Table 2. N₂ fixation and ethylene (C₂H₄) production rates in Lepidothamnus fonkii.

	N2 fixation (μmol N g−1 d.w. d−1)	C2H4 production (μmol C2H4 g−1 d.w. d−1)	C2H4/N2
L. fonkii (entire plants)*, site OBS	1.02 ± 0.27	2.43 ± 0.45	4.90 ± 0.92
L. fonkii (entire plants)*, site SKY	1.25 ± 0.21	1.68 ± 0.25	2.69 ± 0.04
L. fonkii, intact roots†	3.09 ± 1.24	n.d.	n.d.
L. fonkii, cut roots‡	2.47 ± 0.28	2.35 ± 0.63	1.85 ± 0.79
T. repens, cut roots‡	3.94 ± 0.63	18.01 ± 5.27	9.07 ± 1.22
Root-free peat (0–10 cm)	1.69 ± 0.68	1.25 ± 0.32	1.67 ± 0.69

Mean ± s.d. in-vitro N₂ fixation rates (determined by the ¹⁵N₂ assay), unconverted C₂H₄ production rates (determined by the acetylene reduction assay), and ratios of C₂H₄ production to N₂ fixation in entire plants of L. fonkii from OBS and SKY (n = 3), in nodulated roots of L. fonkii and Trifolium repens (white clover) and peat of 0–10 cm depth (all n = 6), n.d. = not detected.

^*Incubation of intact plants and weighted average of N₂ fixation in nodulated roots, stems and leaf biomass.

†N₂ fixation of live roots, obtained from incubations of intact plants.

‡incubation of freshly cut, nodulated roots.