Table 2.

REML (residual maximum likelihood) variance component analysis statistics

Predicted means (loge)

Wald tests for fixed effects

Herbs

Shrubs

Trees

Plant growth form

UV‐B

Plant growth form × UV‐B

Plant parameter

Ambient UV‐B

Enhanced UV‐B

Ambient UV‐B

Enhanced UV‐B

Ambient UV‐B

Enhanced UV‐B

Wald χ2 statistic

d.f.

Wald χ2 statistic

d.f.

Wald χ2 statistic

d.f.

Leaf pigments and metabolites

Chlorophyll a

2·286a

2·233a

1·005b

1·040b

1·222b

1·379c

34·9***

2

0·9

1

10·6**

2

Chlorophyll b

0·696a

0·622a

–0·686b

–0·652b

–0·238b

–0·109c

35·7***

2

0·1

1

6·3*

2

Carotenoids

1·213a

1·161a

0·022b

0·015b

–0·020b

0·123c

27·3***

2

0·0

1

9·7**

2

Flavonoids

4·760a

4·830a

5·203a

5·180a

4·164b

4·386c

15·0***

2

5·5*

1

17·2***

2

Non–structural carbohydrates

5·687a

5·664a

5·470a

5·506a

4·592b

4·528b

12·2**

2

0·0

1

2·0

2

Leaf morphology, plant canopy area and dry mass

SLA

5·434a

5·395a

4·362b

4·378b

4·846c

4·876c

48·9***

2

0·1

1

2·7

2

Leaf shape index

0·195a

0·203a

0·345a

0·339a

0·164a

0·172a

5·0

2

0·3

1

1·9

2

Canopy area

6·399a

6·153a

5·466a

5·370a

4·913b

4·761b

4·2

2

11·0***

1

1·9

2

Plant dry mass

2·06a

1·854a

1·954a

1·850a

1·491a

1·448a

0·8

2

8·1**

1

1·9

2

LAR

4·296a

4·283a

3·512b

3·520b

3·424b

3·322b

10·1**

2

0·5

1

1·9

2

Differences between predicted means with different letters exceeding two s.e. and significant at P < 0·05.

Significant effects at * P < 0·05, ** P < 0·01, *** P < 0·001 presented in bold type.