Effects on physiological characteristics of Honeysuckle (Lonicera japonica Thunb) and the role of exogenous calcium under drought stress

Lonicera japonica Thunb as the traditional Chinese herb is widely planted in southwestern China to harness rocky desertification due to its adaptability to the rock-desertificated environment. However, how the drought stress limits the Lonicera japonica Thunb’s physiological and photosynthetic characteristics is not clear. Therefore, a series of pot-cultivation experiments were dealt/performed with 30 mmol.L and 15 mmol.L of exogenous CaCl2 to investigate the chlorophyll content, soluble sugar content, proline content and the photosynthetic rate of Lonicera japonica Thunb under drought stress. Moreover, the possible roles of Ca in plant processes, are discussed. Under the drought stress, the content of chlorophyll, soluble sugar, proline, catalase enzyme activity and the photosynthetic characteristics in Lonicera japonica Thunb are changed by 1.5 mg.g, 0.11 mg.g, 13 mg.g, 0.5 u.mg and 4.3 umol.m.s, respectively. The samples dealt with the additional/higher Ca content during drought stress have a higher catalase enzyme activity and chlorophyll content because it can alleviate the cell membrane leakage and the chlorophyll decomposition. Moreover, proline content and soluble sugar content were found decreased/lower compared with the results without the additional Ca in the soil.