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Impatiens nushanensis (Balsaminaceae), a new species from Yunnan, China
No full textImpatiens nushanensis (Balsaminaceae), a new species from Yunnan, China, is described and illustrated here. The new species is morphologically most similar to I. purpurea, but differs by having two pairs of lateral sepals and deep purple lower lobe of the lateral united petal with an acuminate and ribbon-like apex. Furthermore, phylogenetic analysis based on molecular data also support the recognization of this new species
Conservation status of threatened land plants in China and priority sites for better conservation targets: distribution patterns and conservation gap analysis
No full textThere are about 10% of the world's land plants in China, of which 11% are threatened species. Here, we used China as a proxy to identify hotspots of threatened species, evaluate the effectiveness of current conservation networks and assess the correlations between distribution patterns of different groups. We built the most complete database of 3,881 species of threatened land plants in China (TLPCs) to date, based on 43,710 occurrence records at county level. A total of 467 counties identified as hotspot by species richness, complementarity, and weighted algorithms, mostly confined to the mountainous areas in southern China, which account for 15.58% of land area, however, hold 95.34% of the total TLPCs. The correlation analysis revealed weak to moderate relationship between the distribution patterns of three groups (bryophytes, ferns, and gymnosperms) and angiosperms of TLPCs. We found 86.34%, 84.05% and 95.77% of TLPCs protected by NNRs, PNRs and NRs [nature reserves, including both national NRs (NNRs) and provincial NRs (PNRs)], respectively. Besides, there were 41.11% and 18.84% of hotspots identified as conservation gaps of NNRs and NRs, respectively. In conclusion, the NNRs do not play a more dominant role in conserving TLPCs diversity in comparison to PNRs. We proposed that conservation planning need to be established in the periphery of Yunnan-Guizhou Plateau due to a large number of hotspots and conservation gaps located in this area. Since a large proportion of unprotected TLPCs are critically endangered and narrow-ranged species, it is urgent to set priorities for their conservation in the nearest future
Gastrochilus xizangensis (Aeridinae, Vandeae, Orchidaceae), a new species from Xizang, China
No full textGastrochilus xizangensis, a new species of Gastrochilus from Xizang, China, is described and illustrated based on morphological characters and DNA evidence. Morphological comparisons indicate that the new species G. xizangensis is highly similar to G. raraensis , G. deltoglossus and G. setosus, from which it differs by its lip with two ridges ranging from spur into central part, ridges with dense short hairs, lip margins membranous and white, sparsely with short hairs
Exogenous application of methyl jasmonate affects the emissions of volatile compounds in lavender (Lavandula angustifolia)
No full textThe plant hormone, methyl jasmonate (MeJA), is an orthodox elicitor of secondary metabolites, including terpenoids. Lavandula angustifolia is an important aromatic plant generating, yet few studies have been performed to evaluate the function of MeJA on the biosynthesis of terpenoids in lavender. Five treatments (with concentrations of 0, 0.4, 4, 8, and 16 mM) were set, and the physiological indicators of each group were determined after 0, 6, 12, 24, 48, and 72 h. The results illustrate that (1) MeJA could affect the diurnal rhythm of the emission of volatiles and MeJA acted in a dose-dependent and time-dependent manner; (2) 8 mM MeJA treatment increased the total content of the volatiles, and the contents of monoterpenoids and sesquiterpenoids were up-regulated 0.46- and 0.74- fold than the control at 24 h and 12 h, respectively; (3) after MeJA treatment, all the genes expression analyzed changed to varying degrees, of which 3-carene synthase (La3CARS) gene changed most significantly (7.66- to 38.02- fold than the control); (4) MeJA application was associated with a rise in glandular trichome density. The positive effects of MeJA indicate that the exogenous application of MeJA could be a beneficial mean for studies on the biosynthesis of terpenoids in lavender
The plastid-encoded protein Orf2971 is required for protein translocation and chloroplast quality control
No full textPhotosynthesis and the biosynthesis of many important metabolites occur in chloroplasts. In these semi-autonomous organelles, the chloroplast genome encodes approximately 100 proteins. The remaining chloroplast proteins, close to 3,000, are encoded by nuclear genes whose products are translated in the cytosol and imported into chloroplasts. However, there is still no consensus on the composition of the protein import machinery including its motor proteins and on how newly imported chloroplast proteins are refolded. In this study, we have examined the function of orf2971, the largest chloroplast gene of Chlamydomonas reinhardtii. The depletion of Orf2971 causes the accumulation of protein precursors, partial proteolysis and aggregation of proteins, increased expression of chaperones and proteases, and autophagy. Orf2971 interacts with the TIC (translocon at the inner chloroplast envelope) complex, catalyzes ATP (adenosine triphosphate) hydrolysis, and associates with chaperones and chaperonins. We propose that Orf2971 is intimately connected to the protein import machinery and plays an important role in chloroplast protein quality control. Repression of Orf2971 induces accumulation of chloroplast precursor proteins and impaired chloroplast quality indicating that Orf2971 is required for protein import and chloroplast quality control
