Smoke Water Research Articles

Species-specific smoke effects on seed germination of plants from different habitats from Sri Lanka

Smoke and in particular karrikinolide (KAR1), a growth promoting compound found in smoke, have been shown to enhance seed germination in phylogenetically diverse plant families from both fire-prone and fire-free ecosystems. We tested the effects of water saturated with smoke, “smoke water” (SW), and KAR1 on seed germination of 18 native and exotic plant species from different habitats affected by anthropogenic fires in Sri Lanka. Seeds were tested with five concentrations of SW (5 %, 25 %, 50 %, 75 %, 100 %) and those that positively responded were tested with three different concentrations of KAR1 (10 nM, 100 nM and 1 μM). Germination percentage of three native (Flueggea leucopyrus, Maesa indica and Phyllanthus emblica) and two exotic (Chromolaena odorata and Hyptis suaveolens) species was significantly increased by both SW and KAR1 treatments. Seed germination percentage of the exotic species Euphorbia heterophylla was increased by SW treatments only. The time taken for 50 % germination (t50) of C. odorata, M. indica and P. emblica was decreased by both SW and KAR1, whilst t50 of E. heterophylla was decreased by SW only. Species-specific seed germination promotion response to SW and KAR1 was observed in both native and exotic plant species tested in the study confirming that the recruitment ecology of at least some species found in fire prone habitats of Sri Lanka is likely to be influenced by fire management practices.

Progress in utilizing plant-derived smoke water and smoke-derived KAR1 in plant tissue culture

Plant-derived smoke, its water extract—the smoke water (SW) and karrikinolide (KAR1) isolated from smoke or synthesized from different substrates stimulate germination of dormant and non-dormant seeds of plants from fire-prone and fire-free areas, including horticultural crops, agricultural crops and weeds. Both SW and KAR1 can be successfully used in in vitro cultures. They are able to stimulate pollen germination and growth of tubes. Growth of callus, efficiency of somatic embryogenesis, germination of somatic embryos and its conversion to plantlets are also positively affected by SW or KAR1. SW can stimulate seed germination in vitro, promote extension of primary root section and increase frequency for initiation of lateral roots. SW and KAR1 can be used as elicitors to increase production of secondary metabolites. This article describes discovery of biological activity of SW and KAR1 and provides an overview research on use of above factors in tissue and organ culture. The similarity of signaling pathways of karrikins compared to strigolactones or gibberellins is also discussed.

Potential of Smoke-Water and One of Its Active Compounds (karrikinolide, KAR1) on the Phytochemical and Antioxidant Activity of Eucomis autumnalis.

Eucomis autumnalis (Mill.) Chitt. subspecies autumnalis is a popular African plant that is susceptible to population decline because the bulbs are widely utilized for diverse medicinal purposes. As a result, approaches to ensure the sustainability of the plants are essential. In the current study, the influence of smoke-water (SW) and karrikinolide (KAR1 isolated from SW extract) on the phytochemicals and antioxidant activity of in vitro and greenhouse-acclimatized Eucomis autumnalis subspecies autumnalis were evaluated. Leaf explants were cultured on Murashige and Skoog (MS) media supplemented with SW (1:500, 1:1000 and 1:1500 v/v dilutions) or KAR1 (10−7, 10−8 and 10−9 M) and grown for ten weeks. In vitro regenerants were subsequently acclimatized in the greenhouse for four months. Bioactive phytochemicals in different treatments were analyzed using ultra-high performance liquid chromatography (UHPLC-MS/MS), while antioxidant potential was evaluated using two chemical tests namely: DPPH and the β-carotene model. Smoke-water and KAR1 generally influenced the quantity and types of phytochemicals in in vitro regenerants and acclimatized plants. In addition to eucomic acid, 15 phenolic acids and flavonoids were quantified; however, some were specific to either the in vitro regenerants or greenhouse-acclimatized plants. The majority of the phenolic acids and flavonoids were generally higher in in vitro regenerants than in acclimatized plants. Evidence from the chemical tests indicated an increase in antioxidant activity of SW and KAR1-treated regenerants and acclimatized plants. Overall, these findings unravel the value of SW and KAR1 as potential elicitors for bioactive phytochemicals with therapeutic activity in plants facilitated via in vitro culture systems. In addition, it affords an efficient means to ensure the sustainability of the investigated plant. Nevertheless, further studies focusing on the use of other types of antioxidant test systems (including in vivo model) and the carry-over effect of the application of SW and KAR1 for a longer duration will be pertinent. In addition, the safety of the resultant plant extracts and their pharmacological efficacy in clinical relevance systems is required.

