Chin J Plant Ecol ›› 2022, Vol. 46 ›› Issue (3): 311-320.DOI: 10.17521/cjpe.2021.0453

• Research Articles • Previous Articles     Next Articles

Responses of non-structural carbohydrates and growth hormone in Morus alba seedlings to flooding stress

LI Si-Yuan, ZHANG Zhao-Xin, RAO Liang-Yi*()   

  1. College of Soil and Water Conservation, Engineering Research Center of Forestry Ecological Engineering of Ministry of Education, Beijing Forestry University, Beijing 100083, China
  • Received:2021-12-06 Accepted:2022-01-21 Online:2022-03-20 Published:2022-04-07
  • Contact: RAO Liang-Yi
  • Supported by:
    National Natural Science Foundation of China(L1322017);Fundamental Research Funds for the Central Universities(2015ZCQ-SB-03)

Abstract:

Aims Mulberry (Morus alba) trees are known to be strongly water-tolerant. This study aims to understand flooding stress affects on mulberry’ non-structural carbohydrates and growth hormone.
Methods This study conducted an indoor simulated water flooding experiment using triennial potted mulberry saplings which were divided into four groups by different water conditions: the control group (CK), root submerged group (GY), shallowly submerged group (QY) and deep submerged group (SY). The content of non-structural carbohydrate (soluble sugar and starch) and endogenous growth hormone (ethylene, abscisic acid and gibberellin) in mulberry’ leaves were recorded regularly.
Important findings The research result suggested: (1) Flooding stress promoted endogenous chemical reactions within leaves of mulberry, resulting in increased content of soluble sugar in leaves. After 75 days of submergence, the content of soluble sugar in leaves of all groups (GY, QY and SY) increased by 182.18%, 170.21% and 94.16%, respectively compared with no-submergence conditions flooding; the difference was significant and the content was significantly higher than that of the CK. Under flooding stress, the leaf starch content did not change significantly from 0-50 days. After 75 days of submergence, the starch content of all groups (GY, QY and SY) increased by 290.84%, 244.65% and 130.04% compared with that at the 50 days; the difference was significant and the content was significantly higher than that of the CK group in the same period. (2) Flooding stress resulted in a significant increase in the content of ethylene and gibberellin in mulberry’ leaves. After 75 days of submergence, the content of ethylene in GY and SY increased by 62.80% and 26.78%, respectively compared with that no-flooding; the content of gibberellin in GY, QY and SY increased by 27.48%, 18.02% and 25.04%, respectively, suggesting significant difference. With the increased duration of submergence, the content of ethylene and gibberellin in GY and SY also increased, while the content of ethylene and gibberellin in QY first increased and then decreased but was still higher than the content non-flooding at the beginning of the experiment. Under flooding stress, the content of abscisic acid in leaves of all groups increased with the depth of submergence. After 75 days of submergence, the content of abscisic acid in QY and SY increased by 19.20% and 36.16%, respectively compared with that on day zero; the content of abscisic acid in GY did not change significantly, demonstrating the strongest resistance to submergence. Our research results suggest that mulberry are a species with strong resistance to submergence and can adapt to flooding stress by regulating the content and allocation of non-structural carbohydrates (soluble sugar and starch) and accumulating endogenous hormones such as ethylene, gibberellin and abscisic acid.

Key words: Morus alba, seedling, flooding stress, non-structural carbohydrate, growth hormone