V7). The increase in NaCl led to a significant difference in germination. Cowpea (V4) would be more osmotolerant than peanut (V3) which is more tolerant than cereals such as millet (V5) and sorghum (V7) to salinity. These varieties would be the most recommended for successful cultivation in a saline environment.

Low temperature and excess moisture affect seed germination of soybean (Glycine max L.) under controlled environments

Cold and excess moisture pose a serious threat to soybean production especially during seed germination in short-season environments. In this study, the effects of low temperature and excess moisture stress on seed germination were investigated in 187 soybean accessions originating from 18 countries. The experiment used a combination of three temperature conditions (i.e., 20 °C/14 °C, 14 °C/10 °C, and 10 °C/10 °C day/night) and two moisture levels (i.e., normal and excess). The seed germinability traits measured included germination rate (GR), germination index, germination time, germination uniformity, and coefficient of velocity of germination. Overall, GR was lowest in the 20 °C/14 °C + excess moisture and germination time was longest in the 10 °C/10 °C + excess moisture. When compared with 20 °C/14 °C + normal moisture treatment, GR at 10 °C/10 °C + excess moisture decreased by 38%; germination time increased by 20 days; seed viability decreased by 83%; germination uniformity decreased by 70%; germination speed decreased by 73%. Differences in GR, germination index, and germination velocity under different treatments were affected by temperature, moisture, and their interaction. Variation in germination time uniformity was determined by temperature, with no significant effects of moisture conditions and the interaction of temperature and moisture. It was shown that the temperature–excess moisture interaction led to a sharp decrease in seed germination. Two genotypes including PI 603147 and PI 507702 were identified with a GR over 90% at 10 °C/10 °C + excess moisture. This study generated new knowledge and data to further the understanding of genetic resistance to cold and excess moisture stress in soybean.

Phytic Acid, Protein, and Oil Contents and Their Relationship With Seed Quality During Seed Maturation of Bambara Nut (Vigna subterranea (L.) Verdc.) Landraces

ABSTRACTPhytic acid, proteins, and oils are seed storage compounds that play a role in germination and seedling growth and may determine seed quality. The pattern of accumulation of these compounds and the relationship of their contents with the seed quality of the Bambara nut (BN) are poorly understood. Seeds of three BN landraces, AbiBam001 (black/cream), LocalBam (brown speckled), and TVSU544 (cream), were harvested from two field experiments at different maturation stages and tested for final germination percentage (FGP), germination velocity index (GVI), and seedling dry weight (SDW). Seed samples from the same experiments were analyzed for phytic acid and proximate composition. Kendall's ranked correlation was used to describe relationships between phytic acid, protein, and oil contents and the seed quality of the landraces. Results showed no differences in the phytate, protein, and oil contents of landraces during seed maturation (p > 0.05), except for the phytate content of AbiBam001 (p < 0.05), which increased in the first experiment. At mass maturity, AbiBam001 and LocalBam had higher phytate and less protein and oil contents than TVSU544, implying that seed coat color may influence the phytate, protein, and oil contents of BN landraces. Higher phytate content in landraces appeared to relate positively with FGP, GVI, and SDW and vice versa. Phytic acid may positively affect seed germinability in BN landraces with high phytate content but may affect it negatively in low‐phytate landraces. The oil content of all landraces had negative correlations with most seed quality characteristics, suggesting that BN oils either are not priority reserves or play a minimal role in germination and seedling growth.

The role of exogenous glutamine on germination, plant development and transcriptional expression of some stress-related genes in onion under salt stress

