Dormancy Breaking Research Articles

The dormancy breaking of garlic seeds through thermal shock storage methods and soaking in gibberellin acid

Garlic seed production is constrained by a long dormancy period, which is 5-6 months. This study aimed to analyses the effect of thermal shock storage methods and soaking in gibberellin acid on the dormancy breaking of garlic seeds. Raw material used in this study was garlic bulbs variety Sangga Sembalun. The experiment was conducted in randomized block design with treatments of storage temperature (low temperature / 12-14°C, high temperature / 38-42°C + low temperature / 12-14°C, high temperature / 38-42°C + room temperature / 28-30°C, and room temperature) and gibberellin acid concentration (0, 125, 250, 375 ppm), with two replications. Total storage duration was 4, 8, and 12 weeks. The results of analysis of variance (ANOVA) showed that storage temperature was significantly different of their germination (p<0.05). Storage of garlic seeds by the thermal shock method can shorten the dormancy period from 5-6 months to 12 weeks. Germination capacity resulting from combination of high temperature (38-42°C) storage for 6 weeks and low temperature (12-14°C) for 6 weeks (a total of 12 weeks) is higher than continuous storage of low temperature and room temperature without requiring the addition gibberellin acid.

THE EFFECT OF CORONA INCANDESCENT PLASMA RADIATION AND STORAGE TEMPERATURE ON THE VIABILITY OF GARLIC SEEDS (ALLIUM SATIVUM L. LUMBU KUNING VARIETY)

Garlic (Allium sativum L.) is an agricultural commodity which is widely consumed by the community. The obstacle experienced in cultivation is that a relatively long dormancy period of about 6-7 months. The dormancy of garlic seeds occurs because the embryo has not yet been fully formed, and the growth hormone and inhibitory hormone are not balanced. The methods used to break dormancy and accelerate germination are by using corona incandescent plasma radiation and storage temperature. The research utilized factorial Completely Randomized Design (CRD), consisting of six treatments with five replications. The first factor was the corona incandescent plasma radiation carried out on the garlic seeds ‘Lumbu Kuning’ variety with time duration of 0, 15, and 30 minutes. The second factor was storage temperature comprising of room temperature and cold temperature of 7oC stored for 30 days. Viability parameters observed are germination percentage dan the length of sprouts. The data were analyzed by using ANOVA followed by the DMRT test at the 95% confidence level. The results showed that corona incandescent plasma radiation influenced the germination percentage using plasma radiation for 15- 30 minutes.

Micropropagación del alcaparro en medio semisólido y en biorreactores de inmersión temporal

El objetivo fue el desarrollo de un sistema eficiente para la micropropagación del alcaparro (Capparis spinosa L.), arbusto leñoso de gran interés por los productos derivados del mismo, su notable resistencia a la sequía y su tolerancia a las altas temperaturas. Primero se establecieron cultivos in vitro se a través de la desinfección y germinación de semillas. Fue necesaria una escarificación de estas con H2SO4 concentrado (98% v/v) para romper la dormancia. Solo 15% de las semillas germinaron. Se obtuvieron segmentos nodales a partir de las plántulas germinadas, mismos que se cultivaron en medio basal de Murashige y Skoog (MS) semisólido adicionado con benciladenina (BA), 2-isopenteniladenina (2iP) y metatopolina (MT), esto con el fin de inducir la brotación múltiple. La mejor respuesta se obtuvo con 2 mg L-1 de estas citocininas, con un número promedio de brotes bien diferenciados por segmento nodal de 3.6 con MT, 2.3 con BA y 1.5 con 2iP, esto a los 54 d de incubación. Se probó también la combinación de las citocininas con una auxina, el ácido naftalenacético. Esta combinación mejoró la respuesta de la BA, alcanzando un promedio de 3.2 brotes por segmento nodal. Con las otras citocininas no mostró un efecto positivo, manteniéndose valores muy similares con y sin la auxina. Además de brotes bien diferenciados, se generaron masas o racimos de numerosos brotes pequeños, no aptos para su transferencia a medio de enraizamiento. Estas masas se transfirieron a biorreactores de inmersión temporal tipo RITA, en donde se generó un promedio de 89 brotes bien diferenciados por explante original, esto en un medio con 1 mg L-1 de BA con inmersiones de 2 min cada 6 h. Los brotes enraizaron con una eficiencia de 80% en el medio basal, generando plantas bien diferenciadas y aptas para su transferencia a suelo. La supervivencia ya en el medio externo de las plantas generadas in vitro fue de 85%, mostrando un desarrollo en apariencia normal ya en condiciones ex vitro.

