Stimulatory effects of smoke solution and biogas digestate slurry application on photosynthesis, growth, and methylation profiling of solanum tuberosum

Figures & data

Table 1. Physicochemical characterization of digestate.

Parameters	Unit	Digestate
Total solids	%	4.16 ± 0.008
Volatile solids	%	3.96 ± 0.010
N measured as NH4^+	mg/L	242.9986 ± 1.85
P measured as P2O5	mg/L	95.626 ± 6.20
Chemical oxygen demand	mg/L	10.836 ± 2.59
pH	-	7.26 ± 0.42
Total Reducing Sugars	mg/L	742 ± 224.33

Figure 1. Evaluation of net photosynthesis rate after application of smoke (SMK) and biogas digestate (BGD) slurry. (a) lab conditions and (b) field conditions. The data are expressed as mean ± standard deviation of three replicates. The bars labeled with different alphabets are statistically significantly different at p < 0.005.

Figure 2. Water use efficiency after SMK and BGD treatment. (a) lab conditions and (b) field conditions. The data are expressed as mean ± standard deviation of three replicates. The bars labeled with different alphabets are statistically significantly different at p < 0.005.

Figure 3. Analysis of pigments in SMK- and BGD-treated plants. (a) Chl a in lab conditions, (b) Chl b in lab conditions, (c) carotenoids in lab conditions, (d) Chl a in field conditions, (e) Chl b in field conditions, (f) carotenoids in field conditions. The data are expressed as mean ± standard deviation of three replicates. The bars labeled with different alphabets are statistically significantly different at p < 0.005.

Figure 4. Analysis of growth parameters in SMK- and BGD-treated plants. (a) Leaf number in lab conditions, (b) dry weight in lab conditions, (c) leaf number in field conditions, (d) dry weight in field conditions. The data are expressed as mean ± standard deviation of three replicates. The bars labeled with different alphabets are statistically significantly different at p < 0.005.

Figure 5. Enhancement in soluble sugars after SMK and BGD treatment. (a) lab conditions and (b) field conditions. The data are expressed as mean ± standard deviation of three replicates. The bars labeled with different alphabets are statistically significantly different at p < 0.005.

Figure 6. Principal component analysis (PCA) of SMK- and BGD-treated plants. (a) Treatments in lab conditions, (b) treatment responses in lab conditions, (c) treatments in in field conditions, (d) treatment responses in field conditions.

Figure 6. (Continued).

Table 2. Methylation profiling of control and treatments.

Plant Name						T Met Ratio %	Full Met Ratio %	Hemi Met Ratio %	Un-Met Ratio %
	Type	Type	Type	Type
	I	II	III	IV	SUM
C	20	18	0	2	40	50	45	5	50
SMK1	23	17	0	0	40	42.5	42.5	0	57.5
SMK2	11	22	1	6	40	72.5	57.5	15	27.5
BGD1	7	14	9	10	40	82.5	57.5	25	17.5
BGD2	4	29	1	6	40	90	75	15	10

Table 3. Comparison of methylation dynamics of control vs treatments.

Response	C vs SMK1	C vs SMK2	C vs BGD1	C vs BGD2
No Change	92.5	62.5	35	55
DeMethylation	7.5	10	30	0
Methylation	0	27.5	35	45

Figure 7. Venn diagram of SMK and BGD treatments. (a) Venn diagram of BGD treatment, (b) venn diagram of smoke treatment, figure 7C: venn diagram of all treatments.