of Botany,Chinese Academy Of Sciences
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Context-Dependency in Relationships Between Herbaceous Plant Leaf Traits and Abiotic Factors
No full textLeaf traits are important indicators of plants' adaptive strategy to environmental changes. It is an established fact that leaf traits are jointly regulated by climatic and edaphic factors besides genetic factors. However, the relative importance of these abiotic forces in determining the general patterns of herbaceous plant leaf traits across different climatic regions in China is far from clear. We collected 1,653 observations of 542 species of herbaceous plant leaf traits including leaf mass per area, leaf nitrogen, and leaf phosphorus from 316 sampling sites across four climatic regions. We found that the leaf mass per area in the arid region was apparently larger than the others, whereas the smallest mass-based leaf nitrogen and mass-based leaf phosphorus were found in the humid region. Increased growing season temperature and evapotranspiration consistently promoted a conservative growth strategy indicated by higher relative benefit of leaf mass per area, especially in the arid region. Solar radiation in growing season promoted an acquisitive growth strategy indicated by higher relative benefits of mass-based leaf nitrogen and phosphorus in the humid region, but opposite patterns were found in the arid region and semi-humid region. Of all the soil nutrients including soil organic matter, total nitrogen, total phosphorus, and available nitrogen, soil available nitrogen was the strongest predictor of relative benefits of leaf traits associated with a nutrient acquisitive strategy, except in the nutrient-rich semi-humid region. There was a relatively larger number of abiotic factors contributing to relative benefits of leaf traits in the arid and humid regions. We concluded that plant functionality could respond divergently to the same factor facing different habitat conditions. Moreover, the relative benefits of leaf traits tended to be more vulnerable to abiotic filtering in more stressful conditions. Our findings have important implications for understanding the context-dependency of plant functionality to environmental filtering and further improving the predictability of plant dynamics under global change
Enhancement of Photosynthetic Capacity in Spongy Mesophyll Cells in White Leaves of Actinidia kolomikta
No full textConsidering that Actinidia kolomikta bears abundant white leaves on reproductive branches during blossoming, we hypothesized that the white leaves may maintain photosynthetic capacity by adjustments of leaf anatomy and physiological regulation. To test this hypothesis, leaf anatomy, gas exchange, chlorophyll a fluorescence, and the transcriptome were examined in white leaves of A. kolomikta during flowering. The palisade and spongy mesophyll in the white leaves were thicker than those in green ones. Chloroplast development in palisade parenchyma of white leaves was abnormal, whereas spongy parenchyma of white leaves contained functional chloroplasts. The highest photosynthetic rate of white leaves was ~82% of that of green leaves over the course of the day. In addition, the maximum quantum yield of PSII (F-v/F-m) of the palisade mesophyll in white leaves was significantly lower than those of green ones, whereas F-v/F-m and quantum yield for electron transport were significantly higher in the spongy mesophyll of white leaves. Photosynthetic capacity regulation of white leaf also was attributed to upregulation or downregulation of some key genes involving in photosynthesis. Particularly, upregulation of sucrose phosphate synthase (SPS), glyeraldehyde-3-phosphate dehydrogenase (GAPDH) and RuBisCO activase (RCA) in white leaf suggested that they might be involved in regulation of sugar synthesis and Rubisco activase in maintaining photosynthetic capacity of white leaf. Conclusions: white leaves contained a thicker mesophyll layer and higher photosynthetic activity in spongy parenchyma cells than those of palisade parenchyma cells. This may compensate for the lowered photosynthetic capacity of the palisade mesophyll. Consequently, white leaves maintain a relatively high photosynthetic capacity in the field
Phylogeny and taxonomy of Cinnamomum (Lauraceae)
