Coordination of leaf hydraulic, anatomical, and economical traits in tomato seedlings acclimation to long-term drought

Shuang Li; Abdoul Kader Mounkaila Hamani; Yingying Zhang; Yueping Liang; Yang Gao; Aiwang Duan

doi:10.1186/s12870-021-03304-y

Coordination of leaf hydraulic, anatomical, and economical traits in tomato seedlings acclimation to long-term drought

BMC Plant Biol. 2021 Nov 15;21(1):536. doi: 10.1186/s12870-021-03304-y.

Authors

Shuang Li^{1

2}, Abdoul Kader Mounkaila Hamani^{1

2}, Yingying Zhang¹, Yueping Liang¹, Yang Gao³, Aiwang Duan⁴

Affiliations

¹ Farmland Irrigation Research Institute, Key Laboratory of Crop Water Use and Regulation, Chinese Academy of Agriculture Sciences, Ministry of Agriculture and Rural Affairs, Xinxiang, Henan, 453002, China.
² Graduate School of Chinese Academy of Agricultural Sciences, Beijing, 100081, China.
³ Farmland Irrigation Research Institute, Key Laboratory of Crop Water Use and Regulation, Chinese Academy of Agriculture Sciences, Ministry of Agriculture and Rural Affairs, Xinxiang, Henan, 453002, China. gaoyang@caas.cn.
⁴ Farmland Irrigation Research Institute, Key Laboratory of Crop Water Use and Regulation, Chinese Academy of Agriculture Sciences, Ministry of Agriculture and Rural Affairs, Xinxiang, Henan, 453002, China. duanaiwang@caas.cn.

Abstract

Background: Leaf hydraulic and economics traits are critical for balancing plant water and CO₂ exchange, and their relationship has been widely studied. Leaf anatomical traits determine the efficiency of CO₂ diffusion within mesophyll structure. However, it remains unclear whether leaf anatomical traits are associated with leaf hydraulic and economics traits acclimation to long-term drought.

Results: To address this knowledge gap, eight hydraulic traits, including stomatal and venation structures, four economics traits, including leaf dry mass per area (LMA) and the ratio between palisade and spongy mesophyll thickness (PT/ST), and four anatomical traits related to CO₂ diffusion were measured in tomato seedlings under the long-term drought conditions. Redundancy analysis indicated that the long-term drought decreased stomatal conductance (g_s) mainly due to a synchronized reduction in hydraulic structure such as leaf hydraulic conductance (K_leaf) and major vein width. Simultaneously, stomatal aperture on the adaxial surface and minor vein density (VD_minor) also contributed a lot to this reduction. The decreases in mesophyll thickness (T_mes) and chlorophyll surface area exposed to leaf intercellular air spaces (S_c/S) were primarily responsible for the decline of mesophyll conductance (g_m) thereby affecting photosynthesis. Drought increased leaf density (LD) thus limited CO₂ diffusion. In addition, LMA may not be important in regulating g_m in tomato under drought. Principal component analysis revealed that main anatomical traits such as T_mes and S_c/S were positively correlated to K_leaf, VD_minor and leaf thickness (LT), while negatively associated with PT/ST.

Conclusions: These findings indicated that leaf anatomy plays an important role in maintaining the balance between water supply and CO₂ diffusion responses to drought. There was a strong coordination between leaf hydraulic, anatomical, and economical traits in tomato seedlings acclimation to long-term drought.

Keywords: Anatomical traits; Drought; Economics traits; Hydraulic traits; Mesophyll conductance; Stomatal conductance.

MeSH terms

Droughts
Mesophyll Cells / metabolism
Mesophyll Cells / physiology
Photosynthesis / physiology
Plant Leaves / metabolism*
Plant Leaves / physiology
Seedlings / metabolism*
Seedlings / physiology
Solanum lycopersicum / metabolism
Solanum lycopersicum / physiology