High genetic diversity and small genetic variation among populations of Magnolia wufengensis (Magnoliaceae), revealed by ISSR and SRAP markers

Background: Genetic diversity and genetic variation of 10 populations and subpopulations of Magnolia wufengensis , a new and endangered endemic species, were examined by inter simple sequence repeat (ISSR) and sequence-related amplified polymorphism (SRAP) molecular markers. Compared with other endangered endemic Magnolia taxa, M. wufengensis holds a relatively high level of genetic variation. Result: Total genetic diversity was found to be 87.7% for ISSR and 88.0% for SRAP markers. For polymorphic loci (P), the effective mean number of alleles (Ae) was 1.414 for ISSR markers and 1.458 for SRAP markers, while the mean expected heterozygosity (H) was 0.256 using ISSR and 0.291 for SRAP markers. Within-population variation was estimated for P as 74.9% using ISSR and 74.6% with SRAP markers; the number of alleles Ae was 1.379 with ISSR and 1.397 for SRAP and H 0.235 with ISSR and 0.247 for SRAP markers. Conclusion: The analysis of molecular variation of both ISSR and SRAP marker systems indicated that most genetic variation is within populations,with values of 90.64% and 82.92% respectively. Mantel tests indicated a moderate association between the two marker systems and a low correlation between genetic and geographic distances. High levels of genetic diversity and low levels of population divergence suggest that genetic drift is not currently of great concern for this species. Severe habitat loss and fragmentation, predominantly ascribed to anthropogenic pressures, caused in-situ developing restriction of this species. Action for conserving this rare species for its long-term survival should be taken immediately

The First Principle in Late Neoplatonism: A Study of the One's Causality in Proclus and Damascius

One of the main issues that dominates Neoplatonism in late antique philosophy of the 3rd–6th centuries A.D. is the nature of the first principle, called the ‘One’. From Plotinus onward, the principle is characterized as the cause of all things, since it produces the plurality of intelligible Forms, which in turn constitute the world’s rational and material structure. Given this, the tension that faces Neoplatonists is that the One, as the first cause, must transcend all things that are characterized by plurality—yet because it causes plurality, the One must anticipate plurality within itself. This becomes the main mo- tivation for this study’s focus on two late Neoplatonists, Proclus (5th cent. A.D.) and Damascius (late 5th–early 6th cent. A.D.): both attempt to address this tension in two rather different ways. Proclus’ attempted solution is to posit intermediate principles (the ‘henads’) that mirror the One’s nature, as ‘one’, but directly cause plurality. This makes the One only a cause of unity, while its production of plurality is mediated by the henads that it produces. Damascius, while appropriating Proclus’ framework, thinks that this is not enough: if the One is posed as a cause of all things, it must be directly related to plurality, even if its causality is mediated through the henads. Damascius then splits Proclus’ One into two entities: (1) the Ineffable as the first ‘principle’, which is absolutely transcendent and has no causal relation; and (2) the One as the first ‘cause’ of all things, which is only relatively transcendent under the Ineffable. Previous studies that compare Proclus and Damascius tend to focus either on the Ineffable or a skeptical shift in epistemology, but little work has been done on the causal framework which underlies both figures’ positions. Thus, this study proposes to focus on the causal frameworks behind each figure: why and how does Proclus propose to assert that the One is a cause, at the same time that it transcends its final effect? And what leads Damascius to propose a notion of the One’s causality that no longer makes it transcendent in the way that a higher principle, like the Ineffable, is? The present work will answer these questions in two parts. In the first, Proclus’ and Damascius’ notions of causality will be examined, insofar as they apply to all levels of being. In the second part, the One’s causality will be examined for both figures: for Proclus, the One’s causality in itself and the causality of its intermediate principles; for Damascius, the One’s causality, and how the Ineffable is needed to explain the One. The outcome of this study will show that Proclus’ framework results in an inner tension that Damascius is responding to with his notion of the One. While Damascius’ own solution implies its own tension, he at least solves a difficulty in Proclus—and in so doing, partially returns to a notion of the One much like Iamblichus’ and Plotinus’ One

Isolation and Functional Analysis of PISTILLATA Homolog From Magnolia wufengensis

PISTILLATA (PI) homologs are crucial regulators of flower development in angiosperms. In this study, we isolated the MAwuPI homolog from Magnolia wufengensis, a basal angiosperm belonging to the Magnoliaceae. Molecular phylogenetic analysis suggested that MAwuPI was grouped into the PI/GLO lineages of B-class MADS-box gene with the distinctive PI motif. Further expression profiling analysis showed that MAwuPI was expressed in tepals and stamens but not in juvenile leaves and carpels, similar to the spatial expression pattern of AtPI in Arabidopsis. Interestingly, MAwuPI had higher expression level in inner-tepals than in outer-tepals, whereas the M. wufengensis flower is homochlamydeous. Moreover, ectopic expression of MAwuPI in Arabidopsis pi-1 mutant emerged filament-like structures but had no obvious petals, suggesting a partial phenotypic recovery of pi-1 mutant. The features of MAwuPI in the expression pattern and gene function improved our acknowledgment of B-class genes in M. wufengensis, and contributed to the clarification of M. wufengensis evolution status and relations with other sibling species in molecular perspective