Effect of plant-derived smoke water and potassium nitrate on germination of understory boreal forest plants

This experiment assessed the effects of plant-derived smoke water, potassium nitrate (KNO3), and their combined effect on germination of cold-stratified and non-stratified seed from 18 native boreal forest plant species. Seeds were treated with smoke water diluted to 1:20, 0.1% KNO3, and smoke water + KNO3. Nine species responded positively to smoke water; these responses were dependent on the type of stratification, and three of these species only had a positive response to smoke water + KNO3 solution. Five species responded positively to KNO3 and four of those were associated with smoke water + KNO3 solution. Smoke water induced germination of several species, but only for seeds that had been previously cold-stratified. Vaccinium myrtilloides Michx. had the largest increase in germination using smoke water and the most reduced germination using KNO3. The interactions between smoke water, KNO3, and stratified seeds are not well understood. The effects and applications of smoke water and KNO3 (or other nitrogen sources) should be further researched to determine alternative approaches to restoration of disturbed boreal forest ecosystems.

Overcoming germination barriers in four native Malvaceae shrub species of Reunion island to improve restoration in arid habitats

Islands are well-known to house an incredible biodiversity, higher level of threatened species and extinctions than mainlands. Because of human activities and climate change, these endangered regions required advanced conservation and restoration strategies.In this study, we investigated seed germination ecology of four native Malvaceae species (Dombeya acutangula, Dombeya populnea, Ruizia cordata and Thespesia populneoides) of degraded dry lowlands of Reunion Island. We measured seed imbibition, investigated the dormancy class of seeds, determined light requirements for germination and identified treatments to improve germination of these species. For this purpose, germination tests were performed over 32 days and two photoperiods (12 h/12 h or 0 h/24 h), by using seeds treated with H2O2, gibberellic acid and smoke water. Mechanical and chemical scarifications as well as heat treatment were also carried out. Germination percentages were analyzed by fitting generalized linear models (GLMs) with a logit link function.For the four species, a significant mass increase is detected for scarified seeds after a week imbibition (>60% mass increase). Germination percentages of seeds treated with H2O2, GA3 and smoke water were not significantly different from control seed. On the contrary, scarified seeds exhibited significantly higher germination percentages than control seeds. In addition, germination speed was also significantly higher for scarified seeds. These results are congruent with a physical dormancy phenomenon of seeds of the four Malvaceae shrubs. In addition, no particular light requirement was observed for germination. Artificial methods to break dormancy and stimulate germination described in this study could improve establishment success in arid habitats.

The effect of biostimulants and light wavelengths on the physiology of Cleome gynandra seeds

Cleome gynandra L. is used as a vegetable that forms a significant part of the local diet in South Africa and other tropical and subtropical parts of the world. Cleome gynandra seeds are negatively photoblastic (light-induced dormancy) and fail to germinate when planted immediately after harvest. To enhance better cultivation practices, seed germination of C. gynandra using different light wavelengths (red, far-red, green and blue light) with and without organic biostimulants [smoke–water (SW), karrikinolide (KAR1), Kelpak® (KEL) and eckol (ECK)] was tested. Among all the tested biostimulants, the best germination percentage (40%) was observed in seeds treated with SW in the dark. However, the biostimulants did not show any significant effect with the light treatments. In this study, blue light generally promoted (≤ 35%) and red light inhibited (≤ 8%) germination. Furthermore, the effect of different biostimulants (under blue and red light) on biochemical content and enzyme activities was tested in seeds of C. gynandra. Seeds treated with biostimulants in blue light showed an overall increase in protein and total carbohydrate content in comparison to seeds subjected to biostimulants in red light. The α-amylase activity in the seeds was highest in KEL-treated seeds in blue light. Superoxide dismutase and catalase activity was generally higher in blue-light treatment, while peroxidase activity was highest in red light. Enhanced germination under blue light and inhibitory effects with red light is an intriguing phenomenon for C. gynandra seeds, which needs more detailed investigation. The study also indicates the potential application of organic biostimulants (particularly SW) for better seed germination and growth of C. gynandra which can be explored by farmers in the field.