Alginate oligosaccharide improves resistance to postharvest decay and quality in kiwifruit (Actinidia deliciosa cv. Bruno)
No full textKiwifruit is an extremely perishable fruit; postharvest disease and senescence during storage can reduce the fruit quality, resulting in economic loss. Considerable research effort has focused on identifying safe and cost-effective ways to preserve fresh kiwifruit. To this end, the present study investigated the effects of alginate oligosaccharide (AOS) soaking treatment on postharvest quality and disease in the 'Bruno' variety of kiwifruit. The involved physiological mechanisms were further explored. The results showed that AOS did not inhibit the growth of Botrytis cinerea in vitro, the causal agent of gray mold in kiwifruit, but reduced the incidence of gray mold and diameter of lesions of kiwifruit during storage. Kiwifruit treated with SO mg . L-1 AOS showed a higher degree of firmness and lower soluble solid content than control fruit treated with distilled water. Moreover, AOS treatment inhibited the activity of polygalacturonase and pectinesterase, while enhancing the activity of polyphenoloxidase, L-phenylalanine ammonia lyase and beta-1,3-glucanase related to pathogen defense, and also improved total antioxidant capacity determined by the DPPH, FRAP, and ABTS methods in kiwifruit. These results indicate that SO mg . L-1 AOS can confer disease resistance in kiwifruit during storage
Confirmation of the taxonomic status of Lysionotus pterocaulis (Gesneriaceae) supported by morphological and molecular evidence
No full textLysionotus serratus var. pterocaulis C.Y.Wu ex W.T.Wang was initially described as a variety, but was treated as an independent species L. pterocaulis (C.Y.Wu ex W.T.Wang) H.W.Li in 1991, although this status was not always retained by subsequent authors. Our observation of wild living plants demonstrated that L. pterocaulis is obviously distinguishable from L. serratus D.Don through its longitudinally angled stems with wings, yellowish to white corolla, tubular to slightly funnelform tube, and linear-lanceolate calyx lobes. Furthermore, the molecular phylogenetic analyses indicated that L. pterocaulis is not clustered with L. serratus but embedded in a different lineage. Therefore, L. pterocaulis is confirmed to be an independent species and an updated description is provided
A mutation in Arabidopsis SAL1 alters its in vitro activity against IP3 and delays developmental leaf senescence in association with lower ROS levels
No full textKey message Our manuscript is the first to find a link between activity of SAL1/OLD101 against IP3 and plant leaf senescence regulation and ROS levels assigning a potential biological role for IP3. Leaf senescence is a genetically programmed process that limits the longevity of a leaf. We identified and analyzed the recessive Arabidopsis stay-green mutation onset of leaf death 101 (old101). Developmental leaf longevity is extended in old101 plants, which coincided with higher peroxidase activity and decreased H2O2 levels in young 10-day-old, but not 25-day-old plants. The old101 phenotype is caused by a point mutation in SAL1, which encodes a bifunctional enzyme with inositol polyphosphate-1-phosphatase and 3 ' (2 '), 5 '-bisphosphate nucleotidase activity. SAL1 activity is highly specific for its substrates 3-polyadenosine 5-phosphate (PAP) and inositol 1, 4, 5-trisphosphate (IP3), where it removes the 1-phosphate group from the IP3 second messenger. The in vitro activity of recombinant old101 protein against its substrate IP3 was 2.5-fold lower than that of wild type SAL1 protein. However, the in vitro activity of recombinant old101 mutant protein against PAP remained the same as that of the wild type SAL1 protein. The results open the possibility that the activity of SAL1 against IP3 may affect the redox balance of young seedlings and that this delays the onset of leaf senescence
Apoplastic sugar may be lost from grape berries and retrieved in pedicels
No full textIn ripening grape (Vitis sp.) berries, the combination of rapid sugar import, apoplastic phloem unloading, and water discharge via the xylem creates a potential risk for apoplastic sugar to be lost from the berries. We investigated the likelihood of such sugar loss and a possible sugar retrieval mechanism in the pedicels of different Vitis genotypes. Infusion of D-glucose-1-C-13 or L-glucose-1-C-13 to the stylar end of attached berries demonstrated that both sugars can be leached from the berries, but only the nontransport sugar L-glucose moved beyond the pedicels. No C-13 enrichment was found in peduncles and leaves. Genes encoding 10 sugar transporters were expressed in the pedicels throughout grape ripening. Using an immunofluorescence technique, we localized the sucrose transporter SUC27 to pedicel xylem parenchyma cells. These results indicate that pedicels possess the molecular machinery for sugar retrieval from the apoplast. Plasmodesmata were observed between vascular parenchyma cells in pedicels, and movement of the symplastically mobile dye carboxyfluorescein demonstrated that the symplastic connection is physiologically functional. Taken together, the chemical, molecular, and anatomical evidence gathered here supports the idea that some apoplastic sugar can be leached from grape berries and is effectively retrieved in a two-step process in the pedicels. First, sugar transporters may actively retrieve leached sugar from the xylem. Second, retrieved sugar may move symplastically to the pedicel parenchyma for local use or storage, or to the phloem for recycling back to the berry