Seed Dormancy Class and Germination Characteristics of Prunus spachiana (Lavallée ex Ed.Otto) Kitam. f. ascendens (Makino) Kitam Native to the Korean Peninsula

Prunus spachiana (Lavallée ex Ed.Otto) Kitam. f. ascendens (Makino) Kitam leaves exert natural anti-inflammatory effects by inhibiting nitric oxide formation. P. spachiana flowers bloom earlier than other Prunus spp. and thus could serve as a valuable resource for the horticulture and pharmaceutical industries. However, its seed dormancy class and germination traits remain uncharacterized. Thus, this study aimed to characterize the seed dormancy and germination of P. spachiana. Imbibition, phenological, and move-along experiments were performed, and the effects of H2SO4 treatment, hormone soaking, warm/cold stratification, and endocarp removal on germination were explored. Observation revealed that ripe seeds of P. spachiana contain developed embryos and are water permeable. Radicle and shoot emergence began in March and April, respectively, under natural conditions in the year following production. No seed germination was observed after 30 days of incubation at 4, 15/6, 20/10, or 25/15 °C under light/dark conditions, indicating the physiological dormancy of the seeds. Germination increased with prolonged stratification and was affected by incubation temperature. Seed scarification by H2SO4 and soaking with gibberellic acid (GA3) and fluridone were ineffective in breaking dormancy. However, GA3 soaking of the seeds after endocarp removal effectively induced germination (100%). These results indicate that P. spachiana seeds exhibit intermediate physiological dormancy.

Bioactive components and nutritional properties of fiber-rich cookies produced with different parts of oleaster (Elaeagnus angustifolia L.)

BACKGROUND

Oleaster (Elaeagnus angustifolia L.) possesses exocarp and endocarp layers enriched with abundant phytochemicals and fiber. Flours produced in different parts of oleaster were used in cookie formulation to improve the bioactive components and nutritional properties of cookies.

RESULTS

The rheological properties of composite flours containing varying levels of oleaster exocarp flour (O'EX-F) and endocarp flour (O'EN-F), ranging from 0% to 30%, were assessed using Mixolab (Chopin Technologies, Villeneuve-la-Garenne, France). The physical, chemical, nutritional, and sensory properties of cookies made with these flours were also analyzed. The substitution of O'EX-F and O'EN-F in the cookies enhanced redness and total color differences at the same time as decreasing hardness and improving the spread ratio. Furthermore, using these flours elevated the dietary fiber content of the cookies, particularly in terms of soluble and total dietary fiber. O'EX-F and O'EN-F also significantly increased free, bound, and total phenolic contents, as well as antioxidant capacity. Sensory evaluation of cookies with 10% and 20% O'EX-F and O'EN-F indicated greater appreciation than control cookies. Incorporating 20% O'EX-F and 20% O'EN-F into cookies resulted in a notable increase in Ca, Mg, K, Fe, and Zn levels.

CONCLUSION

The utilization of O'EX-F and O'EN-F, which contain a wealth of bioactive components, has significantly impacted the dough of rheology. Including these ingredients in cookie formulations has demonstrated improvements in ash, dietary fiber content, phenolics, antioxidant activity, and overall technological quality at the same time as providing distinctive sensory properties. The present study has contributed a new composite flour to the existing literature and has facilitated the development of novel cookie products for the functional food industry. © 2023 Society of Chemical Industry.

Contribution of the LAC Genes in Fruit Quality Attributes of the Fruit-Bearing Plants: A Comprehensive Review

Laccase genes produce laccase enzymes that play a crucial role in the production of lignin and oxidation reactions within plants. Lignin is a complex polymer that provides structure and toughness to the cell walls of numerous fruit plants. The LAC genes that encode laccase enzymes play vital roles in plant physiology, including the synthesis of pigments like PA that contribute to the colors of fruits, and in defending against pathogens and environmental stresses. They are crucial for fruit development, ripening, structural maintenance in plants, and adaptation to various environmental factors. As such, these genes and enzymes are essential for plant growth and development, as well as for various biotechnological applications in environmental remediation and industrial processes. This review article emphasizes the significance of genes encoding laccase enzymes during fruit growth, specifically pertaining to the strengthening of the endocarp through lignification. This process is crucial for ensuring fruit defense and optimizing seed scattering. The information gathered in this article will aid breeders in producing future fruit-bearing plants that are resistant to disease, cost-effective, and nutrient-rich.

