Table 2 Cell and nuclear size of secondary proximal tubule of trunk kidney and its nuclear number in diploid and triploid far eastern catfish, Silurus asotus

	Diploid	Triploid	Ratio^*
Secondary proximal tubule cell of trunk kidney^**
Major axis (μm)	10.34 ± 1.178^a	12.19 ± 1.375^b	1.18
Minor axis (μm)	8.33 ± 7.706^a	9.72 ± 8.222^b	1.67
Surface area (μm²)	64.67 ± 6.275^a	90.35 ± 9.978^b	1.40
Secondary proximal tubule nucleus of trunk kidney^**
Major axis (μm)	3.26 ± 0.328^a	4.11 ± 0.420^b	1.26
Minor axis (μm)	3.01 ± 0.397^a	3.42 ± 0.307^b	1.14
Surface area (μm²)	7.70 ± 0.755^a	11.01 ± 8.181^b	1.43
Volume (μm³)	14.64 ± 7.658^a	27.05 ± 2.106^b	1.85
Nucleus number in secondary proximal tubule	15.70 ± 2.080^b	9.80 ± 1.111^a	0.63

^*Triploid/diploid.
^**Values are means ± SD. Values in same row having the different superscripts are significantly different (P<0.05).