Chromium (VI) Uptake and Tolerance Potential in Cotton Cultivars: Effect on Their Root Physiology, Ultramorphology, and Oxidative Metabolism

Table 2

Tolerance indices of both transgenic cotton cultivars and their hybrid line under Cr stress.

Variety	Cr levels (μM)	Root length	Plant height	Root fresh weight	Root water contents
J208	0	1.00 ± 0.00^a	1.00 ± 0.00^a	1.00 ± 0.00^a	1.00 ± 0.00^a
	10	0.88 ± 0.07^a	0.91 ± 0.06^a	0.66 ± 0.24^ab	1.00 ± 0.00^a
	50	0.67 ± 0.10^b	0.70 ± 0.04^b	0.51 ± 0.33^b	1.02 ± 0.05^a
	100	0.49 ± 0.06^c	0.57 ± 0.06^c	0.31 ± 0.20^b	0.99 ± 0.05^a
Z905	0	1.00 ± 0.00^a	1.00 ± 0.00^a	1.00 ± 0.00^a	1.00 ± 0.00^a
	10	0.84 ± 0.16^a	0.82 ± 0.10^b	0.54 ± 0.54^b	0.98 ± 0.00^a
	50	0.45 ± 0.05^b	0.61 ± 0.09^c	0.31 ± 0.31^c	0.94 ± 0.12^a
	100	0.30 ± 0.07^b	0.40 ± 0.06^d	0.12 ± 0.12^c	0.90 ± 0.13^a
ZD14	0	1.00 ± 0.00^a	1.00 ± 0.00^a	1.00 ± 0.00^a	1.00 ± 0.00^a
	10	0.92 ± 0.22^ab	0.98 ± 0.09^a	0.61 ± 0.26^b	0.98 ± 0.07^a
	50	0.75 ± 0.07^bc	0.77 ± 0.02^b	0.41 ± 0.20^bc	0.96 ± 0.11^a
	100	0.64 ± 0.05^c	0.65 ± 0.02^c	0.19 ± 0.08^c	0.91 ± 0.03^a

Tolerance index of the above parameters was calculated as TI = mean values in treatment/mean values in control. Mean values of TI =/> 1 show the tolerance behavior of the cultivar, while mean values of TI < 1 show the susceptibility of the cultivar towards Cr stress. Values are the means ± SD of three replications. Variants possessing the same letter are not statistically significant at 𝑃<0.05.