Water uptake in germinating pecan (Carya illinoinensis) seed

• Water uptake is the fundamental and essential requirement for seed germination. Pecan seed has a hard woody endocarp and plays an important role during water uptake. • To explore the laws of water uptake during germination, the spatiotemporal pattern of water and the effect of endocarp were analysed by water measuring, high-field magnetic resonance imaging (MRI), dye-tracing, blocking and scanning electron microscopy (SEM). • Isolated seeds finish water uptake in 8h while whole seeds take 6d, and the cracking of endocarp plays an important role. The hilum is the channel for water to enter the seed, the rest of the seed coat consist of cells covered with a waxy layer and act as a barrier that made it difficult to absorb water. The region with the highest water contents in pecan seed was the edge of the U-shaped region and the water progressively diffused from the edge of the U-shaped region to the whole kernel. • There seems to be a new water absorption stage between phase II and phase III of triphasic model of water uptake of pecan seeds. The cracking of endocarp changed the water distribution in pecan seeds, which may be the trigger for further water absorption and radicle elongation.

Mechanism of Stone (Hardened Endocarp) Formation in Fruits: An Attempt toward Pitless Fruits, and Its Advantages and Disadvantages

Stone (hardened endocarp) has a very important role in the continuity of plant life. Nature has gifted plants with various seed protection and dispersal strategies. Stone-fruit-bearing species have evolved a unique adaptation in which the seed is encased in an extremely hard wood-like shell called the stone. The lignification of the fruit endocarp layer produces the stone, a feature that separates drupes from other plants. Stone cells emerge from parenchyma cells after programmed cell death and the deposition of cellulose and lignin in the secondary cell wall. Generally, the deposition of lignin in primary cell walls is followed by secondary thickening of cell walls to form stone cells. This review article describes the molecular mechanisms and factors that influence the production of stone in the fruit. This is the first review article that describes the molecular mechanisms regulating stone (harden endocarp) formation in fruits. This article will help breeders understand the molecular and genetic basis for the stone formation in fruit, and this could lead to new and innovative directions to breed stoneless fruit cultivars in the future.

Study on pecan seed germination influenced by seed endocarp

Nondeep physiological dormancy exists in freshly harvested pecan (Carya illinoinensis) seed, and the endocarp inhibits the seed germination. New methods were tried to detect if "chemical dormancy" or "mechanical dormancy" was caused by the endocarp. The germination of freshly harvested pecan seed with the removal of different parts of the endocarp and the fracture pressure of the endocarp of pecan seed soaked in water at different temperatures were tested. The results showed that (1) there was no significant difference in germination rate between the pecan kernel keeping in touch and out of touch with the same part of the endocarp, (2) whether a part of endocarp was removed to expose the radicle, preventing endocarp from splitting by glue inhibited the radicle elongation significantly, (3) the fracture pressure of the endocarp decreased significantly over water uptake time, and (4) little difference in the fracture pressure of the endocarp between different soaking temperatures. In conclusion, it suggested that (1) the endocarp caused "mechanical dormancy" but "chemical dormancy," (2) the prevention of radicle elongation was due to the endocarp pressuring the cotyledon rather than the direct physical restriction on the radicle, and (3) the radicle elongation seemed to be able to respond to the suture split and the pressure on the cotyledon.

