Chinese Bulletin of Botany ›› 2022, Vol. 57 ›› Issue (2): 171-181.DOI: 10.11983/CBB21191

• EXPERIMENTAL COMMUNICATIONS • Previous Articles     Next Articles

Effects of Exogenous Melatonin on Physiological Response and DNA Damage of Ardisia mamillata and A. crenata Under Lead Stress

Jinxiang Ai1, Jiayi Song1, Zhenan Yan1, Zhichao Wang1, Wenqian Chen1, Yuhuan Wu2,3, Yanyan Wang1, Leilei Pan1, Yutao Xu1, Peng Liu1,*()   

  1. 1Botany Laboratory, Zhejiang Normal University, Jinhua 321004, China
    2College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou 310036, China
    3Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China
  • Received:2021-11-10 Accepted:2022-02-07 Online:2022-03-01 Published:2022-03-24
  • Contact: Peng Liu

Abstract:

Lead (Pb) is a major abiotic constraint affecting plant growth. To compare the anti-lead ability of two Ardisiaspecies and investigate the physiological responses and DNA damage to the treatments of exogenous melatonin (MT) under lead stress, hydroponic experiment was carried out with 2-year-old seedlings of A. mamillata and A. crenata. The results showed that with the increasing of the lead stress concentration in the same period of time, the three antioxidant enzyme activities, proline (Pro) and soluble protein (SP) contents of the A. mamillata and A. crenata were all increased first and then decreased, while malondialdehyde (MDA) content decreased at first and then increased, the root tip callosin content continues to rise, DNA damage in roots was increased. After the application of appropriate concentrations of exogenous MT, the activities of antioxidant enzymes in both plants were effectively enhanced and reached a maximum at 100 µmol∙L-1 MT treatment under different concentrations of Pb, and the contents of Pro and SP were significantly increased. However, the MDA content decreased significantly at first and then increased slowly. The root tip callosin content continues to increase and the root DNA damage was improved. With the increasing of MT concentration, the alleviating effect of melatonin on A. mamillata and A. crenata gradually weakened. A. crenata is more resistant to lead stress and its physiological response is more stable than A. mamillata. Exogenous application of MT can effectively alleviate the toxic effect of lead stress on A. mamillata and A. crenata (relief effect of A. crenata > A. mamillata), and enhance its tolerance to lead toxicity, among which 100 µmol∙L-1 MT treatment has the best mitigation effect. We revealed the superiority of lead resistance of A. mamillata and A. crenata, and the alleviating effect of exogenous MT on lead poisoning, thus providing a theoretical reference for the study of lead resistance of Ardisia.

Key words: Ardisia mamillata, A. crenata, lead stress, melatonin, DNA damage