Mature Seeds Research Articles

Smallholder social networks: Advice seeking and adaptation in rural Kenya

CONTEXTSmallholder farmers in Africa are among those most impacted by climate change. Employing strategies such as planting early maturing or drought tolerant hybrid seeds is one common climate adaptive strategy for these households. However, seed choice has become increasingly complex for farmers. One way farmers look for clarity about seeds is to consult with other farmers. OBJECTIVEWe investigate smallholders' advice seeking within the context of a community water project in rural Kenya, a type of community-based common pool resource management organization. We examine a maize seed advice seeking network and compare it with a more general advice seeking network to better understand the social networks of maize seed advice seeking, and to characterize how peer-to-peer advice networks might factor into farmer decision-making about seeds. METHODSWe use exponential random graph modeling for the maize seed advice and general advice networks to test what factors predict advice-seeking among farmers in 104, or 92% of households in the community water project. RESULTS AND CONCLUSIONSThe maize seed advice network is less dense than the general advice network, with farmers on average seeking out fewer people for advice about maize. The features that shape each network also differ. There are some farmers who are significantly more active in seeking advice about maize seeds, and farmers who are already employing more adaptive practices on their farm are more likely to seek such advice. Farmers also seek each other out based on homophily, kinship, and physical proximity, and some farmers are sought out more often. We find evidence that physical infrastructure of the community water project drives advice-seeking ties, where farmers who are attached to the same branch of the water infrastructure are likely to seek advice from each other. SIGNIFICANCEMaize seed is not a topic about which many farmers in this network seek advice, and those who might be perceived as more experienced or educated are not necessarily those most sought for advice. Farmers hold key information due to their on-farm experience, and in the absence of robust extension services and consistent information about hybrid seeds, it is unclear to what extent the advice seeking that farmers do undertake fills those gaps. In addition, co-management of a common-pool resource facilitates advice sharing in both the maize and general advice networks, that is, on topics outside of the immediate reason for being part of a CWP, which is water management.

Temperature conditions optimization for storing tropical orchid seeds on the example of <i>Eulophia streptopetala</i> and <i>Stanhopea tigrina</i>

The paper presents the results of the study of temperature regime optimization for storing seeds of tropical orchids on the example of Eulophia streptopetala Lindley and Stanhopea tigrina Batem ex Lindl. Mature seeds were frozen at temperatures of 18C, 40C or 80C for a period of 1, 3, 6 or 12 months, the storage temperature was +4C. Before and after freezing, the viability of seeds was determined by visual and tetrazole methods. After defrosting, the seeds were sown and the plants grown from them were cultivated on a nutrient asymmetric medium, then the dynamics of plant development was recorded, the content of photosynthesis pigments (chlorophyll and carotenoids) was quantified. The analysis of the data obtained showed that the viability of seeds significantly decreases after storage, including in conditions of low temperatures. At the same time, in experimental groups of plants, the terms of early ontogenetic states were shortened, and the growth rate of protocorms increased. Freezing of seeds caused further restructuring of the photosynthetic apparatus. The optimal temperatures for storing seeds of the species Eulophia streptopetala were +4C, and for Stanhopea tigrina 80C and 40C.

A rapid detection and sorting system for seed maturity

To solve the problems of low speed and low efficiency of seed sorting, this study designs an efficient seed separation method. In this method, a vibrator is used to scatter the seeds and make them fall rapidly through parallel multi-tracks. The seeds are irradiated by a light source with a wavelength of 670 nm after passing through the identification area. The high-speed linear array camera takes photos of the irradiated seeds. The convolution neural network algorithm combining residual learning and attention mechanism is used to analyze and judge the maturity of the seeds. The algorithm model can effectively capture the characteristics of the seed photos and conduct efficient processing analysis and judgment, Finally, the low maturity seeds are blown away by an air compressor and blower to achieve rapid and efficient seed sorting. The test shows that the sorting speed can reach 50 particles/s and above, and the sorting accuracy can reach 96%.

Commercial scale genetic transformation of mature seed embryo explants in maize.