Fire cues trigger germination and stimulate seedling growth of grass species from Brazilian savannas.

Although fire cues (high temperatures and smoke) influence seed germination in numerous species from fire-prone environments, their effects on seed germination of species from neotropical savannas are poorly understood. We exposed seeds of eight grass species from the Cerrado, the Brazilian savanna to heat-shock (80°C or 110°C for 5 min) and/or smoke water, and then set them to germinate in light or dark, at either summer (28°C/18°C) or winter (27°C/14°C) temperature regimes in an incubator. In addition, we evaluated the effects of smoke water on seedling root and shoot growth for four of the species. Smoke interacted with the dark treatment to increase germination from 28% to 93% in Aristida recurvata and 77% to 95% in Aristida riparia. Smoke had no effect on germination of either of these species in the light. Heat-shock alone also promoted seed germination in A. recurvata. For Digitaria lehmanniana, smoke interacted with heat-shock to improve germination from 5% to 16%. In contrast, the fire treatments did not have any effect on the seed germination of the remaining five species. Smoke water stimulated root growth for A. riparia, A. recurvata, and Ctenium cirrosum but had no effect on their shoot growth. The strong promotive effect of smoke on Aristida germination suggests that these species are fire-adapted. Aristida species have an active awn system, which facilitates seed burial, and the smoke and dark interaction would ensure buried seeds germinated post-fire. The species that showed no response to fire cues may either have adapted via alternative strategies or require different concentrations of smoke or levels of heat. This study is one of very few examples showing a positive germination and seedling growth response to smoke for species from neotropical savannas.

Role of Smoke Stimulatory and Inhibitory Biomolecules in Phytochrome-Regulated Seed Germination of Lactuca sativa.

The biologically active molecules karrikinolide (KAR1) and trimethylbutenolide (TMB) present in wildfire smoke play a key role in regulating seed germination of many plant species. To elucidate the physiological mechanism by which smoke-water (SW), KAR1, and TMB regulate seed germination in photosensitive 'Grand Rapids' lettuce (Lactuca sativa), we investigated levels of the dormancy-inducing hormone abscisic acid (ABA), three auxin catabolites, and cytokinins (26 isoprenoid and four aromatic) in response to these compounds. Activity of the hydrolytic enzymes α-amylase and lipase along with stored food reserves (lipids, carbohydrate, starch, and protein) were also assessed. The smoke compounds precisely regulated ABA and hydrolytic enzymes under all light conditions. ABA levels under red (R) light were not significantly different in seeds treated with TMB or water. However, TMB-treated seeds showed significantly inhibited germination (33%) compared with water controls (100%). KAR1 significantly enhanced total isoprenoid cytokinins under dark conditions in comparison with other treatments; however, there was no significant effect under R light. Enhanced levels of indole-3-aspartic acid (an indicator of high indole-3-acetic acid accumulation, which inhibits lettuce seed germination) and absence of trans-zeatin and trans-zeatin riboside (the most active cytokinins) in TMB-treated seeds might be responsible for reduced germination under R light. Our results demonstrate that SW and KAR1 significantly promote lettuce seed germination by reducing levels of ABA and enhancing the activity of hydrolytic enzymes, which aids in mobilizing stored reserves. However, TMB inhibits germination by enhancing ABA levels and reducing the activity of hydrolytic enzymes.