No full textTaxonomy of Cinnamomum Schaeff. of Lauraceae remains problematic because recent phylogenetic studies have suggested that this genus is not monophyletic. In this study, we assembled three sequence matrices including plastomes (datamatrix I), nrITS sequences alone (datamatrix II), and nrITS plus plastid psbA-trnH sequences (datamatrix III) of the Cinnamomum-Ocotea complex of Lauraceae and conducted a new phylogenetic study with thusfar the most extensive species sampling of the Cinnamomum-Ocotea group. We determined that the Old World Cinnamomum is diphyletic: sect. Camphora Meisn. is sister to Sassafras J.Presl and sect. Cinnamomum is sister to the African Kuloa Trofimov & Rohwer. A recent study indicated that characters of leaf micromorphological anatomy can define the two clades: one possessing reticulate periclinal and the other having non-reticulate periclinal walls. As result, we divided the genus Cinnamomum of Lauraceae into two genera, i.e., Cinnamomum and Camphora Fabr. The generic name Cinnamomum is retained for those species mainly having reticulate periclinal epidermal cell walls, inconspicuous non-perulate terminal buds and usually tripliveined leaves; the oldest generic name, Camphora, is applied to the second group which contains those species mainly possessing non-reticulate periclinal epidermal cell walls, prominent perulate terminal buds and pinnately-veined leaves. A census of the species and their type specimens listed under Cinnamomum in Asia resulted in the transfer of 18 species to Camphora, including 15 new combinations
Dam impoundment elevates soil phosphorus and some trace elements in reservoir hydro-fluctuation belts
No full textTo examine the role of dam impoundment in elevating the levels of soil-associated phosphorus (P) and trace elements in reservoir hydro-fluctuation belts (RHB), soil samples in RHB and adjacent uplands (non-flooded area, NFA) in the Three Gorges Reservoir, China, were collected and analyzed. Concentrations of available P, copper (Cu), chromium (Cr), and zinc (Zn) were found to be higher in RHB than in NFA (p .05). The elevated levels of Cu, Cr, and Zn in RHB were probably associated the repeated drying-rewetting cycles created by the dam impoundment. The 95th percentile of the single-factor pollution index and geo-accumulation index in RHB were 1.29 and -0.21 for Zn, 3.21 and 1.15 for Cu and 3.37 and 1.17 for Cr. Elevated pollution potential of soil-associated Zn, Cu, and Cr existed in RHB of the Three Gorges Reservoir. Core Ideas Dam impoundments decreased total C and total N concentrations in reservoir flooded soils. Cu, Zn, and Cr concentrated in the reservoir flood areas. Variability of Cu, Zn, and Cr was captured in single-factor pollution index and geo-accumulation inde
Linking leaf traits to the temporal stability of above- and belowground productivity under global change and land use scenarios in a semi-arid grassland of Inner Mongolia (vol 818, 151858, 2022)
No full textGlobal patterns in mycorrhizal mediation of soil carbon storage, stability, and nitrogen demand: A meta-analysis
No full textUnderstanding what controls the soil organic matter (SOM) storage and its stability is important to predict how SOM will respond to environmental changes. The role of mycorrhizal fungi in mediating soil carbon (C) and nitrogen (N) cycling is increasingly recognized. However, how mycorrhizal fungi could affect C distribution and N demand of different soil fractions is largely unknown. Here, we compiled a global dataset of C and N concentrations in different SOM fractions from arbuscular mycorrhizal (AM) and ectomycorrhizal (EcM) dominated ecosystems, covering major biomes, including tropical forest, temperate forest, boreal forest, and grassland. Based on this dataset, we evaluated the effect of mycorrhiza symbiosis on C storage and C: N stoichiometry of SOM fractions with different stability. We found that for both topsoil and subsoil, bulk soil C storage and C: N ratio in EcM ecosystems were higher than those in AM ecosystems, and a similar pattern was also observed in the particulate organic matter fraction (POM). However, the C storage in the mineral-associated organic matter fraction (MAOM) was not different between AM and EcM ecosystems. Moreover, with the increase in bulk soil C concentration, the C storage in topsoil MAOM reached a stable level in EcM ecosystems but continued to increase in AM ecosystems. With the increase in soil N concentration, bulk soil C storage of EcM ecosystems increased more rapidly than that of AM ecosystems, which was mainly driven by the increase in POM C storage. Our study highlights that soil C storage and relative stability are different between AM and EcM ecosystems. Although EcM ecosystems have a higher soil C storage and lower N demand per unit soil C, most C is distributed in relative labile POM. Therefore, SOM in EcM ecosystems could be more susceptible to disturbances caused by land use and climate changes
Identification of leucine-rich repeat receptor-like protein kinase (LRR-RLK) genes in paper mulberry and their potential roles in response to cold stress
