Mature Seeds Research Articles

Insights into the regulation of energy metabolism during the seed-to-seedling transition in marine angiosperm Zostera marina L.: Integrated metabolomic and transcriptomic analysis.

Seed development is a crucial phase in the life cycle of seed-propagated plants. As the only group of angiosperms that evolved from terrestrial plants to complete their life cycle submerged in marine environments, the mechanisms underlying seed development in seagrasses are still largely unknown. In the present study, we attempted to combine transcriptomic, metabolomic, and physiological data to comprehensively analyze the molecular mechanism that regulates energy metabolism in Zostera marina seeds at the four major developmental stages. Our results demonstrated that seed metabolism was reprogrammed with significant alteration of starch and sucrose metabolism, glycolysis, the tricarboxylic acid cycle (TCA cycle), and the pentose phosphate pathway during the transition from seed formation to seedling establishment. The interconversion of starch and sugar provided energy storage substances in mature seeds and further acted as energy sources to support seed germination and seedling growth. The glycolysis pathway was active during Z. marina germination and seedling establishment, which provided pyruvate for TCA cycle by decomposing soluble sugar. Notably, the biological processes of glycolysis were severely inhibited during Z. marina seed maturation may have a positive effect on seed germination, maintaining a low level of metabolic activity during seed maturation to preserve seed viability. Increased acetyl-CoA and ATP contents were accompanied with the higher TCA cycle activity during seed germination and seedling establishment, indicating that the accumulations of precursor and intermediates metabolite that can strengthen the TCA cycle and facilitate energy supply for Z. marina seed germination and seedling growth. The large amount of oxidatively generated sugar phosphate promotes fructose 1,6-bisphosphate synthesis to feed back to glycolysis during seed germination, indicating that the pentose phosphate pathway not only provides energy for germination, but also complements the glycolytic pathway. Collectively, our findings suggest these energy metabolism pathways cooperate with each other in the process of seed transformation from maturity to seedling establishment, transforming seed from storage tissue to highly active metabolic tissue to meet the energy requirement seed development. These findings provide insights into the roles of the energy metabolism pathway in the complete developmental process of Z. marina seeds from different perspectives, which could facilitate habitat restoration of Z. marina meadows via seeds.

Lipophilic profile of mature seeds of unconventional edible tree legumes

Lipophilic profile of mature seeds of unconventional edible tree legumes

Red fluorescence protein (DsRed2) promotes the screening efficiency in peanut genetic transformation.

Peanut (Arachis hypogaea L.), one of the leading oilseed crops worldwide, is an important source of vegetable oil, protein, minerals and vitamins. Peanut is widely cultivated in Asia, Africa and America, and China is the largest producer and consumer of peanut. Genetic engineering has shown great potential to alter the DNA makeup of an organism which is largely hindered by the low transformation and screening efficiency including in peanut. DsRed2 is a reporter gene widely utilized in genetic transformation to facilitate the screening of transformants, but never used in peanut genetic transformation. In this study, we have demonstrated the potential of the red fluorescence protein DsRed2 as a visual reporter to improve screening efficiency in peanut. DsRed2 was firstly expressed in protoplasts isolated from peanut cultivar Zhonhua 12 by PEG, and red fluorescence was successfully detected. Then, DsRed2 was expressed in peanut plants Zhonghua 12 driven by 35S promoter via Agrobacterium tumefaciens-mediated transformation. Red fluorescence was visually observed in calli and regenerated shoots, as well as in roots, leaves, flowers, fresh pod shells and mature seeds, suggesting that transgenic screening could be initiated at the early stage of transformation, and continued to the progeny. Upon screening with DsRed2, the positive plant rate was increased from 56.9% to 100%. The transgenic line was then used as the male parent to be crossed with Zhonghua 24, and the hybrid seeds showed red fluorescence as well, indicating that DsRed2 could be applied to hybrid plant identification very efficiently. DsRed2 was also expressed in hairy roots of Huayu 23 via Agrobacterium rhizogenes-mediated transformation, and the transgenic roots were easily selected by red fluorescence. In summary, the DsRed2 is an ideal reporter to achieve maximum screening efficiency and accuracy in peanut genetic transformation.

