The complete plastomes of thirteen Libanotis (Apiaceae, Apioideae) plants: comparative and phylogenetic analyses provide insights into the plastome evolution and taxonomy of Libanotis.

BACKGROUND: The genus Libanotis Haller ex Zinn, nom. cons., a contentious member of Apiaceae, encompasses numerous economically and medicinally significant plants, comprising approximately 30 species distributed across Eurasia. Despite many previous taxonomic insights into it, phylogenetic studies of the genus are still lacking. And the establishment of a robust phylogenetic framework remains elusive, impeding advancements and revisions in the taxonomic system for this genus. Plastomes with greater variability in their genetic characteristics hold promise for building a more robust Libanotis phylogeny. RESULTS: During our research, we sequenced, assembled, and annotated complete plastomes for twelve Libanotis species belong to three sections and two closely related taxa. We conducted a comprehensive comparative analysis through totally thirteen Libanotis plastomes for the genus, including an additional plastome that had been published. Our results suggested that Libanotis plastome was highly conserved between different subclades, while the coding regions were more conserved than the non-coding regions, and the IR regions were more conserved than the single copy regions. Nevertheless, eight mutation hotspot regions were identified among plastomes, which can be considered as candidate DNA barcodes for accurate species identification in Libanotis. The phylogenetic analyses generated a robustly framework for Libanotis and revealed that Libanotis was not a monophyletic group and their all three sections were polygenetic. Libanotis schrenkiana was sister to L. sibirica, type species of this genus, but the remainders scattered within Selineae. CONCLUSION: The plastomes of Libanotis exhibited a high degree of conservation and was effective in enhancing the support and resolution of phylogenetic analyses within this genus. Based on evidence from both phylogeny and morphology, we propose the recognition of "Libanotis sensu stricto" and provide taxonomic recommendations for other taxa that previously belonged to Libanotis. In conclusion, our study not only revealed the phylogenetic position and plastid evolution of Libanotis, but also provided new insights into the phylogeny of the family Apiaceae and phylogenetic relationships within the tribe Selineae.

Research advance in effects of solar radiation on litter decomposition in terrestrial ecosystems.

Litter decomposition significantly influences the carbon (C) dynamics of terrestrial ecosystems. Solar radiation is not only essential for photosynthetic C fixation and primary productivity, but also can directly or indirectly promote litter decomposition through photodegradation. Recently, photodegradation has been identified as a key factor driving litter decomposition and potentially impacts terrestrial C cycle. To enrich and develop the theory of litter decomposition, we summarized the mechanisms and main driving factors of photodegradation, and compared the responses of photodegradation to environment and climate changes at different scales. Photodegradation primarily includes photomineralization, photoinhibition, and photofaciliation, each affecting litter decomposition differently under various environmental conditions. Photodegradation is closely related to factors such as solar radiation, litter traits, temperature, moisture, microorganisms, and vegetation cover. The interactions among these factors complicate the patterns of photodegradation. Finally, we identified the main issues in litter photodegradation research and prospected future research directions. We emphasized the needs for in-depth exploration of photodegradation pathways and intrinsic mechanisms, quantification of its interactive effects with environmental factors, and optimization of traditional carbon turnover models.

Latitudinal responses of litter decomposition to solar radiation.

Photodegradation driven by solar radiation has been confirmed as an important driving factor for litter decomposition. However, previous single-site studies could not quantify the relative contribution of variation in solar radiation to litter decomposition. To address it, we conducted a field experiment in Heshan National Field Research Station of Forest Ecosystem, Guangdong (Heshan Station, south subtropical climate), Jigongshan Ecological Research Station, Xinyang, Henan (Jigongshan Station, north subtropical climate) and Daqinggou Ecological Research Station, Institute of Applied Ecology, Chinese Academy of Sciences (Daqinggou Station, temperate climate) at intervals of 10 degrees. We examined litter decomposition of Populus davidiana and Larix olgensis, two species with significant differences in initial litter quality through an in-situ spectral-attenuation experiment. Treatments included full-spectrum, No-UV-B (attenuating UV-B radiation <315 nm) and No-UV & Blue (attenuating all UV and blue wavelengths <500 nm). After nearly 1-year decomposition, litter dry mass remaining of P. davidiana and L. olgensis under full-spectrum treatment was lowest at Heshan (30.2% and 36.3%), and highest at Jigongshan (37.3% and 45.8%). Among all sites, litter dry mass remaining was lowest under the full-spectrum, and lower than that of No-UV-B and No-UV & blue. UV and blue light significantly increased litter mass loss of P. davidiana and L. olgensis, with contributions of 59.7% and 57.0% (Heshan), 46.4% and 42.1% (Jigongshan), and 39.0% and 45.9% (Daqinggou), respectively. The contribution of UV-A and blue light (315-500 nm) was greater than UV-B (280-315 nm); the cumulative irradiance, soil temperature and moisture were the main driving factors for litter photodegradation.