High genetic diversity and small genetic variation among populations of Magnolia wufengensis (Magnoliaceae), revealed by ISSR and SRAP markers

Background: Genetic diversity and genetic variation of 10 populations and subpopulations of Magnolia wufengensis, a new and endangered endemic species, were examined by inter simple sequence repeat (ISSR) and sequence-related amplified polymorphism (SRAP) molecular markers. Compared with other endangered endemic Magnolia taxa, M. wufengensis holds a relatively high level of genetic variation. Result: Total genetic diversity was found to be 87.7% for ISSR and 88.0% for SRAP markers. For polymorphic loci (P), the effective mean number of alleles (Ae) was 1.414 for ISSR markers and 1.458 for SRAP markers, while the mean expected heterozygosity (H) was 0.256 using ISSR and 0.291 for SRAP markers. Within-population variation was estimated for P as 74.9% using ISSR and 74.6% with SRAP markers; the number of alleles Ae was 1.379 with ISSR and 1.397 for SRAP and H 0.235 with ISSR and 0.247 for SRAP markers. Conclusion: The analysis of molecular variation of both ISSR and SRAP marker systems indicated that most genetic variation is within populations, with values of 90.64% and 82.92% respectively. Mantel tests indicated a moderate association between the two marker systems and a low correlation between genetic and geographic distances. High levels of genetic diversity and low levels of population divergence suggest that genetic drift is not currently of great concern for this species. Severe habitat loss and fragmentation, predominantly ascribed to anthropogenic pressures, caused in-situ developing restriction of this species. Action for conserving this rare species for its long-term survival should be taken immediately

Survival and Recovery Growth of Riparian Plant Distylium chinense Seedlings to Complete Submergence in the Three Gorges Reservoir Region

AbstractTo investigate whether Distylium chinense can adapt to the artificial water-level-fluctuation zone, which has longer submergence duration and different hydrological regime, its seedlings were submitted to the un-submerged and completely submerged treatments with submergence under 2m water depth. Four different submergence durations included 15, 30, 90 and 120 d and meanwhile with two recovery growth durations of 15 and 60 d after de-submergence. The survival, main stem length, number of epicormic shoots, number of leaf showing chlorosis/senescence, stem basal diameter, aboveground biomass, belowground biomass, root/shoot ratio and total biomass were determined at the end of the submergence experiment. In addition, the recovery growth rate of seedlings was calculated after a 60-day recovery period. The results showed that D. chinense had the high survival and good recovery growth after long-term submergence, which indicated that D. chinense is a relatively high submergence-tolerant species. Thus, D. chinense can be considered as one of the native pioneer tree species in the revegetation and restoration of water-level-fluctuation zone in Three Gorges Reservoir region, China

Characterization of Two AGL6–Like Genes from a Chinese Endemic Woody Tree, Manglietia patungensis (Magnoliaceae) Provides Insight into Perianth Development and Evolution in Basal Angiosperms

Manglietia patungensis (Magnoliaceae) exhibits radially symmetric flowers with perianth consisting of three separate sepaloid tepals in whorl 1 and six petaloid tepals in the inner two whorls, which shows an obvious difference from flowers of most Magnoliaceae species that contain three uniform petaloid tepals whorls, and make it an excellent model for understanding perianth morphology differentiation during early flower evolution. Here, two AGL6 orthologs, MapaAGL6-1 and MapaAGL6-2, were isolated from M. patungensis. Sequence alignment and phylogenetic analyses grouped both genes into the AGL6 lineage. MapaAGL6-1 is expressed only in the perianth whorls, while MapaAGL6-2 is strongly expressed in the perianth whorls but is lowly expressed in gynoecium. Furthermore, ectopic expression of MapaAGL6-1 results in strong complementation phenotypes in the Arabidopsis ap1-10 flower and production of normal floral organs in four floral whorls only with the petal number reduced in whorl 2, while ectopic expression of MapaAGL6-2 only results in petals partly rescued but failing to terminate carpelloid development in Arabidopsis ap1-10 mutant. In addition, the daughter lines generated from a cross between 35S::MapaAGL6-1 transgenic plants showing strong phenotypes and 35S::MapaAGL6-2 transgenic plants showing phenotypic changes produce normal flowers. Our results suggest that MapaAGL6-1 is a reasonable A-function gene controlling perianth identity in Magnoliaceae, which infers from its expression region and complementation phenotypes in Arabidopsis ap1 mutant, while MapaAGL6-2 is mainly involved in petaloid tepal development. Our data also provide a new clue to uncover the perianth development and early evolution in basal angiosperms

Fall Ethephon Application Enhances the Freezing Tolerance of Magnolia wufengensis During Overwintering