Effect of foliar treatment with chitosan on phenolic composition of ῾Fetească neagră’ grapes and wines

The objective of this study was to determine the influence of chitosan treatments, applied in vineyard for plan protection, on the phenolic quality of grapes. The study was conducted for two consecutive years (2020-2021) in the wine center of Murfatlar, Romania, on ‘Fetească neagră’, an ancient but well-known indigenous Romanian grape variety for red wines. Chitosan is meant to offer an alternative for the classic treatment with Bordeaux mixture (BM), which represented the control variant. A combination treatment with half dose of chitosan and half dose of BM was also applied and evaluated. Chemical composition at harvest time was evaluated by measuring the content of sugar, total acidity, pH, total anthocyanin potential (ApH1), anthocyanins extractable at wine pH (ApH3.2), total polyphenol index, skin tannins, seed tannins and seeds maturity. In wines the colour parameters were determined by spectrophotometry and individual phenolic compounds by UHPLC-HRMS. In grapes, accumulation of anthocyanins increased with the total dose of chitosan applied in the vineyard, with higher values in 2020 when temperatures were higher and the rainfall values were typical for the region. Accumulation of tannins in grape skins followed a similar trend. In wine, chitosan determined a significant 72% increase in colour intensity in 2020. Among the individual phenols gallic acid was predominant, with higher values in the rainier year (2021) and significant increases determined by chitosan treatment (especially in 2021 when it increased by 97% as compared to BM treatment). Catechin and epicatechin recorded important increases in the less favourable year (2021), with confirmed increases in both years elicited by the chitosan. Quercetin and myricetin were not influenced by the chitosan treatment, but their increase was correlated with higher temperatures and inversely correlated to the amount of rainfall. Trans-resveratrol ranged between 4.3-8.0 mg L-1 in 2020 and 5.0-6.5 mg L-1 in 2021, with an important increase determined by the chitosan treatment in 2020 (89% increase compared to BM treatment).

Coicis Semen for the treatment of malignant tumors of the female reproductive system: A review of traditional Chinese medicinal uses, phytochemistry, pharmacokinetics, and pharmacodynamics.

Coicis Semen is an important food product and traditional Chinese medicine (TCM) derived from the dried and mature seeds of Coix lacryma-jobi L.var.ma-yuen (Roman.) Stapf. An increasing number of studies have investigated its use, either alone or in combination with other botanical drugs, to treat female reproductive system malignancies, and its pharmacological effects have been confirmed clinically. This review aims to provide an overview of Coicis Semen's historical role in treating female reproductive system malignancies based on TCM theory, to summarize clinical trials results, and to analyze information pertaining to the main phytochemical components, pharmacokinetics, related anti-cancer pharmacological effects, and toxicology of Coicis Semen. Information on Coicis Semen was collected from internationally accepted scientific databases. Seventy-four clinical trials were identified that used Coicis Semen in combination with other Chinese medicine to treat female reproductive system malignancies, most of which demonstrated good anti-tumor efficacy and few adverse reactions. To date, more than 80 individual compounds have been isolated from this botanical drug. In terms of anti-tumor effects, Coix seed oil has been studied the most. Pharmacokinetic data suggest that the active ingredients in Coicis Semen are widely distributed after administration, and Coicis Semen and its active compounds play a beneficial role in treating female reproductive system malignancies. Mechanistically, the anti-cancer effects may be related to inhibition of tumor cell proliferation and promotion of apoptosis, inhibition of tumor angiogenesis, suppression of the chronic inflammatory microenvironment of tumors, modulation of immune function, and regulation of the female reproductive system. Most acute toxicity and genotoxicity studies have shown that Coicis Semen is non-toxic. However, the existing studies have many limitations, and the future research direction should emphasize 1) the relationship between drug concentration and pharmacological action as well as toxicity; 2) the structural modification or the synthesis of analogues led by the active ingredients of Coicis Semen to enhance pharmacological activities and bioavailability; 3) accurately revealing the anti-cancer pharmacological effects of Coicis Semen and its compounds through multi-omics technology. We hope that this review can determine future directions and inform novel drug development for treating female reproductive malignancies.

Characterization of Oil Body and Starch Granule Dynamics in Developing Seeds of Brassica napus.

