Capacitance Characteristics of Pinus densata, Pinus tabuliformis, Pinus yunnanensis and the hybrids Pinus tabuliformis × Pinus Yunnanensis

We employed capacitance to evaluate the kinship and interspecific variation of homoploid hybrid conifer Pinus densata, P. tabuliformis, P. yunnanensis and artificial hybrids of P. tabuliformis (maternal parent) and P. yunnanensis (paternal parent) which were cultivated and selected in the common garden experiment.  By measuring capacitance spectra under different voltage frequencies, we could differentiate different germplasms based on the electrical response. We aims to demonstrate that P. densata as the hybrid of P. tabuliformis and P. yunnanensis based on the capacitance values of the species, and to provide new evidence to the previously known biological evidence, as well as and the parental effect on the hybrids. Our results revealed that capacitance values between the species are significantly different in the spectra where P. yunnanensis positioned at the lowest and P. densata was much higher than all other species, indicating that P. densata had possessed a great capacity to store electrical energy. The capacitance spectra of P. densata and the artificial hybrid are not similar, which rejected our hypothesis. Both of the capacitance values of P. densata and the hybrids were closer to P. tabuliformis than to P. yunnanensis, which shows that the maternal influence was stronger than the paternal influence. Correlation analysis on the relationship between capacitance and fitness-related characteristics showed that capacitance is negatively correlated to mortality rate, and positively correlated with second-year survival rate. High capacitance values of P. densata and some of the hybrids reveal their superior adaptability to harsh environment in the Tibet Plateau. We concluded that capacitance as a new indicator for plant fitness and evolution evidence of homoploid hybrid conifers.