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Porcine interleukin-6 gene and CpG sequences were used as immunoadjuvants to enhance the immune responses of newborn piglets to Pseudorabies attenuated vaccine (PAV). The titer of specific antibodies to PAV, the proliferation of lymphocytes and induced IL-2 activities were all examined to identify the immune response of the piglets. The results showed that the immune responses with CpG ODN and porcine interleukin-6 gene were significantly stronger than routine immunities. The data suggests that porcine IL-6 and CpG motifs could be employed as effective immunoadjuvants to raise the humoral and cellular responses of newborn piglets to Pseudorabies attenuated vaccine. [ABSTRACT FROM AUTHOR]

The leaves of many plants are red during particular stages of their lives, but the adaptive significance of leaf colouration is not yet clearly understood. In order to reveal whether anthocyanins play a similar role (i.e. antioxidants) in different seasonal contexts, this study investigated species with red young leaves in the subtropical forest of Dinghushan biosphere reserve (South China) during summer and winter and compared group leaf characteristics between the two seasons. Of 62 total species, 33 exhibited red young leaves in summer only, 6 in winter only, and 23 in both seasons. The anthocyanins extracted from most of these species had an absorption peak at ~530 nm. Frequency distribution analysis showed that the species containing anthocyanins at levels ranging from 0.02 to 0.04 μmol cm−2 occurred most frequently in summer or winter. Based on conditional grouping of the species, no significant variation was observed in the average anthocyanin contents and antioxidant abilities between summer and winter; the flavonoid content in summer was 2-fold that in winter, whereas the anthocyanin:flavonoid ratio in summer was only half that in winter. Moreover, a positive correlation between anthocyanins and flavonoids was found in summer. Therefore, it is less likely for anthocyanins to serve as antioxidants in summer than winter, because such a function in summer leaves is readily replaced by other flavonoids. [ABSTRACT FROM AUTHOR]

To reveal effects of elevated atmospheric CO2 on tolerance to the herbicide glyphosate in the populations of goosegrass (Eleusine indica) known to have resistance to this herbicide, two biotypes of goosegrass, a resistant (R) and a susceptible (S) biotype, were analyzed after exposed to ambient (400 μmol mol-1) and elevated CO2 (800 μmol mol-1) for 25 d. The results showed that elevated CO2 had little effect on growth of both biotypes. At elevated CO2, shoot biomass of R biotype was statistically lower than of S biotype (P<0.5). The dose-response analysis showed that glyphosate tolerance was reduced by 60% in R biotype exposed to elevated Co2 while it was slightly increased in S biotype. Elevated Co2 also had more adverse effects on photosynthetic capacity of R biotype than S biotype. As a result, maximum rate of net photosynthesis (Amax) and carboxylation efficiency (CE) under elevated CO2 in R biotype were significantly lower than in S biotype (P<0.5). These results indicate that elevated atmospheric Co2 can lead to a compromise in glyphosate tolerance of R biotype associated with poor photosynthetic characteristics, and thus will affect weed management involved with herbicide resistance in prospective agricultural systems. © 2015 Friends Science Publishers [ABSTRACT FROM AUTHOR]

Coumarin is an allelochemical that is widely present in the plant kingdom and has great potential for weed control. However, its mechanisms of action remain largely unknown. This study employed metabolomic and transcriptomic analyses along with evaluations of amino acid profiles and related physiological indicators to investigate how coumarin inhibits the germination and seedling growth of Eleusine indica by modifying metabolic pathways. At 72 h of germination at 50 and 100 mg L−1 coumarin, E. indica had lower levels of soluble sugar and activities of amylases and higher levels of starch, O 2 −, H 2 O 2 , auxin (IAA) and abscisic acid (ABA) compared to the control. Metabolomic analysis demonstrated that coumarin treatments had a significant impact on the pathways associated with amino acid metabolism and transport and aminoacyl-tRNA biosynthesis. Exposure to coumarin induced significant alterations in the levels of 19 amino acids, with a decrease in 15 of them, including Met, Leu and γ-aminobutyric acid (GABA). Additionally, transcriptomic analysis showed that coumarin significantly disrupted several essential biological processes, including protein translation, secondary metabolite synthesis, and hormone signal transduction. The decrease in TCA cycle metabolite (cis-aconitate, 2-oxoglutarate, and malate) contents was associated with the suppression of transcription for related enzymes. Our findings indicate that the inhibition of germination and growth in E. indica by coumarin involves the suppression of starch conversion to sugars, modification of the amino acid profile, interference of hormone signalling and the induction of oxidative stress. The TCA cycle appears to be one of the most essential pathways affected by coumarin. • The mechanisms of coumarin to inhibit seed germination were investigated in Eleusine indica. • Seed germination of Eleusine indica were sensitive to coumarin. • Exposure to coumarin induced significant alteration in the amino acid profile. • The metabolites and genes related to the TCA cycle was dramatically affected by coumarin. [ABSTRACT FROM AUTHOR]

