Table 4 Summary for multiple regression analyses.

From: Comparative physiology of canopy tree leaves in evergreen and deciduous forests in lowland Thailand

Response traits (Dependent variables)

Explanatory variables in the selected models (Independent variables)

Explanatory variables (Independent variables)

Coefficients (Slopes)

S.E.

Parameter d.f.

Residual d.f.

Student’s T values

P values

n

Area-based Asat

Site, LMA, Pa, Na, Site:Pa

Intercept

15.27

1.78

9

216

8.59

<0.001***

225

(Aa)

 

Site(DEF)

−10.64

2.56

9

216

−4.15

<0.001***

225

  

Site(MDF)

−8.04

2.15

9

216

−3.74

<0.001***

225

  

LMA

−0.03

0.01

9

216

−3.36

<0.001***

225

  

Pa

0.11

0.15

9

216

0.77

0.4410

225

  

Na

0.02

0.01

9

216

3.08

<0.01**

225

  

Site(DEF):Pa

0.72

0.26

9

216

2.84

<0.01**

225

  

Site(MDF):Pa

0.56

0.2

9

216

2.83

<0.01**

225

Mass-based Asat

Site, LMA, Pm, Nm, Site:Pm

Intercept

220.70

35.51

9

216

6.22

<0.001***

225

(Am)

 

Site(DEF)

−87.42

26.57

9

216

−3.29

<0.01**

225

  

Site(MDF)

−122.93

27.36

9

216

−4.49

<0.001***

225

  

LMA

−1.02

0.17

9

216

−6.06

<0.001***

225

  

Pm

0.11

0.19

9

216

0.61

0.5422

225

  

Nm

28.52

9.11

9

216

3.13

<0.01**

225

  

Site(DEF):Pm

0.50

0.24

9

216

2.08

<0.05*

225

  

Site(MDF):Pm

0.85

0.23

9

216

3.78

<0.001***

225

 

Site, LMA, Pm, Nm, Pm:Nm

Intercept

260.22

44.49

8

217

5.85

<0.001***

225

  

Site(DEF)

−41.42

9.16

8

217

−4.52

<0.001***

225

  

Site(MDF)

−24.45

8.59

8

217

−2.85

<0.01**

225

  

LMA

−1.09

0.17

8

217

−6.34

<0.001***

225

  

Pm

−0.22

0.28

8

217

−0.79

0.4289

225

  

Nm

−13.79

17.51

8

217

−0.79

0.4322

225

  

Pm:Nm

0.41

0.13

8

217

3.3

<0.01**

225

  1. The results in the selected regression models of leaf area-based (Aa) or mass-based (Am) net photosynthetic rates (Asat) versus leaf mass per area (LMA), leaf area-based or mass-based nitrogen (N) and phosphorous (P), and sites (Site), including their interactions (P:N, Site:P, and Site:N), were shown. According to the AIC values, one model and two models are selected in Aa and Am, respectively (see Supplementally Table 1). “Coefficients”, “S.E.”, “d.f.”, and “n” indicate the slope, the standard error, the denominator degree of freedom, and the number of samples in each explanatory variable (independent variable), respectively. Three study sites of DDF (Dry deciduous forest or Dry dipterocarp forest), DEF (Dry evergreen forest), and MDF (Mixed deciduous forest) are used. The values of intercept, Site(DEF) and Site(MDF) correspond to the y-intercept in DDF and its deviations in DEF and MDF, respectively. Due to the significant interactive effects of P variables across different sites in leaf area and mass bases, the slopes of foliar P (phosphorous) correspond to the values in DDF. P values indicate the significant levels in the explanatory variables (*** < 0.001, ** < 0.01, * < 0.05).
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