Table 2 Calibration range and prediction errors of the partial least squares models RMSEC: root mean square error of prediction

Total sugars

425.36

628.92

537.29

35.84

21.43

10

4

Rhamnose

0.31

2.1

1

0.41

0.22

5

22

Fucose

−0.23

1.42

0.49

0.25

0.26

12

53

Arabinose

6.47

46.06

25.57

8.02

2.19

5

9

Xylose

103.24

224.83

161.4

27.61

9.14

5

6

Mannose

0.87

31.64

9.86

7.24

3.41

5

35

Galactose

2.62

11.53

7.22

2.75

0.94

4

13

Glucose

228.49

359.41

300.5

30.91

17.43

10

6

Uronic acids

19.97

48.61

31.26

6.5

3.9

4

12

Phenolics

Minimum

(μg/mg)

Maximum

(μg/mg)

Average

(μg/mg)

SD

RMSEC

Factors

RMSEC as % of average

Klason lignin

107.63

241.21

168.91

21.79

14.4

10

9

Acid insoluble ash

1.47

28.89

14.3

6.27

6.09

10

43

Corrected lignin

101.44

232.16

154.79

21.31

11.63

10

8

Protocatechuic aldehyde

0.002

0.013

0.007

0.002

0.002

10

35

p-OH-Benzoic acid

−0.011

0.364

0.105

0.064

0.061

10

58

Vanillic acid

0.079

0.389

0.205

0.061

0.051

10

25

p-OH-Benzaldehyde

0.002

0.301

0.102

0.056

0.032

10

32

Truxillic acid (CA)

−0.004

0.021

0.01

0.005

0.005

10

46

Truxillic acid (FA)

0.007

0.032

0.02

0.004

0.005

10

25

Vanillin

−0.011

0.423

0.216

0.082

0.069

10

32

t-p-Coumaric acid

1.445

20.043

7.501

3.565

2.098

10

28

8,8'-DiFA (aryl tetralin form)

0

0

0

0

0

t-Ferulic acid

1.669

7.942

4.462

1.059

1.015

10

23

8,8'-DiFA

0.005

0.149

0.078

0.026

0.019

10

25

8,5'-DiFA

−0.035

1.004

0.459

0.23

0.117

10

26

5,5'-DiFA

0.047

0.389

0.202

0.08

0.035

10

17

8-O-4'-DiFA

0.172

1.066

0.655

0.21

0.103

10

16

8,5'-DiFA (benzofuran form)

0.091

0.279

0.164

0.034

0.033

10

20

Total phenolic acids

5.637

32.61

14.356

4.558

3.345

10

23

Total phenolic acids (plus estimated unknown peaks)

5.25

32.659

14.438

4.591

3.344

10

23

Tissues

Minimum

Maximum

Average

SD

RMSEC

Factors

RMSEC as % of average

Internode

18.00%

42.70%

30.00%

6.10%

1.70%

6

6

Node

3.00%

7.70%

4.80%

1.00%

0.60%

9

12

Leaf

27.90%

52.80%

40.50%

5.40%

2.20%

6

5

Ear

17.30%

33.70%

24.70%

3.60%

1.90%

6

8