Magnolia wufengensis L.Y. Ma et L. R. Wang, a rare species which has been introduced and cultivated from southern China to northern China, frequently suffers from freezing injuries. To figure out the influence of ethephon (ETH) application on the cold tolerance during the natural overwintering of M. wufengensis, one-year shoots subjected to ethephon application at four concentrations (0, 700, 1000, and 1500 mg·L−1) were collected to measure the physiological and biochemical changes from September 2017 to 1 April 2018. The fall ETH application increased the freezing tolerance of M. wufengensis, and the optimum concentration for M. wufengensis was 1000 mg·L−1 (T2), which not only improved the shoot freezing tolerance by 1.4 times, but also led to a 25.0% faster cold acclimation rate and 13.7% slower de-acclimation rate. Moreover, 1000 mg·L−1 ETH delayed bud-burst in the spring by 10. 7 d, which was helpful for effectively avoiding cold spells in the spring, and improved the rates of bud survival by 47.1%. The improved freezing tolerance under exogenous ETH application was associated with an increased dehydration and accumulation of proline content. It seems that exogenous ETH application may be used on M. wufengensis grown in northern China to protect against freezing tolerance during the overwintering period

Floral organ MADS-box genes in Cercidiphyllum japonicum (Cercidiphyllaceae): Implications for systematic evolution and bracts definition.

The dioecious relic Cercidiphyllum japonicum is one of two species of the sole genus Cercidiphyllum, with a tight inflorescence lacking an apparent perianth structure. In addition, its systematic place has been much debated and, so far researches have mainly focused on its morphology and chloroplast genes. In our investigation, we identified 10 floral organ identity genes, including four A-class, three B-class, two C-class and one D-class. Phylogenetic analyses showed that all ten genes are grouped with Saxifragales plants, which confirmed the phylogenetic place of C. japonicum. Expression patterns of those genes were examined by quantitative reverse transcriptase PCR, with some variations that did not completely coincide with the ABCDE model, suggesting some subfunctionalization. As well, our research supported the idea that thebract actually is perianth according to our morphological and molecular analyses in Cercidiphyllum japonicum

Fine-Scale analysis of both wild and cultivated horned galls provides insight into their quality differentiation

Abstract Background Galla chinensis is a traditional Chinese medicine (TCM) produced due to the interaction between the Fordinae aphids and the Rhus plant species. Horned galls with high tannin content are the most widely cultivated gall type, and Wufeng county of Hubei province in China is the center of cultivation. However, long-term artificial cultivation and domestication of horned galls to meet the increasing production demand have led to quality degradation. Understanding the reasons underlying quality degradation is urgent for horned gall production and application. The present study used a combination of metabolic, genetic, and ecological analyses to investigate the quality and genetic differentiation of the horned galls under long-term domestication as well as the potential relationships between them. Results Analysis of gallic acid content and other three phenotypic traits (fresh weight, gall size, and wall thickness) revealed quality differentiation of horned galls collected from five locations in Wufeng, in which the cultivated samples from Wang Jiaping (WJP) showed the highest degradation. Genetic differentiation between the cultivated and wild Rhus chinensis trees in WJP, and between WJP and the other populations was detected based on SSR molecular markers, however, no significant difference in genetic structure was seen for the aphid populations. Among the various ecological factors examined, temperature was identified as the primary one affecting the quality of horned galls. Conclusions Both genetic and ecological factors caused quality differentiation of horned galls. The collection of diverse germplasm of host trees and aphids will help reduce the quality degradation of horned galls in Wufeng

Epidermal cells of leaves and floral parts of <i>Cercidiphyllum japonicum</i>.

<p>Since male and female flowers are the same besides floral organs, so just female ones were displayed. (A) Abaxial (bar = 50 μm) and amplified (inset; bar = 10 μm) epidermal cells of a outer scale at mature stage. (B) Adaxial (bar = 30 μm) epidermal cells of a outer a scale at mature stage. (C) Abaxial (bar = 25 μm) and adaxial (inset; bar = 20 μm) epidermal cells of a inner scale at mature stage, showing irregular striation. (D) Abaxial (bar = 30 μm) and adaxial (inset; bar = 10 μm) epidermal cells of a inner scale at mature stage. (E) Carpels from a mature flower (bar = 200 μm). (F) Epidermal cells of a stigma (left; bar = 15 μm) and back (right; bar = 5 μm) of carpel. (G) A stamen from a mature flower (bar = 200 μm). (H) Surface of anther (left; bar = 10 μm) and filament (right; bar = 20 μm). (I) Juvenile leaves (bar = 200 μm) and the abaxial and amplified epidermal cells (inset; bar = 15 μm). (J) Epidermal cells of glands (bar = 30 μm). (K) Surface of a stipule (bar = 500 μm), showing relatively regular sculpturing (insert; bar = 30 μm). (L) Bracts (bar = 300 μm), showing middle slotted or tee or cross grooves (bar = 20 μm).</p