S-nitrosoglutathione Reductase-Mediated Nitric Oxide Affects Axillary Buds Outgrowth of Solanum lycopersicum L. by Regulating Auxin and Cytokinin Signaling

Auxin and cytokinin are two kinds of important phytohormones that mediate outgrowth of axillary buds in plants. How nitric oxide and its regulator of S-nitrosoglutathione reductase (GSNOR) take part in auxin and cytokinin signaling for controlling axillary buds outgrowth remains elusive. We investigated the roles of GSNOR during tomato axillary bud outgrowth by using physiological, biochemical and genetic approaches. GSNOR negatively regulated NO homeostasis. Suppression of GSNOR promoted axillary bud outgrowth by inhibiting the expression of FZY in both apical and axillary buds. Meanwhile, AUX1 and PIN1 were down-regulated in apical buds but up-regulated in axillary buds in GSNOR-suppressed plants. Thus, reduced IAA accumulation was shown in both apical buds and axillary buds of GSNOR-suppressed plants. GSNOR-mediated changes of NO and auxin affected cytokinin biosynthesis, transport, and signaling. And a decreased ratio of auxin: cytokinin was shown in axillary buds of GSNOR-suppressed plants, leading to bud dormancy breaking. We also found that the original NO signaling was generated by nitrate reductase (NR) catalyzing nitrate as substrate. NR-mediated NO reduced the GSNOR activity through S-nitrosylation of Cys-10, then induced a further NO burst, which played the above roles to promote axillary buds outgrowth. Together, GSNOR-mediated NO played important roles in controlling axillary buds outgrowth by altering the homeostasis and signaling of auxin and cytokinin in tomato plants.

Effects of Light and Temperature on Germination of Eggert's Sunflower (Helianthus eggertii)

Helianthus eggertii is a rare perennial sunflower of barrens and open habitats in Kentucky, Tennessee, Alabama, and South Carolina in the United States (U.S.). Despite its delisting in the U.S. Endangered Species Act in 2005, little is known about the germination biology of H. eggertii other than seeds require cold stratification for optimal germination. Knowledge about the germination biology of rare species can aid in the management of natural populations and inform strategies for ex situ seed conservation and propagation. We examined how cold stratification, light, and temperature interact to affect seed germination in H. eggertii, and whether germination proportions varied among populations. At the time of maturity in October, seeds have primary physiological dormancy and require cold stratification or prolonged (> 8 wk) incubation in light at cool (15/6 C) temperatures to germinate. Seeds maintained a light requirement for germination when cold stratified in darkness, but not after cold stratification in light. However, seeds germinated to lower proportions after cold stratification in light relative to darkness, and when incubated at temperatures that mimic summer (35/20 C) compared to late spring (25/15 C). Germination varied widely among populations (23-58%), with plants from more open sites exhibiting lower germination proportions than those from partially shaded sites. Our results indicate seeds most likely germinate in early- to mid-spring, and light promotes germination of H. eggertii. Our results highlight the interactive role of light and temperature in determining seed dormancy break and germination in H. eggertii.

Protective action of priming agents on Urochloa brizantha seeds under water restriction and salinity conditions

Abstract: Analyses of germination of seeds under artificial stress conditions are tools for a better understanding of the survival and adaptation capacity of species under natural stress conditions. Therefore, the aim of this study was to evaluate the effect of priming on seed germination, on breaking of dormancy, and on the length of Urochloa brizantha seedlings under water restriction and salt stress conditions. A completely randomized experimental design was used with four replications in a 3 × 6 factorial arrangement consisting of 3 germination conditions (water, water restriction with PEG, and salinity with NaCl) and 6 treatments [five priming solutions (distilled water, potassium nitrate, spermidine, gibberellin, and sodium nitroprusside) and a control (unprimed seeds)]. The following determinations were made: seed moisture content after priming (before drying) and after drying the seeds, germination test at seven and twenty-one days after sowing, germination speed index, viability by the tetrazolium test of the seeds remaining from the germination test, and seedling length. Priming is effective in minimizing the negative effects of water restriction and salinity. Use of sodium nitroprusside as a priming solution results in a lower percentage of dormant seeds and greater germination, vigor, and plant development.