Effects of light qualities on growth and physiological-biochemical traits of Scutellaria baicalensis.

Canopy spectral composition significantly affects growth and functional traits of understory plants. In this study, we explored the optimal light condition suitable for enhancing Scutellaria baicalensis's yield and quality, aiming to provide scientific reference for the exploitation and utilization of medicinal plant resources in the understory of forests. We measured the responses of growth, morphology, biomass allocation, physiological traits, and secon-dary metabolites of S. baicalensis to different light qualities. S. baicalensis was cultured under five LED-light treatments including full spectrum light (control), ultraviolet-A (UV-A) radiation, blue, green, and red light. Results showed that UV-A significantly reduced plant height, base diameter, leaf thickness, leaf area ratio, and biomass of each organ. Red light significantly reduced base diameter, biomass, effective quantum yield of photosystem Ⅱ (ФPSⅡ), and total flavonoid concentration. Under blue light, root length and total biomass of S. baicalensis significantly increased by 48.0% and 10.8%, respectively, while leaf number and chlorophyll content significantly decreased by 20.0% and 31.6%, respectively. The other physiological and biochemical traits were consistent with their responses in control. Our results suggested that blue light promoted photosynthesis, biomass accumulation, and secondary metabolite synthesis of S. baicalensis, while red light and UV-A radiation negatively affected physiological and biochemical metabolic processes. Therefore, the ratio of blue light could be appropriately increased to improve the yield and quality of S. baicalensis.

Morphological and molecular evidence gives insight into the taxonomic position of Peucedanumpubescens (Apiaceae, Selineae).

In this study, morphological and molecular evidences were combined to determine the taxonomic position of Peucedanumpubescens Hand.-Mazz. Morphologically, Peucedanumpubescens is similar to the species of the genus Ligusticopsis in having fibrous remnant sheaths at the stem base, pinnate and linear coexisted bracts, strongly compressed dorsally mericarps, filiform median and lateral ribs, winged marginal ribs, numerous vittae in each furrow and commissure, but can also be easily distinguished from members of Ligusticopsis by its hispid fruit and linear-lanceolate bracteoles. Molecular phylogenetic analyses based on the single-copy protein-coding sequences (CDS) of plastomes and internal transcribed space (ITS) region showed that Peucedanumpubescens nested in the genus Ligusticopsis. As both morphological and molecular data supported the inclusion of Peucedanumpubescens within Ligusticopsis, the species is here transferred and the new combination, Ligusticopsispubescens (Hand.-Mazz.) J.J.Deng, C.K.Liu & X.J.He, made.

[Effects of canopy spectral composition on growth and photosynthetic fluorescence characteristics of Pinus koraiensis and Quercus mongolica seedlings]. / å† å±‚å ‰è°±ç»„æˆå¯¹çº¢æ¾å’Œè’™å¤æ Žå¹¼è‹—ç”Ÿé•¿å’Œå ‰åˆè§å ‰ç‰¹æ€§çš„å½±å“.