Quantification of karrikins in smoke water using ultra-high performance liquid chromatography\u2013tandem mass spectrometry

BackgroundKarrikins (KARs) are plant growth regulators that promote seed germination and the subsequent growth and development of seedlings of many plant species. In nature they are generated and released by combustion of plant material and promote the restoration of burned ecosystems. Smoke water can be artificially prepared as a saturated extract of all substances in smoke produced by burning plants, and it has various horticultural and agricultural applications.ResultsWe have developed, validated and applied the first fast, specific and sensitive method, based on ultra-high performance liquid chromatography–tandem mass spectrometry, for quantifying KARs in smoke water. To assist these efforts and further analyses, standards of the main KARs (which are not commercially available) were synthesized. Due to the complex matrix of smoke waters, two quantification approaches (standard dilution with a structural KAR analogue and standard addition) were compared. The standard addition method allowed absolute quantification of KARs in six of eight smoke water samples of diverse origins and ages.ConclusionsOur findings reveal differences in both total and relative levels of KARs in smoke water, and indicate that differences in its KAR composition may be linked to variations in its bioactivity.

Preparation and Standardisation of Smoke-Water for Seed Germination and Plant Growth Stimulation

Smoke-water (SW) has a positive effect on seed germination in many plant species and its application in various fields of plant science has become popular. The method of preparing SW is relatively easy and inexpensive. However, many researchers working in the field of smoke biology are still unfamiliar with preparing SW and testing it for bioactivity. Thus, the aim of this study was to develop a low-cost efficient apparatus to produce SW using grasses, its standardisation and quantification of major active biomolecules. The prepared crude SW was diluted with distilled water (SW:DW) to 75:25, 50:50 and 25:75 (v/v) and these sub-dilutions were further diluted to 1:500; 1:1000; 1:1500; 1:2000; 1:2500; 1:3000 and 1:3500 (v/v). For the standardisation of SW, lettuce seeds (Lactuca sativa L. cv. Grand Rapids) were tested to determine the best working concentration. The ratio 1:2500 (v/v) from the sub-dilution 25:75 (v/v) of SW was the best for germination of lettuce seeds in the dark, achieving 91% germination against the water control that had only 7–10% germination. This is the first study which reports the levels of stimulatory (karrikinolide 1, KAR1 and karrikinolide 2, KAR2) and inhibitory (trimethylbutenolide, TMB) compounds present in SW using ultrahigh-performance liquid chromatography–electrospray positive ionisation tandem mass spectrometry (UHPLC-ESI(+)-MS/MS).

Temporal dynamics of seedling emergence among four fire ephemerals: the interplay of after-ripening and embryo growth with smoke

AbstractThe flora of Mediterranean ecosystems contains families with species having fully and under-developed embryos in their seeds. After-ripening for physiological dormancy release and smoke influence germination in many species. We investigated how after-ripening and embryo growth interact with smoke to influence the temporal dynamics of seedling emergence among fire ephemerals. Seeds were placed in the field and under standardized (50% relative humidity, 30°C) laboratory conditions to test the effects of summer conditions on physiological dormancy loss. Germination was tested with water or smoke compounds (smoke water, KAR1) at a simulated autumn/winter temperature (18/7°C). The timing and amount of seedling emergence with smoke was observed for seeds exposed to near-natural conditions. During summer, physiological dormancy was broken in all species, enabling germination at autumn/winter but not summer temperatures; no embryo growth occurred in seeds with under-developed embryos. At the start of the wet season, seedling emergence from seeds with fully developed embryos occurred earlier than from seeds with under-developed embryos. In a non-consistent manner among our study species, smoke and smoke compounds influenced the rate of embryo growth and amount of germination. Effects of smoke were noticeable in terms of number of emergents in the first emergence season. Among ecologically similar species, we have shown (1) that both thermal and embryo traits exclude germination in the summer, (2) how embryo size influences the timing of seedling emergence in autumn–winter, and (3) a reduced requirement for smoke in the second emergence season after a fire with a shift to reliance on seasonal cues for emergence.

