Physiological Response Characteristics of Moso Bamboo under Drought Stress Based on Calcium Signal

Abstract

This study aimed to evaluate the dominant factors of physiological responses of Phyllostachys edulis (Carrière) J. Houz to drought stress. The calcium (Ca2+) fluxes in root tips of P. edulis treated by polyethylene glycol were monitored via non-invasive micro-test technology. The physiological indexes of P. edulis under different soil moisture contents were determined. The regression model was built by curve fitting with the main physiological factors of P. edulis using PCA analysis. The variance contribution rates of the first three principal components of the physiological indicators were 75.0%, 13.3% and 5.0%. Calcium signal sensing protein kinase (CDPK) contents accounted for a larger contribution to the load of the first principal component. The contents of calcium signal sensor protein calmodulin (CaM) and calcium-dependent protein kinase (CDPK) increased. Meanwhile, drought induced strong Ca2+ influxes in root tips. Additionally, as the soil water content decreased, the contents of malondialdehyde (MDA), proline, betaine, jasmonic acid (JA) and abscisic acid (ABA) increased, and auxin (IAA) decreased in P. edulis leaves, strongly correlating with the CaM and CDPK contents. The calcium signal of P. edulis is activated and cascades plant physiological responses to drought stress. This study will provide physiological evidence for research regarding mechanisms of drought resistance of P. edulis.