Quantitative Proteome Analysis of Jatropha curcas L. Genotypes with Contrasting Levels of Phorbol Esters

The phorbol esters in the seeds of Jatropha curcas are a major hindrance to the full exploitation of the potential of this oil crop as a source of raw material for the production of biodiesel. Here, various quantitative proteomic strategies are used to establish the proteomes of roots, leaves, and endosperm of two genotypes of J. curcas with contrasting levels of phorbol esters in the seeds. In total 4532, 1775, and 503 proteins are identified respectively in roots, leaves, and endosperm, comprising 5068 unique proteins; of this total, 185 are differentially abundant in roots, 72 in leaves, and 20 in the endosperm. The biosynthetic pathways for flavonoids and terpenoids are well represented in roots, including the complete set of proteins for the mevalonate and non-mevalonate/Deoxyxylulose 5-Phosphate pathways, and proteins involved in the branches which lead to the synthesis tricyclic diterpenoids and gibberellins. Also, casbene synthase which catalyzes the first committed step in the biosynthesis of tigliane-type diterpenes is identified in roots of both genotypes, but not in leaves and endosperm. This dataset will be a valuable resource to explore the biochemical basis of the low toxicity of Jatropha genotypes with low concentration of phorbol esters in the seeds.

Metabolism of Stone Fruits: Reciprocal Contribution Between Primary Metabolism and Cell Wall

Cell wall turnover and modification in its composition are key factors during stone fruit development and patterning. Changes in cell wall disassembly and reassembly are essential for fruit growth and ripening. Modifications in cell wall composition, resulting in the formation of secondary cell walls, are necessary for producing the most distinctive trait of drupes: the lignified endocarp. The contribution of primary metabolism to cell wall synthesis has been investigated in detail, while the knowledge on the contribution of the cell wall to primary metabolites and related processes is still fragmented. In this review, starting from peculiarities of cell wall of drupes cells (in mesocarp and endocarp layers), we discuss the structure and composition of cell wall, processes related to its modification and contribution to the synthesis of primary metabolites. In particular, our attention has been focused on the ascorbate synthesis cell wall-related and on the potential role of cyanogenic compounds in the deposition of the secondary cell wall.

Peach Fruit Development: A Comparative Proteomic Study Between Endocarp and Mesocarp at Very Early Stages Underpins the Main Differential Biochemical Processes Between These Tissues

Peach (Prunus persica) is an important economically temperate fruit. The development follows double sigmoid curve with four phases (S1-S4). We centered our work in the early development. In addition to S1, we studied the very early stage (E) characterized by the lag zone of the exponential growing phase S1, and the second stage (S2) when the pit starts hardening. "Dixiland" peach fruit were collected at 9 (E), 29 (S1), and 53 (S2) days after flowering (DAF) and endocarp and mesocarp were separated. There was a pronounced decrease in total protein content along development in both tissues. Quantitative proteomic allowed the identification of changes in protein profiles across development and revealed the main biochemical pathways sustaining tissue differentiation. Protein metabolism was the category most represented among differentially proteins in all tissues and stages. The decrease in protein synthesis machinery observed during development would be responsible of the protein fall, rather than a proteolytic process; and reduced protein synthesis during early development would reroute cell resources to lignin biosynthesis. These changes were accompanied by net decrease in total amino acids in E1-S1 and increase in S1-S2 transitions. Amino acid profiling, showed Asn parallels this trend. Concerted changes in Asn and in enzymes involved in its metabolism reveal that increased synthesis and decreased catabolism of Asn may conduct to an Asn increase during very early development and that the β-Cyano-Alanine synthase/β-Cyano-Alanine hydratase could be the pathway for Asn synthesis in "Dixiland" peach fruit. Additionally, photosynthetic machinery decays during early development in mesocarp and endocarp. Proteins related to photosynthesis are found to a higher extent in mesocarp than in endocarp. We conclude mesocarpic photosynthesis is possible to occur early on the development, first providing both carbon and reductive power and latter only reductive power. Together with proteomic, histological tests and anatomical analysis help to provide information about changes and differences in cells and cell-walls in both tissues. Collectively, this work represents the first approach in building protein databases during peach fruit development focusing on endocarp and mesocarp tissues and provides novel insights into the biology of peach fruit development preceding pit hardening.

