Controlled-Release of Plant Volatiles:New Composite Materials of Porous Carbon-Citral and Their Fungicidal Activity against Exobasidium vexans

Citral(Eo)exhibits excellent fungicidal activities.However,it is difficult to maintain long-term fungicidal activity due to its strong volatility.Herein,a controlled-release strategy by using biomass-derived porous carbon(BC)was developed to overcome the drawback of Eo.New composite materials were prepared by loading Eo on tea stem porous carbon(BC@Eo),and their controlled-release fungicidal activity against Exobasidium vexans was assessed.BC with a large specific surface area of 1001.6 m2/g and mesoporous structure was fabricated through carbonization tempera-ture of 700℃.The BC@Eo materials were characterized using Fourier-transform infrared spectroscopy and X-ray powder diffraction.The results suggested that chemical and physical interactions occurred in BC@Eo.The Eo release profile suggested a biphasic pattern with an initial fast release on days 1–14 and a subsequent controlled phase on days 14–30.The in vitro cumulative release percentage of Eo from BC@Eo was 51%during one month,and this result was significantly lower than that from free Eo(cumulative release percentage of Eo of 82%in one week).The anti-fungal activities of Eo and BC@Eo against E.vexans were determined using the inhibition zone method.The results indicated that Eo and BC@Eo formed large inhibition zones of 19.66±0.79 and 21.92±0.77 mm,respectively.The influence on the hyphal structure of E.vexans was observed by scanning electron microscopy on day 30.The hyphal structure of E.vexans treated with BC@Eo was more shrunken than that treated with Eo at 30 days,suggesting that BC@Eo prolongs the fungicidal activity against E.vexans.This study demonstrated that the encapsulation of Eo in BC for developing the BC@Eo materials could be a promising strategy to inhibit volatility and maintain the fungicidal activity of Eo and provide a potential alternative for the reuse of abundant tea biomass waste resources.

Differences in taste characteristics and antioxidant properties of four substitute teas based on a targeted metabolomics approach

To investigate the differences in taste characteristics and antioxidant properties of four types of tea substitutes.After sensory review and electronic tongue indicated that the taste characteristics of the four substitute teas were sweetness,bitterness and astringency.There were a total of 136 flavonoid metabolites in 12 categories and 12 sugar metabolites were identified in the four substitute teas with ultra-performance liquid chromatography tandem-mass spectrometry metabolomics targeted detection.Flavonoids were significantly positively correlated with antioxidant properties,among them,15 were positively associated with clearing ABTS radicals and five were positively associated with clearing DPPH radicals,and sugars were significantly negatively correlated with antioxidant properties.The antioxidant properties were in the following order:TC>KD>LY>QQ.The conclusion is that significant differences in the content of flavonoids and sugar metabolites are the main reasons for the formation of the flavour characteristics and antioxidant differences of the four substitute teas.

Species Diversity of Arbuscular Mycorrhizal Fungi in the Rhizosphere of Hevea brasiliensis in Hainan Island,China

Hevea brasiliensis is one of the important economic trees with a great economic value for natural rubber production.Symbiosis between roots of H.brasiliensis and arbuscular mycorrhizal fungi(AMF)is widely recognized,and can provide a range of benefits for both of them.Hainan Island harbors is one of the largest plantations of H.brasiliensis in China,whereas the information regarding the diversity of AMF in the rhizosphere of H.brasiliensis on this island is scarce.The diversity of AMF species in the rhizosphere of rubber tree plantations in Hainan was investigated in this study.A total of 72 soil samples from the rhizosphere of H.brasiliensis RY7-33-97 were collected.These included 48 samples from plantations in 11 cities or counties that had been planted for 15–25 years,and 24 samples from a demonstrating plantation site of the China National Rubber Tree Germplasm Repository representing plantations with tree plantation ages from one to 40 year-old.Collectively,a total of 68 morphotypes of AMF,belonging to the genera of Archaeospora(1),Glomus(43),Acaulospora(18),Entrophospora(3),Scutellospora(2),and Gigaspora(1)were isolated and identified,as per morphological characteristics of spores presented in the collected soil samples.Glomus(Frequency,F=100%)and Acaulospora(F=100%)were the predominant genera,and A.mellea(F=63.9%)and A.scrobiculata(F=63.9%)were the predominant species.AMF species differed significantly among collected sites in spore density(SD,290.7–2,186.7 spores per 100 g dry soil),species richness(SR,4.3–12.3),and Shannon-Weiner index of diversity(H,1.24–2.24).SD was negatively correlated with available phosphorus level in the soil;SR was positively correlated with soil total phosphorus content;and H was positively correlated with levels of soil organic matter and total phosphorus.Similarly,SD,SR,and H were also correlated with H.brasiliensis plantation age,and an increasing trend was observed up to 40 years.These results suggest that the AMF community was complex and ubiquitous in the island plantation ecosystems of H.brasiliensis,with high species abundance and diversity.Soil factors and plantation age dramatically affected AMF diversity at species level.

Refined families of Dothideomycetes:orders and families incertae sedis in Dothideomycetes

Numerous new taxa and classifications of Dothideomycetes have been published following the last monograph of families of Dothideomycetes in 2013.A recent publication by Honsanan et al.in 2020 expanded information of families in Dothideo-mycetidae and Pleosporomycetidae with modern classifications.In this paper,we provide a refined updated document on orders and families incertae sedis of Dothideomycetes.Each family is provided with an updated description,notes,including figures to represent the morphology,a list of accepted genera,and economic and ecological significances.We also provide phylogenetic trees for each order.In this study,31 orders which consist 50 families are assigned as orders incertae sedis in Dothideomycetes,and 41 families are treated as families incertae sedis due to lack of molecular or morphological evidence.The new order,Catinellales,and four new families,Catinellaceae,Morenoinaceae Neobuelliellaceae and Thyrinulaceae are introduced.Seven genera(Neobuelliella,Pseudomicrothyrium,Flagellostrigula,Swinscowia,Macroconstrictolumina,Pseudobogoriella,and Schummia)are introduced.Seven new species(Acrospermum urticae,Bogoriella complexoluminata,Dothiorella ostryae,Dyfrolomyces distoseptatus,Macroconstrictolumina megalateralis,Patellaria microspora,and Pseu-domicrothyrium thailandicum)are introduced base on morphology and phylogeny,together with two new records/reports and five new collections from different families.Ninety new combinations are also provided in this paper.