Brassica napus is the most important oilseed crop in the world, and the lipid was stored in the oil body (OB) in the form of triacylglycerol. At present, most of studies on the relationship between oil body morphology and seed oil content in B. napus was focused on mature seeds. In the present study, the OBs in different developing seeds of B. napus with relatively high oil content (HOC) of about 50% and low oil content (LOC) of about 39% were analyzed. It was revealed that the size of OBs was first increased and then decreased in both materials. And in late seed developmental stages, the average OB size of rapeseed with HOC was higher than that of LOC, while it was reversed in the early seed developmental stages. No significant difference was observed on starch granule (SG) size in HOC and LOC rapeseed. Further results indicated that the expression of genes that involved in malonyl-CoA metabolism, fatty acid carbon chain extension, lipid metabolism, and starch synthesis in the rapeseed with HOC was higher than that of rapeseed with LOC. These results give some new insight for understanding the dynamics of OBs and SGs in embryos of B. napus.

Physiological changes involved in the acquisition of seed vigor during maturation of sunflower seed

Maturity is an important factor in regulating seed vigor, while inappropriate harvest date affects seed vigor seriously. Here we reported that the seed vigor was the highest among 25–28 days after pollination, and these days were the best harvest time for sunflower seeds. Seed moisture content increased first and then decreased, while seed dry weight increased continuously with the advancement of seed development. Oil and protein are the main nutriments in mature sunflower seeds and changes in both contents were consistent with the seed dry weight. For antioxidases, the activity of ascorbate peroxidase (APX) was decreased gradually before seed maturity. Compared to gibberellin (GA), whose content decreased, abscisic acid (ABA) accumulated first and then decreased during the seed development. Moreover, the content of spermidine (Spd) increased continually, although no regularity of variation was found in putrescine (Put) and spermine (Spm). Further analysis showed that the activities of GA3ox and GA20ox, NCED and ABA8ox, SAMDC and SPDS and corresponding genes expression resulted in changes of GA, ABA and Spd accumulation, respectively. In addition, seed moisture, soluble sugar, GA, ABA content and APX activity were significantly negatively correlated with seed vigor indexes, while seed dry weight, oil, protein and Spd content were significantly positively correlated with seed vigor indexes. These metabolic processes may be closely related to seed vigor formation, and can be used to predict seed vigor.

The Arabidopsis thaliana Gulono-1,4 γ-lactone oxidase 2 (GULLO2) facilitates iron transport from endosperm into developing embryos and affects seed coat suberization

Plants synthesize ascorbate (ASC) via the D-mannose/L-galactose pathway whereas animals produce ASC and H2O2via the UDP-glucose pathway, with Gulono-1,4 γ-lactone oxidases (GULLO) as the last step. A. thaliana has seven isoforms, GULLO1-7; previous in silico analysis suggested that GULLO2, mostly expressed in developing seeds, might be involved in iron (Fe) nutrition. We isolated atgullo2-1 and atgullo2-2 mutants, quantified ASC and H2O2 in developing siliques, Fe(III) reduction in immature embryos and seed coats. Surfaces of mature seed coats were analysed via atomic force and electron microscopies; suberin monomer and elemental compositions of mature seeds, including Fe, were profiled via chromatography and inductively coupled plasma-mass spectrometry.Lower levels of ASC and H2O2 in atgullo2 immature siliques are accompanied by an impaired Fe(III) reduction in seed coats and lower Fe content in embryos and seeds; atgullo2 seeds displayed reduced permeability and higher levels of C18:2 and C18:3 ω-hydroxyacids, the two predominant suberin monomers in A. thaliana seeds. We propose that GULLO2 contributes to ASC synthesis, for Fe(III) reduction into Fe(II). This step is critical for Fe transport from endosperm into developing embryos. We also show that alterations in GULLO2 activity affect suberin biosynthesis and accumulation in the seed coat.

Phenolic Compound Profile and Antioxidant Capacity of Flax (Linum usitatissimum L.) Harvested at Different Growth Stages.