The Influence of Light on Olive (Olea europaea L.) Fruit Development Is Cultivar Dependent

In olive, the response to environmental conditions, such as light availability, is under genetic control and requires a combination of biochemical and physiological events. We investigated the effect of irradiance in fruit development in two Italian cultivars, Leccino and Frantoio. Morphological and cyto-histological analyses, as well as water and oil content determination, were carried out in fruits exposed to a different light regime (named as light and shade fruits). Results demonstrated that the influence of light availability on fruit development depends on the cultivar. In Leccino, the fresh and the dry weight, the percentage of dry matter, the kernel and fruit diameter, the mesocarp thickness and the mesocarp cell size were higher in the light exposed fruits than in the ones grown in the shade. In Frantoio, differences between light and shade fruits were observed only at 140 DAF (Days After Flowering) and only in the kernel and fruit diameter and in the dry and fresh weight, which were higher in the light exposed fruits. Leccino, therefore, showed a greater sensitivity to the light availability. This may be related to the observed delay in the endocarp lignification as compared to the Frantoio cultivar. In each cultivar, moreover, shade and light fruits did not show differences in the timing of cell differentiation. Finally, the investigation of oil storage carried out in cyto-histological studies demonstrated that differences in oil content between fruit subjected to different light regimes correlated with the number of oil containing cells, rather than the oil content per cell. A different behaviour was observed in the two cultivars: in Leccino, the mesocarp cell size was almost twice of Frantoio, while oil drops were only 30% larger; therefore, the percentage of cell volume occupied by the oil drops was lower in Leccino than in Frantoio. The chemical analysis confirmed this observation.

Fossil moonseeds from the Paleogene of West Gondwana (Patagonia, Argentina)

PREMISE OF THE STUDY

The fossil record is critical for testing biogeographic hypotheses. Menispermaceae (moonseeds) are a widespread family with a rich fossil record and alternative hypotheses related to their origin and diversification. The family is well-represented in Cenozoic deposits of the northern hemisphere, but the record in the southern hemisphere is sparse. Filling in the southern record of moonseeds will improve our ability to evaluate alternative biogeographic hypotheses.

METHODS

Fossils were collected from the Salamanca (early Paleocene, Danian) and the Huitrera (early Eocene, Ypresian) formations in Chubut Province, Argentina. We photographed them using light microscopy, epifluorescence, and scanning electron microscopy and compared the fossils with similar extant and fossil Menispermaceae using herbarium specimens and published literature.

KEY RESULTS

We describe fossil leaves and endocarps attributed to Menispermaceae from Argentinean Patagonia. The leaves are identified to the family, and the endocarps are further identified to the tribe Cissampelideae. The Salamancan endocarp is assigned to the extant genus Stephania. These fossils significantly expand the known range of Menispermaceae in South America, and they include the oldest (ca. 64 Ma) unequivocal evidence of the family worldwide.

CONCLUSIONS

Our findings highlight the importance of West Gondwana in the evolution of Menispermaceae during the Paleogene. Currently, the fossil record does not discern between a Laurasian or Gondwanan origin; however, it does demonstrate that Menispermaceae grew well outside the tropics by the early Paleocene. The endocarps' affinity with Cissampelideae suggests that diversification of the family was well underway by the earliest Paleocene.

Variability in Lignin Composition and Structure in Cell Walls of Different Parts of Macaúba (Acrocomia aculeata) Palm Fruit

The lignins from different anatomical parts of macaúba (Acrocomia aculeata) palm fruit, namely stalks, epicarp, and endocarp, were studied. The lignin from stalks was enriched in S-lignin units (S/G 1.2) and β-ether linkages (84% of the total) and was partially acylated at the γ-OH of the lignin side-chains (26% lignin acylation), predominantly with p-hydroxybenzoates and acetates. The epicarp lignin was highly enriched in G-lignin units (S/G 0.2) and consequently depleted in β-ethers (65%) and enriched in condensed structures such as phenylcoumarans (24%) and dibenzodioxocins (3%). The endocarp lignin was strikingly different from the rest and presented large amounts of piceatannol units incorporated into the polymer. This resulted in a lignin polymer depleted in β-ethers but enriched in condensed structures and linked piceatannol moieties. The incorporation of piceatannol into the lignin polymer seems to have a role in seed protection.