Burial depths favor Italian ryegrass persistence in the soil seed bank

Italian ryegrass (Lolium multiflorum Lam.) is a weed broadly found in fields cultivated with wheat and barley crops. Seed inputs into the soil before harvesting winter crops increase seed bank, ensuring survival. This study evaluated the persistence of Italian ryegrass seeds subjected to burial depths over time. Experiments were carried out in the field for two years in randomized block experimental design with four repetitions. Dormant seeds harvested from mother-plants were put in nylon bags containing soil. Previously, seed viability was evaluated in a 1 % tetrazolium solution, and 50 viable seeds by repetition were buried at 0.5, 5.0, 10, and 20 cm depths. Seed persistence was evaluated by the percentage of deteriorated and remaining seeds, non-dormant seeds, abnormal seedlings, and viable and non-viable dormant seeds at 0, 30, 60, 90, 180, 360, 540, and 720 days after burial (DAB). Seed persistence increased at 10 and 20 cm of burial depth compared to seeds in the soil layers up to 5 cm. Moreover, burial depth at 10 and 20 cm showed lower percentage of deteriorated seeds (10 % lower) compared to 0.5 cm at 360 DAB. For non-dormant seeds, a higher percentage was found at 90 DAB, regardless of seed burial depth. Dormancy breakage occurred until 180 DAB, and more rapidly at 10 and 20 cm depths. At 540 DAB, more than 95 % of seeds were unviable, demonstrating short persistence of Italian ryegrass in the soil seed bank.

Post-seminal development and cryopreservation of endemic or endangered bromeliads.

Vriesea bahiana, Hohenbergia castellanosii and Encholirium spectabile are endemic Brazilian species that are considered endemic or endangered. Development of strategies to conserve these species is important to prevent irreversible genetic erosion. The objective of this study was to evaluate the post-seminal development and seed cryopreservation of three endemic or in danger of extinction bromeliad species in Brazil, to obtain a protocol that can safeguard the genetic variability of these species. In the seed cryopreservation assay, we evaluated five desiccation periods. The seeds in the cryotubes were taken from the desiccator and immediately plunged into liquid nitrogen. For the analysis of post-seminal development, seeds in different germination stages were collected and evaluated by light and scanning electron microscopy. Vriesea bahiana seeds frozen in liquid nitrogen presented almost 100% germination, indicating dormancy break of this species. Vriesea bahiana can be cryopreserved with 5.9% water content after being dried for 24 hours. Hohenbergia castellanosii and E. spectabile seeds did not need to be desiccated before being cryopreserved. The most relevant morphological traits for differentiation of genera and subfamilies of Bromeliaceae are the shape and type of seed appendages. In this study, all three species presented well-differentiated size and shape of their structures.

Effects of Aeschynomene histrix Poir. seed treatment on germination

Description of the subject. Poor germination associated with physical dormancy was experienced in the legume Aeschynomene histrix Poir. seeds and can reduce the establishment and growth of this species. Objectives. To evaluate the effects of different pre-planting treatments, including digestion by Lagune cattle or other preplanting treatments on the germinability of A. histrix seeds. Method. The experiment was divided into three phases. Firstly, six Lagune cattle (three young bulls and three heifers) were fed individually with 1,000 seeds and these seeds were subsequently collected from faeces. Secondly, seed germination was compared among seeds defecated by cattle and seeds submitted to seven other pre-planting treatments: control (intact untreated seeds); seeds scarified using sandpaper; and seeds immersed in 80 °C-hot water for 2, 4, 6, 8, and 10 min. Thirdly, we also assessed the effect of crumbling cattle faeces on A. histrix germinability. Results. The results show that Lagune cattle can disperse seeds of A. histrix with maximum recovery on the second day after ingestion. Of the number of seeds fed 13.42% were recovered. The germination percentage was greatest for sandpaper scarified seeds (96%) and seeds pre-heated during 2 min (86%), but least for digested seeds (4.27%). Breaking-down the dung doubled seedling emergence from digested seeds. Conclusions. As it is desirable to break dormancy of A. histrix seeds, the use of mechanical scarification using sandpapering or hot water scarification 80 °C at 2 min may be more beneficial than cattle digestion.