A novel, efficient maize genetic transformation system was developed using Agrobacterium-mediated transformation of embryo explants from mature seeds. Seeds from field grown plants were sterilized and crushed to isolate embryo explants consisting of the coleoptile, leaf primordia, and shoot apical meristem which were then purified from the ground seed bulk preparation. The infection of relevant tissues of seed embryo explants (SEEs) by Agrobacterium was improved by the centrifugation of the explants. Transgenic plants were obtained by multiple bud induction on high cytokinin media, followed by plant regeneration on hormone-free medium. Three different selectable markers (cp4 epsps, aadA, and nptII) were successfully used for producing transgenic plants. Stable integration of transgenes in the maize genome was demonstrated by molecular analyses and germline transmission of the inserted transgenes to the next generation was confirmed by pollen segregation and progeny analysis. Phenotypic evidence for chimeric transgenic tissue was frequently observed in initial experiments but was significantly reduced by including a second bud induction step with optimized cytokinin concentration. Additional improvements, including culturing explants at an elevated temperature during bud induction led to the development of a revolutionary system for efficient transgenic plant production and genome editing. To our knowledge, this is the first report of successful transgenic plant regeneration through Agrobacterium-mediated transformation of maize mature SEEs. This system starts with mature seed that can be produced in large volumes and the SEEs explants are storable. It has significant advantages in terms of scalability and flexibility over methods that rely on immature explants.

Phenylalanine Ammonia Lyase GmPAL1.1 Promotes Seed Vigor under High-Temperature and -Humidity Stress and Enhances Seed Germination under Salt and Drought Stress in Transgenic Arabidopsis

Seed vigor is an important agronomic attribute, essentially associated with crop yield. High-temperature and humidity (HTH) stress directly affects seed development of plants, resulting in the decrease of seed vigor. Therefore, it is particularly important to discover HTH-tolerant genes related to seed vigor. Phenylalanine ammonia lyase (PAL, EC 4.3.1.24) is the first rate-limiting enzyme in the phenylpropanoid biosynthesis pathway and a key enzyme involved in plant growth and development and environmental adaptation. However, the biological function of PAL in seed vigor remains unknown. Here, GmPAL1.1 was cloned from soybean, and its protein was located in the cytoplasm and cell membrane. GmPAL1.1 was significantly induced by HTH stress in developing seeds. The overexpression of GmPAL1.1 in Arabidopsis (OE) accumulated lower level of ROS in the developing seeds and in the leaves than the WT at the physiological maturity stage under HTH stress, and the activities of SOD, POD, and CAT and flavonoid contents were significantly increased, while MDA production was markedly reduced in the leaves of the OE lines than in those of the WT. The germination rate and viability of mature seeds of the OE lines harvested after HTH stress were higher than those of the WT. Compared to the control, the overexpression of GmPAL1.1 in Arabidopsis enhanced the tolerance to salt and drought stresses during germination. Our results suggested the overexpression of GmPAL1.1 in Arabidopsis promoted seed vigor at the physiological maturation period under HTH stress and increased the seeds' tolerance to salt and drought during germination.

Characterization of Phytochemical and Nutrient Compounds from the Leaves and Seeds of Moringa oleifera and Moringa peregrina

Moringa oleifera and M. peregrina are robust and fast-growing trees. These trees are considered some of the most highly valued trees worldwide because of their properties and uses. This study aimed to investigate and determine the content of phytochemical and nutrient compounds in the fresh leaves and the mature seeds of both M. oleifera and M. peregrina. The experimental data analysis showed that all four extracts were rich in proximate minerals, fatty acids (FA), and un-saponified and polyphenolic components. The total percentages of saturated and unsaturated fatty acids compounds obtained from the leaves and seeds of M. oleifera and M. peregrina were (45.02 and 54.93%), (10.80 and 89.19%), (37.13 and 62.8%), and (11.95 and 88.03%), respectively. The major polyphenols compositions were identified as gallic acid, chlorogenic acid, methyl gallate, and coffeic acid. The outcomes of the present study indicate that the leaves and seeds of Egyptian Moringa (M. oleifera and M. peregrina) contain various phytochemical and nutrient compounds, which can provide several health advantages and play an important role in the metabolism of the human body, especially in diseases such as atherosclerosis, heart disease, obesity, and high cholesterol and triglycerides.

Multiplex CRISPR/Cas9-mediated raffinose synthase gene editing reduces raffinose family oligosaccharides in soybean.