Chemical Composition and Bioactivities of Two Common Chaenomeles Fruits in China: Chaenomeles speciosa and Chaenomeles sinensis

Contents of total flavonoids, total phenolics, total triterpenes, total condensed tannin and total saponins in peels, flesh and endocarps of Chaenomeles speciosa (CSP) and Chaenomeles sinensis (CSS) were determined by colorimetric method, while 5 phenolics (vanillic, gallic, chlorogenic, ferulic and p-coumaric acids), 2 triterpenes (oleanolic and ursolic acids), and 3 flavonoids (rutin, catechin and epicatechin) were identified and quantified by high-performance liquid chromatography-mass spectrometry (HPLC-MS) and HPLC, and antioxidant and α-glucosidase inhibitory activities of them also were evaluated as well as their digestive characteristics. In the correlation analysis, total phenolics, vanillic acid, catechin, ursolic acid and oleanolic acid all contribute to DPPH(·) scavenge capacity, gallic acid contributes to total ferric reducing antioxidant power, while total triterpenes, total saponins, chlorogenic acid and ferullic acid contribute to α-glucosidase inhibitory activity. In the principal component analysis, endocarps of CSP and CSS both show better quality than their peels and flesh, respectively. In vitro digestion can increase contents of total flavonoids, total condensed tannin and total saponins, while contents of total phenolics and total triterpenes decreased greatly. Our study would contribute to the full use of discarded parts of the 2 Chaenomeles and be helpful to establish a good foundation for further research of CSP and CSS.

Icacinaceae from the eocene of Western North America

PREMISE OF THE STUDY

The Icacinaceae are a pantropical family of trees, shrubs, and climbers with an extensive Paleogene fossil record. Our improved understanding of phylogenetic relationships within the family provides an excellent context for investigating new fossil fruit and leaf material from the Eocene of western North America.

METHODS

We examined fossils from early and middle Eocene sediments of western Wyoming, northeastern Utah, northwestern Colorado, and Oregon and compared them with extant species of Iodes and other icacinaceous genera as well as previously described fossils of the family.

KEY RESULTS

Three new fossil species are described, including two based on endocarps (Iodes occidentalis sp. nov. and Icacinicaryites lottii sp. nov.) and one based on leaves (Goweria bluerimensis sp. nov.). The co-occurrence of I. occidentalis and G. bluerimensis suggests these might represent detached organs of a single species. A new genus, Biceratocarpum, is also established for morphologically distinct fossil fruits of Icacinaceae previously placed in Carpolithus. Biceratocarpum brownii gen. et comb. nov. resembles the London Clay species "Iodes" corniculata in possessing a pair of subapical protrusions.

CONCLUSIONS

These fossils increase our knowledge of Icacinaceae in the Paleogene of North America and highlight the importance of the Northern Hemisphere in the early diversification of the family. They also document interchange with the Eocene flora of Europe and biogeographic connections with modern floras of Africa and Asia, where Icacinaceae are diverse today. The present-day restriction of this family to tropical regions offers ecological implications for the Eocene floras in which they occur.

Evolution of the fruit endocarp: molecular mechanisms underlying adaptations in seed protection and dispersal strategies

Plant evolution is largely driven by adaptations in seed protection and dispersal strategies that allow diversification into new niches. This is evident by the tremendous variation in flowering and fruiting structures present both across and within different plant lineages. Within a single plant family a staggering variety of fruit types can be found such as fleshy fruits including berries, pomes, and drupes and dry fruit structures like achenes, capsules, and follicles. What are the evolutionary mechanisms that enable such dramatic shifts to occur in a relatively short period of time? This remains a fundamental question of plant biology today. On the surface it seems that these extreme differences in form and function must be the consequence of very different developmental programs that require unique sets of genes. Yet as we begin to decipher the molecular and genetic basis underlying fruit form it is becoming apparent that simple genetic changes in key developmental regulatory genes can have profound anatomical effects. In this review, we discuss recent advances in understanding the molecular mechanisms of fruit endocarp tissue differentiation that have contributed to species diversification within three plant lineages.