Methods of overcoming dormancy in seeds and initial development of Black Wattle

The objective of this work was to analyze the efficacy of different methods of dormancy break in seeds of Acacia mearnsii De Wild. The work was performed at the UFSM Botany Lab and Forest Nursery, in Frederico Westphalen, RS. The treatments were: (T1) control; (T2) immersion in hot water (90 °C) for 5 minutes, followed by rest; (T3) immersion in hot water (90 °C) for 10 minutes, followed by rest; (T4) chemical scarification with concentrated sulfuric acid for 3 minutes, followed by washing under running water; (T5) chiseling with concentrated sulfuric acid for 5 minutes, followed by washing under running water. The seeds were sown in plastic trays with Oxisol and vermiculite. The results were submitted to analysis of variance and data were differentiated by Test t with 5% of probability. The most efficient treatment to overcome dormancy was T2, presenting 81.29% of germinated seeds and IVG of 18.23 days for germination. This treatment was also the best for the variables of physical vigor and best performing root length and aerial part, and did not differ from improved treatments for diameter and green mass weight.

Effect of chemical treatments used for dormancy breaking on the number of stems and tubers of Hungarian potato varieties

The length of tuber dormancy of potato varieties is an important factor in the profitability of the potato sector. Under temperate climatic conditions longer dormancy is more advantageous. However, in case of multiple planting within one growing season, in seed multiplication programs or during rapid post-harvest disease testing, breaking or shortening of dormancy is often needed. Numerous ways for chemical regulation of dormancy period were developed, but the efficiency of such methods is strongly genotype dependent. Recently a comparative study of chemical treatments for breaking tuber dormancy of some new Hungarian potato varieties was carried out. Continuing this work, here we report about the effects of chemical treatments used for breaking dormancy on the number of stems and tubers of progeny plants. The experiment was conducted in three consecutive vegetation period, with three varieties having different maturity type and different dormancy period: Balatoni rózsa, Botond and Démon. Treatments were performed using gibberellic-acid, benzyl-adenine and Rindite in different concentrations and combinations. After the dormancy period, tubers were planted into pots and grown under controlled conditions. Number of developed stems and tubers was counted. According to the results, applied treatments had a large effect on the number of developing stems and tubers of the progeny plants. Combined treatments of Rindite+gibberellic-acid, and gibberellic-acid at 100 ppm increased significantly the number of stems and tubers. Correlation between the efficiency of dormancy breaking and the number of developed tubers was found. Based on our data, Rindite and gibberellic-acid have an important role not only in breaking dormancy, but also in increasing the tuber number/plant. This positive effect could be utilized in seed potato production.

Seed tolerance to post-fire temperature fluctuation of Cerrado legume shrubs with micromorphological implications

Multiple environmental cues may break seed physical dormancy (PY) in fire-prone ecosystems, but disentangling the roles of such cues remains challenging. Current research has mostly focused on the role of high temperatures (heat shocks) in PY alleviation, while post-fire environmental conditions are less understood. Here, we examined the role of post-fire temperature fluctuation on seed germination and viability of Cerrado legume shrubs. Specifically, we investigated (1) whether PY is broken by temperature fluctuation; (2) whether seed viability is affected by temperature fluctuations; and (3) micromorphological changes in the seed coat following exposure to temperature fluctuation. Seeds of nine legume species were collected in frequently burned Cerrado savannas. We simulated post-fire temperature fluctuation in germination chambers, with daily temperature fluctuation ranging from 18 to 55 °C for 90 days; controls consisted of untreated seeds (room temperature). We conducted germination trials with unblocked and blocked hilar region of seeds. In addition, seed samples were fixed and subjected to micromorphological analysis. Instead of dormancy break, three species showed decreased seed germination for both unblocked and blocked hilar regions, while other two species showed decreased germination in blocked seeds only. Nevertheless, random cracks formed across the seed coat were found in control and treated seeds, which displayed a proportion of nondormant seeds. Within nondormant seeds, both hilar and extra-hilar regions (such as the pleurogram) may take part on water uptake. Despite the lack of dormancy break, most Cerrado legume seeds persisted viable after post-fire temperature fluctuation, thus avoiding establishment under hazardous conditions. Seed tolerance to heat shocks and post-fire temperature fluctuation likely drives regeneration from seed in burned Cerrado areas.

