Evaluation of the physiological alterations in Ceratophyllum demersum L along a diurnally changing solar irradiance gradient

Figures & data

Figure 1. Top view of the schematic diagram showing open flow and shaded flow treatments with two static (open vs shaded) treatments.

Figure 2. Rapid light curves of Ceratophyllum demersum under the four habitat conditions. The data presented are the means of four replicates, and the vertical bars denote the standard deviation.

Table 1. Two-way ANOVA results showing the effects of irradiance and water flow on the physiological conditions of Ceratophyllum demersum at noon (12:00 pm). ANOVA results were significant at P < 0.05. For all response variables, DF = 1 for water flow, DF = 1 for irradiance, and DF = 1 for water flow × irradiance

Response	Factor	F	P
Y(dark)_II	Irradiance	13.35	0.003
	Water Flow	3.47	0.087
	Irradiance × water flow	14.93	0.002
PSII_ETR max	Irradiance	8.92	0.011
	Water flow	2.59	0.133
	Irradiance × water flow	0.03	0.862
Chlorophyll a	Irradiance	7.20	0.028
	Water flow	0.09	0.768
	Irradiance × water flow	3.90	0.083
Chlorophyll b	Irradiance	3.01	0.121
	Water flow	2.29	0.168
	Irradiance × water flow	4.53	0.066
Carotenoids’	Irradiance	7.97	0.022
	Water flow	4.62	0.064
	Irradiance × water flow	1.09	0.326
H2O2	Irradiance	13.52	0.006
	Water flow	19.76	0.002
	Irradiance × water flow	0.06	0.811
POD	Irradiance	71.17	<0.0001
	Water flow	303.45	<0.0001
	Irradiance × water flow	16.54	0.004
CAT	Irradiance	68.68	<0.0001
	Water flow	21.68	0.002
	Irradiance × water flow	0.04	0.843
APX	Irradiance	33.15	<0.0001
	Water flow	110.21	<0.0001
	Irradiance × water flow	3.43	0.101

Figure 3. Pigment (Chl a, Chl b and carotenoid) concentrations in Ceratophyllum demersum plants grown under the four growth conditions. The data presented are the means of three replicates, and the different lower case letters at each time point indicate significant differences between treatments.

Figure 4. Hourly concentration of H₂O₂ (A) and activities of POD (B), APX (C), and CAT (D) in Ceratophyllum demersum plants grown under the four growth conditions. The data presented are the means of three replicates, and the vertical bars denote the standard deviation.

Figure 5. Diurnal variation in irradiance over a 12-hour period. The data presented are the means of three replicates, and the vertical bars denote the standard deviation.