The profile of phenolic compounds changes during the growth of a plant and this change affects its antioxidant potential. The aim of this research has been to find the growth stage of flax with the highest antioxidant capacity, and to determine the phenolic compounds responsible for such a capacity. Flax was harvested in six growth stages: from stem extension to mature seeds. The phenolic compounds were identified using LC-TOF-MS and quantified in an extract and in the fresh matter (FM) of each growth stage. The radical scavenging activity against ABTS•+ and DPPH•, the ferric-reducing antioxidant power (FRAP), and the antioxidant activity in the β-carotene-linoleic acid emulsion system were determined. Mono- and di-C-glycosyl flavones were found to be the most abundant phenolics of the aerial parts of flax, which also showed the highest content of isoorientin (210-538 µg/g FM). Coniferin, its derivative, and hydroxycinnamic acid derivatives were also detected. The plant was richer in flavone C-glycosides from stem extension to seed ripening (1105-1413 µg/g FM) than at the mature seed stage (557 µg/g FM). Most of the individual flavone C-glycoside contents in the extracts decreased when increasingly older plants were considered; however, the isoorientin content did not change significantly from the steam extension to the seed ripening stages. The antiradical activity against ABTS•+ and FRAP was higher for the aerial parts of the flax harvested at the flowering, brown capsule, and seed ripening stages, mainly due to the presence of flavone C-glycosides. The oxidation of β-carotene-linoleic acid emulsion was instead inhibited more effectively by the extracts from plants at the brown capsule and mature seed stages. Coniferin and its derivative were significantly involved in this activity. The extracts from the aerial parts of the flax harvested from flowering to seed ripening could be a valuable source of flavone C-glycosides for use as nutraceuticals and components of functional foods.

Genetic Variations among Fleabane (Conyza bonariensis (L.) Cronquist) Populations in Jordan and Their Susceptibility Levels to Contact Herbicides

A field demonstration and pot experiments were implemented to assess the effect of paraquat, oxadiazon, and oxyfluorfen herbicides in controlling selected populations of fleabane Conyza bonariensis (L.), grown in the central valley of Jordan. Conyza mature seeds were collected from six investigated sites (five from Jordan valley named P1, P2, P3, P4, P5, and one from the University of Jordan Campus named P6). Only populations proved to be C. bonariensis via ITS assessment were involved in the glasshouse experiments at the University of Jordan in 2017 and 2019. Results showed that recommended or two-fold higher rates (2.5 and 5 kg ha−1) of paraquat failed to affect weed plants in a date palm orchard located at Tal-al-Ramel in the Central Jordan Valley. Paraquat, oxyfluorfen, and oxadiazon (2.5, 3.3, and 5 kg ha−1, respectively), failed to control plants of the same weed population grown in pot experiments. Treated plants at Tal-al-Ramel grew similarly to untreated control, mostly due to different genetic backgrounds. The other C. bonariensis populations (University Research Station, al-Twal, and University Campus) were effectively controlled with all herbicides. The application of recommended or 10-fold higher rates of herbicides failed to control or slightly injured the resistant population. Seed DNA analysis of the ITS region showed genetic differences among the investigated populations. It indicated that four populations are C. bonariensis (P1, P3, P4, and P6). At the same time, two are C. canadensis (a closely related species) collected from the University Research Station (P2) and al-Twal sites (P5), and also that the population of C. bonariensis in the date palm orchard was genetically distinct from the other C. bonariensis populations. It is concluded that C. bonariensis population in the Tal-al-Ramel site developed resistance to paraquat, oxadiazon, and oxyfluorfen herbicides. Thus, novel alternative practices in controlling the resistant weed population are necessary to prevent its possible spread to other regions in the country and obstruct the development of new herbicide-resistance weed populations.

Symbiotic Seed Germination and Seedling Development of Epidendrum geminiflorum Knuth from Ecuador

A greater understanding of the relationship between native orchids and their mycorrhizal symbionts is needed to ensure more effective orchid conservation strategies. A protocol for symbiotic seed germination and seedling development was developed for E. geminiflorum. Mature seeds were collected from a naturally occurring orchid population in Ecuador. Putative mycorrhizal fungi isolated from other native orchid species were used to screen their ability to facilitate germination and seedling development in vitro in either a 0/24 h or 12/12 h light/dark photoperiod at 20 °C. The mycorrhizal fungus Tulasnella calospora (UAMH 9824) isolated from Spiranthes brevilabris in Florida, USA, was also included in this study. Sterilization treatments using 0.3%, 0.5% sodium hypochlorite/ethanol or 2% calcium hypochlorite were tested for their effectiveness as sterilant and their subsequent effects on seed germination percentage. Effective surface seed sterilization was achieved with either 0.5% NaClO/ethanol or 2% calcium hypochlorite. However, significantly higher percentages of germinated embryos developed into protocorms when NaOCl solutions were used compared to the other treatments. Seed germination occurred in both photoperiods tested; however, delayed germination was observed under complete darkness. Seeds of E. geminiflorum germinated without fungal inoculation; however, co-culture with Tulasnella strains improved germination significantly. Seedling development was only observed when seeds were cultured in asymbiotic medium or co-cultured with T. caloscopa (UAMH 9824). Significantly longer seedlings were obtained when T. calospora was present in the culture compared with seedlings cultured in asymbiotic medium. The establishment of mycorrhizal associations was confirmed by the presence of pelotons in the roots of E. geminiflorum seedlings.