No full textLeucine-rich repeat receptor-like protein kinases (LRR-RLKs) represent the largest group of receptor-like kinases in plants, which have been previously reported to play vital roles in plant growth, development, stress adaptation and signal transduction. However, there is lack of comprehensive analysis of this family in paper mulberry (Broussonetia papyrifera). In the present investigation, a genome-wide scan revealed the presence of 236 LRR-RLK genes in paper mulberry, which were classified into 21 subgroups based on the maximum-likelihood phylogenetic tree. Gene structure and conserved motif analyses suggested genes in the same subgroup had highly consistent motif composition and intron/exon arrangement, but were divergent among subgroups. Total of 223 BpLRR-RLK genes were unevenly distributed across all 13 chromosomes, while the remaining 13 genes were localized to the unassembled scaffolds. Tandem and segmental duplications were confirmed to contribute to the expansion of BpLRR-RLK family. Further Ka/Ks showed that the duplicated BpLRR-RLKs had experienced strong purifying selection. The global promoter composition, transcriptome and phosphorylation analysis indicated that many of BpLRR-RLKs were associated with plant development, biotic and abiotic stress response, especially for cold stress. Furthermore, protein-protein interaction network was constructed for the 127 and 14 BpLRR-RLKs that responded to cold stress at the transcriptomics and phosphorylation level, respectively. All these findings will facilitate the studies on the evolutionary history of the LRR-RLK gene family in paper mulberry, also establish a solid foundation to further explore the potential functions of LRR-RLK genes in higher plants, particularly with regards to cold resistance
Plastid and nuclear phylogenomic incongruences and biogeographic implications of Magnolia s.l. (Magnoliaceae)
No full textMagnoliaceae, an assemblage of early diverged angiosperms, comprises two subfamilies, speciose Magnolioideae with approximately 300 species in varying numbers of genera and monogeneric Liriodendroideae with two species in Liriodendron L. This family occupies a pivotal phylogenetic position with important insights into the diversification of early angiosperms, and shows intercontinentally disjunct distribution patterns between eastern Asia and the Americas. Widespread morphological homogeneity and slow substitution rates in Magnolia L. s.l. resulted in poorly supported phylogenetic relationships based on morphology or molecular evidence, which hampers our understanding of the genus' temporal and spacial evolution. Here, based on the newly generated genome skimming data for 48 Magnolia s.l. species, we produced robust Magnolia phylogenies using genome-wide markers from both plastid genomes and single nucleotide polymorphism data. Contrasting the plastid and nuclear phylogenies revealed extensive cytonuclear conflicts in both shallow and deep relationships. ABBA-BABA and PhyloNet analyses suggested hybridization occurred within sect. Yulania, and sect. Magnolia, which is in concordance with the ploidy level of the species in these two sections. Divergence time estimates and biogeographic reconstruction indicated that the timing of the three tropical Magnolia disjunctions coincided with the mid-Eocene cooling climate and/or late Eocene climate deterioration, and two temperate disjunctions occurred much later, possibly during the warm periods of the Miocene, hence supporting the boreotropical flora concept of Magnolia s.l
Jujube metabolome selection determined the edible properties acquired during domestication
No full textPlants supply both food and medicinal compounds, which are ascribed to diverse metabolites produced by plants. However, studies on domestication-driven changes in the metabolome and genetic basis of bioactive molecules in perennial fruit trees are generally lacking. Here, we conducted multidimensional analyses revealing a singular domestication event involving the genomic and metabolomic selection of jujube trees (Ziziphus jujuba Mill.). The genomic selection for domesticated genes was highly enriched in metabolic pathways, including carbohydrates and specialized metabolism. Domesticated metabolome profiling indicated that 187 metabolites exhibited significant divergence as a result of directional selection. Malic acid was directly selected during domestication, and the simultaneous selection of specialized metabolites, including triterpenes, consequently lead to edible properties. Cyclopeptide alkaloids (CPAs) were specifically targeted for the divergence between dry and fresh cultivars. We identified 1080 significantly associated loci for 986 metabolites. Among them, 15 triterpenes were directly selected at six major loci, allowing the identification of a homologous cluster containing seven 2,3-oxidosqualene cyclases (OSCs). An OSC gene was found to contribute to the reduction in the content of triterpenes during domestication. The complete pathway for synthesizing ursolic acid was dissected by integration of the metabolome and transcriptome. Additionally, an N-methyltransferase involved in the biosynthesis of CPA and responsible for inter-cultivar content variation was identified. The present study promotes our understanding of the selection process of the global metabolome subsequent to fruit tree domestication and facilitates the genetic manipulation of specialized metabolites to enhance their edible traits