Soybean [Glycine max (L.) Merr.] is an important world economic crop. It is rich in oil, protein, and starch, and soluble carbohydrates in soybean seeds are also important for human and livestock consumption. The predominant soluble carbohydrate in soybean seed is composed of sucrose and raffinose family oligosaccharides (RFOs). Among these carbohydrates, only sucrose can be digested by humans and monogastric animals and is beneficial for metabolizable energy, while RFOs are anti-nutritional factors in diets, usually leading to flatulence and indigestion, ultimately reducing energy efficiency. Hence, breeding efforts to remove RFOs from soybean seeds can increase metabolizable energy and improve nutritional quality. The objective of this research is to use the multiplex Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)/Cas9-mediated gene editing system to induce the knockout of soybean raffinose synthase (RS) genes RS2 and RS3 simultaneously to reduce RFOs in mature seeds. First, we constructed five types of multiplex gene editing systems and compared their editing efficiency in soybean hairy roots. We confirmed that the two-component transcriptional unit (TCTU) and single transcriptional unit (STU) systems with transfer RNA (tRNA) as the cleavage site performed better than other systems. The average editing efficiency at the four targets with TCTU-tRNA and STU-tRNA was 50.5% and 46.7%, respectively. Then, we designed four single-guide RNA (sgRNA) targets to induce mutations at RS2 and RS3 by using the TCTU-tRNA system. After the soybean transformation, we obtained several RS2 and RS3 mutation plants, and a subset of alleles was successfully transferred to the progeny. We identified null single and double mutants at the T2 generation and analyzed the seed carbohydrate content of their progeny. The RS2 and RS3 double mutants and the RS2 single mutant exhibited dramatically reduced levels of raffinose and stachyose in mature seeds. Further analysis of the growth and development of these mutants showed that there were no penalties on these phenotypes. Our results indicate that knocking out RS genes by multiplex CRISPR/Cas9-mediated gene editing is an efficient way to reduce RFOs in soybean. This research demonstrates the potential of using elite soybean cultivars to improve the soybean meal trait by multiplex CRISPR(Clustered Regularly Interspaced Short Palindromic Repeats)/Cas9-mediated gene editing.

A lipidomics platform to analyze the fatty acid compositions of non-polar and polar lipid molecular species from plant tissues: Examples from developing seeds and seedlings of pennycress (Thlaspi arvense).

The lipidome comprises the total content of molecular species of each lipid class, and is measured using the analytical techniques of lipidomics. Many liquid chromatography-mass spectrometry (LC-MS) methods have previously been described to characterize the lipidome. However, many lipidomic approaches may not fully uncover the subtleties of lipid molecular species, such as the full fatty acid (FA) composition of certain lipid classes. Here, we describe a stepwise targeted lipidomics approach to characterize the polar and non-polar lipid classes using complementary LC-MS methods. Our "polar" method measures 260 molecular species across 12 polar lipid classes, and is performed using hydrophilic interaction chromatography (HILIC) on a NH2 column to separate lipid classes by their headgroup. Our "non-polar" method measures 254 molecular species across three non-polar lipid classes, separating molecular species on their FA characteristics by reverse phase (RP) chromatography on a C30 column. Five different extraction methods were compared, with an MTBE-based extraction chosen for the final lipidomics workflow. A state-of-the-art strategy to determine and relatively quantify the FA composition of triacylglycerols is also described. This lipidomics workflow was applied to developing, mature, and germinated pennycress seeds/seedlings and found unexpected changes among several lipid molecular species. During development, diacylglycerols predominantly contained long chain length FAs, which contrasted with the very long chain FAs of triacylglycerols in mature seeds. Potential metabolic explanations are discussed. The lack of very long chain fatty acids in diacylglycerols of germinating seeds may indicate very long chain FAs, such as erucic acid, are preferentially channeled into beta-oxidation for energy production.

Achieving of high-diet-fiber barley via managing fructan hydrolysis

High fructan content in the grain of cereals is an important trait in agriculture such as environmental resilience and dietary fiber food production. To understand the mechanism in determining final grain fructan content and achieve high fructan cereal, a cross breeding strategy based on fructan synthesis and hydrolysis activities was set up and have achieved barley lines with 11.8% storage fructan in the harvested grain. Our study discovered that high activity of fructan hydrolysis at later grain developmental stage leads to the low fructan content in mature seeds, simultaneously increasing fructan synthesis at early stage and decreasing fructan hydrolysis at later stage through crossing breeding is an efficient way to elevate grain diet-fiber content. A good correlation between fructan and beta glucans was also discovered with obvious interest. Field trials showed that the achieved high fructan barley produced over seven folds higher fructan content than control barley and pull carbon-flux to fructan through decreasing fructan hydrolysis without disruption starch synthesis will probably not bring yield deficiency.