Cell differentiation and tissue formation in the unique fruits of devil's claws (Martyniaceae)

• Premise of the study: Martyniaceae are characterized by capsules with two upwardly curved, horn-shaped extensions representing morphologically specialized epizoochorous fruits. Because the capsules are assumed to cling to hooves and ankles of large mammals, fiber arrangement and tissue combinations within the endocarp ensuring proper attachment to the vector's feet during transport are of particular interest. In this first detailed anatomical investigation, the functional adaptation of the fruits and their implications for the specific dispersal mode are provided. The peculiar fiber arrangement may also be of interest for future biomimetic composite materials.• Methods: Endocarp anatomy and details of tissue differentiation were examined in fruits of Ibicella lutea and Proboscidea louisianica subsp. fragrans combining light microscopy, SEM, and x-ray microtomography analysis.• Key results: While tips of the extensions are predominantly reinforced by longitudinally oriented fibers, in the middle segment these fibers are densely packed in individual bundles entwined and separated by transversely elongated cells. Within the capsule wall, the fiber bundles are embedded in a dense mesh of transversely oriented fibers that circularly reinforce and protect the loculus. This fibrous pericarp tissue develops within few days by localized cell divisions and intrusive growth of primarily isodiametric parenchyma cells in the pistil.• Conclusions: The study allows insight into a unique and complex example of functionally driven cell growth and tissue formation. Long-horned fruits of Martyniaceae obviously are highly specialized to epizoochorous dispersal, pointing to primary vector-related seed dispersal. The highly ordered arrangement of fibers results in a great mechanical firmness.

Phylogeny and fruit evolution in Menispermaceae

PREMISE OF THE STUDY

This work surveys endocarp morphology of Menispermaceae in the context of a well-supported molecular phylogeny. The study is important since menispermaceous endocarps appear often in the fossil record and indicate the presence of a wet forest ecosystem. •

METHODS

Three chloroplast regions were used to derive phylogenies for 53 genera and 60 species. Endocarps of 47 genera and 92 species were dissected and morphological characters scored. Photographs of key features are presented. We superimposed our morphological matrix onto the phylogeny to explore character evolution. A detailed key to fruits is presented, allowing identification of extant and fossil specimens to the level of clade or genus. •

KEY RESULTS

Menispermaceae consists of two major subfamilies: Tinosporoideae and Menispermoideae. Within Tinosporoideae, tribe Coscineae is basal. Within Menispermoideae, tribe Menispermeae is basal. Tinosporoideae consists mainly of taxa with apical style scars, bilateral curvature, subhemispherical condyles, and foliaceous cotyledons with divaricate or imbricate orientation. Menispermoideae consists almost entirely of taxa with basal or subbasal style scars, dorsoventral curvature, bilaterally and/or dorsoventrally compressed condyles, and subterete or fleshy cotyledons oriented dorsoventrally or laterally. •

CONCLUSIONS

Several fruit characters differentiate major clades, and further synapomorphies are diagnostic of various subclades. Fruit characters that can be inferred as ancestral in the family are basal or subbasal stylar scars, endocarps with dorsoventral curvature, endocarp walls woody or bony, presence of a condyle, locule without ribs, sublateral vascular traces, presence of endosperm, and foliaceous or subterete cotyledons.

Identification and thermochemical analysis of high-lignin feedstocks for biofuel and biochemical production

BACKGROUND

Lignin is a highly abundant biopolymer synthesized by plants as a complex component of plant secondary cell walls. Efforts to utilize lignin-based bioproducts are needed.

RESULTS

Herein we identify and characterize the composition and pyrolytic deconstruction characteristics of high-lignin feedstocks. Feedstocks displaying the highest levels of lignin were identified as drupe endocarp biomass arising as agricultural waste from horticultural crops. By performing pyrolysis coupled to gas chromatography-mass spectrometry, we characterized lignin-derived deconstruction products from endocarp biomass and compared these with switchgrass. By comparing individual pyrolytic products, we document higher amounts of acetic acid, 1-hydroxy-2-propanone, acetone and furfural in switchgrass compared to endocarp tissue, which is consistent with high holocellulose relative to lignin. By contrast, greater yields of lignin-based pyrolytic products such as phenol, 2-methoxyphenol, 2-methylphenol, 2-methoxy-4-methylphenol and 4-ethyl-2-methoxyphenol arising from drupe endocarp tissue are documented.

CONCLUSIONS

Differences in product yield, thermal decomposition rates and molecular species distribution among the feedstocks illustrate the potential of high-lignin endocarp feedstocks to generate valuable chemicals by thermochemical deconstruction.