Mutu Fisik Dan Teknik Pematahan Dormansi Benih Kayu Kuku (Pericopsis mooniana (Thw.) Thw.)

The presence of Pericopsis mooniana (Thw.) Thw. in nature is endangered. Meanwhile, Pericopsis mooniana plants have its obstacles in generative propagation because the seeds have mechanical dormancy. Studies carried out to: (1) observe the morphology of pods, seeds and sprouts of Pericopsis mooniana; (2) determine the physical quality of Pericopsis mooniana seeds, and (3) analyze the proper dormancy breaking treatment for Pericopsis mooniana seeds. Research is conducted in laboratories and in greenhouses. The physical quality of the seeds measured was the weight of 1,000 seeds and the moisture content. The treatment for breaking the dormancy of the Pericopsis mooniana seeds were control, scarification of the seeds using nail clippers and soaking in hot to cold water for 48 hours. Morphologically, the fruit of Pericopsis mooniana is pod-shaped, with orange seeds, oval-shaped and curved edges. Pericopsis mooniana sprouts include in the epigeal type. In 1 kg of weight there are ± 4,000 Pericopsis mooniana seeds, with the post harvest seed moisture content amounting to 7.62%. The dormancy breaking treatment of Pericopsis mooniana seeds increased seeds germination by 60% compared to controls. The scarification of Pericopsis mooniana seeds using nail clippers for breaking mechanical dormancy is the best treatment because it can increase the number of seeds germinating in a short time and simultaneously.&#x0D; Key words: breaking seed dormancy, morphology, Pericopsis mooniana, physical quality, seed scarificatio

Effect of dry heat on seed germination of Desmodium and Stylosanthes species

Mechanical scarification with a scalpel is the best treatment to break physical dormancy and reach high germination percentages in many legumes. However, it is highly time-consuming. Given the ecological relationship between the presence of physical dormancy and high temperatures in tropical grasslands, dry heat treatment could also promote breaking of physical dormancy in Desmodium and Stylosanthes species. This study assessed seed germination of several accessions of nine species of Desmodium and Stylosanthes. Seeds were treated with dry heat (80°C for 30 minutes) and scarified with a scalpel to determine whether dry heat is a reliable alternative treatment to overcome physical dormancy. Mechanical scarification with a scalpel was effective and resulted in high germination for all species. In S. guianensis, both treatments had an equivalent effect, making dry heat a feasible alternative. Dry heat could also be a reliable alternative in D. heterocarpon, D. velutinum, S. hamata, and S. scabra, but tetrazolium tests may be necessary to confirm viability. For D. barbatum and D. scorpiurus, dry heat could be an alternative but further research is needed to confirm this, while in S. capitata and S. viscosa dry heat is not a reliable alternative.

Integrated transcriptome and proteome analysis provides insight into chilling-induced dormancy breaking in Chimonanthus praecox

Chilling has a critical role in the growth and development of perennial plants. The chilling requirement (CR) for dormancy breaking largely depends on the species. However, global warming is expected to negatively affect chilling accumulation and dormancy release in a wide range of perennial plants. Here, we used Chimonanthus praecox as a model to investigate the CR for dormancy breaking under natural and artificial conditions. We determined the minimum CR (570 chill units, CU) needed for chilling-induced dormancy breaking and analyzed the transcriptomes and proteomes of flowering and non-flowering flower buds (FBs, anther and ovary differentiation completed) with different CRs. The concentrations of ABA and GA3 in the FBs were also determined using HPLC. The results indicate that chilling induced an upregulation of ABA levels and significant downregulation of SHORT VEGETATIVE PHASE (SVP) and FLOWERING LOCUS T (FT) homologs at the transcript level in FBs when the accumulated CR reached 570 CU (IB570) compared to FBs in November (FB.Nov, CK) and nF16 (non-flowering FBs after treatment at 16 °C for −300 CU), which suggested that dormancy breaking of FBs could be regulated by the ABA-mediated SVP-FT module. Overexpression in Arabidopsis was used to confirm the function of candidate genes, and early flowering was induced in 35S::CpFT1 transgenic lines. Our data provide insight into the minimum CR (570 CU) needed for chilling-induced dormancy breaking and its underlying regulatory mechanism in C. praecox, which provides a new tool for the artificial regulation of flowering time and a rich gene resource for controlling chilling-induced blooming.