The begomovirus tomato leaf curl New Delhi virus is seed-borne but not seed-transmitted in melon.

Seed transmission can be of considerable relevance to the dissemination of plant viruses in nature and for their prevalence and perpetuation. Long-distance spread of isolates of the begomovirus species Tomato leaf curl New Delhi virus (genus Begomovirus, family Geminiviridae) has recently occurred from Asia to the Middle East and the Mediterranean Basin. Here we investigated the possible transmission by melon (Cucumis melo L.) seeds of a tomato leaf curl New Delhi virus (ToLCNDV) isolate of the "Spain" strain widely distributed in the Mediterranean area as an alternative mechanism for long-distance spread. Polymerase chain reaction (PCR) amplification detection of ToLCNDV in floral parts and mature seeds of melon plants reveals that this virus is seed-borne. Seed-borne is defined as the ability of a virus to be carried through seeds, which does not necessarily lead to transmission to the next generation. Treatment with a chemical disinfectant significantly reduced the detectable virus associated with melon seeds, suggesting ToLCNDV contamination of the external portion of the seed coat. Also, when the internal fraction of the mature seed (seed cotyledons + embryo) was analyzed by quantitative PCR amplification, ToLCNDV was detectable at low levels, suggesting the potential for viral contamination or of infection of the internal portions of seed. However, grow-out studies conducted with melon progeny plants germinated from mature seeds collected from ToLCNDV-infected plants and evaluated at early (one leaf) or at late (20 leaf) growth stages did not support the transmission of ToLCNDV from seeds to offspring.

Distinctly localized lipid phosphate phosphatases mediate endoplasmic reticulum glycerolipid metabolism in Arabidopsis.

Inter-organelle communication is an integral subcellular process in cellular homeostasis. In plants, cellular membrane lipids are synthesized in the plastids and endoplasmic reticulum (ER). However, the crosstalk between these organelles in lipid biosynthesis remains largely unknown. Here, we show that a pair of lipid phosphate phosphatases (LPPs) with differential subcellular localizations is required for ER glycerolipid metabolism in Arabidopsis (Arabidopsis thaliana). LPPα2 and LPPε1, which function as phosphatidic acid phosphatases and thus catalyze the core reaction in glycerolipid metabolism, were differentially localized at ER and chloroplast outer envelopes despite their similar tissue expression pattern. No mutant phenotype was observed in single knockout mutants; however, genetic suppression of these LPPs affected pollen growth and ER phospholipid biosynthesis in mature siliques and seeds with compromised triacylglycerol biosynthesis. Although chloroplast-localized, LPPε1 was localized close to the ER and ER-localized LPPα2. This proximal localization is functionally relevant, because overexpression of chloroplastic LPPε1 enhanced ER phospholipid and triacylglycerol biosynthesis similar to the effect of LPPα2 overexpression in mature siliques and seeds. Thus, ER glycerolipid metabolism requires a chloroplast-localized enzyme in Arabidopsis, representing the importance of inter-organelle communication in membrane lipid homeostasis.

English

Pachyrhizus seeds-induced toxicity is very well-known to have developed in humans, fishes, insects, and some micro-organisms. Yet, there is a paucity of studies addressing it in their germplasm, as well as its effects on some phytopathogens. This work aimed to assess the Pachyrhizus genetic variability on toxicity and to determine Pachyrhizus extract toxicity on Sclerotium rolfsii and Ralstonia solanacearum in vitro. In the findings, it was shown to only have toxicity genetic diversity in immature seeds. Its toxicity in mature seeds was very high and its genetic variability was not detected. There was a toxic effect on S. rolfsii and R. solanacearum.  In S. rolfsii it was determined that the most toxic dose was 1: 1000 with P40 genotype. It decreased the mycelial growth by 72% following 5 days. In R. solanacearum it was determined that the most toxic dose was 1:200 with P40 genotype. It reduced bacterial multiplication by 57% between 24 and 48 h. Key words: Pachyrhizus extract, genetic variability, toxicity, Sclerotium rolfsii, Ralstonia solanacearum.