Huangqin Qingre Qubi Capsule inhibits RA pathology by binding FZD8 and further inhibiting the activity of Wnt/β-catenin signaling pathway

Ethnopharmacological relevanceHuangqin Qingre Qubi Capsule (HQC) is a Chinese herbal compound for the treatment of rheumatoid arthritis (RA), which is made from dry roots of Scutellaria baicalensis Georgi, dry mature seeds of Gardenia jasminoides J.Ellis, dry and mature seeds of Coix lacryma-jobi var. stenocarpa Oliv., dry mature seeds of Amygdalus persica L. and roots and rhizomes of Clematis chinensis Osbeck in the proportion of 10:9:30:5:10. HQC has a significant effect in clinical treatment of RA, which can inhibit RA inflammation, improve oxidative stress state, and effectively relieve symptoms of RA patients. Aim of the studyThe anti-arthritis effect of HQC and its mechanism, especially whether it improves RA through FZD8-Wnt/β-catenin signal axis, were studied using adjuvant arthritis (AA) rats and FLS from RA patients. Materials and methodsReal time qPCR (RT-qPCR), Western blot (WB), confocal microscopy and other molecular biological methods were used to study the anti-RA effect of HQC and its mechanism. ResultsThe expression of FZD8 was significantly up-regulated in synovium and FLS of AA rats and RA FLS. FZD8 significantly activated the Wnt/β-catenin signaling pathway, promoted abnormal proliferation of FLS, increased the levels of inflammatory factors IL-1β, IL-6 and IL-8, and significantly increased the expression of matrix metalloproteinase 3 (MMP3) and fibronectin. HQC has significant therapeutic effect on AA rats. Molecular docking and molecular dynamics showed that HQC had a good binding ability with FZD8. We also confirmed that HQC inhibited Wnt/β-catenin signaling pathway by binding FZD8, and reduced the levels of the above inflammatory factors and pathological genes of RA. ConclusionsThe expression of FZD8 is significantly increased in AA rats and FLS from RA patients. Clarify that HQC improves RA through the FZD8-Wnt/β-catenin signal axis, provide a clear therapeutic mechanism for HQC to improve RA, and also provide a basis for clinical promotion of HQC.

Pinus sylvestris L. mature seeds megagamethophytes cultured in vitro. Influence of the genotype and the growth regulators content in nutrient medium on the initiation of callus formation

Pinus sylvestris L. mature seeds megagamethophytes cultured in vitro. Influence of the genotype and the growth regulators content in nutrient medium on the initiation of callus formation

Impact of seed maturity on season-long physiological performance and offspring seed quality in peanut (Arachis hypogaea L.)

Cultivated peanut produces pods of varying maturity throughout most of the plant developmental stages, often leading to a considerable proportion of immature seeds at harvest. Plants originating from immature seeds not only have reduced emergence and physiological performance, but also reduced vigor of both mature and immature seeds produced in subsequent generations. Therefore, seed maturity effects on plant performance could potentially extend from physiology to the initiation and progression of reproduction. This study aimed to elucidate the impacts of seed maturity on plant performance and productivity. In this two-year experiment, season-long physiological and reproductive performance was compared among plants established from mature and immature seed of eight peanut cultivars differing in maturity potential. Our results suggest that plants produced from mature seeds had higher emergence and canopy coverage than plants produced from immature seeds over the season. Further, descendent seed quality was also affected: plants that originated from immature seeds produced mature seeds with average 9.91 % decreased mass, particularly for those formed earliest in plant development, and average 37.18 % less mature pods formed latest in plant development. At harvest, seeds were collected and tested for biochemical characteristics. Seeds that were produced by plants originating from mature seeds generally had higher carbohydrates, protein, oleic acids and lower lipid content than seeds produced by plants originating from immature seeds. Given these results, the use of mature seeds in production appears to be of utmost importance for both the performance of the subsequent plant and the resulting quality of the seed produced by these plants. • This two-year study tested peanut plant performance and the quality of their offspring seeds that formed at different time periods (represented as cohort groups) based on whether the plants and their offspring seeds originated from mature or immature seeds. • Plants produced from mature seeds had enhanced emergence and greater canopy cover than plants produced from immature seeds over the season. • Plants originating from immature vs. mature seeds produced pods/seeds differed in the numbers of mature pods, seed mass and biochemical compounds within each cohort group. • The impact of seed maturity on plant development is highly dependent to environmental influence.