SEED GERMINATION PLASTICITY OF TWO ENDANGERED SPECIES OF FERULA IN THE CONTEXT OF CLIMATE CHANGE

Ferula assa-foetida and F. gummosa, Apiaceae, are important endemic and endangered medicinal plants. Survival of the species is threatened by climate change, overexploiting (as source of oleo-gum resin and for-age) and lack of organized cultivation. Cultivation of these valuable medicinal plants is restricted by insuffi-cient domestication knowledge. Germination characteristics of different populations of Ferula taxa were studied with the aim of describing and comparing their responses to continuous cold stratification condition. Germination cues for the species were complex, with dormancy mechanisms present to restrict germination until cold stratification are fulfilled. Results indicated that a period of 4 weeks of stratification is sufficient for germination of F. assa-foetida, but optimal germination of F. gummosa require stratification for periods of 8 weeks. Both species were able to germinate at very low temperatures (4°C). Within-taxon differences in dor-mancy breaking and seedling emergence may interpret as local adaptations. The continued regeneration and propagation of the species in the wild will depend on the temperature and moisture status of the soil during winter and the maintenance of conditions suitable for stratification for an appropriate length of time.

The effect of different treatments on seed dormancy breaking and germination inducing in Louisiana variety of Okra (Abelmoschus esculentus L.)

To investigate the methods of dormancy breaking in okra seeds; a study was conducted in the winter season of 2019 under laboratory conditions in Samangan Higher Education Institute. The experiment was carried out based on a completely randomized design within 10 treatments and 3 replications. The treatments included gibberellic acid at 4 levels (100, 500, 700, and 1000 ppm), hot water (70°C), hydrochloric acid (75%) at three levels (5, 10, and 15 minutes), 7-day chilling at 3°C and control treatment (distilled water). The results showed that the highest percentage (100%) with a germination rate of 86 seeds were available due to the application of 7-day cold treatment. Moreover, the treatments such as 7-day chilling, gibberellic acid 500 ppm, and hydrochloric acid 10 and 15 minutes had significant effects on the fresh and dry weight of roots and shoots as well as on their length. we observed that the 7- day cooling at 3°C is the best and most appropriate solution to break down the seed dormancy and stimulate seed germination of the above-mentioned crop.

Different levels of morphophysiological seed dormancy in Ribes alpinum and R. uva-crispa (Grossulariaceae) facilitate adaptation to differentiated habitats

Aim of the study: To study the germination ecology of two species of the genus Ribes to reveal their levels of morphophysiological dormancy (MPD) and to facilitate the production of plants from seeds, a key tool for population reinforcement.Area of study: Experiments were carried out both outdoors and in the laboratory in Albacete (Spain) with seeds from the Meridional Iberian System mountain range.Material and methods: Seeds from one population of Ribes alpinum and from other of Ribes uva-crispa were collected during several years. Embryo length, radicle and seedling emergence, and effects on germination of stratification and GA3 were analysed to determine the level of MPD.Main results: In R. alpinum, embryo length in fresh seeds was 0.49 mm, needing to grow to 1.30 mm to germinate. Warm stratification (25/10ºC) promoted embryo length enlargement to 0.97 mm. Afterwards, seeds germinated within a wide temperature range. Embryo growth and seedling emergence occur late summer-early autumn. In R. uva-crispa, embryo length in fresh seeds was 0.52 mm, being 2.10 mm the minimal size to germinate. Embryos exposed to a moderately warm stratification (20/7ºC + 15/4ºC) followed by cold (5ºC) grew to 2.30 mm. Then, seeds germinated ≥ 80% when incubated at temperatures ≥ 15/4ºC. Embryos grew in autumn/early winter, and seedlings emerged late winter-early spring.Research highlights: These results showed that R. alpinum seeds have a nondeep simple MPD while R. uva-crispa seeds have a nondeep complex MPD. Moreover, the different germinative models found for each species help explain their installation in distinct habitats.Keywords: Ribes; seed dormancy break; radicle emergence; seedling emergence; nondeep simple and nondeep complex MPD.Abbreviations used: Morphophysiological dormancy (MPD), morphological dormancy (MD), Gibberellic acid (GA3), months (m).

