. 2019 Feb 28;7:e6513. doi: 10.7717/peerj.6513

Table 2. Mean values of biomass variables, root branching variables and root morphological variables of P. euphratica seedlings at 110 days under drought treatments.

Variables		OW (control)	MD	SD
Biomass	Total plant biomass (g)	0.46 ± 0.02^a	0.35 ± 0.02^b	0.22 ± 0.02^c
	Above-ground biomass (g)	0.30 ± 0.02^a	0.23 ± 0.02^b	0.13 ± 0.01^c
	Below-ground biomass (g)	0.16 ± 0.01^a	0.12 ± 0.01^b	0.09 ± 0.01^c
	Taproot biomass (g)	0.043 ± 0.003^a	0.032 ± 0.002^b	0.030 ± 0.002^b
Morphology	Total root length (cm)	662 ± 37^a	516 ± 44^b	393 ± 41^c
	Average root length (cm)	0.376 ± 0.048^a	0.367 ± 0.038^a	0.236 ± 0.027^a
	Root diameter (mm)	0.348 ± 0.007^a	0.357 ± 0.006^a	0.359 ± 0.009^a
	SRL (cm/g)	4,766 ± 290^a	4,846 ± 357^a	5,141 ± 343^a
	Average distal root length (cm)	0.319 ± 0.122^a	0.279 ± 0.191^b	0.156 ± 0.057^c
	Distal root diameter (mm)	0.278 ± 0.006^c	0.302 ± 0.007^b	0.337 ± 0.007^a
	SDRL(cm/g)	10,032 ± 425^a	9,487 ± 661^ab	7,843 ± 361^b
	Average lateral root length (cm)	5.113 ± 0.324^a	4.680 ± 0.333^ab	3.765 ± 0.298^c
	Lateral root diameter (mm)	0.881 ± 0.035^a	0.757 ± 0.034^b	0.653 ± 0.029^c
	Taproot length (cm)	35.3 ± 1.1^a	27.3 ± 0.8^b	26.2 ± 0.7^b
	Taproot diameter (mm)	1.60 ± 0.091^a	1.48 ± 0.093^a	1.35 ± 0.082^a
Architecture	TI	0.713 ± 0.007^b	0.731 ± 0.008^ab	0.757 ± 0.010^a
	DBI	0.101 ± 0.010^b	0.153 ± 0.016^ab	0.216 ± 0.020^a
	Lateral root branching density (n/cm)	1.21 ± 0.09^a	1.03 ± 0.05^b	0.85 ± 0.04^c

Notes:

Differences in variables among treatments were tested using factorial analysis of variance (ANOVA). Values are means ± standard error (OW: n = 25; MD: n = 28; SD: n = 28). In each row, means followed by different letters are significantly different (P < 0.05). OW, MD, and SD refers to optimal water content (control), moderate drought stress and severe drought stress separately.

SRL, specific root length; SRDL, specific distal root length; TI, topology index; DBI, dichotomous branching index.