We investigated the responses of leaf and individual traits, growth, and fluorescence characteristics of seedlings of two dominant species of broad-leaved Korean pine forest in Changbai Mountain, i.e., Pinus koraiensis and Quercus mongolica, to five spectrum-attenuation treatments. Results showed that the architecture and growth of P. koraiensis and Q. mongolica seedlings were mainly regulated by ultraviolet B (UV-B) radiation and blue light. The attenuation of blue light significantly decreased leaf area ratio and relative growth rate of two species. The attenuation of UV-B radiation significantly increased leaf area ratio and relative growth rate of P. koraiensis seedlings by 41.8% and 47.7%, respectively, and significantly decreased plant height, total leaf area, and biomass accumulation of Q. mongolica seedlings. Furthermore, the attenuation of UV-B radiation significantly decreased the fluorescence regulation ability of two tree seedlings, with lower magnitude of P. koraiensis than Q. mongolica. The non-regulatory quantum yield (ΦNO) of P. koraiensis increased by 31.6%, and the ΦNPQ/ΦNO ratio, an indicator for photosynthetic fluorescence regulation ability, decreased by 37.5%. These results suggested that those two species might have evolved adaptation strategies to changes in canopy spectral compositions of their respective habitats. Q. mongolica seedlings tended to improve light capture ability through rapid morphological responses, while P. koraiensis seedlings preferred to increase carbon assimilation efficiency by adjusting fluorescence characteristics.

Accounting of gross ecosystem product in Fuzhou City,China.

Carrying out the accounting of ecological system gross ecosystem product (GEP) is a necessary measure to promote the construction of ecological civilization system and an important measure for the integration of ecological benefits into the economic and social development evaluation system. Taking Fuzhou City as the object, we constructed an ecosystem value accounting system with the characteristics of "mountain, sea, and city" to calculate the GEP of Fuzhou City in 2015 and 2018, and compared them from the perspective of temporal and spatial changes. The results showed that the GEP of Fuzhou in 2015 and 2018 was 920.592 and 1047.242 billion yuan, respectively. The per capita GEP in 2015 and 2018 was 130200 and 143900 yuan, the supply service value of ecological products was 94.181 and 110.261 billion yuan, the value of ecological regulation was 636.42 and 598.851 billion yuan, and the service value of ecological culture was 189.991 and 338.13 billion yuan, respectively. Compared with that in 2015, the GEP of Fuzhou City in 2018 increased by 126.65 billion yuan, with an increase of 13.8%, which was mainly due to the increases in ecological product supply service and cultural service. The value of ecological regulation services decreased by 37.569 billion yuan, with a reduction of 5.9%, which was mainly due to the decreases in climate regulation, water flow regulation and water purification services. Fuzhou City took the lead in exploring the establishment of accounting system with the characteristics of "mountain, sea, and city", which could provide a "Fuzhou model" for the accounting work of other cities in Fujian Province and other regions in China, and promote the establishment of a long-term mechanism for realizing the value of ecological products.

[Effects of different land use patterns on the soil microbial community diversity in montane region of eastern Liaoning Province, China.] / ä¸åŒåœŸåœ°åˆ©ç”¨æ¨¡å¼å¯¹è¾½ä¸œå±±åŒºåœŸå£¤å¾®ç”Ÿç‰©ç¾¤è½å¤šæ ·æ€§çš„å½±å“.

An experiment was conducted to examine the differences of soil microbial diversity across different land use patterns in montane region of eastern Liaoning Province, China. The relationships between soil physicochemical properties and soil microbial diversity in five different land use types, including Quercus mongolic forest, shrubland, Larix gmelinii plantation, Pinus koraiensis plantation, and Zea mays cropland were analyzed by Biolog-Eco method. The results showed that both soil total C and N contents were the highest in the Q. mongolica forest, which were 57.74 and 4.40 g·kg-1, followed by shrubland, but only 17.46 and 1.31 g·kg-1 in the Z. mays cropland, respectively. There were significant differences in microbial utilization rate of different land use types. The carbon utilization capacity by soil microbial communities was following the order of Q. mongolica forest > shrubland > L. gmelinii plantation > P. koraiensis plantation > Z. mays cropland, indicating that soil microbial metabolism and activity in Z. mays cropland were the lowest. The Shannon diversity index (2.997), Simpson diversity index (0.942) and McIntosh diversity index (5.256) of soil microbial community in the Z. mays cropland were significantly lower than those in other ecosystems. The average absorbance value (AWCD) was associated with Simpson diversity index and McIntosh diversity index. Esters, alcohols and amines were the primary carbon sources for the differentiation, which might be due to a joint action of many factors such as litter, soil nutrients, and specific soil microorganisms. The soil nutrient and soil microbial community diversity in forest land after reclamation sharply decreased, causing the loss of soil fertility and productivity. The region should keep the Q. mongolica forest, which could help restore soil fertility.