Effect of organic biostimulants on the growth and biochemical composition of Amaranthus hybridus L.

Despite its high level of both plant and animal biodiversity, South Africa has not been spared from the scourge of malnutrition, poor health, hunger and even starvation, particularly in rural communities. There are appeals for increased consumption of indigenous leafy vegetables which have been generally neglected and underutilised by modern agricultural systems. These vegetables are cheap and rich in nutrients and contain many beneficial health-promoting compounds. Amaranthus hybridus L. is one of such indigenous leafy vegetables rediscovered as a promising food crop mainly due to its superior nutritional value of both seeds and leaves. However, critical information on its improvement and commercial cultivation is still scanty. The present research was targeted at promoting the commercial cultivation of A. hybridus by evaluating the effects of some natural biostimulants such as smoke-water (SW), karrikinolide (KAR1), vermicompost leachate (VCL), Kelpak® (KEL) and eckol (ECK) on seed germination, growth, nutrition and phytochemical levels under different modes of application (drenching, foliar spray and combined drenching and foliar spray). SW (1:500 v/v), KAR1 (10−6 M), VCL (1:5 v/v) and KEL (0.8%) showed a significant (P < 0.05) increase in shoot/root length, shoot fresh/dry weight, number of leaves, total leaf area and stem thickness compared with the control. Plant fresh and dry weights were significantly influenced by all the tested biostimulants. Significant increases in protein, carbohydrate and chlorophyll content were recorded in plants treated with foliar treatments of VCL, KEL, KAR1 and ECK. Such biostimulants should be considered as a worthwhile production strategy for achieving viable and superior yields of the nutritionally valuable but neglected and underutilised indigenous leafy vegetable (morogo/imifino) Amaranthus hybridus in South Africa.

Seed mix type but not planting method or seed priming affect grassland restoration outcomes: a greenhouse trial

Commercial seed mixes and various mechanical planting methods have been implemented to overcome barriers to successful restoration of degraded grasslands but their effectiveness in aiding the restoration process has been understudied. Harvested seed must be cleaned of chaff to allow mechanical planting, which can exclude small seeds. We propose that fluid seed drilling techniques (suspending uncleaned harvested seed in a cellulose-based gel matrix, which may then be injected into the soil with a mechanical planter) may overcome these challenges. As a preliminary investigation of the proposed method we designed a greenhouse pot trial experiment aimed at quantifying restoration success through the measurement of seedling recruitment, biomass production and composition responses of commercial and harvested seed mixes under simulated fluid seed drilling and smoke water priming (collectively termed application method). These data were analysed using generalised linear modelling and multivariate analyses. Commercial mixed seed resulted in greater recruitment, whereas harvested seed produced the greatest biomass production. There was large multivariate separation between seed types and seed type × application method centroids for recruitment responses and only seed type for biomass responses. Application method had minimal effects on restoration measurements whilst seed type greatly affected these measurements. Careful selection of the restoration seed mix is advised.

Smoke compounds aggravate stress inflicted on Brassica seedlings by unfavourable soil conditions

The aim of the study was to assess the physiological status of Brassica seedlings grown in two types of soils following a single application of smoke water (SW). One soil was contaminated with heavy metals from a local smelter, and another was sandy and poor in nutrients. Three-week monitoring indicated that soil composition was the primary factor affecting chlorophyll fluorescence (CF) parameters, growth, and development of seedlings, and the contaminants affected the plants more than the lack of nutrients. SW aggravated the negative impact of heavy metals, which became visible when the plants transiently suffered from the heavy metal exposure. Most of CF parameters changed suddenly but then the trend reversed indicating that plants gradually adapted to the specific conditions. However, this was not reflected in the final biomass of the seedlings. This might be due to redirection of photosynthates towards protective mechanisms against toxic effects of metals.