ABSCISIC ACID INSENSITIVE4 coordinates eoplast formation to ensure acquisition of seed longevity during maturation in Medicago truncatula.

Seed longevity, the capacity to remain alive during dry storage, is pivotal to germination performance and is essential for preserving genetic diversity. It is acquired during late maturation concomitantly with seed degreening and the de-differentiation of chloroplasts into colorless, non-photosynthetic plastids, called eoplasts. As chlorophyll retention leads to poor seed performance upon sowing, these processes are important for seed vigor. However, how these processes are regulated and connected to the acquisition of seed longevity remains poorly understood. Here, we show that such a role is at least provided by ABSCISIC ACID INSENSITIVE4 (ABI4) in the legume Medicago truncatula. Mature seeds of Mtabi4 mutants contained more chlorophyll than wild-type seeds and exhibited a 75% reduction in longevity and reduced dormancy. MtABI4 was necessary to stimulate eoplast formation, as evidenced by the significant delay in the dismantlement of photosystemII during the maturation of mutant seeds. Mtabi4 seeds also exhibited transcriptional deregulation of genes associated with retrograde signaling and transcriptional control of plastid-encoded genes. Longevity was restored when Mtabi4 seeds developed in darkness, suggesting that the shutdown of photosynthesis during maturation, rather than chlorophyll degradation perse, is a requisite for the acquisition of longevity. Indeed, the shelf life of staygreen mutant seeds that retained chlorophyll was not affected. Thus, ABI4 plays a role in coordinating the dismantlement of chloroplasts during seed development to avoid damage that compromises the acquisition of seed longevity. Analysis of Mtabi4Mtabi5 double mutants showed synergistic effects on chlorophyll retention and longevity, suggesting that they act via parallel pathways.

Disruption of BG14 results in enhanced callose deposition in developing seeds and decreases seed longevity and seed dormancy in Arabidopsis.

Seed longevity is an important trait for agriculture and the conservation of genetic resources. β-1,3-Glucanases were first recognized as pathogenesis-related proteins involved in plant defense, but their roles in seeds are largely unknown. Here, we report a glycosylphosphatidylinositol-anchored β-1,3-glucanase, BG14, that degrades callose in seed embryos and functions in seed longevity and dormancy in Arabidopsis. The loss of function of BG14 significantly decreased seed longevity, whereas functional reversion (RE) and overexpression (OE) lines reversed and increased the impaired phenotype, respectively. The loss of function of BG14 enhanced callose deposition in the embryos of mature seeds, confirmed by quantitative determination and the decreased callose degrading ability in bg14. The drop-and-see (DANS) assay revealed that the fluorescence signal in bg14 was significantly lower than that observed in the other three genotypes. BG14 is located on the periphery of the cell wall and can completely merge with callose at the plasmodesmata of epidermal cells. BG14 was highly expressed in developing seeds and was induced by aging and abscisic acid (ABA). The loss of function of BG14 led to a variety of phenotypes related to ABA, including reduced seed dormancy and reduced responses to treatment with ABA or pacolblltrazol, whereas OE lines showed the opposite phenotype. The reduced ABA response is because of the decreased level of ABA and the lowered expression of ABA synthesis genes in bg14. Taken together, this study demonstrated that BG14 is a bonafide BG that mediates callose degradation in the plasmodesmata of embryo cells, transcriptionally influences ABA synthesis genes in developing seeds, and positively affects seed longevity and dormancy in Arabidopsis.

