Chin J Plant Ecol ›› 2024, Vol. 48 ›› Issue (4): 416-427.DOI: 10.17521/cjpe.2023.0253

• Research Articles • Previous Articles     Next Articles

Nutrient foraging strategies of arbuscular mycorrhizal tree species in a subtropical evergreen broadleaf forest and their relationship with fine root morphology

QU Ze-Kun1, ZHU Li-Qin1, JIANG Qi1, WANG Xiao-Hong1, YAO Xiao-Dong1, CAI Shi-Feng2, LUO Su-Zhen2, sCHEN Guang-Shui1,*()   

  1. 1School of Geosciences, Key Laboratory of Humid Subtropical Ecological and Geographic Processes, Ministry of Education, Fujian Normal University, Fuzhou 350007, China
    2Youxi State Owned Forest Farm, Fuzhou 365100, China
  • Received:2023-09-04 Accepted:2023-12-21 Online:2024-04-20 Published:2024-05-11
  • Contact: * (gschen@fjnu.edu.cn)
  • Supported by:
    National Natural Science Foundation of China(31830014)

Abstract:

Aims The nutrient foraging strategies of fine roots and arbuscular mycorrhizal (AM) fungi directly affect plant productivity and carbon sequestration, which are a key factor influencing the stability of forest ecosystems. Nutrient foraging accuracy is an important aspect of the nutrient foraging strategy, which refers to the ability of plants to accurately deploy their roots and mycelia to relatively nutrient-rich patches. However, the tradeoff between foraging precision of root length and foraging precision of mycelia of arbuscular mycorrhizal tree species and whether fine root morphology can predict foraging accuracy are still controversial.
Methods In this study, 17 AM tree species in a natural broadleaf evergreen forest in the central subtropics were tested for responses to phosphorus addition to in situ root bags in the field to simulate phosphorus nutrient patches in the soil. After 4 months application of phosphorus fertilizer, morphological scanning and analysis were carried out on the fine roots of the control group and the phosphorus addition group. Mycelia in the soil were extracted by the membrane filtration method and observed by electron microscope. Mycelia with no septa in the middle and easy to stain were screened as AM mycelia, and their length was calculated. On this basis, root length foraging precision and mycelial foraging precision were calculated to investigate their trade-off and also their correlation with fine root morphology in subtropical AM tree species.
Important findings Root length foraging precision and mycelial foraging precision of AM species were independent of each other. There was a significant positive correlation between fine root tissue density and root length foraging precision, a significant negative correlation between fine root diameter and mycelial foraging precision, and a significant positive correlation between specific root length and mycelial foraging precision. These results can help understand root nutrient foraging strategies of AM species in subtropical evergreen broadleaf forests, and suggest that easily observable metrics such as fine-root morphology can be used for assessing the accuracy of fine-root nutrient foraging of AM species.

Key words: endophytic mycorrhiza, root length, mycelia, foraging precision, fine root morphology, underground ecology of plants