The short-term effects of elevated CO2 and ammonium concentrations on physiological responses in Gracilariopsis lemaneiformis (Rhodophyta)

Table 2 Results from two-way ANOVA of physiological activities (relative growth rate (% day⁻¹), extent of variation in pH, photosynthetic oxygen evolution rate (μmol O₂ g⁻¹ FW h⁻¹), ammonium uptake rate (μmol NH₄ ⁺ g⁻¹ FW h⁻¹), and photosynthetic efficiency (F _v/F _m)) by samples of Gracilariopsis lemaneiformis

Parameter/source of variation	df	MS	F value	p value
Relative growth rate
pH level	1	0.69	21.50	<0.01
NH₄ ⁺ concentration	2	4.26	132.54	<0.01
pH level × NH₄ ⁺ concentration	2	0.12	3.66	0.04
Extent of variation in pH
pH level	1	1.09	166.48	<0.01
NH₄ ⁺ concentration	2	0.38	57.63	<0.01
pH × NH₄ ⁺	2	0.01	0.10	0.90
Photosynthetic oxygen evolution rate
pH level	1	198.72	68.85	<0.01
NH₄ ⁺ concentration	2	3678.60	1274.53	<0.01
pH × NH₄ ⁺	2	22.50	7.80	<0.01
NH₄ ⁺ uptake rate
pH level	1	0.17	24.72	<0.01
NH₄ ⁺ concentration	2	85.78	12,108.59	<0.01
pH × NH₄ ⁺	2	0.13	18.95	<0.01
Photosynthetic efficiency
pH level	1	<0.01	0.58	0.46
NH₄ ⁺ concentration	2	0.13	51.60	<0.01
pH × NH₄ ⁺	2	<0.01	0.92	0.42

ISSN: 2234-1757