Table 2 Correlations (Pearson’s r) between daytime and nocturnal sap flows of Amorpha fruticosa seedlings and the associated soil and meteorological factors with and without soil water stress.

From: Sap flow of Amorpha fruticosa: implications of water use strategy in a semiarid system with secondary salinization

Sap flow

Condition

PAR

Ta

VPD

us

SWC0–40

SWC40–80

EC0–40

EC40–80

Daytime

REW0–40 cm > 0.4 (n = 86)

0.76**

0.76**

0.46**

0.09

− 0.10

− 0.12

− 0.19

− 0.04

REW0–40 cm < 0.4 (n = 19)

0.65**

0.64**

0.51*

0.13

0.55*

− 0.24

− 0.46*

0.22

Nocturnal

REW0–40 cm > 0.4 (n = 86)

–

0.43**

0.40**

− 0.20

0.12

0.04

− 0.14

0.20

REW0–40 cm < 0.4 (n = 19)

–

0.20

− 0.16

− 0.34

0.54*

− 0.12

− 0.46*

0.39

  1. Significance levels: *P < 0.05; **P < 0.01. Parameter definitions: REW0–40 cm, relative extractable water in the top 40 cm of the soil (< 0.4 represents soil water stress); PAR, photosynthetically active radiation; Ta, air temperature; VPD, vapor-pressure deficit; us, wind speed; SWC, soil water content; EC, electrical conductivity. For the last four variables, numbers refer to the depths (cm) in the soil.
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