Table 3 Extraction of the important sensitive spectral band intervals based on the variable importance in projection (VIP) and loading weights of PLSR analysis over the entire wavelengths and the most influential wavelengths using the stepwise multiple linear regression for shoot dry weight per square meter (SDW), net photosynthesis rate (Pn), stomatal conductance (Gs), and transpiration rate (E)) under each season (n = 18), salinity level (n = 12), and variety (n = 18) individually and all pooled data (n = 36).

Pooled data

SDW

350–651

450

0.78^***

203.7

384.7

690–752

720

0.77^***

207.5

386.1

P _n

350–651

533

0.69^***

2.40

64.95

689–817

715, 719, 817

0.77^***

2.11

57.57

Gs

350–647

481, 548

0.77^***

33.9

256.5

690–760

721

0.74^***

35.5

258.9

E

350–606

536, 605

0.56^**

0.459

−53.13

699–1149

734

0.53^**

0.469

−52.50

1252–1273

1273

0.26^*

0.587

−36.44

1^st Season

SDW

350–751

540

0.86^***

174.8

187.8

P _n

402–916

533, 903

0.85^***

1.88

25.46

Gs

350–651

533

0.80^***

31.8

126.4

E

350–740

368, 382

0.74^***

0.334

−36.81

1356–1413

—

—

—

—

1486–1889

1830

0.23^*

0.560

−19.02

2023–2500

2300

0.26^*

0.550

−19.62

2^nd Season

SDW

350–747

724

0.81^***

178.6

188.5

1001–1330

1330

0.54^**

276.3

204.2

P _n

407–735

716

0.72^***

2.12

28.88

1336–2500

2395, 2452, 2493

0.80^***

1.92

26.95

Gs

350–758

727

0.79^***

33.6

128.4

788–1308

1138

0.47^*

53.1

144.9

E

350–570

537, 570

0.61^***

0.483

−23.46

712–1141

738

0.55^**

0.449

−26.95

Control

SDW

350–702

356, 358

0.87^***

71.2

104.9

744–1337

—

—

—

—

P _n

741–1415

1252

0.69^***

1.87

16.83

1557–1848

1680, 1830, 1848

0.94^***

0.92

1.26

Gs

696–728

—

—

—

—

756–1407

760, 1078

0.73^***

13.8

65.6

2266–2312

—

—

—

—

E

355–695

482

0.70^***

0.215

−35.08

1426–1485

1452

0.48^**

0.283

−28.51

1878–2500

1904

0.67^***

0.226

−33.86

60 mM NaCl

SDW

440–737

722

0.73^***

108.8

114.4

1153–1830

1709

0.59^**

134.5

119.5

1861–2500

2488, 2492, 2497

0.88^***

82.2

109.0

P _n

483–744

723

0.79^***

1.14

5.06

761–784

—

—

—

—

1001–1305

1198

0.53^**

1.71

14.66

Gs

435–737

720

0.77^***

14.9

66.7

1319–2500

1710, 1831

0.76^***

16.2

69.4

E

350–514

—

—

—

—

735–953

762

0.35^*

0.275

−29.15

1001–1136

—

—

—

—

120 mM NaCl

SDW

413–725

566

0.68^***

86.2

108.8

1321–2500

1386, 1547, 1832

0.88^***

59.6

101.2

P _n

350–733

569

0.68^***

1.13

4.64

1396–1501

1489

0.53^**

1.35

9.06

1869–2500

2492, 2500

0.75^***

1.05

3.82

Gs

449–716

598

0.61^***

10.7

58.8

739–937

—

—

—

—

1412–1471

1435

0.38^**

12.1

61.7

1866–2123

1927

0.42^**

11.6

60.7

2309–2500

2448, 2500

0.64^***

9.7

57.1

E

350–389

—

—

—

—

727–1303

924

0.57^**

0.239

–32.58

Sakha 93

SDW

353–744

578

0.76^***

205.4

193.6

P _n

353–743

579

0.72^***

2.28

31.59

1322–1381

—

—

—

—

Gs

353–744

573

0.66^***

40.3

134.9

920–1000

—

—

—

—

1310–1354

—

—

—

—

E

353–747

569

0.64^***

0.413

–29.95

1346–1402

—

—

—

—

1540–1666

—

—

—

—

1818–1856

—

—

—

—

Sakha 61

SDW

350–747

547

0.87^***

156.6

183.8

P _n

450–737

714

0.80^***

1.48

16.06

1149–2500

2309

0.71^***

1.80

23.06

Gs

350–670

468, 555

0.90^***

22.7

115.1

678–770

717

0.88^***

24.0

116.3

E

408–736

532

0.75^***

0.349

−36.01

1162–1215

1191, 1215

0.71^***

0.386

−31.58

1304–2500

2300

0.66^***

0.402

−30.95