Jasmonic acid serves as a signal role in smoke-isolated butenolide-induced tanshinones biosynthesis in Salvia miltiorrhiza hairy root

Although smoke-water (SW) and butenolide (KAR1) isolated from smoke show stimulating effects on the production of secondary metabolites in medicinal plants, the underlying mechanisms are not well understood. This study was initiated to investigate the signal molecule in the KAR1-induced tanshinones biosynthesis in Salvia miltiorrhiza hairy root. KAR1 treatment resulted in substantial improvement in the accumulation of jasmonic acid (JA), followed by an increase in lipophilic tanshinones production in S. miltiorrhiza hairy root. Treatment of external JA stimulated the biosynthesis of tanshinones without KAR1 treatment. KAR1-stimulated tanshinones biosynthesis was inhibited with the treatment of SHAM and PrGall, which are JA synthesis inhibitors. This study indicated that JA serves as a role in the signal transduction involved in KAR1-stimulated tanshinones biosynthesis in the S. miltiorrhiza.

Effects of smoke-water and smoke-derived butenolide on accumulation of phenolic acids in cultured hairy roots of Salvia miltiorrhiza Bung

Smoke-water (SW) and biologically active compound butenolide (KAR1) isolated from smoke show stimulating effects on the plant growth of agricultural and horticultural crops, while little has been known on their effects on the secondary metabolism of medicinal plants. Hairy root culture of Salvia miltiorrhiza, an important medicinal plant, was treated with SW and butenolide. The results showed that the contents of salvianolic acid (SAB) and rosmarinic acid (RA) were enhanced with the treatments of SW and KAR1. The expressions of genes (PAL, C4H, 4CL, TAT and HPPR) involved in phenolic acids biosynthesis were upregulated by treatments of SW and KAR1. Responses of C4H and 4CL to SW and KAR1 treatment were later than PAL, TAT and HPPR. It suggests that SW and KAR1have the potential to be used as elicitor to increase the accumulation of secondary metabolites in S. miltiorrhiza hairy root.

Effects of smoke-water and smoke-isolated karrikinolide on tanshinones production in Salvia miltiorrhiza hairy roots

Smoke–water (SW) and the biologically-active compound karrikinolide (KAR1), isolated from plant-derived smoke, is known to show stimulating effects on the plant growth of agricultural and horticultural crops. However, little knowledge has been obtained on their effects on the secondary metabolism of medicinal plants. In this study, hairy root cultures of Salvia miltiorrhiza, one of the most renowned herbs in traditional Chinese medicine (commonly known as “danshen”), were treated with SW at dilutions of 1:500 (v/v), 1:1000 (v/v), 1:2000 (v/v) or KAR1 solution at 10−9 M. The effects of SW and KAR1 treatment on the content of tanshinones (tanshinone I, tanshinone IIA, cryptotanshinone and dihydrotanshinone) and the expressions pattern of genes involved in biosynthesis of tanshinones: Acetyl CoA acyltransferase (AACT), 3-hydroxy-3-methylglutaryl CoA synthase (HMGS), 3-hydroxy-3-methylglutaryl CoA redutase (HMGR), 1-deoxy-D-xylulose5-phosphate synthase (DXS), 1-deoxy-D-xylulose5-phosphate reductoisomerase (DXR), 4-(5-pyrophosphate cytidine) -2-C-methyl-Derythritol kinase (CMK), Cobaxyl pyrophosphate synthase (CPS), isopentenyl diphosphate isomerase (IPPI) and geranylgeranyl diphosphate synthase (GGPPS) in S.miltiorrhiza hairy root during elicitation in the S.miltiorrhiza hairy roots were evaluated. The results showed that both SW and KAR1 treatments markedly increased the content of tanshinones in hairy roots of S.miltiorrhiza. The content of tanshinone I was significantly improved, and was evaluated as 3.1-, 3.3-, 1.3- and 1.2-fold of that in the control on 1, 3, 5 and 9 d after treatment with SW 1:1000, respectively. The content of tanshinone IIA was slightly increased by SW and KAR1. The effects of SW treatments on cryptotanshinone content were concentration-dependent. Compared to the control, the accumulation of dihydrotanshinone increased significantly (p < 0.05) with SW and KAR1(p < 0.05) treatments in the earlier stage (day 1–3post-treatment). Enzymes of the tanshinone pathways showed different responses to the treatments of SW and KAR1 due to their multiple roles in the secondary metabolite pathways. The transcript of HMGS was more sensitive to the SW and KAR1 elicitation, whilst the responses of DXS, DXR, CPS and GGPPS to SW and KAR1 treatments were later than AACT and HMGS. Our results indicate that smoke–water and KAR1 have the potential to be used as elicitors to increase the accumulation of secondary metabolites in S.miltiorrhiza hairy roots, as well as to provide insights into the mechanisms of biosynthesis of liposoluble tanshinones in S.miltiorrhiza.

