Table 2.

Twist-to-bend ratios calculated for the artificial cross-sections shown in figure 3. Vascular bundles of the standard cross-sections were replaced either by strands of collenchyma fibres or by sclerenchyma fibres. The highest value for each geometry is shown in italics. Twist-to-bend ratios of the fibre-modified cross-sections were normalized to the value of the standard cross-sections. Resulting change factors indicate an increase (greater than 1.0) or decrease (less than 1.0) of the twist-to-bend ratio.

		vasc. bundles	collenchyma	sclerenchyma	change factor	change factor
geometry	artificial design	twist-to-bend ratio Dmin/Dz	twist-to-bend ratio Dmin/Dz	twist-to-bend ratio Dmin/Dz	collenchyma/vasc. bundles	sclerenchyma/vasc. bundles
circle	(a.1)	1.36	1.37	1.37	1.00	1.01
	(a.2)	4.53	9.18	66.36	2.03	14.64
	(a.3)	1.37	1.39	1.38	1.01	1.01
	(a.4)	8.56	19.09	124.23	2.23	14.51
	(a.5)	5.91	12.67	73.05	2.14	12.36
	(a.6)	9.12	20.13	131.62	2.21	14.43
ellipse	(b.1)	0.85	0.86	0.86	1.00	1.00
	(b.2)	2.99	5.95	30.19	1.99	10.10
	(b.3)	0.86	0.86	0.87	1.00	1.00
	(b.4)	6.57	14.52	88.11	2.21	13.50
	(b.5)	4.90	10.40	53.92	2.12	11.00
	(b.6)	6.84	15.24	92.29	2.23	13.50
square	(c.1)	1.54	1.50	1.45	0.98	0.95
	(c.2)	10.76	23.38	147.72	2.17	13.73
	(c.3)	1.77	1.79	1.80	1.01	1.02
	(c.4)	11.07	24.49	154.40	2.21	13.95
	(c.5)	6.52	13.46	71.89	2.06	11.02
	(c.6)	11.68	25.98	165.11	2.22	14.14
	(c.7)	15.45	29.93	80.07	1.94	5.18
triangle	(d.1)	2.15	2.11	2.05	0.98	0.95
	(d.2)	16.49	34.42	143.70	2.09	8.71
	(d.3)	2.18	2.18	2.17	1.00	1.00
	(d.4)	15.72	34.42	181.23	2.17	11.53
	(d.5)	9.19	18.62	87.86	2.03	9.56
	(d.6)	16.52	36.08	195.90	2.18	11.86
	(d.7)	26.31	45.79	90.02	1.74	3.42
U-profile	(e.1)	2.41	2.29	2.19	0.95	0.91
	(e.2)	9.72	19.05	70.76	1.96	7.28
	(e.3)	1.95	2.10	2.44	1.07	1.25
	(e.4)	12.81	26.35	113.86	2.06	8.89
	(e.5)	11.55	23.20	90.71	2.01	7.85
	(e.6)	13.60	28.07	125.67	2.06	9.24