Identification of phytoplasmas on poamceous fruit tree species in Hungary

In Hungary local occurrence of Apple proliferation disease(AP) on apple was described for the first time in the early sixties, since that time the disease has been found in different part of the country based on the results of biological indexing. The first suspicious sign for the presence of Pear decline disease (PD) in Hungarian pear orchard was indicated in the early 70s, but at the time there were no adequate laboratory techniques for identification. The aim of the present study was the molecular identification of phytoplasmas in symptom-showing apple trees, as well as confirmation of the occurrence of PD phytoplasma in symptomatic pear trees, testing them in parallel also on woody indicators. Symptom showing trees, indicating possible phytoplasma infection, were sampled in different growing regions in 2002 for indexing. AP was detected on Golden Delicious using root and double grafting. Typical symptoms of PD did not appear on root or double grafted Pyrus communis cv. Comice. Nucleic acids were prepared from all samples by chloroform/phenol extraction from fresh, frozen or dry phloem tissue of leaves and young branches. Nested PCR procedures were employed with different sets of primers to amplify phytoplasma 16SrDNA, or 16SrDNA plus spacer region. The identity of PCR products was confirmed by RFLP as 16SrX-A (AP) and 16SrX-C (PD). It was concluded that molecular methods were useful for identification of phytoplasmas in several of the symptomatic orchard trees of apple and pear respectively. Both greenhouse indexing and nested PCR/RFLP were suitable for detection and identification of AP from bearing trees and the phytoplasma was identified by molecular methods also in the inoculated AP indicators. PD could not be detected in greenhouse indexing

The roles of lithium-philic giant nitrogen-doped graphene in protecting micron-sized silicon anode from fading

A stable Si-based anode with a high initial coulombic efficiency (ICE) for lithium-ion batteries (LIB) is critical for energy storage. In the present paper, a new scalable method is adopted in combination with giant nitrogen-doped graphene and micron-size electrode materials. We first synthesize a new type of freestanding LIB anode composed of micron-sized Si (mSi) particles wrapped by giant nitrogen-doped graphene (mSi@GNG) film. High ICE (>85%) and long cycle life (more than 80 cycles) are obtained. In the mSi@GNG composite, preferential formation of a stable solid electrolyte interphase (SEI) on the surface of graphene sheets is achieved. The formation and components of SEI are identified for the first time by using UV-resonance Raman spectroscopy and Raman mapping, which will revive the study of formation and evolution of SEI by Raman. New mechanism is proposed that the giant graphene sheets protect the mSi particles from over-lithiation and fracture. Such a simple and scalable method may also be applied to other anode systems to boost their energy and power densities for LIB