The effect of smoke derivatives and carbon utilisation on symbiotic germination of the endangered Pterostylis despectans

Orchids are highly dependent on exogenous nutritional sources and mycorrhizal associations to survive, particularly when challenged by extreme environmental stress such as bushfires that contribute significantly to its existence in nature. In this study, the effect of smoke derivatives and carbon utilisation was explored to improve germination and seedling establishment of an Australian endangered orchid, Pterostylis despectans (Lowly Greenhood) and on mycorrhizal fungi to improve its survivorship in the rhizosphere and functionality on host plants. Stored seeds were germinated in vitro with peloton-isolated fungal isolates with varying concentrations of smoke water (0–1.0 mL L-1) to simulate fire and sucrose as the carbon source (10 g L-1). Smoke water significantly increased germination, with advanced protocorms and robust seedlings produced. Sucrose inhibited germination such that protocorms and leafing was absent with sucrose inclusion. Fungal isolates were highly variable on its germination efficacy and tolerance to smoke water, highlighting the importance of fungal diversity and supports research-based conservation strategies to circumvent environmental challenges.

New and Scalable Access to Karrikin (KAR1) and Evaluation of Its Potential Application on Corn Germination

Karrikin (KAR1), also named ‘karrikinolide’, was isolated in 2004 from smoke water and identified as a very potent germination stimulant as well as controlling early seedling development for a large variety of plant species. We reported herein an unprecedented and scalable synthesis of Karrikin (KAR1) based on an elegant and efficient 6‐endo‐dig cyclization. Moreover, we evaluated the effect of KAR1 on corn seeds germination, we carried out additional studies on the uptake of this butenolide into corn seeds, and the main soil chemiodynamic properties (i.e., persistence and mobility) were calculated or estimated. Finally, we provided a rationalization of the experimental results by building a homology model of corn KAI2, using as template the X‐ray of the KAI2 protein from Arabidopsis thaliana.

Breaking seed dormancy inLobostemon fruticosus

Lobostemon fruticosus (Boraginaceae) is one of the most important South African endangered medicinal plants, which is rare in nature due to over exploitation and poor seed germination. Natural regeneration of the crop is furthermore limited by over exploitation of the root system in nature. In an effort to improve and promote the cultivation of this plant by means of seed, the effects of four temperatures (15, 20, 25 and 30°C), exogenous gibberellic acid (GA3) (100 and 200 ppm) and water extracts of smoked paper (extracted in 10 and 5% concentration) were investigated on dormancy breaking and germination. The treatments were arranged in a factorial experiment (randomized complete block design) with three replicates of 25 seeds each on a double layer of filter paper (Whatman No. 1) in Petri dishes (90-mm sterile). The highest germination rates obtained were 80 and 76% for 100 ppm GA3 and smoke water (extracted in 10% concentration) treatments respectively, after 4 days, at 25°C compared to the control (46%) under similar conditions. The GA3 and smoke water treatments were easy to apply, and can therefore be recommended to growers for breaking dormancy in L. fruticosus seeds. The findings of this research will promote the cultivation of L. fruticosus by means of seed and significantly contribute to the conservation of this important and over exploited medicinal plant species.