Weak Tradeoff and Strong Segmentation Among Plant Hydraulic Traits During Seasonal Variation in Four Woody Species

Xiao Liu; Qiang Li; Feng Wang; Xiaohan Sun; Ning Wang; Huijia Song; Rong Cui; Pan Wu; Ning Du; Hui Wang; Renqing Wang

doi:10.3389/fpls.2020.585674

Weak Tradeoff and Strong Segmentation Among Plant Hydraulic Traits During Seasonal Variation in Four Woody Species

Front Plant Sci. 2020 Nov 24:11:585674. doi: 10.3389/fpls.2020.585674. eCollection 2020.

Authors

Xiao Liu^{1

2

3}, Qiang Li^{1

2

3}, Feng Wang^{1

2

3}, Xiaohan Sun^{1

2

3}, Ning Wang^{1

2

3}, Huijia Song^{1

2

3}, Rong Cui^{1

2

3}, Pan Wu^{1

2

3}, Ning Du^{1

2

3}, Hui Wang^{1

2

3}, Renqing Wang^{1

2

3}

Affiliations

¹ School of Life Sciences, Institute of Ecology and Biodiversity, Shandong University, Qingdao, China.
² Shandong Provincial Engineering and Technology Research Center for Vegetation Ecology, Shandong University, Qingdao, China.
³ Qingdao Forest Ecology Research Station of National Forestry and Grassland Administration, Shandong University, Qingdao, China.

Abstract

Plants may maintain long-term xylem function via efficiency-safety tradeoff and segmentation. Most studies focus on the growing season and community level. We studied species with different efficiency-safety tradeoff strategies, Quercus acutissima, Robinia pseudoacacia, Vitex negundo var. heterophylla, and Rhus typhina, to determine the seasonality of this mechanism. We separated their branches into perennial shoots and terminal twigs and monitored their midday water potential (Ψ_md), relative water content (RWC), stem-specific hydraulic conductivity (K_s), loss of 12, 50, and 88% of maximum efficiency (i.e., P₁₂, P₅₀, P₈₈) for 2 years. There were no correlations between water relations (Ψ_md, RWC, K_s) and embolism resistance traits (P₁₂, P₅₀, P₈₈) but they significantly differed between the perennial shoots and terminal twigs. All species had weak annual hydraulic efficiency-safety tradeoff but strong segmentation between the perennial shoots and the terminal twigs. R. pseudoacacia used a high-efficiency, low-safety strategy, whereas R. typhina used a high-safety, low-efficiency strategy. Q. acutissima and V. negundo var. heterophylla alternated these strategies. This mechanism provides a potential basis for habitat partitioning and niche divergence in the changing warm temperate zone environment.

Keywords: annual; embolism resistance; habitat partitioning; niche divergence; warm temperate zone; water relation.