Influence of Cultivar, Harvest Date, and Selected Weather Conditions on the Essential Oils Content in Inflorescences of Hemp Cannabis sativa L

ABSTRACT In the presented research work, the impact of two harvesting dates, temperature, and precipitation on the content of essential oils in inflorescences of three hemp cultivars in fresh and dry plant matter was assessed. Plants were harvested at full flowering and at full hemp seeds maturity. The highest content of essential oils in the dry matter of inflorescences was characteristic of the “Białobrzeskie” cultivar in full flowering, and the smallest of the ”Zołotonowska 13” cultivar, regardless of the harvest date. When the harvest was delayed from full flowering to full maturity, the content of essential oils in the fresh mass of the inflorescence increased. On the basis of the obtained results, it was concluded that the content of essential oils in hemp in the dry matter of inflorescence is determined mainly by the cultivar, while the harvest date and the influence of various weather factors modify these values. On the other hand, the content of essential oils in the fresh mass of the inflorescence depends mainly on the harvest date – the closer to full maturity, the higher their content.

Influence of Seed-Covering Layers on Caper Seed Germination.

Caper is a perennial shrub that is widespread in the Mediterranean Basin. Although the fruits contain many seeds, they germinate slowly and with very low percentages, due to their nondeep physiological dormancy. The influence of the testa and endosperm, as well as the effect of applying gibberellic acid (GA3) solutions on seed germination to release its dormancy, are reported in this study. The mechanical resistance exerted by the testa and endosperm against radicle protrusion in mature caper seeds was measured. The best germination results were obtained with seeds devoid of testa wetted with water and with intact seeds wetted with a 500 mg L-1 GA3 solution, without statistical differences between them. The GA3 addition triggers an increase in both the content of endogenous gibberellins (GA) and the GA/abscisic acid ratio, increasing germination. Its germination consists of two temporally separated events: testa cracking and endosperm piercing. Testa cracking begins in the hilum-micropillar area; it involves a signal from the embryo, which GA can replace, possibly by increasing the growth potential of the embryo. After testa cracking, the radicle emerges through a hole in the micropylar endosperm. The puncture force necessary to pierce the micropylar endosperm decreased drastically during the first day of imbibition, remaining practically constant until testa cracking, decreasing afterwards, regardless of the addition or not of gibberellins.

Antioxidant Capacity and Shelf Life of Radish Microgreens Affected by Growth Light and Cultivars

Microgreens are young, immature vegetables that contain higher concentrations of active compounds compared to mature vegetables and seeds. Radish microgreens are a good source of antioxidants, phenolic compounds, ascorbic acid, carotenoids, and anthocyanins. The production of microgreens is limited by their short shelf life due to higher dark respiration and accelerated senescence. The study was performed on three radish cultivars (Raphanus sativus L.): purple radish (cvP), red radish (cvR), and green radish (cvG). Radish microgreens were grown in chambers with controlled conditions (24 °C and a photoperiod of 16/8 h) under two types of artificial LED light (45 μmol m−2s−1): under white light (B:G:R) and a blue/red light combination (B:2R). The effect of the two types of light was examined on the 3rd, 7th, and 14th day after storage at a low temperature (+4 °C). The physiological status of the three cultivars of radish microgreens was examined by measuring the contents of total soluble phenolics, ascorbic acid, proteins, sugars, dry matter, anthocyanins, carotenoids, and chlorophyll as well as the total antioxidant activity. The results revealed that radish microgreens’ antioxidant capacity and phytochemical profile depend on the radish cultivar and on the type of LED light used for cultivation. It was shown that B:2R and red cultivar were most beneficial for the synthesis of most of the determined phytochemicals compared to B:G:R, or the purple and green cultivar, respectively. Storage at a low temperature in darkness slowed down most of the metabolic reactions during the first seven days, thus preserving most of the antioxidant activity.

Development of Clonal Micropropagation Technology for Ludisia Discolor (Ker Gawl.) A. Rich. In Vitro Conditions

The features of clonal micropropagation in three variations of Ludisia discolor were studied. Brood buds, apical shoot meristems, immature seeds and mature seeds were used as explants. They are grown using Murashige & Skoog modified medium. A special technique has been developed for the sterilization and planting of microscopic mature seeds. Mature seeds germinated for 60-70 days. Seeds from 25-day-old capsules showed the best results among immature seeds. They gave mass shoots already on the 25-30 day after planting. The roller of the future first leaf of the protocorms was laid in the dark 2 months after germination. Switching to the light mode induced rapid gemmorizogenesis - the formation of the first green leaves, stem and adventitious roots. Seeds from 15-day-old capsules did not germinate at all. Planting with immature seeds is the most effective method of clonal reproduction of L. discolor in vitro.