Table 3 Pairwise correlation analyses using BestKeeper

UBQ7

0.892

0.001

CDC2

0.970

0.001

18S rRNA

0.964

0.001

CDC2

0.993

0.001

18S rRNA

0.810

0.001

ANT

0.963

0.001

ACT2

0.962

0.001

PT1

0.993

0.001

CDC2

0.718

0.003

ACT2

0.961

0.001

CDC2

0.943

0.001

ACT2

0.983

0.001

PT1

0.660

0.007

18S rRNA

0.799

0.001

ANT

0.917

0.001

UBQ7

0.980

0.001

ACT2

0.655

0.008

PT1

0.610

0.016

UBQ7

0.845

0.001

ANT

0.970

0.001

CYC063

0.639

0.010

UBQ7

0.532

0.041

PT1

0.663

0.007

CYC063

0.969

0.001

ANT

0.360

0.188

TIP4-like

0.517

0.048

TIP4-like

0.088

0.754

TIP4-like

0.957

0.001

TIP4-like

0.223

0.427

CYC063

−0.008

0.977

CYC063

−0.477

0.072

18S rRNA

0.650

0.009

Populus tremula x Populus alba

Shoot tips/buds

Coeff. of corr. ( r )

p -value

Young leaves

Coeff. of corr. ( r )

p -value

Mature leaves

Coeff. of corr. ( r )

p -value

Bark

Coeff. of corr. ( r )

p -value

CDC2

0.905

0.001

CDC2

0.977

0.001

ACT2

0.894

0.001

PT1

0.812

0.001

ACT2

0.862

0.001

ANT

0.944

0.001

18S rRNA

0.816

0.001

CDC2

0.793

0.001

ANT

0.788

0.001

18S rRNA

0.886

0.001

ANT

0.653

0.008

ANT

0.738

0.002

18S rRNA

0.659

0.008

ACT2

0.881

0.001

CDC2

0.569

0.027

ACT2

0.650

0.009

UBQ7

0.651

0.009

PT1

0.562

0.029

CYC063

0.420

0.119

CYC063

0.647

0.009

PT1

0.562

0.029

TIP4-like

0.416

0.123

UBQ7

0.323

0.240

UBQ7

0.644

0.009

TIP4-like

0.457

0.087

UBQ7

0.358

0.191

TIP4-like

0.057

0.837

TIP4-like

0.633

0.011

CYC063

0.129

0.646

CYC063

−0.717

0.003

PT1

0.050

0.860

18S rRNA

0.389

0.152