ABSTRACT The purpose of this research was to explore the role of glutamine (Gln) on plant germination and growth under salinity [0, 50, 100, 150, 200 mM sodium chloride (NaCl)], and on the activation of some stress-related genes [CuZn-Superoxide Dismutase (SOD), Mn-SOD, L-ascorbate oxidase (AO), DNA Polymerase Delta 1 (POLD)-1, Chaperon (CHAPE) and Heat Shock Protein (HSP)-21], genetic template stability and photosynthetic pigment activation. Under salt stress, 2 mM Gln application reduced the mean germination time (MGT) (4.51 days), increased the coefficient of velocity of germination (CVG) (75.85), germination index (GI) (1.46) and germination percentage (GP) (82%), indicating that it was the best application for germination under stress. Gln promoted the development of aboveground plant organs. 3 mM Gln increased the number of leaves from 5.3 to 13.7 and 4.3 to 6.6 under unstress and stress conditions, respectively. Under salt stress, Gln increased photosynthetic pigments and genomic template stability (GTS) (80%). At 2 mM Gln, total chlorophyll and carotenoid content increased from 1.59 mg · g-1 TA to 2.23 mg · g-1 TA and from 0.28 mg · g-1 TA to 0.37 mg · g-1 TA, respectively. The effect on gene expression levels varied with the concentration. The application of 2 mM Gln, which enhanced germination and vegetative parameters under stress, caused a raise in CuZn-SOD gene expression and a 43% decrease in the transcriptional expression of the HSP-21 gene as an indicator of the functionality of the repair mechanism. The improved growth of Gln-treated plants under stress suggests that Gln is involved in bridging the energy deficit of the plant by acting as an alternative fuel for metabolic activities under stress.

Mechanical Scarification: The Key to Optimal Germination Parameters in Nine Flowering Species Of The United Arab Emirates.

Seed germination is the most essential stage of the plant life. Prior to germination, seed dormancy provides protection to the seed against germinating under unfavorable conditions. The seeds of many plants in arid regions are particularly characterized by having a hard seed coat. Seed dormancy is essential to the survival of plants, however in some incidents such as reforestation on desert areas, it is important for ecologists to investigate methods of breaking the dormancy of seeds in order to maximize the production of plants. In this study, we tested four methods of seed pre-treatment (Mechanical scarification (MChip), chemical scarification with sulfuric acid at two exposure durations (SAcid15, SAcid30), and soaking in water for 24h (Soak)) on 9 flowering plants (Senna italica, Sorghum sudanese, Tephrosia nubica, Senna angustifolia, Acacia tortilles, Senna occidentalis, Abutilon pannosum, Prosopis cineraria, Crotalaria persica) of the UAE. Six germination parameters (Final germination percentage (G) %, Mean germination time (MGT) day, Mean germination rate (MGR) day, Coefficient of velocity of germination (CVG) %, Mean Daily Germination Percentage (MDG) %, and Germination index (GI) day) were calculated to assess the germination. Final Germination Percentage (G) significantly improved (P

Low concentration of nitrate increases germination velocity of intact seeds of Nepeta micrantha in the first few days of germination

Nitrate promotes seed germination at low concentrations in many plant species. Meanwhile, mucilage plays a crucial role in germination by regulating seed responses to different environmental factors. This study investigated the effect of nitrate and mucilage on seed germination of the ephemeral plant Nepeta micrantha. Nitrate had distinct effects on intact and demucilaged seeds. Specifically, low nitrate concentration significantly increased the germination velocity of intact seeds, but decreased that of demucilaged seeds in the first few days. The addition of nitrate did not significantly affect the final germination percentage and germination index of intact and demucilaged seeds within the 20-day germination period, except for the demucilaged seeds treated with 0.01 mmol L-1 KNO3. This study suggests that nitrate and mucilage have a positive impact on germination of N. micrantha seeds in harsh environments.

Allelopathic Potential of Aqueous Extracts and Essential Oils of Rosmarinus officinalis L. and Thymus vulgaris L

Allelopathic effects of essential oils and aqueous extracts from Rosmarinus officinalis (rosemary) and Thymus vulgaris (thyme) have been investigated as a source of new natural herbicidal compounds to suppress two weeds: Chenopodium album and Echinochloa crus-galli associated with two important economic crops, Triticum aestivum (wheat) and Oryza sativa (rice), respectively. A petri-dish experiment was performed, and 10, 20, 50, and 100% aqueous solutions, and doses of 0, 2, 4, 8, and 16 µL of essential oil per petri dish were applied. The number of germinated seeds in each Petri dish was counted daily. After 15 days, germination percentage, the coefficient of velocity of germination, speed of germination, germination energy, germination index, mean germination time, seedling shoot length, root length, shoot–root ratio, and seedling vigour index were recorded. The chemical profiles of both essential oils were identified with GC–MS analysis. Eucalyptol (1,8-cineole), α-pinene, and camphor were identified as the dominant constituents of the rosemary essential oil. The major components detected in thyme essential oil were thymol, o-cymene, caryophyllene, and gamma-terpinene. The results showed that thyme essential oils had the most negative effect by inhibiting the germination of weeds. Both rosemary and thyme essential oils had a generally reducing effect on the growth parameters of weeds. The essential oils of rosemary and thyme have allelopathic potential and should be assessed as allelopathic agents to be used for weed control.