The successful development of photosynthetic organs is the basis of plant growth and community development. To reveal photo-acclimation to high irradiance in tree species during the course of leaf development and plant succession of subtropical forests, photosynthetic efficiency and photoprotective compounds were analyzed in young and mature leaves of three mid-successional tree species ( Castanopsis fissa , Castanopsis chinensis and Schima superba ) and three late-successional tree species ( Machilus chinensis , Cryptocarya chinensis and Cryptocarya concinna ), grown in 100% full sunlight (FL) or 30% of FL (low light, LL). Young leaves of the two species groups exhibited lower chlorophyll (Chl) content, Rubisco content, net photosynthetic rate ( P n ), carboxylation efficiency ( CE ), effective photochemical yield ( Φ PSII ), photorespiratory electron flow ( J O ), but higher dark respiration ( R d ), and ratios of carotenoids/chlorophylls (Car/Chl), anthocyanins/chlorophylls (Anth/Chl), flavonoids/chlorophylls (Flav/Chl), phenols/chlorophylls (Phen/Chl) and total antioxidant capacity/chlorophylls (TAC/Chl) than those of mature leaves, regardless of growth irradiance. Young leaves of both species groups demonstrated a higher flexibility of Anth/Chl, Flav/Chl, Phen/Chl and TAC/Chl in response to different light conditions than mature leaves. Flav/Chl in young leaves of late-successional group was remarkably higher than that of mid-successional group under the same light conditions. There was a negative correlation between antioxidant-dependent photoprotective potential and photosynthetic efficiency in young and mature leaves of the six tree species grown under either FL or LL. Our results explain partial mechanisms that lie behind the replacement of communities in subtropical forests: highly integrated photoprotective potential allows young leaves of shade-tolerant late-successional species to develop smoothly into mature organs under high irradiance. [ABSTRACT FROM AUTHOR]

The abundance of phenolic compounds (including anthocyanins) in leaves is associated with photosynthetic performance, but the regulatory mechanism is unclear. Schima superba Gardn. et Champ. and Cryptocarya concinna Hance. which exhibit distinct anthocyanin accumulation patterns, are dominant tree species in the early- and late-successional stages, respectively, of subtropical forests in China. RNA-seq and analyses of phenolic concentrations, antioxidant capacity and photosynthetic characteristics were performed on young and mature leaves of these two species under contrasting light conditions. The high-light-acclimated young leaves of S. superba and C. concinna and low-light-acclimated young leaves of C. concinna were red. These red leaves had higher ratios of electron transport rate to gross photosynthesis (ETR: P gross) and total antioxidant capacity to chlorophyll (TAC:Chl) than did the green leaves, regardless of light conditions. In addition, the red leaves had a higher expression level of the UDP-glucose:flavonoid 3-O-glucosyltransferase (UFGT) gene than did the green leaves, irrespective of light conditions. Total antioxidant capacity was positively correlated with flavonoid content in C. concinna leaves and with total phenolic content in leaves of both species under both high and low light. Consistent with the measurements of photosynthetic performance and flavonoids:Chl ratio, photosynthesis-related genes were extensively downregulated and flavonoid-pathway-related genes were extensively upregulated in young leaves relative to mature leaves. Under high and low light, both non-photochemical quenching and TAC:Chl, which serve as different types of photoprotective tools, were enhanced in young leaves of S. superba, whereas only TAC:Chl was enhanced in young leaves of C. concinna. Our results indicate that the biosynthesis of phenolic compounds in young leaves is likely enhanced by an imbalance between photosynthetic electron supply and demand and that flavonoids play a larger role in meditating photoprotection in late-successional species than in early-successional ones. [ABSTRACT FROM AUTHOR]

Temperatures are expected to fluctuate widely under climate change but little is known about how extreme temperatures might affect the physiology and performance of invasive compared to native plant species. In this study, we evaluated the effects of high (40/35°C) and low (10/5°C) temperature regimes on the growth and photosynthesis of the invasive Asteraceae species Bidens alba and its native congener B. biternata using a growth chamber experiment. Results showed that invasive B. alba had significantly greater total biomass and relative growth rate, accompanied by higher net photosynthetic rate (Pn), than native B. biternata at both low and high temperature extremes. The reduction in Pn for B. alba was mainly caused by stomatal limitations, but for B. biternata it was caused by non-stomatal factors, indicating that greater damage to physiological processes may occur in native B. biternata under both low and high temperature stress. Higher cyclic electron flow around photosystem I in invasive B. alba than in native B. biternata under extreme temperatures might alleviate the negative effect of temperature extremes to photosynthetic and thus promote its photosynthetic efficiency. To conclude, the invasive B. alba has both greater cold and heat tolerance than its native congener B. biternata, suggesting that the invader may outperform native species under future extreme temperature conditions. [ABSTRACT FROM AUTHOR]