Practical Methods for Breaking Seed Dormancy in a Wild Ornamental Tulip Species Tulipa thianschanica Regel

The innate physiological dormancy of Tulipa thianschanica seeds ensures its survival and regeneration in the natural environment. However, the low percentage of germination restricts the establishment of its population and commercial breeding. To develop effective ways to break dormancy and improve germination, some important factors of seed germination of T. thianschanica were tested, including temperature, gibberellin (GA3) and/or kinetin (KT), cold stratification and sowing depth. The percentage of germination was as high as 80.7% at a constant temperature of 4 °C, followed by 55.6% at a fluctuating temperature of 4/16 °C, and almost no seeds germinated at 16 °C, 20 °C and 16/20 °C. Treatment with exogenous GA3 significantly improved the germination of seeds, but KT had a slight effect on the germination of T. thianschanica seeds. The combined treatment of GA3 and KT was more effective at enhancing seed germination than any individual treatment, and the optimal hormone concentration for the germination of T. thianschanica seeds was 100 mg/L GA3 + 10 mg/L KT. In addition, it took at least 20 days of cold stratification to break the seed dormancy of T. thianschanica. The emergence of T. thianschanica seedlings was the highest with 82.4% at a sowing depth of 1.5 cm, and it decreased significantly at a depth of &gt;3.0 cm. This study provides information on methods to break dormancy and promote the germination of T. thianschanica seeds.

Biological responses of Sri Lankan rice (Oryza sativa L.) varieties to rhythmic sound patterns (music and religious chants)

Abstract. Munasinghe DSP, Weerakoon SR, Somaratne S. 2020. Biological responses of Sri Lankan rice (Oryza sativa L.) varieties to rhythmic sound patterns (music and religious chants). Nusantara Bioscience 12: 154-161. Influences of music cause either promoting or restricting the growth of plants. The effects of Pirith chanting and rhythmic sound patterns (Western classical music, Eastern classical music, Rock music) were focused in the present study. Seeds of Two (02) rice varieties (Bg 300 and Kuruluthuda) in f0 and f1 generations were subjected to dormancy break treatment, kept in a soundproof confined chamber, and arranged in Randomized Complete Block Design (RCBD) with two (02) replicates and 10 seeds per replicate. Seeds were germinated under the three sound rhythms, Pirith chanting, and silence. Plants kept under silence served as the control. Sound rhythms and Pirith were played separately for an hour, at 30 cm distance away from the seeds with an intensity of 55-60 dB for seven (07) days continuously, maintaining equal environmental conditions. Following seven (07) days, the percentile germination rate was recorded. Germinated seeds were planted in plastic pots filled with paddy soil, up to ¾ of the total depth, and pots were arranged in Randomized Complete Block Design (RCBD) with five (05) replicates and three (03) plants per replicate. Following one week, plants were subjected to sound rhythm treatments and silence for three (03) months continuously. Measurement of growth and yield performance were recorded every fortnight. Significantly different (p &lt; 0.05) growth and yield performances in both generations were observed under Pirith, Eastern Classical and Western Classical music. Higher rates of growth were observed for rice varieties exposed to Pirith, Eastern and Western classical music. Similarly, yield was also higher compared to rice varieties exposed to rock music. The findings suggest that soft rhythmic sounds are the most appropriate type of music which improved growth and yield performance of rice varieties, Bg 300, and Kuruluthuda. However, further studies are needed to confirm present results and to elucidate the mechanism of responses to Pirith chanting and other rhythmic sound patterns using phytochemical and biochemical analyses.