Allelopathic interactions of brown mustard (Brassica juncea L.) with other aromatic plants during germination and seedling development

Organic compounds originating from plant metabolism and reaching the environment may inhibit or stimulate germination and early developmental processes of other plants grown in the vicinity. The aim of this study was to investigate the allelopathic interactions of brown mustard with four other aromatic plants (summer savoury, coriander, caraway and common sage). While health-promoting metabolites of brown mustard are thoroughly investigated and the plant receives an increasing interest from cultivators of aromatic and medicinal plants, its allelopathic interactions with other aromatic plants are poorly documented. The experiments were performed in closed germination vessels, under controlled conditions. The influence of the presence or absence of light, as well as of a sufficient or reduced water supply on the co-germination of brown mustard seeds with each of the other four aromatic plants was also evaluated. The presence of brown mustard reduced the germination velocity of caraway, coriander, sage and savoury. It inhibited stem elongation, but stimulated root growth of savoury. Shoot growth of coriander seedlings was enhanced by the vicinity of brown mustard plantlets. Caraway slowed down the germination of brown mustard seeds, but it stimulated root and stem elongation of the seedlings. The presence of savoury enhanced the fresh biomass production of brown mustard. Common sage inhibited root growth, but stimulated stem elongation of brown mustard plantlets. Most of the allelopathic effects were more pronounced under water shortage than under sufficient water supply. Positive interspecific influences on biomass production were, in most cases, more pronounced in the presence of light. The findings may contribute to optimization of brown mustard cultivation in small parcels, in the vicinity of other aromatic plants, some allelopathic interactions being able to stimulate growth and developmental processes in an environmental-friendly and cost-effective manner.

Screening for Salt Tolerance in Chenopodium quinoa Genotype Seedlings through Germination in a Hydroponic System

Quinoa (Chenopodium quinoa Willd.) is poised to be a global life changer with its ability to adapt to a wide range of abiotic stresses and as a highly nutritious and sustainable food source. A trial on screening of salt tolerance was conducted at the germination and seedling stages of 69 quinoa genotypes in different concentrations of NaCl 0 (CK), 100, 200, 300, 400, and 500 mM for 21 days in the MS/2 mixture. This results in 16 genotypes with >50% germination at 400 mM NaCl. These were reassessed in germination indices and relative growth. Results indicated that Chadmo had the highest germinability of 97% and 32.76% relative height among the 16 genotypes. Considering the germination indices, Chadmo had significantly different values (3.05±0.19 day-1) in mean germination time, coefficient of variation of the germination time (38.76±1.97%), the velocity of germination (0.23±0.01 day-1), the uncertainty of germination (0.54±0.08 bit), synchrony of germination (0.42±0.05 and Timson’s index (48.89) with significant differences (P<0.05) among the genotypes. Moreover, Chadmo had the highest membrane stability index (MSI) (60.03±11.84) at 400 mM NaCl and the least relative change between the CK and 400 mM NaCl with 30.87±2.01%. Assessing the stress inhibitory effect of the 16 genotypes, Chadmo had the least relative difference between the CK and 400 mM NaCl with shoot length of 34.34%, root length of 25.57%, fresh weight of 22.05%, dry weight of 3.62% and moisture content of 1.99% with Tukey analyses identifying significant differences (p<0.05). To select the salt-sensitive genotype, an assessment was done on five genotypes that exhibited the least germination at 200 mM NaCl. Kankolla had the least germinability with 12 and 4% at 100 and 200 mM NaCl, respectively. Considering all these parameters, Chadmo and Kankolla were selected as salt-tolerant and salt-sensitive for further analyses.