Analysis of Cyperus esculentus SMP family genes reveals lineage-specific evolution and seed desiccation-like transcript accumulation during tuber maturation

Seed maturation proteins (SMPs) represent a class of late embryogenesis-abundant proteins that are highly hydrophilic and abundant in mature seeds. Although it has been proven that SMPs are indispensable for the desiccation resistance of orthodox seeds , information on their putative roles in the desiccation resistance of non-seed storage organs is still scarce. This study presents a first transcriptome-based characterization of SMP family genes in tigernut ( Cyperus esculentus L., Cyperaceae), whose underground tubers represent a unique system that contains a considerably low moisture content of less than 10% without affecting the sprouting capability. Five family members identified from the full-length tigernut transcriptome are relatively more than four found in the genome of Carex littledalei , another Cyperaceae plant. Moreover, 69 family genes were also identified from 15 representative plant species and comparative genomics analysis supports the monogenic origin of this special family as well as lineage-specific evolution after monocot-eudicot split. In the Cyperaceae lineage, four clades present in the last common ancestor of tigernut and C. littledalei , which represent four out of 11 orthogroups proposed in this study, are more likely to result from transposed and dispersed duplications. In contrast to seed- or embryo-preferential expression of SMP genes in seed-bearing plants (e.g. rice and maize), transcriptional profiling and qRT-PCR analysis showed that most CeSMP genes are predominantly expressed in late stages of developmental tigernut tubers, negatively correlating with the moisture content. This seed desiccation-like accumulation of CeSMP transcripts during tuber maturation implies their putatively important roles in the desiccation resistance of tigernut tubers as observed in orthodox seeds. These findings not only improve the knowledge on lineage-specific evolution of the SMP gene family, but also provide valuable information for further functional analysis and genetic improvement in tigernut. • This is a first transcriptome-based analysis of SMP family genes in tigernut. • Comparative genomics analysis reveals the monogenic origin of the SMP family. • Lineage-specific family evolution was observed after monocot-eudicot split. • CeSMP transcripts are negatively correlating the moisture content of tubers. • Accumulation of CeSMPs in mature tubers implies a role in desiccation resistance.

IN VITRO PLANT REGENERATION IN LOCAL AUS RICE THROUGH MATURED SEED CULTURE

An investigation was carried out to decipher the effect of genotypes and concentrations of growth regulators for callus induction and subsequent plant regeneration from mature seeds of rice. Two local rice cultivars viz. Nayanmony and Kalomona and two growth regulators viz. 2, 4-D and NAA were used to evaluate their performance. The seeds were cultured under aseptic condition onto MS basal medium at varying concentrations and combinations of 2, 4-D (1.0, 1.5 and 2.0 mgL- 1) and NAA (0.0, 0.5 and 1.0 mgL-1) for callus induction. For plant regeneration MS medium fortified with 0.5 mgL- 1 NAA and 3.0 mgL-1 BAP was applied. Between the two cultivars Nayanmony showed better responses in callus induction frequency (91.38%), weight of callus (0.90 g)as well as diameter of callus (7.48 mm). Among the combinations 2, 4-D (1.5 mgL-1) alone produced the best callus (95.16%) and the highest weight of callus (1.88 g) but diameter of callus (8.27 mm) was the highest from 2, 4-D 1.0 mgL-1 +0.5 mgL-1 NAA. It was observed that both genotype and growth regulator significantly affected callus induction and plant regeneration. The medium supplemented with 2, 4-D 1.5 mgL-1 + NAA0.0 mgL-1 exhibited better performance in callus induction (99.33%) and weight of callus (1.92 g) in cultivar Nayanmony whereas Kalomona was better for diameter of callus (8.38 mm) at 2, 4-D 1.0 mgL-1 + NAA0.5 mgL-1. The cultivar Nayanmony performed better regarding plant regeneration (88.15%) compared to Kalomona (86.67%). Plantlets derived from the 2, 4-D 1.5 mgL-1+ NAA 0.0 mgL-1 showed the best results for survival. Therefore, it is suggested that application of MS medium supplemented with 2,4-D 1.5 mgL-1 and NAA 0.0 mgL-1 is advantageous to accomplish overall efficiency of callus induction, subsequent plant regeneration and survival from seeds of Nayanmony cultivars. Thus, selection of better responsive cultivar like Nayanmony and MS medium fortified with 1.5 to 2.0 mgL-1 2, 4-D would be beneficial in transformation attempts to improve the crop.

