ABSTRACT
Phoebe chekiangensis, as one original species of 'Nanmu with golden tint', harbors limited natural distribution regions, which is recognized as a vulnerable species in China under nationwide protection. Under the background of global climate change, it is of scientific significance to study the community structure and diversity of the natural populations of P. chekiangensis. In this study, community structure, species diversity and the phenotypic variation leaf traits in the communities of thirteen residue natural populations were analyzed. A total of 235 vascular species from 162 genera and 87 families were found in 16 plots within 13 natural populations, including 221 seed plants from 151 genera and 79 families. The species diversity in tree layer of community in Kaihua, Zhejiang and Linan, Zhejiang was significantly lower than that of other communities due to severe disturbance, while intermediate disturbance promoted the species diversity of shrub layer in community in Jianning, Fujian, and slight disturbance was beneficial to natural regeneration of P. chekiangensis. Foliage phenotype was important for species identification within Phoebe genus. There existed substantial variation in foliage phenotypic diversity among and within populations. The mean coefficient of variation was 17.2%, ranging from 10.4% to 27.5%. The variation was greater among populations (53.6%) than within populations (17.0%). Mean phenotypic differentiation coefficient was 75.1% among populations, indicating that the variance among populations was the main source for the phenotypic variation of the species. Results from the cluster analysis indicated that the 13 natural populations were divided into two distinct groups based on the Euclidean distance (10 cm), with stochastic variation.
Subject(s)
Biodiversity , Genetic Variation , Lauraceae/genetics , Phenotype , China , Climate Change , Plant LeavesABSTRACT
The sodium chloride (NaCl) salt has been reported to be associated with glucose metabolism. However, the effect of it on non-invasive detection of blood glucose using near-infrared spectroscopy is still an open question. The aim of this study was to investigate this affection through transform background correction analysis two-dimensional (2D) correlation synchronous spectrum and the partial least-squares (PLS) regression. First, the transmittances of glucose aqueous solutions with different NaCl content are collected and the pure water and NaCl aqueous solution are measured as the background. Results show that, the dissolving of NaCl in water changes the amplitude and position of the absorption peak of water. There are two negative peaks in 1 400 and 1 500~1 700 nm corrected spectra of NaCl aqueous obviously and the amplitude of peaks associated with NaCl concentration. That's because NaCl affect the molecular binding and vibration of water. Then the glucose aqueous solutions without NaCl and with NaCl are corrected by the spectra of pure water and NaCl aqueous solution, respectively. So we get the conclusion that NaCl also affect the combination of glucose and water molecules. And the two-dimensional correlation spectroscopy analysis is performed under the perturbation of glucose concentration. The slice spectra of synchronous correlation spectra show that, the adding of NaCl weakens the spectral variation due to glucose concentration change in the wavelength of 1 400 and 1 520~1 700 nm. Finally, the partial least square (PLS) regression models were built to quantitatively conduct the influence of NaCl on glucose prediction accuracy. Comparison results showed that, NaCl molecule in aqueous solution will deteriorate the model accuracy, where root mean square error of prediction increases with the NaCl content; the mean difference of predicted glucose concentration between models based on glucose aqueous solutions with NaCl and without NaCl, is linear with NaCl concentration in samples.
