Jiangtao Shi·Feng Wang·Yaoli Zhang

In the original publication of the article,under the section‘Materials and methods’,the fifth paragraph was not included.The paragraph is given below:

FTIR

Samples were scarped from xylem and phloem closing cambium.The FTIR spectra were measured by direct transmittance using the KBr pellet technique.Spectra were recorded using a Nicolet 360(USA)spectrometer.Spectral data between 400 and 4000 cm-1were collected averaging 40 scans at a resolution of 4 cm-1.Peak heights of absorption bands were measured by OMNIC software(version 8.0,Nicolet Instruments Corporation,USA).