Genome-Wide Identification of miRNAs and Its Downstream Transcriptional Regulatory Network during Seed Maturation in Tilia tuan

Seed maturation not only determines the qualities and yields of seeds, but also affects seed storage and quality preservation. MicroRNAs (miRNAs) are a ubiquitous regulatory factor of gene expression in eukaryotes, which participate in the complex regulatory network of gene expression during seed maturation. However, miRNAs involved in maturation of Tilia tuan are still unknown. To reveal the role of miRNAs in T. tuan, small RNAs were profiled by high-throughput sequencing during seed maturation at five developmental stages. By predicting the target genes of miRNAs, the expression patterns of miRNAs during seed maturation were analyzed to identify those related to seed maturation. A total of 187 known miRNAs belonging to 42 miRNA families were found at five different seed maturation stages. Based on the analysis of unknown sequences, eight novel miRNAs were identified; 11,775 targets of 195 miRNAs were identified. Large numbers of miRNAs with diverse expression patterns, multiple-targeting and co-targeting of many miRNAs, and a complex regulatory network of miRNA-target genes were identified during seed maturation. These miRNAs and their targets may be involved in fatty acid, ABA, and lignin biosynthesis. Our study provides more information about the miRNA regulatory network and deepens our understanding of the function of miRNAs in T. tuan. miRNAs are revealed to be crucial during seed maturation, which provides a basis for further study of the regulatory role of miRNAs during seed maturation.

Desiccation induced physiological and biochemical changes of Gymnacranthera canarica (King.) Warb. seeds in the Myristica swamp forests, Southern Western Ghats, India

Gymnacranthera canarica (King.) Warb. is an endemic tree species that dominates the Myristica swamp ecosystem of southern Western Ghats. This tropical tree species has become more threatened due to limited natural seed germination and habitat loss. Mature seeds were collected from the myristica swamp ecosystem subjected to desiccation study. This research evaluated the physiological (moisture content, tetrazolium reduction, lipid peroxidation, electrolyte leakage) and biochemical response of seeds during different desiccation treatments. Results showed that G. canarica seeds are highly sensitive to desiccation and total viability loss was seen within 15 days following harvest indicating the active seed metabolism of mature seeds showing absence of metabolic arrest. Desiccation enhanced malondialdehyde and electrolyte leakage while reducing formazan formation. Seed desiccation increases protease activity, which peaks when viability is lost. Desiccation reduced the quantity of phenol and starch, whereas proline, fat, sucrose and total soluble carbohydrates increased. The early viability loss in G. canarica seeds could be due to loss of membrane integrity, which was linked to ROS formation and associated lipid peroxidation products indicating seeds are truly recalcitrant.

Flowering effort and reproductive phenology of intertidal colonizing Zostera marina

The seagrass Zostera marina can inhabit the intertidal where the variable environmental conditions mean that the seagrass meadows are frequently in a continuous state of colonization, influencing, among others, their phenology and flowering effort. This could be especially notable in the southern limits of the species' distribution, where light exposure and temperature reach extreme values during the warmer seasons. In this study, we evaluate the flowering effort, phenology, photophysiology and vegetative development of recent colonizing Z. marina patches inhabiting the intertidal of a lagoon located near its southern limit of distribution, in the Ria de Aveiro (Portugal). To evaluate the effects of low tide exposure, tidepool and emerged seagrass patches were selected. Results showed short-lived differences in the phenology of the flowering of the patches and in their vegetative development, but in general, the photosynthetic activity, timing of flowering, densities of spathes and flowering shoots were similar in emerged and tidepool patches throughout the entire reproductive period (from June to August). The spathes per flowering shoot and the spathe and flowering shoot densities per unit of area of the colonizing patches were comparable to that obtained in other perennial intertidal meadows of this species and its timing was adjusted to that which occurred in areas of similar latitudes, ending when the temperature exceeded 25 °C. These results imply that intertidal colonizing Z. marina patches can flowering similarly to perennial meadows, regardless of whether or not they are submerged in pools at low tide, which implies a great adaptability of the species to intertidal areas. However, to fully understand the reproductive capacity of Z. marina in the Ria de Aveiro, future studies should determine the capacity of these flowers to form mature seeds, as well as their ability to germinate naturally in the area.

Endosperm ontogeny through the lens of epigenetics

Endosperm tissue is crucial to seed development. Monocots and dicots have evolved different fates for their endosperm: it is usually consumed in dicots during seed development, while monocots seeds retain the endosperm till maturity. Recently, Wu et al. addressed the role of divergent epigenetic regulation over functionally conserved IKU2 gene contributing to silenced or persistent endosperm proliferation and has provided insights into diverged seed ontogeny pattern in plants. Here, we highlight the novel findings of this study and their potential significance. Seed production represents a remarkable life-history adaptation that has been established during plant evolution. In flowering plants, a double fertilization event initiates seed development, producing embryo and the endosperm. Endosperm (3n) is a triploid outcome of second fertilization, which occurs when a female central cell (2n) fuses with one of the two male gametes (n) carried by the pollen tube (Ingram, 2020). It develops precociously and is primed to perform nutritional and developmental functions for embryo growth (Povilus & Gehring, 2022). Different taxa have evolved specific seed formation patterns that elicit different levels of endosperm perseverance during development (Baroux et al., 2002). As a result of this, the endosperm-to-embryo ratio in mature seeds has varied gradually among different plants. As an example, endosperm in cereals is formed and retained as a nutritive reserve till seed maturity. In several eudicots such as Arabidopsis, early formed endosperm is substantially devoured to serve during embryo maturation. In peas with non-persistent endosperm, the tissue appears to be absorbed in the early free nuclear division phase before cell wall formation. The Podostomenaceae and Orchidaceae are the two endosperm-free lineages because their seeds lack or terminate endosperm nuclear divisions during early stages. Endosperm develops through two major phases: first syncytial involving continuous nuclear divisions, and the subsequent cellularization in which the free nuclear state develops cell wall (Baroux et al., 2002). Despite that the embryo produces the next generation progeny, endosperm proliferation and cellularization timing is crucial to embryo viability.

Genetic variability in Ethiopian faba bean (Vicia faba L.) accessions

Knowledge on genetic variability in faba bean (Vicia faba L.) is crucial to enhance its production and productivity. However, there has been very limited information on variability of Ethiopian faba bean accessions. Therefore, the present study was conducted to evaluate the phenotypic and genotypic variability, heritability and genetic advance of yield and associated traits in Mecha district during 2019 main cropping season. A total of 81 faba bean accessions were evaluated using 9 × 9 simple lattice design. Data were collected for 14 quantitative and three qualitative traits. The result of analysis of variance showed highly significant (p < 0.01) differences among accessions for all quantitative traits except days to maturity and number of seeds per pod. High phenotypic and genotypic coefficient of variation was observed for hundred-seed weight (24.02 and 20.29), biomass yield (27.25 and 25.35), harvest index (30.06 and 26.67), grain yield (31.32 and 30.77), number of branches per plant (36.81 and 27.52), number of pods per plant (43.66 and 37.600), and for scores for diseases like ascochyta blight (46.17 and 45.64), chocolate spot (50.1 and 47.9), and rust (66.03 and 64.43), indicating the presence of ample variability residing within the accessions; as a result, these traits could be improved through direct selection. High heritability coupled with high genetic advance was observed for hundred-seed weight, harvest index, number of pods per plant, grain yield, biomass yield, and disease-related traits, indicating the importance of genetic variance for the expression of these traits, and these traits could easily be improved through direct selection.

Seed maturation and its practical implications

The use of high vigour seeds for crop production is increasing in importance. Seed vigour develops during the late maturation phase, after deposition of reserves and attainment of maximum dry weight. During this phase, various protective mechanisms are imposed in the seeds that will aid survival after release from the mother plant. These mechanisms include the production of protective metabolites such as antioxidants and pigments, specific proteins and degradation of chlorophyll. All are essential for maximum quality of seeds used as propagation material, since they aid in providing increased tolerance to diverse biotic and abiotic stresses. Physical sanitation treatments, ageing during storage and threat by pathogens are some of the stresses that the seeds can experience during production, processing and germination. However, harvesting seeds at the fully mature stage and with maximum vigour is a big challenge in seed production. For most seeds, analysis of chlorophyll levels can be used as a measure of relative maturity. This is a rather sensitive technique as it uses the fluorescence properties of chlorophyll, and can also be used for upgrading seed lots containing relatively large fractions of less mature seeds. Sorted seed fractions are also useful to study processes during late seed maturation and the different seed vigour aspects gained during late seed maturation.